Science.gov

Sample records for surfactants

  1. Lung surfactant.

    PubMed Central

    Rooney, S A

    1984-01-01

    Aspects of pulmonary surfactant are reviewed from a biochemical perspective. The major emphasis is on the lipid components of surfactant. Topics reviewed include surfactant composition, cellular and subcellular sites as well as pathways of biosynthesis of phosphatidylcholine, disaturated phosphatidylcholine and phosphatidylglycerol. The surfactant system in the developing fetus and neonate is considered in terms of phospholipid content and composition, rates of precursor incorporation, activities of individual enzymes of phospholipid synthesis and glycogen content and metabolism. The influence of the following hormones and other factors on lung maturation and surfactant production is discussed: glucocorticoids, thyroid hormone, estrogen, prolactin, cyclic AMP, beta-adrenergic and cholinergic agonists, prostaglandins and growth factors. The influence of maternal diabetes, fetal sex, stress and labor are also considered. Nonphysiologic and toxic agents which influence surfactant in the fetus, newborn and adult are reviewed. PMID:6145585

  2. Surfactant compositions

    SciTech Connect

    Novakovic, M.; Abend, P.G.

    1987-09-29

    A surfactant composition is described for subsequent addition to a soap slurring comprising an acyloxy alkane sulfonate salt. The sulfonate salt is present in an amount by weight of about 44 percent of about 56 percent. The polyol is present in an amount by weight of about 2 percent to about 6 percent, and water is present in an amount by weight of 26 to 36 percent. The composition constituting a solid reversible solution at ambient temperature and having a solids content of about 58 to 72 percent, whereby subsequent addition of the surfactant composition to a soap slurry results in formation of a soap/detergent bar having a smooth texture, uniform wear properties and a lack of grittiness.

  3. Immunogenicity of surfactant. I. Human alveolar surfactant.

    PubMed Central

    Strayer, D S; Hallman, M; Merritt, T A

    1991-01-01

    The immunogenicity of lung surfactant derived from amniotic fluid has been well established. We have set out to examine the antigenic similarity of human surfactant to non-human alveolar surfactants currently being used therapeutically in clinical trials with neonatal respiratory distress syndrome. To this end, we raised a series of eight monoclonal antibodies in rats directed to human surfactant (H1 to H8). All antibodies bound human surfactant as measured by ELISA. Four of these monoclonal antibodies bound surfactant components by Western blot analysis: all bound a 9-10-kD species. In addition, one antibody (H2) bound a protein of 16 kD, one (H8) a 6-kD protein, and one (H6) a 30-kD protein. When mixed with surfactant, three antibodies, H4, H7 and H8, profoundly altered surfactant activity in vitro in the pulsating bubble surfactometer. Three other antibodies, H1, H2, and H5 moderately inhibited surfactant's surface activity. We also examined the cross-reactivity of these monoclonal antibodies with bovine (CLSE) and porcine (Curosurf) surfactants. By Western blot analysis, only H6 bound these heterologous surfactants. Other antibodies did so by ELISA. However, functional assays indicated that antibodies H7, H8 and H4 all greatly inhibited CLSE surface activity in vitro. Five antibodies (H1-H4 and H8) inhibited Curosurf function. Thus, human surfactant species, especially low molecular weight species, are highly antigenic. Antibodies to alveolar surfactants may inhibit surfactant function in vitro. As indicated by Western blot and cross-inhibition data, human lower molecular weight surfactants share epitopes with proteins from therapeutically important porcine and bovine surfactants. The potential importance of these findings to treatment of neonatal respiratory distress syndrome with heterologous surfactants is discussed. PMID:1988229

  4. Thermally cleavable surfactants

    DOEpatents

    McElhanon, James R.; Simmons, Blake A.; Zifer, Thomas; Jamison, Gregory M.; Loy, Douglas A.; Rahimian, Kamyar; Long, Timothy M.; Wheeler, David R.; Staiger, Chad L.

    2009-11-24

    Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments or the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.

  5. Thermally cleavable surfactants

    DOEpatents

    McElhanon, James R.; Simmons, Blake A.; Zifer, Thomas; Jamison, Gregory M.; Loy, Douglas A.; Rahimian, Kamyar; Long, Timothy M.; Wheeler, David R.; Staiger, Chad L.

    2006-04-04

    Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments and the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.

  6. Thermally cleavable surfactants

    DOEpatents

    McElhanon, James R.; Simmons, Blake A.; Zifer, Thomas; Jamison, Gregory M.; Loy, Douglas A.; Rahimian, Kamyar; Long, Timothy M.; Wheeler, David R.; Staiger, Chad L.

    2009-09-29

    Two new surfactant molecules are reported which contain thermally labile Diels-Alder adducts connecting the polar and non-polar sections of each molecule. The two surfactants possess identical non-polar dodecyl tail segments but exhibit different polar headgroups. The surfactants become soluble in water when anionic salts are formed through the deprotonation of the surfactant headgroups by the addition of potassium hydroxide. When either surfactant is exposed to temperature above about 60.degree. C., the retro Diels-Alder reaction occurs, yielding hydrophilic and hydrophobic fragments or the aqueous solutions of the surfactants subsequently exhibit loss of all surface-active behavior.

  7. Research progress of surfactant

    NASA Astrophysics Data System (ADS)

    Zheng, Minyi; Mo, Lingyun; Qin, Ruqiong; Liang, Liying; Zhang, Fan

    2017-01-01

    With the rapid development of surfactant and the large growing use of the materials, the safety of surfactant may be a problem that draw worldwide attention. The surfactant can be discharged into environment through various approach and may cause toxic effects in organism. This paper reviews the environmental effects of surfactant materials for plants and animals, and raises some questions by describing the results of environmental toxicology. We put it that it is a great significant of promote the sustainable development of surfactant industry through a comprehensive understanding of surfactant environmental safety.

  8. Surfactant Enhanced DNAPL Removal

    DTIC Science & Technology

    2001-08-01

    or the permeability contrast (i.e., degree of heterogeneity) that is present in the DNAPL zone. To solubilize DNAPL with surfactants, a sufficient...with respect to the effects of permeability and heterogeneity upon the costs of SEAR: as permeability decreases and/or the degree of heterogeneity...not be an issue for surfactant recovery at all sites. The degree to which MEUF will concentrate the calcium is a function of the surfactant itself

  9. Surfactant phospholipid metabolism

    PubMed Central

    Agassandian, Marianna; Mallampalli, Rama K.

    2012-01-01

    Pulmonary surfactant is essential for life and is comprised of a complex lipoprotein-like mixture that lines the inner surface of the lung to prevent alveolar collapse at the end of expiration. The molecular composition of surfactant depends on highly integrated and regulated processes involving its biosynthesis, remodeling, degradation, and intracellular trafficking. Despite its multicomponent composition, the study of surfactant phospholipid metabolism has focused on two predominant components, disaturated phosphatidylcholine that confers surface-tension lowering activities, and phosphatidylglycerol, recently implicated in innate immune defense. Future studies providing a better understanding of the molecular control and physiological relevance of minor surfactant lipid components are needed. PMID:23026158

  10. Surfactants, skin cleansing protagonists.

    PubMed

    Corazza, M; Lauriola, M M; Zappaterra, M; Bianchi, A; Virgili, A

    2010-01-01

    The correct choice of cosmetic products and cleansers is very important to improve skin hydration, to provide moisturizing benefits and to minimize cutaneous damage caused by surfactants. In fact, surfactants may damage protein structures and solubilize lipids. Soaps, defined as the alkali salts of fatty acids, are the oldest surfactants and are quite aggressive. Syndets (synthetic detergents) vary in composition and surfactant types (anionic, cationic, amphotheric, non-ionic). These new skin cleansing products also contain preservatives, fragrances, and sometimes emollients, humectants and skin nutrients. We present a revision of the literature and discuss recent findings regarding skin cleansers.

  11. Towards unravelling surfactant transport

    NASA Astrophysics Data System (ADS)

    Sellier, Mathieu; Panda, Satyananda

    2015-11-01

    Surfactant transport arises in many natural or industrial settings. Examples include lipid tear layers in the eye, pulmonary surfactant replacement therapy, or industrial coating flows. Flows driven by the surface tension gradient which arises as a consequence of surfactant concentration inhomogeneity, also known as Marangoni-driven flows, have attracted the attention of fluid dynamists for several decades and has led to the development of sophisticated models and the undeniable advancement of the understanding of such flows. Yet, experimental confirmation of these models has been hampered by the difficulty in reliably and accurately measuring the surfactant concentration and its temporal evolution. In this contribution, we propose a methodology which may help shed some light on surfactant transport at the surface of thin liquid films. The surface stress induced by surfactant concentration induces a flow at the free surface which is visible and measurable. In the context of thin film flows for which the lubrication approximation hold, we demonstrate how the knowledge of this free surface flow field provides sufficient information to reconstruct the surfactant tension field. From the surface tension and an assumed equation of state, the local surfactant concentration can also be calculated and other transport parameters such as the surfactant surface diffusivity indirectly inferred. In this contribution, the proposed methodology is tested with synthetic data generated by the forward solution of the governing partial differential equations in order to illustrate the feasibility of the algorithm and highlight numerical challenges.

  12. Mechanisms to explain surfactant responses.

    PubMed

    Jobe, Alan H

    2006-01-01

    Surfactant is now standard of care for infants with respiratory distress syndrome. Surfactant treatments are effective because of complex metabolic interactions between surfactant and the preterm lung. The large treatment dose functions as substrate; it is taken up by the preterm lung and is reprocessed and secreted with improved function. The components of the treatment surfactant remain in the preterm lung for days. If lung injury is avoided, then surfactant inhibition is minimized. Prenatal corticosteroids complement surfactant to further enhance lung function. The magic of surfactant therapy results from the multiple interactions between surfactant and the preterm lung. Copyright (c) 2006 S. Karger AG, Basel.

  13. Immunogenicity of surfactant. II. Porcine and bovine surfactants.

    PubMed Central

    Strayer, D S; Hallman, M; Merritt, T A

    1991-01-01

    Protein-containing surfactants of human and animal origin are being used increasingly to treat neonatal and adult respiratory distress syndromes. This trend led us to examine the antigenicity of two important preparations of animal surfactant, cow lung surfactant extract (CLSE) and a porcine surfactant preparation, Curosurf. We describe here 15 monoclonal antibodies against Curosurf and four against CLSE. Antibodies were studied by Western blot analysis to determine their ability to recognize protein components of their respective surfactant preparations. They were also tested for their ability to inactivate surfactant in vitro, assayed using the pulsating bubble surfactometer. Several antibodies directed against CLSE or Curosurf functionally inactivate the surfactant to which they were raised. We determined the degree of immunologic cross-reactivity between antibodies directed to CLSE and Curosurf against the other surfactant and also against human surfactant, both by Western blot and by examining functional inactivation in vitro. Antibodies to these animal surfactants that are commonly used therapeutically may inactivate the specific animal surfactant to which they were raised, as well as human and other surfactants. Generally, when antibodies inactivate surfactant from more than one animal species, they inactivate heterologous surfactants comparably to the extent to which they inactivate the surfactant to which they are directed. Immune complexes between anti-surfactant antibodies and surfactant have been described in the course of neonatal respiratory distress syndrome. The potential pathophysiological importance of anti-surfactant antibodies may therefore lie in their ability to inactivate administered surfactant, other similar surfactants and endogenous surfactant. In so doing, these antibodies may potentiate surfactant deficiency or pulmonary injury initiated by other stimuli. Images Fig. 1 Fig. 2 PMID:1988231

  14. SURFACTANTS AND SUBSURFACE REMEDIATION

    EPA Science Inventory

    Because of the limitations of pump-and-trat technology, attention is now focused on the feasibility of surfactant use to increase its efficiency. Surfactants have been studied for use in soil washing and enhanced oil recovery. Although similarities exist between the application...

  15. SURFACTANTS AND SUBSURFACE REMEDIATION

    EPA Science Inventory

    Because of the limitations of pump-and-trat technology, attention is now focused on the feasibility of surfactant use to increase its efficiency. Surfactants have been studied for use in soil washing and enhanced oil recovery. Although similarities exist between the application...

  16. SURFACTANTS IN LUBRICATION

    USDA-ARS?s Scientific Manuscript database

    Surfactants are one of the most widely applied materials by consumers and industry. The application areas for surfactants span from everyday mundane tasks such as cleaning, to highly complex processes involving the formulation of pharmaceuticals, foods, pesticides, lubricants, etc. Even though sur...

  17. New generation synthetic surfactants.

    PubMed

    Curstedt, Tore; Calkovska, Andrea; Johansson, Jan

    2013-01-01

    The treatment of preterm newborn rabbits with synthetic surfactants containing simple phospholipid mixtures and peptides gives similar tidal volumes to treatment with poractant alfa (Curosurf®). The addition of both surfactant protein B and C analogs to the phospholipid mixture will stabilize the alveoli, measured as lung gas volumes at end expiration, even if no positive end-expiratory pressure is applied. The effect on lung gas volumes seems to depend on the structure of the peptides as well as the phospholipid composition. It seems that synthetic surfactants containing two peptides and a more complex phospholipid composition will be able to replace natural surfactants within the near future, but more experiments need to be performed before any conclusion can be drawn about the ideal composition of this new generation of synthetic surfactants.

  18. Surfactants in the environment.

    PubMed

    Ivanković, Tomislav; Hrenović, Jasna

    2010-03-01

    Surfactants are a diverse group of chemicals that are best known for their wide use in detergents and other cleaning products. After use, residual surfactants are discharged into sewage systems or directly into surface waters, and most of them end up dispersed in different environmental compartments such as soil, water or sediment. The toxic effects of surfactants on various aquatic organisms are well known. In general, surfactants are present in the environment at levels below toxicity and in Croatia below the national limit. Most surfactants are readily biodegradable and their amount is greatly reduced with secondary treatment in wastewater treatment plants. The highest concern is the release of untreated wastewater or wastewater that has undergone primary treatment alone. The discharge of wastewater polluted with massive quantities of surfactants could have serious effects on the ecosystem. Future studies of surfactant toxicities and biodegradation are necessary to withdraw highly toxic and non-biodegradable compounds from commercial use and replace them with more environmentally friendly ones.

  19. Metathesis depolymerizable surfactants

    DOEpatents

    Jamison, Gregory M.; Wheeler, David R.; Loy, Douglas A.; Simmons, Blake A.; Long, Timothy M.; McElhanon, James R.; Rahimian, Kamyar; Staiger, Chad L.

    2008-04-15

    A class of surfactant molecules whose structure includes regularly spaced unsaturation in the tail group and thus, can be readily decomposed by ring-closing metathesis, and particularly by the action of a transition metal catalyst, to form small molecule products. These small molecules are designed to have increased volatility and/or enhanced solubility as compared to the original surfactant molecule and are thus easily removed by solvent extraction or vacuum extraction at low temperature. By producing easily removable decomposition products, the surfactant molecules become particularly desirable as template structures for preparing meso- and microstructural materials with tailored properties.

  20. Recent advances in gemini surfactants: oleic Acid-based gemini surfactants and polymerizable gemini surfactants.

    PubMed

    Sakai, Kenichi; Sakai, Hideki; Abe, Masahiko

    2011-01-01

    Gemini surfactants recently developed by our research group are introduced from the standpoints of their syntheses, aqueous solution properties, and potential applications. Two series of gemini surfactants are introduced in this short review, the first of which is the oleic acid-based gemini surfactants, and the second is the polymerizable gemini surfactants. These gemini surfactants have been developed not only as environmentally friendly materials (the use of gemini surfactants enables the reduction of the total consumption of surfactants in chemical products owing to their excellent adsorption and micellization capabilities at low concentrations) but also as functional organic materials.

  1. Phosphine oxide surfactants revisited.

    PubMed

    Stubenrauch, Cosima; Preisig, Natalie; Laughlin, Robert G

    2016-04-01

    This review summarizes everything we currently know about the nonionic surfactants alkyl dimethyl (C(n)DMPO) and alkyl diethyl (C(n)DEPO) phosphine oxide (PO surfactants). The review starts with the synthesis and the general properties (Section 2) of these compounds and continues with their interfacial properties (Section 3) such as surface tension, surface rheology, interfacial tension and adsorption at solid surfaces. We discuss studies on thin liquid films and foams stabilized by PO surfactants (Section 4) as well as studies on their self-assembly into lyotropic liquid crystals and microemulsions, respectively (Section 5). We aim at encouraging colleagues from both academia and industry to take on board PO surfactants whenever possible and feasible because of their broad variety of excellent properties.

  2. Ionic liquids as surfactants

    NASA Astrophysics Data System (ADS)

    Smirnova, N. A.; Safonova, E. A.

    2010-10-01

    Problems of self-assembling in systems containing ionic liquids (ILs) are discussed. Main attention is paid to micellization in aqueous solutions of dialkylimidazolium ILs and their mixtures with classical surfactants. Literature data are reviewed, the results obtained by the authors and co-workers are presented. Thermodynamic aspects of the studies and problems of molecular-thermodynamic modeling receive special emphasis. It is shown that the aggregation behavior of dialkylimidazolium ILs is close to that of alkyltrimethylammonium salts (cationic surfactants) though ILs have a higher ability to self-organize, especially as it concerns long-range ordering. Some aspects of ILs applications are outlined where their common features with classical surfactants and definite specificity are of value.

  3. Surfactant mixing rules applied to surfactant enhanced alkaline flooding

    SciTech Connect

    Taylor, K.C. )

    1992-01-01

    This paper discusses surfactant mixing rules which have been used to describe crude oil/alkali/surfactant phase behavior, using David Lloydminster crude oil and the surfactant Neodol 25-3S. It was found that at a fixed salinity and alkali concentration, a specific mole fraction of synthetic surfactant to petroleum soap was required to produce optimal phase behavior as the water-to-oil ratio varied. This methodology is useful in understanding the relationship between the variables of water-to-oil ratio and synthetic surfactant concentration in phase behavior systems that produce a petroleum soap.

  4. Surfactant-enhanced bioremediation

    SciTech Connect

    Churchill, P.F.; Dudley, R.J.; Churchill, S.A.

    1995-12-31

    This study was undertaken to examine the effect of three structurally related, non-ionic surfactants, Triton X-45, Triton X-100 and Triton X-165, as well as the oleophilic fertilizer, Inipol EAP 22, on the rate of biodegradation of phenanthrene by pure bacterial cultures. Each surfactant dramatically increased the apparent aqueous solubility of phenanthrene. Model studies were conducted to investigate the ability of these surfactants to enhance the rate of transport and uptake of polycyclic aromatic hydrocarbons into bacterial cells, and to assess the impact that increasing the aqueous solubility of hydrocarbons has on their rate of biodegradation. The results indicate that increasing the apparent aqueous solubility of hydrocarbons can lead to enhanced biodegradation rates by two Pseudomonas saccharophila strains. However, the experiments also suggest that some surfactants can inhibit aromatic hydrocarbon biodegradation by certain bacteria. The data also support the hypothesis that surface-active components present in the oleophilic fertilizer formulation, Inipol EAP 22, may have significantly contributed to the positive results reported in tests of remedial agent impact on bioremediation, which was used as a supplemental clean-up technology on Exxon Valdez crude oil-contaminated Alaskan beaches.

  5. Diseases of Pulmonary Surfactant Homeostasis

    PubMed Central

    Whitsett, Jeffrey A.; Wert, Susan E.; Weaver, Timothy E.

    2015-01-01

    Advances in physiology and biochemistry have provided fundamental insights into the role of pulmonary surfactant in the pathogenesis and treatment of preterm infants with respiratory distress syndrome. Identification of the surfactant proteins, lipid transporters, and transcriptional networks regulating their expression has provided the tools and insights needed to discern the molecular and cellular processes regulating the production and function of pulmonary surfactant prior to and after birth. Mutations in genes regulating surfactant homeostasis have been associated with severe lung disease in neonates and older infants. Biophysical and transgenic mouse models have provided insight into the mechanisms underlying surfactant protein and alveolar homeostasis. These studies have provided the framework for understanding the structure and function of pulmonary surfactant, which has informed understanding of the pathogenesis of diverse pulmonary disorders previously considered idiopathic. This review considers the pulmonary surfactant system and the genetic causes of acute and chronic lung disease caused by disruption of alveolar homeostasis. PMID:25621661

  6. Surfactant treatments alter endogenous surfactant metabolism in rabbit lungs

    SciTech Connect

    Oetomo, S.B.; Lewis, J.; Ikegami, M.; Jobe, A.H. )

    1990-04-01

    The effect of exogenous surfactant on endogenous surfactant metabolism was evaluated using a single-lobe treatment strategy to compare effects of treated with untreated lung within the same rabbit. Natural rabbit surfactant, Survanta, or 0.45% NaCl was injected into the left main stem bronchus by use of a Swan-Ganz catheter. Radiolabeled palmitic acid was then given by intravascular injection at two times after surfactant treatment, and the ratios of label incorporation and secretion in the left lower lobe to label incorporation and secretion in the right lung were compared. The treatment procedure resulted in a reasonably uniform surfactant distribution and did not disrupt lobar pulmonary blood flow. Natural rabbit surfactant increased incorporation of palmitate into saturated phosphatidylcholine (Sat PC) approximately 2-fold (P less than 0.01), and secretion of labeled Sat PC increased approximately 2.5-fold in the surfactant-treated left lower lobe relative to the right lung (P less than 0.01). Although Survanta did not alter incorporation, it did increase secretion but not to the same extent as rabbit surfactant (P less than 0.01). Alteration of endogenous surfactant Sat PC metabolism in vivo by surfactant treatments was different from that which would have been predicted by previous in vitro studies.

  7. Coacervation with surfactants: From single-chain surfactants to gemini surfactants.

    PubMed

    Zhao, Weiwei; Wang, Yilin

    2017-01-01

    Coacervation is a spontaneous process during which a colloidal dispersion separates into two immiscible liquid phases: a colloid-rich liquid phase in equilibrium with a diluted phase. Coacervation is usually divided into simple coacervation and complex coacervation according to the number of components. Surfactant-based coacervation normally contains traditional single-chain surfactants. With the development of surfactants, gemini surfactants with two amphiphilic moieties have been applied to form coacervation. This review summarizes the development of simple coacervation and complex coacervation in the systems of single-chain surfactants and gemini surfactants. Simple coacervation in surfactant solutions with additives or at elevated temperature and complex coacervation in surfactant/polymer mixtures by changing charge densities, molecular weight, ionic strength, pH, or temperature are reviewed. The comparison between gemini surfactants and corresponding monomeric single-chain surfactants reveals that the unique structures of gemini surfactants endow them with higher propensity to generate coacervation. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Mixed surfactant systems for enhanced oil recovery

    SciTech Connect

    Llave, F.M.; Gall, B.L.; Noll, L.A.

    1990-12-01

    The results of an evaluation of mixed surfactant systems for enhanced oil recovery are described. Several surfactant combinations have been studied. These include alkyl aryl sulfonates as primary surfactants and carboxymethylated ethoxylated (CME) surfactants and ethoxylated sulfonates (ES) as secondary surfactants. The ethoxylated surfactants increase the salinity tolerance of the primary surfactants and, in theory, allow tailoring of the surfactant system to match selected reservoir conditions. The experiments conducted included interfacial tension (IFT) measurements, phase behavior measurements, adsorption and/or chromatographic separation of mixed surfactant systems, measurements of solution properties such as the critical micelle concentration (CMC) of surfactant mixtures, and crude oil displacement experiments. The effects of temperature, surfactant concentration, salinity, presence of divalent ions, hydrocarbon type, and component proportions in the mixed surfactant combinations, and injection strategies on the performance potential of the targeted surfactant/hydrocarbon systems were studied. 40 refs., 37 figs., 8 tabs.

  9. Surfactants at the Design Limit.

    PubMed

    Czajka, Adam; Hazell, Gavin; Eastoe, Julian

    2015-08-04

    This article analyzes how the individual structural elements of surfactant molecules affect surface properties, in particular, the point of reference defined by the limiting surface tension at the aqueous cmc, γcmc. Particular emphasis is given to how the chemical nature and structure of the hydrophobic tails influence γcmc. By comparing the three different classes of surfactants, fluorocarbon, silicone, and hydrocarbon, a generalized surface packing index is introduced which is independent of the chemical nature of the surfactants. This parameter ϕcmc represents the volume fraction of surfactant chain fragments in a surface film at the aqueous cmc. It is shown that ϕcmc is a useful index for understanding the limiting surface tension of surfactants and can be useful for designing new superefficient surfactants.

  10. Surfactant monitoring by foam generation

    DOEpatents

    Mullen, Ken I.

    1997-01-01

    A device for monitoring the presence or absence of active surfactant or other surface active agents in a solution or flowing stream based on the formation of foam or bubbles is presented. The device detects the formation of foam with a light beam or conductivity measurement. The height or density of the foam can be correlated to the concentration of the active surfactant present.

  11. ADSORPTION OF SURFACTANT ON CLAYS

    EPA Science Inventory

    Surfactants used to enhance remediation of soils by soil washing are often lost in the process. Neither the amount nor the cause of this loss is known. It is assumed that clays present in the soil are responsible for the loss of the surfactant. In this papere, adsorption prope...

  12. Surfactant adsorption kinetics in microfluidics

    PubMed Central

    Riechers, Birte; Maes, Florine; Akoury, Elias; Semin, Benoît; Gruner, Philipp; Baret, Jean-Christophe

    2016-01-01

    Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than 90% to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning—here through ion exchange—unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore–surfactant interactions. PMID:27688765

  13. ADSORPTION OF SURFACTANT ON CLAYS

    EPA Science Inventory

    Surfactants used to enhance remediation of soils by soil washing are often lost in the process. Neither the amount nor the cause of this loss is known. It is assumed that clays present in the soil are responsible for the loss of the surfactant. In this papere, adsorption prope...

  14. Surfactant-assisted coal liquefaction

    NASA Technical Reports Server (NTRS)

    Hsu, G. C.

    1977-01-01

    Improved process of coal liquefaction utilizing nonaqueous surfactant has increased oil yield from 50 to about 80%. Asphaltene molecule formation of colloid particles is prevented by surfactant. Separated molecules present more surface area for hydrogenation reaction. Lower requirements for temperature, pressure, and hydrogen lead to reduction in capital and operation costs.

  15. Surfactant-assisted coal liquefaction

    NASA Technical Reports Server (NTRS)

    Hsu, G. C.

    1977-01-01

    Improved process of coal liquefaction utilizing nonaqueous surfactant has increased oil yield from 50 to about 80%. Asphaltene molecule formation of colloid particles is prevented by surfactant. Separated molecules present more surface area for hydrogenation reaction. Lower requirements for temperature, pressure, and hydrogen lead to reduction in capital and operation costs.

  16. Surfactant adsorption kinetics in microfluidics.

    PubMed

    Riechers, Birte; Maes, Florine; Akoury, Elias; Semin, Benoît; Gruner, Philipp; Baret, Jean-Christophe

    2016-10-11

    Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than [Formula: see text] to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning-here through ion exchange-unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore-surfactant interactions.

  17. Surfactant adsorption kinetics in microfluidics

    NASA Astrophysics Data System (ADS)

    Riechers, Birte; Maes, Florine; Akoury, Elias; Semin, Benoît; Gruner, Philipp; Baret, Jean-Christophe

    2016-10-01

    Emulsions are metastable dispersions. Their lifetimes are directly related to the dynamics of surfactants. We design a microfluidic method to measure the kinetics of adsorption of surfactants to the droplet interface, a key process involved in foaming, emulsification, and droplet coarsening. The method is based on the pH decay in the droplet as a direct measurement of the adsorption of a carboxylic acid surfactant to the interface. From the kinetic measurement of the bulk equilibration of the pH, we fully determine the adsorption process of the surfactant. The small droplet size and the convection during the droplet flow ensure that the transport of surfactant through the bulk is not limiting the kinetics of adsorption. To validate our measurements, we show that the adsorption process determines the timescale required to stabilize droplets against coalescence, and we show that the interface should be covered at more than 90% to prevent coalescence. We therefore quantitatively link the process of adsorption/desorption, the stabilization of emulsions, and the kinetics of solute partitioning—here through ion exchange—unraveling the timescales governing these processes. Our method can be further generalized to other surfactants, including nonionic surfactants, by making use of fluorophore-surfactant interactions.

  18. On-line surfactant monitoring

    SciTech Connect

    Mullen, K.I.; Neal, E.E.; Soran, P.D.; Smith, B.

    1995-04-01

    This group has developed a process to extract metal ions from dilute aqueous solutions. The process uses water soluble polymers to complex metal ions. The metal/polymer complex is concentrated by ultrafiltration and the metals are recovered by a pH adjustment that frees the metal ions. The metal ions pass through the ultrafiltration membrane and are recovered in a concentrated form suitable for reuse. Surfactants are present in one of the target waste streams. Surfactants foul the costly ultrafiltration membranes. It was necessary to remove the surfactants before processing the waste stream. This paper discusses an on-line device the authors fabricated to monitor the process stream to assure that all the surfactant had been removed. The device is inexpensive and sensitive to very low levels of surfactants.

  19. Innovation in surfactant therapy II: surfactant administration by aerosolization.

    PubMed

    Pillow, J Jane; Minocchieri, S

    2012-01-01

    Instilled bolus surfactant is the only approved surfactant treatment for neonatal respiratory distress syndrome. However, recent trends towards increased utilization of noninvasive respiratory support for preterm infants with surfactant deficiency have created a demand for a similarly noninvasive means of administering exogenous surfactant. Past approaches to surfactant nebulization met with varying success due to inefficient aerosol devices resulting in low intrapulmonary delivery doses of surfactant with variable clinical effectiveness. The recent development of vibrating membrane nebulizers, coupled with appropriate positioning of the interface device, indicates that efficient delivery of aerosolized surfactant is now a realistic goal in infants. Evidence of clinical effect despite low total administered dose in pilot studies, together with suggestions of enhanced homogeneity of pulmonary distribution indicate that this therapy may be applied in a cost-effective manner, with minimal patient handling and disruption. These studies need to be subjected to appropriately designed randomized controlled trials. Further work is also required to determine the optimum delivery route (mask, intranasal prong, nasopharyngeal or laryngeal), dosing amount and redosing interval. Copyright © 2012 S. Karger AG, Basel.

  20. Surfactant damping of water waves

    NASA Astrophysics Data System (ADS)

    Lapham, Gary S.; Dowling, David R.; Schultz, William W.

    1997-11-01

    The most well known and perhaps most important distinguishing characteristic of a water surface laden with surfactant is the profound increase in small-wave damping with the addition of even small amounts of surfactant material. It would seem to follow that damping increases with increasing surfactant concentration. This is undoubtedly true for some surfactants, however our experiments with a soluble surfactant show that it is possible to increase surfactant concentration and measure a decrease in damping. While the increased concentration is accompanied by a dramatic decrease in measured static surface tension, some of the capillary-wave frequency regime is less damped. Experimental measurements of the real and imaginary parts of the wave speed are compared with existing theory where at least one other physical quantity besides surface tension is needed to properly model the interface. Our on-going work with insoluble surfactants may also provide an example of this type of behavior for materials that do not readily transfer to and from the bulk water. [Supported by the Office of Naval Research

  1. Electrokinetic investigation of surfactant adsorption.

    PubMed

    Bellmann, C; Synytska, A; Caspari, A; Drechsler, A; Grundke, K

    2007-05-15

    Fuerstenau [D.W. Fuerstenau, in: M.L. Hair (Ed.), Dekker, New York, 1971, p. 143] has already discussed the role of hydrocarbon chain of surfactants, the effect of alkyl chain length, chain structure and the pH of the solution on the adsorption process of surfactants. Later Kosmulski [M. Kosmulski, Chemical Properties of Material Surfaces, Surfactant Science Series, vol. 102, Dekker, New York, Basel, 2001] included the effect of surfactant concentration, equilibration time, temperature and electrolyte in his approaches. Certainly, the character of the head groups of the surfactant and the properties of the adsorbent surface are the basis for the adsorption process. Different surfactants and adsorbents cause different adsorption mechanisms described firstly by Rosen [M.J. Rosen, Surfactants and Interfacial Phenomena, second ed., Wiley, New York, 1989]. These adsorption mechanisms and their influencing factors were studied by electrokinetic investigations. Here only changes of the charges at the surfaces could be detected. To control the results of electrokinetic investigations they were compared with results from ellipsometric measurements. In the case of surfactant adsorption the chain length was vitally important. It could be shown by the adsorption of alkyl trimethyl ammonium bromides onto polymer films spin coated at wafer surfaces. The influence of the chain length depending on surface properties of the polymer film was studied. Streaming potential measurements were applied for these investigations. The obtained results enabled us to calculate the molar cohesive free energy per mol of CH2-group in the alkaline chain of the surfactant if all other specific adsorption effects were neglected.

  2. Structural Studies of Protein-Surfactant Complexes

    SciTech Connect

    Chodankar, S. N.; Aswal, V. K.; Wagh, A. G.

    2008-03-17

    The structure of protein-surfactant complexes of two proteins bovine serum albumin (BSA) and lysozyme in presence of anionic surfactant sodium dodecyl sulfate (SDS) has been studied using small-angle neutron scattering (SANS). It is observed that these two proteins form different complex structures with the surfactant. While BSA protein undergoes unfolding on addition of surfactant, lysozyme does not show any unfolding even up to very high surfactant concentrations. The unfolding of BSA protein is caused by micelle-like aggregation of surfactant molecules in the complex. On the other hand, for lysozyme protein there is only binding of individual surfactant molecules to protein. Lysozyme in presence of higher surfactant concentrations has protein-surfactant complex structure coexisting with pure surfactant micelles.

  3. Pulmonary surfactant for neonatal respiratory disorders.

    PubMed

    Merrill, Jeffrey D; Ballard, Roberta A

    2003-04-01

    Surfactant therapy has revolutionized neonatal care and is used routinely for preterm infants with respiratory distress syndrome. Recent investigation has further elucidated the function of surfactant-associated proteins and their contribution toward surfactant and lung immune defense functions. As the field of neonatology moves away from intubation and mechanical ventilation of preterm infants at birth toward more aggressive use of nasal continuous positive airway pressure, the optimal timing of exogenous surfactant therapy remains unclear. Evidence suggests that preterm neonates with bronchopulmonary dysplasia and prolonged mechanical ventilation also experience surfactant dysfunction; however, exogenous surfactant therapy beyond the first week of life has not been well studied. Surfactant replacement therapy has been studied for use in other respiratory disorders, including meconium aspiration syndrome and pneumonia. Commercial surfactant preparations currently available are not optimal, given the variability of surfactant protein content and their susceptibility to inhibition. Further progress in the treatment of neonatal respiratory disorders may include the development of "designer" surfactant preparations.

  4. Minimally invasive approaches for surfactant administration.

    PubMed

    Trevisanuto, D; Marchetto, L

    2013-01-01

    Respiratory distress syndrome (RDS) is the most common respiratory morbidity in preterm infants. In addition to respiratory support, the current clinical treatment includes endotracheal intubation and rapid instillation of exogenous surfactant. However, this approach needs skilled operators and has been associated with complications such as hemodynamic instability and electroencephalogram abnormalities. New, less invasive methods for surfactant administration are needed. In this article, we reviewed the available noninvasive procedures for surfactant administration. In particular, we focused on aerosolized surfactant and surfactant administration through LMA.

  5. Genetics Home Reference: surfactant dysfunction

    MedlinePlus

    ... easy. Without normal surfactant, the tissue surrounding the air sacs in the lungs (the alveoli ) sticks together (because of a force called surface tension) after exhalation, causing the alveoli ...

  6. Surfactant-enhanced aquifier remediation

    SciTech Connect

    Fountain, J.C.

    1996-12-31

    Surfactants can be used to rapidly remove NAPL from contaminated aquifers. They are effective for virtually any organic contaminant. Use in LNAPL contaminated sites requires adequate hydraulic conductivity and control of flow using either hydraulic or physical methods. The presence of DNAPL requires consideration of vertical mobility; a competent confining layer (aquitard) is required if additional aquifers are present at greater depths. Surfactant processes, whether based upon mobilization or solubilization, can be effective at mass removal, but cannot be expected to provide resortation to drinking water standards. The fraction of mass removal, and the cost of remediation using surfactants are dependent upon a sites hydrogeology. Both minimization of cost and maximization of NAPL removal requires detailed characterization of sites contaminant distribution and hydrogeology. Assessment of the feasibility of surfactant-enhanced remediation is dependent upon a detailed site characterization.

  7. Interactions between polymers and surfactants

    SciTech Connect

    de Gennes, P.G. )

    1990-11-01

    A surfactant film (at the water/air interface, or in a bilayer) is exposed to a solution of a neutral, flexible, polymer. Depending on the interactions, and on the Langmuir pressure II of the pure surfactant film, the authors expected to find three types of behavior: (I) the polymer does not absorb; (II) the polymer absorbs and mixes with the surfactant; (III) the polymer absorbs but segregates from the surfactant. Their interest here is in case II. They predict that (a) bilayers become rigid; (b) bilayers, exposed to polymer on one side only, tend to bend strongly; (c) the surface viscosity of monolayers or bilayers is considerably increased; soap films or foams, which usually drain by turbulent (two-dimensional) flows, may be stabilized in case II.

  8. Biomimicry of surfactant protein C.

    PubMed

    Brown, Nathan J; Johansson, Jan; Barron, Annelise E

    2008-10-01

    Since the widespread use of exogenous lung surfactant to treat neonatal respiratory distress syndrome, premature infant survival and respiratory morbidity have dramatically improved. Despite the effectiveness of the animal-derived surfactant preparations, there still remain some concerns and difficulties associated with their use. This has prompted investigation into the creation of synthetic surfactant preparations. However, to date, no clinically used synthetic formulation is as effective as the natural material. This is largely because the previous synthetic formulations lacked analogues of the hydrophobic proteins of the lung surfactant system, SP-B and SP-C, which are critical functional constituents. As a result, recent investigation has turned toward the development of a new generation of synthetic, biomimetic surfactants that contain synthetic phospholipids along with a mimic of the hydrophobic protein portion of lung surfactant. In this Account, we detail our efforts in creating accurate mimics of SP-C for use in a synthetic surfactant replacement therapy. Despite SP-C's seemingly simple structure, the predominantly helical protein is extraordinarily challenging to work with given its extreme hydrophobicity and structural instability, which greatly complicates the creation of an effective SP-C analogue. Drawing inspiration from Nature, two promising biomimetic approaches have led to the creation of rationally designed biopolymers that recapitulate many of SP-C's molecular features. The first approach utilizes detailed SP-C structure-activity relationships and amino acid folding propensities to create a peptide-based analogue, SP-C33. In SP-C33, the problematic and metastable polyvaline helix is replaced with a structurally stable polyleucine helix and includes a well-placed positive charge to prevent aggregation. SP-C33 is structurally stable and eliminates the association propensity of the native protein. The second approach follows the same design

  9. Surfactant therapy and spontaneous diuresis.

    PubMed

    Bhat, R; John, E; Diaz-Blanco, J; Ortega, R; Fornell, L; Vidyasagar, D

    1989-03-01

    The effect of artificial surfactant therapy on renal function and the onset of spontaneous diuresis was prospectively evaluated in 19 infants with hyaline membrane disease in a double-blind, controlled study. Twelve infants were in the surfactant group; seven infants received placebo (0.9% saline solution). There was no difference in the time of onset of spontaneous diuresis (as defined by output greater than or equal to 80% of intake). The glomerular filtration rate, determined by endogenous creatinine clearance, was also similar in the surfactant- and placebo-treated infants during the first 3 days of life. The fractional excretion of sodium was significantly higher in the placebo group at 24 hours and 36 hours. Infants in the placebo group had a higher negative sodium balance than those in the surfactant group. Ventilatory status improved significantly soon after surfactant treatment, as evidenced by improvement in the alveolar/arterial oxygen pressure ratio and by a lower mean airway pressure. These data suggest that ventilatory status can be improved without diuresis; the factors that regulate diuresis are multiple and not fully understood.

  10. Preparations of organobentonite using nonionic surfactants.

    PubMed

    Shen, Y H

    2001-08-01

    Due to hydrophilic environment at its surface, natural bentonite is an ineffective sorbent for nonpolar nonionic organic compounds in water even though it has high surface area. The surface properties of natural bentonite can be greatly modified by simple ion-exchange reactions with large organic cations (cationic surfactants) and this organobentonite is highly effective in removing nonionic organic compounds from water. Cationic surfactant derived organobentonites have been investigated extensively for a wide variety of environmental applications. In this study, the preparation of organobentonite using nonionic surfactants has been investigated for the first time. Results indicate that nonionic surfactants intercalates into the interlamellar space of bentonite and may demonstrate higher sorption capacity than cationic surfactant. It is possible to create large interlayer spacing and high organic carbon content organobentonite by use of nonionic surfactants with suitable balance between the hydrocarbon and ethylene oxide chain lengths. In addition, nonionic surfactant derived organobentonites are more chemically stable than cationic surfactant derived organobentonites.

  11. Surfactant recovery from water using foam fractionation

    SciTech Connect

    Tharapiwattananon, N.; Osuwan, S.; Scamehorn, J.F.

    1996-05-01

    The purpose of this study was to investigate the use of foam fractionation to recover surfactant from water. A simple continuous mode foam fractionation was used and three surfactants were studied (two anionic and one cationic). The effects of air flow rate, foam height, liquid height, liquid feed surfactant concentration, and sparger porosity were studied. This technique was shown to be effective in either surfactant recovery or the reduction of surfactant concentration in water to acceptable levels. As an example of the effectiveness of this technique, the cetylpyridinium chloride concentration in water can be reduced by 90% in one stage with a liquid residence time of 375 minutes. The surfactant concentration in the collapsed foam is 21.5 times the feed concentration. This cationic surfactant was easier to remove from water by foam fractionation than the anionic surfactants studied.

  12. Synthesis of carbohydrate-based surfactants

    SciTech Connect

    Pemberton, Jeanne E.; Polt, Robin L.; Maier, Raina M.

    2016-11-22

    The present invention provides carbohydrate-based surfactants and methods for producing the same. Methods for producing carbohydrate-based surfactants include using a glycosylation promoter to link a carbohydrate or its derivative to a hydrophobic compound.

  13. Surfactant for Pediatric Acute Lung Injury

    PubMed Central

    Willson, Douglas F.; Chess, Patricia R.; Notter, Robert H.

    2008-01-01

    Synopsis This article reviews exogenous surfactant therapy and its use in mitigating acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) in infants, children, and adults. Biophysical and animal research documenting surfactant dysfunction in ALI/ARDS is described, and the scientific rationale for treatment with exogenous surfactant is discussed. Major emphasis is on reviewing clinical studies of surfactant therapy in pediatric and adult patients with ALI/ARDS. Particular advantages from surfactant therapy in direct pulmonary forms of these syndromes are described. Also discussed are additional factors affecting the efficacy of exogenous surfactants in ALI/ARDS, including the multifaceted pathology of inflammatory lung injury, the effectiveness of surfactant delivery in injured lungs, and composition-based activity differences among clinical exogenous surfactant preparations. PMID:18501754

  14. Polymer/surfactant transport in micellar flooding

    SciTech Connect

    Chiou, C.S.; Kellerhals, G.E.

    1981-10-01

    For the surfactant formulations used (particular surfactant concentration, surfactant type, cosolvent type, cosolvent concentration, etc.), the results show that surfactant systems containing polymer as a mobility control agent may exhibit adverse polymer transport behavior during flow through porous media. Polymer generally lagged behind the surfactant even though the two species were injected simultaneously in the surfactant slug. This poor polymer transport definitely could have a detrimental effect on the efficiency of a micellar flooding process in the field. Phase studies show that when some surfactant systems containing xanthan gum are mixed with crude oil at various salinities, a polymer-rich, gel-like phase forms. The polymer lag phenomenon in core tests can be related to phase separation due to divalent cations generated in situ as a result of ion exchange with the clays and the surfactant. 18 refs.

  15. Biofoams and natural protein surfactants

    PubMed Central

    Cooper, Alan; Kennedy, Malcolm W.

    2010-01-01

    Naturally occurring foam constituent and surfactant proteins with intriguing structures and functions are now being identified from a variety of biological sources. The ranaspumins from tropical frog foam nests comprise a range of proteins with a mixture of surfactant, carbohydrate binding and antimicrobial activities that together provide a stable, biocompatible, protective foam environment for developing eggs and embryos. Ranasmurfin, a blue protein from a different species of frog, displays a novel structure with a unique chromophoric crosslink. Latherin, primarily from horse sweat, but with similarities to salivary, oral and upper respiratory tract proteins, illustrates several potential roles for surfactant proteins in mammalian systems. These proteins, together with the previously discovered hydrophobins of fungi, throw new light on biomolecular processes at air–water and other interfaces. This review provides a perspective on these recent findings, focussing on structure and biophysical properties. PMID:20615601

  16. Fiber coating with surfactant solutions

    NASA Astrophysics Data System (ADS)

    Shen, Amy Q.; Gleason, Blake; McKinley, Gareth H.; Stone, Howard A.

    2002-11-01

    When a fiber is withdrawn at low speeds from a pure fluid, the variation in the thickness of the entrained film with imposed fiber velocity is well-predicted by the Landau-Levich-Derjaguin (LLD) equation. However, surfactant additives are known to alter this response. We study the film thickening properties of the protein BSA (bovine serum albumin), the nonionic surfactant Triton X-100, and the anionic surfactant SDS (sodium dodecyl sulfate). For each of these additives, the film thickening factor alpha (the ratio of the measured thickness to the LLD prediction) for a fixed fiber radius varies as a function of the ratio of the surfactant concentration c to the critical micelle concentration (CMC). In the case of BSA, which does not form micelles, the reference value is the concentration at which multilayers form. As a result of Marangoni effects, alpha reaches a maximum as c approaches the CMC from below. However, when the surfactant concentration c exceeds the CMC, the behavior of alpha varies as a consequence of the dynamic surface properties, owing for example to different sorption kinetics of these additives, or possibly surface or bulk rheological effects. For SDS, alpha begins to decrease when c exceeds the CMC and causes the surface to become partially or completely remobilized, which is consistent with the experimental and theoretical results published for studies of slug flows of bubbles and surfactant solutions in a capillary tube and the rise of bubbles in surfactant solutions. However, when the SDS or Triton X-100 surfactant concentration is well above the CMC, we observe that the film thickening parameter alpha increases once again. In the case of SDS we observe a second maximum in the film thickening factor. For all the experiments, transport of monomers to the interface is limited by diffusion and the second maximum in the film thickening factor may be explained as a result of a nonmonotonic change in the stability characteristics of suspended SDS

  17. SURFACTANT ENHANCED AQUIFER REMEDIATION WITH SURFACTANT REGENERATION/REUSE

    EPA Science Inventory

    A demonstration of surfactant-enhanced aquifer remediation was conducted during the spring of 1999 at Marine Corps Base, Camp LeJeune, NC. A PCE-DNAPL zone was identified and delineated by extensive soil sampling in 1997, and was further characteized by a partitioning interwell t...

  18. Physical properties of botanical surfactants.

    PubMed

    Müller, Lillian Espíndola; Schiedeck, Gustavo

    2017-08-24

    Some vegetal species have saponins in their composition with great potential to be used as natural surfactants in organic crops. This work aims to evaluate some surfactants physical properties of Quillaja brasiliensis and Agave angustifolia, based on different methods of preparation and concentration. The vegetal samples were prepared by drying and grinding, frozen and after chopped or used fresh and chopped. The neutral bar soap was used as a positive control. The drying and grinding of samples were the preparation method that resulted in higher foam column height in both species but Q. brasiliensis was superior to A. angustifolia in all comparisons and foam index was 2756 and 1017 respectively. Critical micelle concentration of Q. brasiliensis was 0.39% with the superficial tension of 54.40mNm(-1) while neutral bar soap was 0.15% with 34.96mNm(-1). Aspects such as genetic characteristics of the species, environmental conditions, and analytical methods make it difficult to compare the results with other studies, but Q. brasiliensis powder has potential to be explored as a natural surfactant in organic farming. Not only the surfactants physical properties of botanical saponins should be taken into account but also its effect on insects and diseases control when decided using them. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Biomimicry of surfactant protein C

    PubMed Central

    Brown, Nathan J.; Johansson, Jan; Barron, Annelise E.

    2012-01-01

    CONSPECTUS Since the widespread use of exogenous lung surfactant to treat neonatal respiratory distress syndrome, premature infant survival and respiratory morbidity have dramatically improved. Despite the effectiveness of the animal-derived surfactant preparations, there still remain some concerns and difficulties associated with their use. This has prompted investigation into the creation of synthetic surfactant preparations. However, to date, no clinically used synthetic formulation is as effective as the natural material. This is largely because the previous synthetic formulations lacked analogues of the hydrophobic proteins of the lung surfactant system, SP-B and SP-C, which are critical functional constituents. As a result, recent investigation has turned towards the development of a new generation of synthetic, biomimetic surfactants that contain synthetic phospholipids along with a mimic of the hydrophobic protein portion of lung surfactant. In this Account, we detail our efforts in creating accurate mimics of SP-C for use in a synthetic surfactant replacement therapy. Despite SP-C’s seemingly simple structure, the predominantly helical protein is extraordinarily challenging to work with given its extreme hydrophobicity and structural instability, which greatly complicates the creation of an effective SP-C analogue. Drawing inspiration from Nature, two promising biomimetic approaches have led to the creation of rationally designed biopolymers that recapitulate many of SP-C’s molecular features. The first approach utilizes detailed SP-C structure-activity relationships and amino acid folding propensities to create a peptide-based analogue, SP-C33. In SP-C33, the problematic and metastable poly-valine helix is replaced with a structurally stable, poly-leucine helix and includes a well placed positive charge to prevent aggregation. SP-C33 is both structurally stable and eliminates the association propensity of the native protein. The second approach

  20. An anionic surfactant for EOR applications

    NASA Astrophysics Data System (ADS)

    Sagir, Muhammad; Tan, Isa M.; Mushtaq, Muhammad

    2014-10-01

    This work is to investigate the new anionic surfactants for the Enhanced Oil Recovery (EOR) application. Sulfonated anionic surfactant was produced by attaching SO3 to an ethoxylated alcohol to increase the performance of the surfactant. Methallyl chloride and ethoxylated alcohol was reacted followed by the reaction with sodium bisulfite to produce anionic sulfonated surfactant in 80.3 % yield. The sulfonation reaction parameters such as reactants mole ratio, reaction temperature and catalyst amount were optimized. The generation and stability of foam from the synthesized surfactant is also tested and results are reported. The synthesized novel surfactant was further investigated for the effect on the CO2 mobility in porous media and the findings are presented here. This in house developed surfactant has a great potential for CO2- EOR applications.

  1. Inactivation of surfactant in rat lungs.

    PubMed

    Bruni, R; Fan, B R; David-Cu, R; Taeusch, H W; Walther, F J

    1996-02-01

    Although surfactant replacement therapy has dramatically improved the outcome of premature infants with respiratory distress syndrome, approximately 30% of treated infants show a transient or no response. Nonresponse to surfactant replacement therapy may be due to extreme lung immaturity and possibly surfactant inactivation. Surfactant inactivation involves aspecific biophysical events, such as interference with the formation or activity of an alveolar monolayer, and specific interactions with serum proteins, including antibodies, leaking into the alveolar space. As formulations containing surfactant proteins appear to better tolerate serum inactivation, we used an excised rat lung model to compare the susceptibility to serum inactivation of a mixture of synthetic phospholipids selected from surfactant lipid constituents, Exosurf (a protein-free synthetic surfactant), Survanta [containing surfactant proteins B and C (SP-B and -C)], and a porcine surfactant (containing SP-A, -B, and -C). For each of these preparations, we used pressure/volume determinations as an in situ measure of surfactant activity and retested the same preparations after mixing with human serum, a nonspecific surfactant inactivator. Human serum inactivated porcine surfactant to a lesser extent than Survanta, Exosurf, or synthetic phospholipids. Temperature exerted a significant effect on deflation stability, as shown by a greater lung compliance in untreated, normal lungs and a larger improvement in compliance after treating lavaged lungs with synthetic phospholipids at 37 degrees C than at 22 degrees C. We conclude that surfactant containing SP-A, -B, and -C is only moderately susceptible to inactivation with whole serum and may therefore exert a greater clinical response than protein-free surfactants or those containing only SP-B and -C.

  2. The influence of surfactant on the deformation and breakup of a viscous drop: The effect of surfactant solubility

    SciTech Connect

    Milliken, W.J. ); Leal, L.G. . Dept. of Chemical and Nuclear Engineering)

    1994-09-01

    The influence of surfactant on the deformation of a viscous drop in a uniaxial extensional flow is considered. Previous studies have examined the role in insoluble surfactant. Here, the authors examine soluble surfactant, i.e., surfactant that may be transferred between the interface and the continuous phase. The transfer of surfactant to and from the interface mitigates many of the effects observed with insoluble surfactant by diminishing the magnitude of surfactant gradients. In the presence of soluble surfactant, the deformation generally lies between that of insoluble surfactant and that of a drop with a constant and uniform coverage of surfactant. However, there are notable exceptions particularly at high surfactant activity. The influence of surfactant on the interfacial velocity of the drop is also explicitly considered. It is shown that while insoluble surfactant can substantially retard a drop interface, interphase surfactant transfer acts to remobilize the interface.

  3. Effect of exogenous surfactant on the development of surfactant synthesis in premature rabbit lung.

    PubMed

    Amato, Maurizio; Petit, Kevin; Fiore, Humberto H; Doyle, Cynthia A; Frantz, Ivan D; Nielsen, Heber C

    2003-04-01

    Surfactant replacement is an effective therapy for neonatal respiratory distress syndrome. Full recovery from respiratory distress syndrome requires development of endogenous surfactant synthesis and metabolism. The influence of exogenous surfactant on the development of surfactant synthesis in premature lungs is not known. We hypothesized that different exogenous surfactants have different effects on the development of endogenous surfactant production in the premature lung. We treated organ cultures of d 25 fetal rabbit lung for 3 d with 100 mg/kg body weight of natural rabbit surfactant, Survanta, and Exosurf and measured their effects on the development of surfactant synthesis. Additional experiments tested how these surfactants and Curosurf affected surfactant protein (SP) SP-A, SP-B, and SP-C mRNA expression. Surfactant synthesis was measured as the incorporation of 3H-choline and 14C-glycerol into disaturated phosphatidylcholine recovered from lamellar bodies. Randomized-block ANOVA showed significant differences among treatments for incorporation of both labels (p < 0.01), with natural rabbit surfactant less than control, Survanta greater than control, and Exosurf unchanged. Additional experiments with natural rabbit surfactant alone showed no significant effects in doses up to 1000 mg/kg. Survanta stimulated disaturated phosphatidylcholine synthesis (173 +/- 41% of control; p = 0.01), increased total lamellar body disaturated phosphatidylcholine by 22% (p < 0.05), and increased 14C-disat-PC specific activity by 35% (p < 0.05). The response to Survanta was dose-dependent up to 1000 mg/kg. Survanta did not affect surfactant release. No surfactant altered the expression of mRNA for SP-A, SP-B, or SP-C. We conclude that surfactant replacement therapy can enhance the maturation of surfactant synthesis, but this potential benefit differs with different surfactant preparations.

  4. Surfactant transport on viscous bilayers

    NASA Astrophysics Data System (ADS)

    Matar, Omar; Craster, Richard; Warner, Mark

    2001-11-01

    We model the external delivery of surfactant to pulmonary airways, an integral part of Surfactant Replacement Therapy (SRT), a method of treatment of Respiratory Distress Syndrome in neonates. We examine the spreading dynamics of insoluble surfactant by Marangoni stresses along the mucus-perciliary liquid bilayers that line the inside of airways. The bilayer is modelled as a thin highly viscous mucus surface film (mucus) overlying a much less viscous perciliary liquid layer (PCL); this is appropriate for small airways. By exploiting this large viscosity constrast, a variant of standard lubrication theory is adopted wherein terms, which would have otherwise been neglected in the lubrication approximation, are promoted in order to model correctly the presence of the mucus. Inclusion of van der Waals forces in the model permit the study of the effect of this mucus 'skin' on the possibility of bilayer rupture, a potential cause of failure of SRT. We find that increasing the viscosity contrast and initial mucus layer thickness delays the onset of rupture, while increasing the relative significance of Marangoni stresses leads to more marked thinning and rapid bilayer rupture [1]. [1] O. K. Matar, R. V. Craster and M. R. Warner, submitted to J. Fluid Mech. (2001).

  5. Permeability reductions induced by sorption of surfactant

    NASA Astrophysics Data System (ADS)

    Renshaw, Carl E.; Zynda, Gregory D.; Fountain, John C.

    Surfactant enhanced aquifer remediation (SEAR) is an attractive alternative to traditional pump and treat methods for remediating aquifers contaminated with nonaqueous phase liquids. However, initial studies indicate that the application of surfactant can reduce aquifer permeability by more than an order of magnitude, limiting the efficiency of SEAR. A series of column experiments using mixtures of medium sand and montmorillonite clay demonstrate that existing permeability reduction models for biofouling and deep-bed filtration poorly predict surfactant induced permeability reductions. An alternative permeability reduction model is proposed which is based on the assumption that the sorbed surfactant effectively increases the volume fraction of the clay. The model is shown to reasonably predict observed permeability reductions, particularly for clay fractions less than 20%. A numerical simulation of surfactant transport that incorporates the effective clay fraction model demonstrates that induced permeability reductions significantly influence the transport of surfactant through an aquifer.

  6. Solution behavior of surfactants. Vol. 1

    SciTech Connect

    Mittal, K.L.; Fendler, E.J.

    1983-01-01

    This three-volume set constitutes the proceedings of the 4th International Symposium on Surfactants in Solution held in Sweden in 1982. Volume 1 considers phase behavior and phase equilibria in surfactant solutions (e.g., thermodynamics of partially miscible micelles and liquid crystals; multi-method characterization of micelles; the surfactant-block model of micelle structure). Volume 2 considers thermodynamic and kinetic aspects of micellization (computation of the micelle-size distribution; salt-induced sphere-rod transition of ionic micelles; micellar effects on kinetics and equilibria of electron transfer reactions). Volume 3 considers reverse micelles, microemulsions and reactions in microemulsions. Topics covered include solubilization, surfactants in analytical chemistry, the adsorption and binding of surfactants, the polymerization of organized surfactant assemblies, light scattering by liquid surfaces, and vesicles.

  7. Surfactant Therapy of ALI and ARDS

    PubMed Central

    Raghavendran, K; Willson, D; Notter, RH

    2011-01-01

    This article examines exogenous lung surfactant replacement therapy and its utility in mitigating clinical acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). Biophysical research has documented that lung surfactant dysfunction can be reversed or mitigated by increasing surfactant concentration, and multiple studies in animals with ALI/ARDS have shown that respiratory function and pulmonary mechanics in vivo can be improved by exogenous surfactant administration. Exogenous surfactant therapy is a routine intervention in neonatal intensive care, and is life-saving in preventing or treating the neonatal respiratory distress syndrome (NRDS) in premature infants. In applications relevant for lung injury-related respiratory failure and ALI/ARDS, surfactant therapy has been shown to be beneficial in term infants with pneumonia and meconium aspiration lung injury, and in children up to age 21 with direct pulmonary forms of ALI/ARDS. However, extension of exogenous surfactant therapy to adults with respiratory failure and clinical ALI/ARDS remains a challenge. Coverage here reviews clinical studies of surfactant therapy in pediatric and adult patients with ALI/ARDS, particularly focusing on its potential advantages in patients with direct pulmonary forms of these syndromes. Also discussed is the rationale for mechanism-based therapies utilizing exogenous surfactant in combination with agents targeting other aspects of the multifaceted pathophysiology of inflammatory lung injury. Additional factors affecting the efficacy of exogenous surfactant therapy in ALI/ARDS are also described, including the difficulty of effectively delivering surfactants to injured lungs and the existence of activity differences between clinical surfactant drugs. PMID:21742216

  8. Surfactant-enhanced cellulose nanocrystal Pickering emulsions.

    PubMed

    Hu, Zhen; Ballinger, Sarah; Pelton, Robert; Cranston, Emily D

    2015-02-01

    The effect of surfactants on the properties of Pickering emulsions stabilized by cellulose nanocrystals (CNCs) was investigated. Electrophoretic mobility, interfacial tension, confocal microscopy and three-phase contact angle measurements were used to elucidate the interactions between anionic CNCs and cationic alkyl ammonium surfactants didecyldimethylammonium bromide (DMAB) and cetyltrimethylammonium bromide (CTAB). Both surfactants were found to adsorb onto CNCs with concentration-dependent morphology. At low concentrations, individual surfactant molecules adsorbed with alkyl tails pointing outward leading to hydrophobic CNCs. At higher concentrations, above the surfactant's apparent critical micelle concentration, surfactant aggregate morphologies on CNCs were inferred and the hydrophobicity of CNCs decreased. DMAB, which has two alkyl tails, rendered the CNCs more hydrophobic than CTAB which has only a single alkyl tail, at all surfactant concentrations. The change in CNC wettability from surfactant adsorption was directly linked to emulsion properties; adding surfactant increased the emulsion stability, decreased the droplet size, and controlled the internal phase of CNC Pickering emulsions. More specifically, a double transitional phase inversion, from oil-in-water to water-in-oil and back to oil-in-water, was observed for emulsions with CNCs and increasing amounts of DMAB (the more hydrophobic surfactant). With CNCs and CTAB, no phase inversion was induced. This work represents the first report of CNC Pickering emulsions with surfactants as well as the first CNC Pickering emulsions that can be phase inverted. The ability to surface modify CNCs in situ and tailor emulsions by adding surfactants may extend the potential of CNCs to new liquid formulations and extruded/spray-dried materials.

  9. Inhibition of Aflatoxin Production by Surfactants

    PubMed Central

    Rodriguez, Susan B.; Mahoney, Noreen E.

    1994-01-01

    The effect of 12 surfactants on aflatoxin production, growth, and conidial germination by the fungus Aspergillus flavus is reported. Five nonionic surfactants, Triton X-100, Tergitol NP-7, Tergitol NP-10, polyoxyethylene (POE) 10 lauryl ether, and Latron AG-98, reduced aflatoxin production by 96 to 99% at 1% (wt/vol). Colony growth was restricted by the five nonionic surfactants at this concentration. Aflatoxin production was inhibited 31 to 53% by lower concentrations of Triton X-100 (0.001 to 0.0001%) at which colony growth was not affected. Triton X-301, a POE-derived anionic surfactant, had an effect on colony growth and aflatoxin production similar to that of the five POE-derived nonionic surfactants. Sodium dodecyl sulfate (SDS), an anionic surfactant, and dodecyltrimethylammonium bromide, a cationic surfactant, suppressed conidial germination at 1% (wt/vol). SDS had no effect on aflatoxin production or colony growth at 0.001%. The degree of aflatoxin inhibition by a surfactant appears to be a function of the length of the hydrophobic and hydrophilic chains of POE-derived surfactants. Images PMID:16349144

  10. Remediation using trace element humate surfactant

    DOEpatents

    Riddle, Catherine Lynn; Taylor, Steven Cheney; Bruhn, Debra Fox

    2016-08-30

    A method of remediation at a remediation site having one or more undesirable conditions in which one or more soil characteristics, preferably soil pH and/or elemental concentrations, are measured at a remediation site. A trace element humate surfactant composition is prepared comprising a humate solution, element solution and at least one surfactant. The prepared trace element humate surfactant composition is then dispensed onto the remediation site whereby the trace element humate surfactant composition will reduce the amount of undesirable compounds by promoting growth of native species activity. By promoting native species activity, remediation occurs quickly and environmental impact is minimal.

  11. Biophysical inhibition of pulmonary surfactant function by polymeric nanoparticles: role of surfactant protein B and C.

    PubMed

    Beck-Broichsitter, Moritz; Ruppert, Clemens; Schmehl, Thomas; Günther, Andreas; Seeger, Werner

    2014-11-01

    The current study investigated the mechanisms involved in the process of biophysical inhibition of pulmonary surfactant by polymeric nanoparticles (NP). The minimal surface tension of diverse synthetic surfactants was monitored in the presence of bare and surface-decorated (i.e. poloxamer 407) sub-100 nm poly(lactide) NP. Moreover, the influence of NP on surfactant composition (i.e. surfactant protein (SP) content) was studied. Dose-elevations of SP advanced the biophysical activity of the tested surfactant preparation. Surfactant-associated protein C supplemented phospholipid mixtures (PLM-C) were shown to be more susceptible to biophysical inactivation by bare NP than phospholipid mixture supplemented with surfactant protein B (PLM-B) and PLM-B/C. Surfactant function was hindered owing to a drastic depletion of the SP content upon contact with bare NP. By contrast, surface-modified NP were capable of circumventing unwanted surfactant inhibition. Surfactant constitution influences the extent of biophysical inhibition by polymeric NP. Steric shielding of the NP surface minimizes unwanted NP-surfactant interactions, which represents an option for the development of surfactant-compatible nanomedicines. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  12. Chest position and pulmonary deposition of surfactant in surfactant depleted rabbits.

    PubMed Central

    Broadbent, R.; Fok, T. F.; Dolovich, M.; Watts, J.; Coates, G.; Bowen, B.; Kirpalani, H.

    1995-01-01

    AIMS--To investigate the correlation between chest position and the distribution of surfactant in the lungs of surfactant depleted rabbits, to corroborate current guidelines on the intratracheal instillation of exogenous surfactant in newborns. METHODS--Twelve tracheotomised rabbits, depleted of pulmonary surfactant by saline bronchoalveolar lavage, were given intratracheal 99m Technetium labelled Exosurf in three positions (prone, right side down, and left side down) (n = 4 in each group). They were monitored for 10 minutes using dynamic gamma scintigraphy monitoring. Instillation completed, the lateral lying animals were turned to the opposite side to determine whether redistribution of the surfactant had taken place. The amount of radiolabelled surfactant deposited at the peripheral, central, dorsal and ventral parts of the lungs was then estimated by gamma counting of the lung sections at necropsy. RESULTS--Both gamma scintigraphy and gamma counting showed similar rates and total amount of surfactant accumulation in both lungs of the prone animals. In the lateral lying animals surfactant accumulated at a significantly faster rate in the dependent lungs: the amount of surfactant deposition was three to 14-fold that in the raised lungs (p = 0.017; nested ANOVA). Changing the chest position immediately after instillation did not redistribute the surfactant. In all three groups of animals there was no significant difference in deposition between the peripheral, central, ventral and dorsal parts of the lungs. CONCLUSIONS--Pulmonary distribution of intratracheally instilled surfactant is largely determined by gravity, and changing the chest position after instillation does not result in any redistribution of the surfactant. During the instillation of exogenous surfactant to newborn infants, keeping the chest in the horizontal position may therefore result in the most even distribution of the surfactant in the two lungs. Further deposition studies are required to

  13. Hemolysis by surfactants--A review.

    PubMed

    Manaargadoo-Catin, Magalie; Ali-Cherif, Anaïs; Pougnas, Jean-Luc; Perrin, Catherine

    2016-02-01

    An overview of the use of surfactants for erythrocyte lysis and their cell membrane action mechanisms is given. Erythrocyte membrane characteristics and its association with the cell cytoskeleton are presented in order to complete understanding of the erythrocyte membrane distortion. Cell homeostasis disturbances caused by surfactants might induce changes starting from shape modification to cell lysis. Two main mechanisms are hypothesized in literature which are osmotic lysis and lysis by solubilization even if the boundary between them is not clearly defined. Another specific mechanism based on the formation of membrane pores is suggested in the particular case of saponins. The lytic potency of a surfactant is related to its affinity for the membrane and the modification of the lipid membrane curvature. This is to be related to the surfactant shape defined by its hydrophobic and hydrophilic moieties but also by experimental conditions. As a consequence, prediction of the hemolytic potency of a given surfactant is challenging. Several studies are focused on the relation between surfactant erythrolytic potency and their physico-chemical parameters such as the critical micellar concentration (CMC), the hydrophile-lipophile balance (HLB), the surfactant membrane/water partition coefficient (K) or the packing parameter (P). The CMC is one of the most important factors considered even if a lytic activity cut-off effect points out that the only consideration of CMC not enough predictive. The relation K.CMC must be considered in addition to the CMC to predict the surfactant lytic capacity within the same family of non ionic surfactant. Those surfactant structure/lytic activity studies demonstrate the requirement to take into account a combination of physico-chemical parameters to understand and foresee surfactant lytic potency.

  14. Exogenous surfactant in ischemia/reperfusion: effects on endogenous surfactant pools.

    PubMed

    Mühlfeld, Christian; Becker, Laura; Bussinger, Christine; Vollroth, Marcel; Nagib, Ragi; Schaefer, Inga-Marie; Knudsen, Lars; Richter, Joachim; Madershahian, Navid; Wahlers, Thorsten; Wittwer, Thorsten; Ochs, Matthias

    2010-03-01

    Pre-ischemic surfactant treatment attenuates ischemia/reperfusion (I/R) injury. In this study we investigate whether exogenous surfactant acts by influencing endogenous intra-alveolar and intracellular surfactant pools and subtype composition. Rat lungs from control with (C + S) or without (C - S) surfactant treatment and I/R with (I/R + S) or without (I/R - S) surfactant treatment were analyzed. In I/R groups, lungs underwent ischemic storage for 4 hours at 4 degrees C and reperfusion for 60 minutes. The ultrastructure of intra-alveolar and intracellular surfactant forms fixed in their natural localization and microorganization was investigated by light- and electron-microscopic stereology. Only slight differences in alveolar epithelial Type II cell number or volume and lamellar body parameters were observed. Intra-alveolar surfactant volume was significantly enhanced in C + S and I/R + S. I/R increased inactivated surfactant forms (unilamellar vesicles) in untreated [mean (SD): C - S: 26.0% (8.0%) vs I/R - S: 64.8% (5.5%); p < 0.01], but not in surfactant-treated rats [I/R + S: 23.5% (11.5%); p < 0.01 vs I/R - S]. The increase in unilamellar vesicles was closely correlated with intra-alveolar edema and decreased perfusate oxygenation. Attenuation of I/R injury by pre-ischemic exogenous surfactant treatment is mainly based on stabilizing and increasing the active endogenous intra-alveolar surfactant pool.

  15. Innovation in surfactant therapy I: surfactant lavage and surfactant administration by fluid bolus using minimally invasive techniques.

    PubMed

    Dargaville, Peter A

    2012-01-01

    Innovation in the field of exogenous surfactant therapy continues more than two decades after the drug became commercially available. One such innovation, lung lavage using dilute surfactant, has been investigated in both laboratory and clinical settings as a treatment for meconium aspiration syndrome (MAS). Studies in animal models of MAS have affirmed that dilute surfactant lavage can remove meconium from the lung, with resultant improvement in lung function. In human infants both non-randomised studies and two randomised controlled trials have demonstrated a potential benefit of dilute surfactant lavage over standard care. The largest clinical trial, performed by our research group in infants with severe MAS, found that lung lavage using two 15-ml/kg aliquots of dilute surfactant did not reduce the duration of respiratory support, but did appear to reduce the composite outcome of death or need for extracorporeal membrane oxygenation. A further trial of lavage therapy is planned to more precisely define the effect on survival. Innovative approaches to surfactant therapy have also extended to the preterm infant, for whom the more widespread use of continuous positive airway pressure (CPAP) has meant delaying or avoiding administration of surfactant. In an effort to circumvent this problem, less invasive techniques of bolus surfactant therapy have been trialled, including instillation directly into the pharynx, via laryngeal mask and via brief tracheal catheterisation. In a recent clinical trial, instillation of surfactant into the trachea using a flexible feeding tube was found to reduce the need for subsequent intubation. We have developed an alternative method of brief tracheal catheterisation in which surfactant is delivered via a semi-rigid vascular catheter inserted through the vocal cords under direct vision. In studies to date, this technique has been relatively easy to perform, and resulted in rapid improvement in lung function and reduced need for

  16. Surfactant effects on soil aggregate tensile strength

    USDA-ARS?s Scientific Manuscript database

    Little is known regarding a soil aggregate's tensile strength response to surfactants that may be applied to alleviate soil water repellency. Two laboratory investigations were performed to determine surfactant effects on the tensile strength of 1) Ap horizons of nine wettable, agricultural soils co...

  17. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2003-07-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. We have conducted adsorption, phase behavior, interfacial tension (IFT) and wettability studies. Addition of Na{sub 2}CO{sub 3} decreases IFT with a minimum at about 0.2 M. Addition of surfactant decreases IFT further. In the absence of surfactant the minerals are oil-wet after aging with crude oil. Addition of surfactant solution decreases the contact angle to intermediate-wet for many surfactants and water-wet for one surfactant. Addition of Na{sub 2}CO{sub 3} decreases anionic surfactant adsorption on calcite surface. Plans for the next quarter include conducting core adsorption, phase behavior, wettability and mobilization studies.

  18. Measuring surfactant concentration in plating solutions

    DOEpatents

    Bonivert, William D.; Farmer, Joseph C.; Hachman, John T.

    1989-01-01

    An arrangement for measuring the concentration of surfactants in a electrolyte containing metal ions includes applying a DC bias voltage and a modulated voltage to a counter electrode. The phase angle between the modulated voltage and the current response to the modulated voltage at a working electrode is correlated to the surfactant concentration.

  19. Cutaneous Delayed-Type Hypersensitivity to Surfactants.

    PubMed

    Fowler, Joseph F; Shaughnessy, Cristin N; Belsito, Donald V; DeKoven, Joel G; Deleo, Vincent A; Fransway, Anthony F; Maibach, Howard I; Marks, James G; Mathias, C G Toby; Pratt, Melanie; Sasseville, Denis; Taylor, James S; Warshaw, Erin M; Zirwas, Matthew J; Zug, Kathryn A; Lorenz, Douglas

    2015-01-01

    Repeated and prolonged use of surfactants can cause irritant as well as allergic contact dermatitis. This study reports the frequency of positive patch test results to surfactants tested on the North American Contact Dermatitis Group screening series including cocamidopropyl betaine (CAPB), amidoamine (AA), dimethylaminopropylamine (DMAPA), oleamidopropyl dimethylamine (OPD), and cocamide diethanolamide (CDEA), and correlations of positive reactions between CAPB and the other surfactants. This was a retrospective analysis of 10 877 patients patch tested between 2009 and 2014 to the surfactants CAPB, AA, DMAPA, OPD, and CDEA. Frequencies of positive reactions to these surfactants were calculated, and trends of reactivity between the surfactants analyzed. The OPD had the highest rate of positive patch reactions (2.3%) followed by DMAPA (1.7%), and CAPB (1.4%). The AA and CDEA had the lowest rate of positive reactions (0.8%). There was a high degree of overlap in positive patch tests between the surfactants. The CDEA was the least likely to coreact with another surfactant.

  20. Hyaluronan decreases surfactant inactivation in vitro.

    PubMed

    Lu, Karen W; Goerke, Jon; Clements, John A; Taeusch, H William

    2005-02-01

    Hyaluronan (HA) is an anionic polymer and a constituent of alveolar fluid that can bind proteins, phospholipids, and water. Previous studies have established that nonionic polymers improve the surface activity of pulmonary surfactants by decreasing inactivation of surfactant. In this work, we investigate whether HA can also have beneficial effects when added to surfactants. We used a modified pulsating bubble surfactometer to measure mixtures of several commercially available pulmonary surfactants or native calf surfactant with and without serum inactivation. Surface properties such as equilibrium surface tension, minimum and maximum surface tensions on compression and expansion of a surface film, and degree of surface area reduction required to reach a surface tension of 10 mN/m were measured. In the presence of serum, addition of HA dramatically improved the surface activities of all four surfactants and in some cases in the absence of serum as well. These results indicate that HA reduces inactivation of surfactants caused by serum and add evidence that endogenous HAs may interact with alveolar surfactant under normal and abnormal conditions.

  1. Surfactant Adsorption: A Revised Physical Chemistry Lab

    ERIC Educational Resources Information Center

    Bresler, Marc R.; Hagen, John P.

    2008-01-01

    Many physical chemistry lab courses include an experiment in which students measure surface tension as a function of surfactant concentration. In the traditional experiment, the data are fit to the Gibbs isotherm to determine the molar area for the surfactant, and the critical micelle concentration is used to calculate the Gibbs energy of micelle…

  2. Surfactant Adsorption: A Revised Physical Chemistry Lab

    ERIC Educational Resources Information Center

    Bresler, Marc R.; Hagen, John P.

    2008-01-01

    Many physical chemistry lab courses include an experiment in which students measure surface tension as a function of surfactant concentration. In the traditional experiment, the data are fit to the Gibbs isotherm to determine the molar area for the surfactant, and the critical micelle concentration is used to calculate the Gibbs energy of micelle…

  3. Metathesis depolymerization for removable surfactant templates.

    SciTech Connect

    Zifer, Thomas; Wheeler, David Roger; Rahimian, Kamayar; McElhanon, James Ross; Long, Timothy Michael; Jamison, Gregory Marks; Loy, Douglas Anson; Kline, Steven R.; Simmons, Blake Alexander

    2005-03-01

    Current methodologies for the production of meso- and nanoporous materials include the use of a surfactant to produce a self-assembled template around which the material is formed. However, post-production surfactant removal often requires centrifugation, calcination, and/or solvent washing which can damage the initially formed material architecture(s). Surfactants that can be disassembled into easily removable fragments following material preparation would minimize processing damage to the material structure, facilitating formation of templated hybrid architectures. Herein, we describe the design and synthesis of novel cationic and anionic surfactants with regularly spaced unsaturation in their hydrophobic hydrocarbon tails and the first application of ring closing metathesis depolymerization to surfactant degradation resulting in the mild, facile decomposition of these new compounds to produce relatively volatile nonsurface active remnants.

  4. Surfactant screening of diesel-contaminated soil

    SciTech Connect

    Peters, R.W.; Montemagno, C.D.; Shem, L. ); Lewis, B.A. . Dept. of Civil Engineering)

    1990-01-01

    At one installation, approximately 60,000 gal of No. 2 diesel fuel leaked into the subsurface environment, with contamination at depths of 6 to 34 m below the surface. Argonne National Laboratory was contracted to perform treatability studies for site remediation. The treatability studies focused on four separate phases: (1) leachability studies on the various contaminated soil borings, (2) air stripping studies, (3) bioremediation studies, and (4) surfactant screening/surfactant flooding studies. This paper summarizes the fourth phase of the research program in which twenty-one surfactants were screened for possible use to mobilize the organics from the contaminated soil prior to bioremediation. Anionic surfactants resulted in the greatest degree of diesel mobilization. The most promising surfactants will be employed on actual contaminated soil samples obtained from the site. 18 refs., 16 figs., 1 tab.

  5. Solubilisation capacity of Brij surfactants.

    PubMed

    Ribeiro, Maria E N P; de Moura, Carolina L; Vieira, Mariano G S; Gramosa, Nilce V; Chaibundit, Chiraphon; de Mattos, Marcos C; Attwood, David; Yeates, Stephen G; Nixon, S Keith; Ricardo, Nágila M P S

    2012-10-15

    The aim of this study was to investigate the potential of selected Brij non-ionic surfactants for enhancing the solubility of poorly water-soluble drugs. Griseofulvin was selected as a model drug candidate enabling comparisons to be made with the solubilisation capacities of other poly(ethylene oxide)-based copolymers. UV/Vis and (1)H NMR spectroscopies were used to quantify the enhancement of solubility of griseofulvin in 1 wt% aqueous micellar solutions of Brij 78 (C(18)H(37)E(20)), Brij 98 (C(18)H(35)E(20)) and Brij 700 (C(18)H(37)E(100)) (where E represents the OCH(2)CH(2) unit of the poly(ethylene oxide) chain) at 25, 37 and 40 °C. Solubilisation capacities (S(cp) expressed as mg griseofulvin per g Brij) were similar for Brij 78 and 98 (range 6-11 mg g(-1)) but lower for Brij 700 (3-4 mg g(-1)) as would be expected for the surfactant with the higher ethylene oxide content. The drug loading capacity of micelles of Brij 78 was higher than many di- and triblock copolymers with hydrophilic E-blocks specifically designed for enhancement of drug solubility.

  6. Fibrinogen stability under surfactant interaction.

    PubMed

    Hassan, Natalia; Barbosa, Leandro R S; Itri, Rosangela; Ruso, Juan M

    2011-10-01

    Differential scanning calorimetry (DSC), circular dichroism (CD), difference spectroscopy (UV-vis), Raman spectroscopy, and small-angle X-ray scattering (SAXS) measurements have been performed in the present work to provide a quantitatively comprehensive physicochemical description of the complexation between bovine fibrinogen and the sodium perfluorooctanoate, sodium octanoate, and sodium dodecanoate in glycine buffer (pH 8.5). It has been found that sodium octanoate and dodecanoate act as fibrinogen destabilizer. Meanwhile, sodium perfluorooctanoate acts as a structure stabilizer at low molar concentration and as a destabilizer at high molar concentration. Fibrinogen's secondary structure is affected by all three studied surfactants (decrease in α-helix and an increase in β-sheet content) to a different extent. DSC and UV-vis revealed the existence of intermediate states in the thermal unfolding process of fibrinogen. In addition, SAXS data analysis showed that pure fibrinogen adopts a paired-dimer structure in solution. Such a structure is unaltered by sodium octanoate and perfluoroctanoate. However, interaction of sodium dodecanoate with the fibrinogen affects the protein conformation leading to a complex formation. Taken together, all results evidence that both surfactant hydrophobicity and tail length mediate the fibrinogen stability upon interaction. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. The future of exogenous surfactant therapy.

    PubMed

    Willson, Douglas F; Notter, Robert H

    2011-09-01

    Since the identification of surfactant deficiency as the putative cause of the infant respiratory distress syndrome (RDS) by Avery and Mead in 1959, our understanding of the role of pulmonary surfactant in respiratory physiology and the pathophysiology of acute lung injury (ALI) has advanced substantially. Surfactant replacement has become routine for the prevention and treatment of infant RDS and other causes of neonatal lung injury. The role of surfactant in lung injury beyond the neonatal period, however, has proven more complex. Relative surfactant deficiency, dysfunction, and inhibition all contribute to the disturbed physiology seen in ALI and acute respiratory distress syndrome (ARDS). Consequently, exogenous surfactant, while a plausible therapy, has proven to be less effective in ALI/ARDS than in RDS, where simple deficiency is causative. This failure may relate to a number of factors, among them inadequacy of pharmaceutical surfactants, insufficient dosing or drug delivery, poor drug distribution, or simply an inability of the drug to substantially impact the underlying pathophysiology of ALI/ARDS. Both animal and human studies suggest that direct types of ALI (eg, aspiration, pneumonia) may be more responsive to surfactant therapy than indirect lung injury (eg, sepsis, pancreatitis). Animal studies are needed, however, to further clarify aspects of drug composition, timing, delivery, and dosing before additional human trials are pursued, as the results of human trials to date have been inconsistent and largely disappointing. Further study and perhaps the development of more robust pharmaceutical surfactants offer promise that exogenous surfactant will find a place in our armamentarium of treatment of ALI/ARDS in the future.

  8. Exogenous Pulmonary Surfactant as a Vehicle for Antimicrobials: Assessment of Surfactant-Antibacterial Interactions In Vitro

    PubMed Central

    2014-01-01

    Owing to its unique surface-active properties, an exogenous pulmonary surfactant may become a promising drug delivery agent, in particular, acting as a vehicle for antibiotics in topical treatment of pneumonia. The purpose of this study was to assess a mutual influence of natural surfactant preparation and three antibiotics (amikacin, cefepime, and colistimethate sodium) in vitro and to identify appropriate combination(s) for subsequent in vivo investigations of experimental surfactant/antibiotic mixtures. Influence of antibiotics on surface-active properties of exogenous surfactant was assessed using the modified Pattle method. Effects of exogenous surfactant on antibacterial activity of antimicrobials against Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa were evaluated using conventional microbiologic procedures. Addition of amikacin or cefepime to surfactant had no significant influence on surface-active properties of the latter. Obvious reduction of surface-active properties was confirmed for surfactant/colistimethate composition. When suspended with antibiotics, surfactant either had no impact on their antimicrobial activity (amikacin) or exerted mild to moderate influence (reduction of cefepime bactericidal activity and increase of colistimethate bacteriostatic activity against S. aureus and P. aeruginosa). Considering favorable compatibility profile, the surfactant/amikacin combination is advisable for subsequent investigation of joint surfactant/antibacterial therapy in animals with bacterial pneumonia. PMID:24876994

  9. Different effects of surfactant proteins B and C - implications for development of synthetic surfactants.

    PubMed

    Curstedt, Tore; Johansson, Jan

    2010-06-01

    Treatment of premature newborn rabbits with synthetic surfactants containing a surfactant protein C analogue in a simple phospholipid mixture gives similar tidal volumes as treatment with poractant alfa (Curosurf(R)) but ventilation with a positive end-expiratory pressure (PEEP) is needed for this synthetic surfactant to stabilize the alveoli at end-expiration. The effect on lung gas volumes seems to depend on the structure of the peptide since treatment with a synthetic surfactant containing the 21-residue peptide (LysLeu(4))(4)Lys (KL(4)) gives low lung gas volumes in experiments also performed with PEEP. Surfactant preparations containing both surfactant proteins B and C or their analogues prevent alveolar collapse at end-expiration even if ventilated without PEEP. Treatment of premature newborn rabbits with different natural surfactants indicates that both the lipid composition and the proteins are important in order to stabilize the alveoli at end-expiration. Synthetic surfactants containing two peptides may be able to replace natural surfactants within the near future but more trials need to be performed before any conclusion can be drawn about the ideal composition of this new generation of synthetic surfactants. Copyright 2010 S. Karger AG, Basel.

  10. Rhamnolipids--next generation surfactants?

    PubMed

    Müller, Markus Michael; Kügler, Johannes H; Henkel, Marius; Gerlitzki, Melanie; Hörmann, Barbara; Pöhnlein, Martin; Syldatk, Christoph; Hausmann, Rudolf

    2012-12-31

    The demand for bio-based processes and materials in the petrochemical industry has significantly increased during the last decade because of the expected running out of petroleum. This trend can be ascribed to three main causes: (1) the increased use of renewable resources for chemical synthesis of already established product classes, (2) the replacement of chemical synthesis of already established product classes by new biotechnological processes based on renewable resources, and (3) the biotechnological production of new molecules with new features or better performances than already established comparable chemically synthesized products. All three approaches are currently being pursued for surfactant production. Biosurfactants are a very promising and interesting substance class because they are based on renewable resources, sustainable, and biologically degradable. Alkyl polyglycosides are chemically synthesized biosurfactants established on the surfactant market. The first microbiological biosurfactants on the market were sophorolipids. Of all currently known biosurfactants, rhamnolipids have the highest potential for becoming the next generation of biosurfactants introduced on the market. Although the metabolic pathways and genetic regulation of biosynthesis are known qualitatively, the quantitative understanding relevant for bioreactor cultivation is still missing. Additionally, high product titers have been exclusively described with vegetable oil as sole carbon source in combination with Pseudomonas aeruginosa strains. Competitive productivity is still out of reach for heterologous hosts or non-pathogenic natural producer strains. Thus, on the one hand there is a need to gain a deeper understanding of the regulation of rhamnolipid production on process and cellular level during bioreactor cultivations. On the other hand, there is a need for metabolizable renewable substrates, which do not compete with food and feed. A sustainable bioeconomy approach should

  11. DNA compaction by azobenzene-containing surfactant

    SciTech Connect

    Zakrevskyy, Yuriy; Kopyshev, Alexey; Lomadze, Nino; Santer, Svetlana

    2011-08-15

    We report on the interaction of cationic azobenzene-containing surfactant with DNA investigated by absorption and fluorescence spectroscopy, dynamic light scattering, and atomic force microscopy. The properties of the surfactant can be controlled with light by reversible switching of the azobenzene unit, incorporated into the surfactant tail, between a hydrophobic trans (visible irradiation) and a hydrophilic cis (UV irradiation) configuration. The influence of the trans-cis isomerization of the azobenzene on the compaction process of DNA molecules and the role of both isomers in the formation and colloidal stability of DNA-surfactant complexes is discussed. It is shown that the trans isomer plays a major role in the DNA compaction process. The influence of the cis isomer on the DNA coil configuration is rather small. The construction of a phase diagram of the DNA concentration versus surfactant/DNA charge ratio allows distancing between three major phases: colloidally stable and unstable compacted globules, and extended coil conformation. There is a critical concentration of DNA above which the compacted globules can be hindered from aggregation and precipitation by adding an appropriate amount of the surfactant in the trans configuration. This is because of the compensation of hydrophobicity of the globules with an increasing amount of the surfactant. Below the critical DNA concentration, the compacted globules are colloidally stable and can be reversibly transferred with light to an extended coil state.

  12. Improvement of Absorber's Performance by a Surfactant

    NASA Astrophysics Data System (ADS)

    Nishimura, Nobuya; Nomura, Tomohiro; Iyota, Hiroyuki; Kawakami, Ryuichiro

    Effects of an addition of surfactant to a lithium bromide aqueous solution have been investigated experimentally. N-octanol was used as a surfactant. The Marangoni convection occurred at/beneath the solution surface in the very beginning of steam absorption was observed both by a real-time type laser holographic visualization and by temperature measurements with extremely fine gauge thermocouples. Generation and growth of the Marangoni convection were both observed and evaluated quantitatively by the flow visualization. Furthermore, solution's surface temperatures with and without addition of the surfactant were measured minutely. Cell's formation pattern and migration speed at the surface were measured varying the initial surfactant's concentration ranging from 0 to 50000 ppm and the shallow liquid layer thickness ranging from 2 to 5 mm. And spacio-temporal scales of the Marangoni convection were determined. Also solution temperature changes at the surface were compared. Temperature increases when the surfactant was added to its solubility limit became almost double than that case of no surfactant. From these temperature differences, effects of the surfactant on absorber's performances were estimated by a calculation quantitatively with diffusion coefficient as an evaluation value.

  13. Surfactants tailored by the class Actinobacteria

    PubMed Central

    Kügler, Johannes H.; Le Roes-Hill, Marilize; Syldatk, Christoph; Hausmann, Rudolf

    2015-01-01

    Globally the change towards the establishment of a bio-based economy has resulted in an increased need for bio-based applications. This, in turn, has served as a driving force for the discovery and application of novel biosurfactants. The class Actinobacteria represents a vast group of microorganisms with the ability to produce a diverse range of secondary metabolites, including surfactants. Understanding the extensive nature of the biosurfactants produced by actinobacterial strains can assist in finding novel biosurfactants with new potential applications. This review therefore presents a comprehensive overview of the knowledge available on actinobacterial surfactants, the chemical structures that have been completely or partly elucidated, as well as the identity of the biosurfactant-producing strains. Producer strains of not yet elucidated compounds are discussed, as well as the original habitats of all the producer strains, which seems to indicate that biosurfactant production is environmentally driven. Methodology applied in the isolation, purification and structural elucidation of the different types of surface active compounds, as well as surfactant activity tests, are also discussed. Overall, actinobacterial surfactants can be summarized to include the dominantly occurring trehalose-comprising surfactants, other non-trehalose containing glycolipids, lipopeptides and the more rare actinobacterial surfactants. The lack of structural information on a large proportion of actinobacterial surfactants should be considered as a driving force to further explore the abundance and diversity of these compounds. This would allow for a better understanding of actinobacterial surface active compounds and their potential for biotechnological application. PMID:25852670

  14. Fluorescence emission of pyrene in surfactant solutions.

    PubMed

    Piñeiro, Lucas; Novo, Mercedes; Al-Soufi, Wajih

    2015-01-01

    The systematic description of the complex photophysical behaviour of pyrene in surfactant solutions in combination with a quantitative model for the surfactant concentrations reproduces with high accuracy the steady-state and the time resolved fluorescence intensity of pyrene in surfactant solutions near the cmc, both in the monomer and in the excimer emission bands. We present concise model equations that can be used for the analysis of the pyrene fluorescence intensity in order to estimate fundamental parameters of the pyrene-surfactant system, such as the binding equilibrium constant K of pyrene to a given surfactant micelle, the rate constant of excimer formation in micelles, and the equilibrium constant of pyrene-surfactant quenching. The values of the binding equilibrium constant K(TX100)=3300·10³ M⁻¹ and K(SDS)=190·10³ M⁻¹ for Triton X-100 (TX100) and SDS micelles, respectively, show that the partition of pyrene between bulk water and micelles cannot be ignored, even at relatively high surfactant concentrations above the cmc. We apply the model to the determination of the cmc from the pyrene fluorescence intensity, especially from the intensity ratio at two vibronic bands in the monomer emission or from the ratio of excimer to monomer emission intensity. We relate the finite width of the transition region below and above the cmc with the observed changes in the pyrene fluorescence in this region. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Adsorption of Gemini surfactants onto clathrate hydrates.

    PubMed

    Salako, O; Lo, C; Couzis, A; Somasundaran, P; Lee, J W

    2013-12-15

    This work addresses the adsorption of two Gemini surfactants at the cyclopentane (CP) hydrate-water interface. The Gemini surfactants investigated here are Dowfax C6L and Dowfax 2A1 that have two anionic head groups and one hydrophobic tail group. The adsorption of these surfactants was quantified using adsorption isotherms and the adsorption isotherms were determined using liquid-liquid titrations. Even if the Gemini surfactant adsorption isotherms show multi-layer adsorption, they possess the first Langmuir layer with the second adsorption layer only evident in the 2A1 adsorption isotherm. Zeta potentials of CP hydrate particles in the surfactant solution of various concentrations of Dowfax C6L and Dowfax 2A1 were measured to further explain their adsorption behavior at the CP hydrate-water interface. Zeta potentials of alumina particles as a model particle system in different concentrations of sodium dodecyl sulfate (SDS), Dowfax C6L and Dowfax 2A1 were also measured to confirm the configuration of all the surfactants at the interface. The determination of the isotherms and zeta-potentials provides an understanding framework for the adsorption behavior of the two Gemini surfactants at the hydrate-water interface. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Tunable, antibacterial activity of silicone polyether surfactants.

    PubMed

    Khan, Madiha F; Zepeda-Velazquez, Laura; Brook, Michael A

    2015-08-01

    Silicone surfactants are used in a variety of applications, however, limited data is available on the relationship between surfactant structure and biological activity. A series of seven nonionic, silicone polyether surfactants with known structures was tested for in vitro antibacterial activity against Escherichia coli BL21. The compounds varied in their hydrophobic head, comprised of branched silicone structures with 3-10 siloxane linkages and, in two cases, phenyl substitution, and hydrophilic tail of 8-44 poly(ethylene glycol) units. The surfactants were tested at three concentrations: below, at, and above their Critical Micelle Concentrations (CMC) against 5 concentrations of E. coli BL21 in a three-step assay comprised of a 14-24h turbidometric screen, a live-dead stain and viable colony counts. The bacterial concentration had little effect on antibacterial activity. For most of the surfactants, antibacterial activity was higher at concentrations above the CMC. Surfactants with smaller silicone head groups had as much as 4 times the bioactivity of surfactants with larger groups, with the smallest hydrophobe exhibiting potency equivalent to sodium dodecyl sulfate (SDS). Smaller PEG chains were similarly associated with higher potency. These data link lower micelle stability and enhanced permeability of smaller silicone head groups to antibacterial activity. The results demonstrate that simple manipulation of nonionic silicone polyether structure leads to significant changes in antibacterial activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Adsorption of dimeric surfactants in lamellar silicates

    NASA Astrophysics Data System (ADS)

    Balcerzak, Mateusz; Pietralik, Zuzanna; Domka, Ludwik; Skrzypczak, Andrzej; Kozak, Maciej

    2015-12-01

    The adsorption of different types of cationic surfactants in lamellar silicates changes their surface character from hydrophilic to hydrophobic. This study was undertaken to obtain lamellar silicates modified by a series of novel dimeric (gemini) surfactants of different length alkyl chains and to characterise these organophilised materials. Synthetic sodium montmorillonite SOMASIF® ME 100 (M) and enriched bentonite of natural origin (Nanoclay - hydrophilic bentonite®) were organophilised with dimeric (gemini) surfactants (1,1‧-(1,4-butanediyl)bis(alkoxymethyl)imidazolium dichlorides). As a result of surfactant molecule adsorption in interlamellar space, the d-spacing (d001) increased from 0.97 nm (for the anhydrous structure) to 2.04 nm. A Fourier transform infrared spectroscopy (FTIR) analysis of the modified systems reveals bands assigned to the stretching vibrations of the CH2 and CH3 groups and the scissoring vibrations of the NH group from the structure of the dimeric surfactants. Thermogravimetric (TG) and derivative thermogravimetric (DTG) studies imply a four-stage process of surfactant decomposition. Scanning electron microscopy (SEM) images provide information on the influence of dimeric surfactant intercalation into the silicate structures. Particles of the modified systems show a tendency toward the formation of irregularly shaped agglomerates.

  18. A study of surfactant-assisted waterflooding

    SciTech Connect

    Scamehorn, J F; Harwell, J H

    1990-09-01

    In surfactant-assisted waterflooding, a surfactant slug is injected into a reservoir, followed by a brine spacer, followed by second surfactant slug. The charge on the surfactant in the first slug has opposite sign to that in the second slug. When the two slugs mix in the reservoir, a precipitate or coacervate is formed which plugs the permeable region of the reservoir. Subsequently injected water or brine is forced through the low permeability region of the reservoir, increasing sweep efficiency of the waterflood, compared to a waterflood not using surfactants. In this part of the work, two major tasks are performed. First, core floods are performed with oil present to demonstrate the improvement in incremental oil production, as well as permeability modification. Second, a reservoir simulation model will be proposed to further delineate the optimum strategy for implementation of the surfactant-assisted waterflooding, as well as indicate the reservoir types for which it would be most effective. Surfactants utilized were sodium dodecyl sulfate and dodecyl pyridinium chloride. 44 refs., 17 figs., 3 tabs.

  19. Influence of surfactants in forced dynamic dewetting.

    PubMed

    Henrich, Franziska; Fell, Daniela; Truszkowska, Dorota; Weirich, Marcel; Anyfantakis, Manos; Nguyen, Thi-Huong; Wagner, Manfred; Auernhammer, Günter K; Butt, Hans-Jürgen

    2016-09-20

    In this work we show that the forced dynamic dewetting of surfactant solutions depends sensitively on the surfactant concentration. To measure this effect, a hydrophobic rotating cylinder was horizontally half immersed in aqueous surfactant solutions. Dynamic contact angles were measured optically by extrapolating the contour of the meniscus to the contact line. Anionic (sodium 1-decanesulfonate, S-1DeS), cationic (cetyl trimethylammonium bromide, CTAB) and nonionic surfactants (C4E1, C8E3 and C12E5) with critical micelle concentrations (CMCs) spanning four orders of magnitude were used. The receding contact angle in water decreased with increasing velocity. This decrease was strongly enhanced when adding surfactant, even at surfactant concentrations of 10% of the critical micelle concentration. Plots of the receding contact angle-versus-velocity almost superimpose when being plotted at the same relative concentration (concentration/CMC). Thus the rescaled concentration is the dominating property for dynamic dewetting. The charge of the surfactants did not play a role, thus excluding electrostatic effects. The change in contact angle can be interpreted by local surface tension gradients, i.e. Marangoni stresses, close to the three-phase contact line. The decrease of dynamic contact angles with velocity follows two regimes. Despite the existence of Marangoni stresses close to the contact line, for a dewetting velocity above 1-10 mm s(-1) the hydrodynamic theory is able to describe the experimental results for all surfactant concentrations. At slower velocities an additional steep decrease of the contact angle with velocity was observed. Particle tracking velocimetry showed that the flow profiles do not differ with and without surfactant on a scales >100 μm.

  20. Surfactant-associated proteins: structure, function and clinical implications.

    PubMed

    Ketko, Anastasia K; Donn, Steven M

    2014-01-01

    Surfactant replacement therapy is now the standard of care for infants with respiratory distress syndrome. As the understanding of surfactant structure and function has evolved, surfactant-associated proteins are now understood to be essential components of pulmonary surfactant. Their structural and functional diversity detail the complexity of their contributions to normal pulmonary physiology, and deficiency states result in significant pathology. Engineering synthetic surfactant protein constructs has been a major research focus for replacement therapies. This review highlights what is known about surfactant proteins and how this knowledge is pivotal for future advancements in treating respiratory distress syndrome as well as other pulmonary diseases characterized by surfactant deficiency or inactivation.

  1. Interfacial behavior of catanionic surfactants.

    PubMed

    Stocco, Antonio; Carriere, David; Cottat, Maximilien; Langevin, Dominique

    2010-07-06

    We report a dramatic increase in foam stability for catanionic mixtures (myristic acid and cetyl trimethylammonium bromide, CTABr) with respect to that of CTABr solutions. This increase was related to the low surface tension, high surface concentration, and high viscoelastic compression moduli, as measured with rising bubble experiments and ellipsometry. Dialysis of the catanionic mixtures has been used to decrease the concentration of free surfactant ions (CTA(+)). The equilibrium surface tension is reached faster for nondialyzed samples because of the presence of these free ions. As a consequence, the foamability of the dialyzed solutions is lower. Foam coarsening has been studied using multiple light scattering: it is similar for dialyzed and nondialyzed samples and much slower than for pure CTABr foams.

  2. Surfactant-Assisted Coal Liquefaction

    NASA Technical Reports Server (NTRS)

    Hickey, Gregory S.; Sharma, Pramod K.

    1993-01-01

    Obtaining liquid fuels from coal which are economically competitive with those obtained from petroleum based sources is a significant challenge for the researcher as well as the chemical industry. Presently, the economics of coal liquefaction are not favorable because of relatively intense processing conditions (temperatures of 430 degrees C and pressures of 2200 psig), use of a costly catalyst, and a low quality product slate of relatively high boiling fractions. The economics could be made more favorable by achieving adequate coal conversions at less intense processing conditions and improving the product slate. A study has been carried out to examine the effect of a surfactant in reducing particle agglomeration and improving hydrodynamics in the coal liquefaction reactor to increase coal conversions...

  3. Surfactant concentration effects on micellar properties.

    PubMed

    Jusufi, Arben; LeBard, David N; Levine, Benjamin G; Klein, Michael L

    2012-01-26

    A hydrophobic theory is combined with a Debye-Hückel approximation to calculate surfactant micellization properties such as the critical micelle concentration (cmc) and concentration effects. The predictive power of the theory is validated by comparison with experimental data of various ionic surfactant types in presence of salt. The theory is also used to describe micellar properties of surfactant models developed for molecular simulations for which cmc computations become infeasible. The theory allows such computations and helps to evaluate the quality of models used in simulations.

  4. Gemini surfactants from natural amino acids.

    PubMed

    Pérez, Lourdes; Pinazo, Aurora; Pons, Ramon; Infante, Mrosa

    2014-03-01

    In this review, we report the most important contributions in the structure, synthesis, physicochemical (surface adsorption, aggregation and phase behaviour) and biological properties (toxicity, antimicrobial activity and biodegradation) of Gemini natural amino acid-based surfactants, and some potential applications, with an emphasis on the use of these surfactants as non-viral delivery system agents. Gemini surfactants derived from basic (Arg, Lys), neutral (Ser, Ala, Sar), acid (Asp) and sulphur containing amino acids (Cys) as polar head groups, and Geminis with amino acids/peptides in the spacer chain are reviewed.

  5. Surfactant-Templated Mesoporous Metal Oxide Nanowires

    DOE PAGES

    Luo, Hongmei; Lin, Qianglu; Baber, Stacy; ...

    2010-01-01

    We demore » monstrate two approaches to prepare mesoporous metal oxide nanowires by surfactant assembly and nanoconfinement via sol-gel or electrochemical deposition. For example, mesoporous Ta 2 O 5 and zeolite nanowires are prepared by block copolymer Pluronic 123-templated sol-gel method, and mesoporous ZnO nanowires are prepared by electrodeposition in presence of anionic surfactant sodium dodecyl sulfate (SDS) surfactant, in porous membranes. The morphologies of porous nanowires are studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses.« less

  6. How to overcome surfactant dysfunction in meconium aspiration syndrome?

    PubMed

    Mokra, Daniela; Calkovska, Andrea

    2013-06-01

    Surfactant dysfunction in meconium aspiration syndrome (MAS) is caused by meconium components, by plasma proteins leaking through the injured alveolocapillary membrane and by substances originated in meconium-induced inflammation. Surfactant inactivation in MAS may be diminished by several ways. Firstly, aspirated meconium should be removed from the lungs to decrease concentrations of meconium inhibitors coming into the contact with surfactant in the alveolar compartment. Once the endogenous surfactant becomes inactivated, components of surfactant should be substituted by exogenous surfactant at a sufficient dose, and surfactant administration should be repeated, if oxygenation remains compromised. To delay the inactivation by inhibitors, exogenous surfactants may be enriched with surfactant proteins, phospholipids, or other substances such as polymers. Finally, to diminish an adverse action of products of meconium-induced inflammation on both endogenous and exogenously delivered surfactant, anti-inflammatory drugs may be administered. A combined therapeutic approach may result in better outcome in patients with MAS and in lower costs of treatment.

  7. Studies on the electrocapillary curves of anionic surfactants in presence of non-ionic surfactants.

    PubMed

    Bembi, R; Goyal, R N; Malik, W U

    1976-09-01

    Polyoxyethylated non-ionic surfactants such as Tween 20, Tween 40, Nonidet P40 and Nonex 501 have been supposed to be associated with cationic characteristics. Studies on the effect of these surfactants on the electrocapillary curves of the anionic surfactants Aerosol IB, Manaxol OT and sodium lauryl sulphate (SLS), show that the electrocapillary maxima shift towards positive potentials. The order of adsorption of the anionic surfactants is SLS > Manaxol OT > Aerosol IB while the shift in maxima is in the order Aerosol IB ~ Manaxol OT > SLS which confirms association of cationic characteristics with the micelles of these non-ionic surfactants. The magnitude of the shift in electrocapillary maxima is Nonex 501 > Nonidet P40 > Tween 20 > Tween 40 which may be the order of magnitude of the positive charge carried by these non-ionic surfactants.

  8. Less invasive surfactant administration (LISA) - ways to deliver surfactant in spontaneously breathing infants.

    PubMed

    Herting, Egbert

    2013-11-01

    The idea to deliver surfactant to spontaneously breathing premature infants is not new. The spectrum of methods reported reaches from aerosol administration over pharyngeal deposition, the use of laryngeal masks, short term intubation, surfactant administration and rapid extubation (INSURE) to an approach of keeping premature neonates on spontaneous breathing with continuous positive airway pressure support and administering surfactant by laryngoscopy via a small diameter tube. This way of Less Invasive Surfactant Administration (LISA) is in increasing use in the last decade in Germany. More than 1000 babies have been included in clinical studies on LISA by now. A first prospective randomized controlled trial (AMV-trial) demonstrated a significant reduction in the use of mechanical ventilation in LISA patients compared to standard treatment with intratracheal bolus administration of surfactant. Another recent study (Take Care study) indicates, that LISA may even be superior to INSURE. The search for even more "gentle" methods (e.g. nebulization) to deliver surfactant continues.

  9. Studies on Octylphenoxy Surfactants 1

    PubMed Central

    Shafer, Warren E.; Bukovac, Martin J.

    1987-01-01

    Sorption characteristics of a polyethoxy (EO) derivative of octylphenol (OP) were determined for enzymically isolated mature tomato (Lycopersicon esculentum Mill. cv Sprinter) fruit cuticles at 25°C. Sorption was followed using 14C-labeled OP + 9.5EO (Triton X-100). Solution pH (2.2-6.2) did not affect surfactant sorption by tomato fruit cuticular membranes (CM). Surfactant concentration (0.001-1.0%, w/v) had a marked impact on sorption. Sorption equilibrium was reached in 24 hours for OP + 9.5EO concentrations below the critical micelle concentration (CMC), whereas 72 to 120 hours were required to reach equilibrium with concentrations greater than the CMC. Regardless of when equilibrium was attained, initial sorption of OP + 9.5EO occurred rapidly. Partition coefficients (K) of approximately 300 were obtained at pre-CMC concentrations, whereas at the highest concentration (1.0%), K values were approximately 15- to 20-fold lower. Sorption was higher for dewaxed CM (DCM) than for CM. At OP + 9.5EO concentrations below the CMC, the amount (millimoles per kilogram) sorbed by CM and DCM increased sharply as the CMC was reached. After an apparent plateau in the amount sorbed at concentrations immediately below and above the CMC, sorption by CM and DCM increased dramatically with OP + 9.5EO concentrations greater than the CMC (0.5 and 1.0%). In contrast, sorption of OP + 5EO (Triton X-45) by CM and DCM differed from one another at relatively high (0.5 and 1.0%) concentrations, where sorption by DCM increased with increasing concentration, but plateaued for the CM. Sorption of OP + 9.5EO was also related to CM concentration, with an inverse relationship existing between sorption and CM at concentrations less than 3.33 milligrams per milliliter. PMID:16665839

  10. Molecular-thermodynamic theory of micellization of multicomponent surfactant mixtures: 2. pH-sensitive surfactants.

    PubMed

    Goldsipe, Arthur; Blankschtein, Daniel

    2007-05-22

    In article 1 of this series, we developed a molecular-thermodynamic (MT) theory to model the micellization of mixtures containing an arbitrary number of conventional (pH-insensitive) surfactants. In this article, we extend the MT theory to model mixtures containing a pH-sensitive surfactant. The MT theory was validated by examining mixtures containing both a pH-sensitive surfactant and a conventional surfactant, which effectively behave like ternary surfactant mixtures. We first compared the predicted micellar titration data to experimental micellar titration data that we obtained for varying compositions of mixed micelles containing the pH-sensitive surfactant dodecyldimethylamine oxide (C12DAO) mixed with either a cationic surfactant (dodecyltrimethylammonium bromide, C12TAB), a nonionic surfactant (dodecyl octa(ethylene oxide), C12E8), or an anionic surfactant (sodium dodecyl sulfate, SDS) surfactant. The MT theory accurately modeled the titration behavior of C12DAO mixed with C12E8. However, C12DAO was observed to interact more favorably with SDS and with C12TAB than was predicted by the MT theory. We also compared predictions to data from the literature for mixtures of C12DAO and SDS. Although the pH values of solutions with no added acid were modeled with only qualitative accuracy, the MT theory resulted in quantitatively accurate predictions of solution pH for mixtures containing added acid. In addition, the predicted degree of counterion binding yielded a lower bound to the experimentally measured value. Finally, we predicted the critical micelle concentration (cmc) of solutions of two pH-sensitive surfactants, tetradecyldimethylamine oxide (C14DAO) and hexadecyldimethyl betaine (C16Bet), at varying solution pH and surfactant composition. However, at the pH values considered, the pH sensitivity of C16Bet could be neglected, and it was equivalently modeled as a zwitterionic surfactant. The cmc's predicted using the MT theory agreed well with the experimental

  11. Influence of surfactant charge on antimicrobial efficacy of surfactant-stabilized thyme oil nanoemulsions.

    PubMed

    Ziani, Khalid; Chang, Yuhua; McLandsborough, Lynne; McClements, David Julian

    2011-06-08

    Thyme oil-in-water nanoemulsions stabilized by a nonionic surfactant (Tween 80, T80) were prepared as potential antimicrobial delivery systems (pH 4). The nanoemulsions were highly unstable to droplet growth and phase separation, which was attributed to Ostwald ripening due to the relatively high water solubility of thyme oil. Ostwald ripening could be inhibited by incorporating ≥75% of corn oil (a hydrophobic material with a low water solubility) into the nanoemulsion droplets. The electrical characteristics of the droplets in the nanoemulsions were varied by incorporating ionic surfactants with different charges after homogenization: a cationic surfactant (lauric arginate, LAE) or an anionic surfactant (sodium dodecyl sulfate, SDS). The antifungal activity of nanoemulsions containing positive, negative, or neutral thymol droplets was then conducted against four strains of acid-resistant spoilage yeasts: Zygosaccharomyces bailli, Saccharomyces cerevisiae, Brettanomyces bruxellensis, and Brettanomyces naardenensis. The antifungal properties of the three surfactants (T80, LAE, SDS) were also tested in the absence of thymol droplets. Both ionic surfactants showed strong antifungal activity in the absence of thymol droplets, but no antimicrobial activity in their presence. This effect was attributed to partitioning of the antimicrobial surfactant molecules between the oil droplet and microbial surfaces, thereby reducing the effective concentration of active surfactants available to act as antimicrobials. This study shows oil droplets may decrease the efficacy of surfactant-based antimicrobials, which has important consequences for formulating effective antimicrobial agents for utilization in emulsion-based food and beverage products.

  12. Lung Surfactant Levels are Regulated by Ig-Hepta/GPR116 by Monitoring Surfactant Protein D

    PubMed Central

    Fukuzawa, Taku; Ishida, Junji; Kato, Akira; Ichinose, Taro; Ariestanti, Donna Maretta; Takahashi, Tomoya; Ito, Kunitoshi; Abe, Jumpei; Suzuki, Tomohiro; Wakana, Shigeharu; Fukamizu, Akiyoshi; Nakamura, Nobuhiro; Hirose, Shigehisa

    2013-01-01

    Lung surfactant is a complex mixture of lipids and proteins, which is secreted from the alveolar type II epithelial cell and coats the surface of alveoli as a thin layer. It plays a crucial role in the prevention of alveolar collapse through its ability to reduce surface tension. Under normal conditions, surfactant homeostasis is maintained by balancing its release and the uptake by the type II cell for recycling and the internalization by alveolar macrophages for degradation. Little is known about how the surfactant pool is monitored and regulated. Here we show, by an analysis of gene-targeted mice exhibiting massive accumulation of surfactant, that Ig-Hepta/GPR116, an orphan receptor, is expressed on the type II cell and sensing the amount of surfactant by monitoring one of its protein components, surfactant protein D, and its deletion results in a pulmonary alveolar proteinosis and emphysema-like pathology. By a coexpression experiment with Sp-D and the extracellular region of Ig-Hepta/GPR116 followed by immunoprecipitation, we identified Sp-D as the ligand of Ig-Hepta/GPR116. Analyses of surfactant metabolism in Ig-Hepta+/+ and Ig-Hepta−/− mice by using radioactive tracers indicated that the Ig-Hepta/GPR116 signaling system exerts attenuating effects on (i) balanced synthesis of surfactant lipids and proteins and (ii) surfactant secretion, and (iii) a stimulating effect on recycling (uptake) in response to elevated levels of Sp-D in alveolar space. PMID:23922714

  13. Surface film formation in vitro by infant and therapeutic surfactants: role of surfactant protein B.

    PubMed

    Danhaive, Olivier; Chapin, Cheryl; Horneman, Hart; Cogo, Paola E; Ballard, Philip L

    2015-02-01

    Pulmonary surfactant provides an alveolar surface-active film that is critical for normal lung function. Our objective was to determine in vitro film formation properties of therapeutic and infant surfactants and the influence of surfactant protein (SP)-B content. We used a multiwell fluorescent assay measuring maximum phospholipid surface accumulation (Max), phospholipid concentration required for half-maximal film formation (½Max), and time for maximal accumulation (tMax). Among five therapeutic surfactants, calfactant (highest SP-B content) had film formation values similar to natural surfactant, and addition of SP-B to beractant (lowest SP-B) normalized its Max value. Addition of budesonide to calfactant did not adversely affect film formation. In tracheal aspirates of preterm infants with evolving chronic lung disease, SP-B content correlated with ½Max and tMax values, and SP-B supplementation of SP-B-deficient infant surfactant restored normal film formation. Reconstitution of normal surfactant indicated a role for both SP-B and SP-C in film formation. Film formation in vitro differs among therapeutic surfactants and is highly dependent on SP-B content in infant surfactant. The results support a critical role of SP-B for promoting surface film formation.

  14. Efficiency of surfactant-enhanced desorption for contaminated soils depending on the component characteristics of soil-surfactant--PAHs system.

    PubMed

    Zhou, Wenjun; Zhu, Lizhong

    2007-05-01

    The sorption of surfactants onto soils has a significant effect on the performance of surfactant enhanced desorption. In this study, the efficiency of surfactants in enhancing desorption for polycyclic aromatic hydrocarbons (PAHs) contaminated soils relative to water was evaluated with a term of relative efficiency coefficient (REC). Since the sorption of surfactants onto soils, surfactants only enhanced PAH desorption when REC values were larger than 1 and the added surfactant concentration was greater than the corresponding critical enhance desorption concentration (CEDC), which was defined as the corresponding surfactant concentration with REC=1. A model was utilized to describe and predict the REC and CEDC values for PAH desorption. The model and experimental results indicated that the efficiency of surfactants in enhancing PAH desorption showed strong dependence on the soil composition, surfactant structure and PAH properties. These results are of practical interest for the selection of surfactant to optimize soil remediation technologies.

  15. Aggregation of sulfosuccinate surfactants in water

    SciTech Connect

    Magid, L.J.; Daus, K.A.; Butler, P.D.; Quincy, R.B.

    1983-12-22

    The aggregation of sodium di-n-alkyl sulfosuccinates in water (H/sub 2/O and D/sub 2/O at 45/sup 0/C) has been investigated. A self-consistent picture of the dependence of sodium ion binding on surfactant concentration is obtained from emf measurements, conductimetry, and small-angle neutron scattering (SANS) measurements. The concentration dependence of the micellar agregation number for the sulfosuccinates and related double-tailed surfactants depends markedly on surfactant solubility. A sphere-to-disk transition in micellar shape, which might have been expected as a precursor to formation of a lamellar mesophase, was not observed as the surfactant concentration was increased. 8 figures, 2 tables.

  16. Surfactant Activated Dip-Pen Nanolithography

    NASA Astrophysics Data System (ADS)

    Collier, C. Patrick

    2005-03-01

    Direct nanoscale patterning of maleimide-linked biotin on mercaptosilane-functionalized glass substrates using dip-pen nanolithography (DPN) is facilitated by the addition of a small amount of the biocompatible nonionic surfactant Tween-20. A correlation was found between activated ink transfer from the AFM tip when surfactant was included in the ink and an increase in the wettability of the partially hydrophobic silanized substrate. Surfactant concentration represents a new control variable for DPN that complements relative humidity, tip-substrate contact force, scan speed, and temperature. Using surfactants systematically as ink additives expands the possible ink-substrate combinations that can be used for patterning biotin and other molecules. For example, we are currently exploring the possibility of developing nickel/nitrilotriacetic acid (NTA)-maleimide based inks that will bind to mercaptosilanized glass surfaces for the reversible immobilization of biomolecules containing polyhistidine tags.

  17. Spatial and temporal control of surfactant systems.

    PubMed

    Liu, Xiaoyang; Abbott, Nicholas L

    2009-11-01

    This paper reviews some recent progress on approaches leading to spatial and temporal control of surfactant systems. The approaches revolve around the use of redox-active and light-sensitive surfactants. Perspectives are presented on experiments that have realized approaches for active control of interfacial properties of aqueous surfactant systems, reversible control of microstructures and nanostructures formed within bulk solutions, and in situ manipulation of the interactions of surfactants with polymers, DNA and proteins. A particular focus of this review is devoted to studies of amphiphiles that contain the redox-active group ferrocene - reversible control of the oxidation state of ferrocene leads to changes in the charge/hydrophobicity of these amphiphiles, resulting in substantial changes in their self-assembly. Light-sensitive surfactants containing azobenzene, which undergo changes in shape/polarity upon illumination with light, are a second focus of this review. Examples of both redox-active and light-sensitive surfactants that lead to large (>20mN/m) and spatially localized ( approximately mm) changes in surface tensions on a time scale of seconds are presented. Systems that permit reversible transformations of bulk solution nanostructures - such as micelle-to-vesicle transitions or monomer-to-micelle transitions - are also described. The broad potential utility of these emerging classes of amphiphiles are illustrated by the ability to drive changes in functional properties of surfactant systems, such as rheological properties and reversible solubilization of oils, as well as the ability to control interactions of surfactants with biomolecules to modulate their transport into cells.

  18. Process for making surfactant capped nanocrystals

    DOEpatents

    Alivisatos, A Paul; Rockenberger, Joerg

    2002-01-01

    Disclosed is a process for making surfactant capped nanocrystals of transition metal oxides. The process comprises reacting a metal cupferron complex of the formula M Cup, wherein M is a transition metal, and Cup is a cupferron, with a coordinating surfactant, the reaction being conducted at a temperature ranging from about 250 to about 300 C., for a period of time sufficient to complete the reaction.

  19. Nonlinear water waves with soluble surfactant

    NASA Astrophysics Data System (ADS)

    Lapham, Gary; Dowling, David; Schultz, William

    1998-11-01

    The hydrodynamic effects of surfactants have fascinated scientists for generations. This presentation describes an experimental investigation into the influence of a soluble surfactant on nonlinear capillary-gravity waves in the frequency range from 12 to 20 Hz. Waves were generated in a plexiglass wave tank (254 cm long, 30.5 cm wide, and 18 cm deep) with a triangular plunger wave maker. The tank was filled with carbon- and particulate-filtered water into which the soluble surfactant Triton-X-100® was added in known amounts. Wave slope was measured nonintrusively with a digital camera running at 225 fps by monitoring the position of light beams which passed up through the bottom of the tank, out through the wavy surface, and onto a white screen. Wave slope data were reduced to determine wave damping and the frequency content of the wave train. Both were influenced by the presence of the surfactant. Interestingly, a subharmonic wave occurring at one-sixth the paddle-driving frequency was found only when surfactant was present and the paddle was driven at amplitudes high enough to produce nonlinear waves in clean water. Although the origins of this subharmonic wave remain unclear, it appears to be a genuine manifestation of the combined effects of the surfactant and nonlinearity.

  20. Surfactant toxicity identification with a municipal wastewater

    SciTech Connect

    Amato, J.R.; Wayment, D.D.

    1998-12-31

    An acute toxicity identification evaluation following US EPA guidelines was performed with a municipal wastewater to identify effluent components responsible for lethality of larval fathead minnows (Pimephales promelas) and Ceriodaphnia dubia. Ammonia toxicity, also present in the effluent, was not the object of this study. The study was designed to characterize effluent toxicity not due to ammonia. To minimize ammonia toxicity interferences, all Phase 1 testing was performed at pH`s where ammonia toxicity would be negligible. Phase 1 toxicity characterization results indicated surfactants as the class of compounds causing acute non-ammonia toxicity for both test species. A distinct toxicant characteristic, specifically sublation at alkaline pH, was employed to track suspect surfactant loadings in the collection system. Concurrently, effluent surfactant residue testing determined nonionic surfactants were at adequate concentrations and were sufficiently toxic to cause the measured adverse effects. Influent surfactant toxicity was determined to be much less than in the final effluent indicating the treatment process was enhancing surfactant toxicity.

  1. SURFACTANT - POLYMER INTERACTION FOR IMPROVED OIL RECOVERY

    SciTech Connect

    Unknown

    1998-10-01

    The goal of this research is to use the interaction between a surfactant and a polymer for efficient displacement of tertiary oil by improving slug integrity, adsorption and mobility control. Surfactant--polymer flooding has been shown to be highly effective in laboratory-scale linear floods. The focus of this proposal is to design an inexpensive surfactant-polymer mixture that can efficiently recover tertiary oil by avoiding surfactant slug degradation high adsorption and viscous/heterogeneity fingering. A mixture comprising a ''pseudo oil'' with appropriate surfactant and polymer has been selected to study micellar-polymer chemical flooding. The physical properties and phase behavior of this system have been determined. A surfactant-polymer slug has been designed to achieve high efficiency recovery by improving phase behavior and mobility control. Recovery experiments have been performed on linear cores and a quarter 5-spot. The same recovery experiments have been simulated using a commercially available simulator (UTCHEM). Good agreement between experimental data and simulation results has been achieved.

  2. Surfactant mediated polyelectrolyte self-assembly

    SciTech Connect

    Goswami, Monojoy; Borreguero Calvo, Jose M.; Pincus, Phillip A.; Sumpter, Bobby G.

    2015-11-25

    Self-assembly and dynamics of polyelectrolyte (PE) surfactant complex (PES) is investigated using molecular dynamics simulations. The complexation is systematically studied for five different PE backbone charge densities. At a fixed surfactant concentration the PES complexation exhibits pearl-necklace to agglomerated double spherical structures with a PE chain decorating the surfactant micelles. The counterions do not condense on the complex, but are released in the medium with a random distribution. The relaxation dynamics for three different length scales, polymer chain, segmental and monomer, show distinct features of the charge and neutral species; the counterions are fastest followed by the PE chain and surfactants. The surfactant heads and tails have the slowest relaxation due to their restricted movement inside the agglomerated structure. At the shortest length scale, all the charge and neutral species show similar relaxation dynamics confirming Rouse behavior at monomer length scales. Overall, the present study highlights the structure-property relationship for polymer-surfactant complexation. These results will help improve the understanding of PES complex and should aid in the design of better materials for future applications.

  3. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2005-01-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. Imbibition in an originally oil-wet 2D capillary is the fastest in the case of Alf-38 and slowest in the case of DTAB (among the surfactants studied). Force of adhesion studies and contact angle measurements show that greater wettability alteration is possible with these anionic surfactants than the cationic surfactant studied. The water imbibition rate does not increase monotonically with an increase in the surfactant concentration. A numerical model has been developed that fits the rate of imbibition. Plans for the next quarter include conducting simulation and imbibition studies.

  4. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2003-07-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. We have conducted adsorption, phase behavior and wettability studies. Addition of Na{sub 2}CO{sub 3} decreases IFT with a minimum at about 0.2 M. Addition of surfactant decreases IFT further. In the absence of surfactant the minerals are oil wet after aging with crude oil. Addition of surfactant solution decreases the contact angle to intermediate wettability. Addition of Na{sub 2}CO{sub 3} decreases anionic surfactant adsorption on calcite surface. Plans for the next quarter include conducting adsorption, phase behavior and wettability studies.

  5. Surfactant mediated polyelectrolyte self-assembly

    DOE PAGES

    Goswami, Monojoy; Borreguero Calvo, Jose M.; Pincus, Phillip A.; ...

    2015-11-25

    Self-assembly and dynamics of polyelectrolyte (PE) surfactant complex (PES) is investigated using molecular dynamics simulations. The complexation is systematically studied for five different PE backbone charge densities. At a fixed surfactant concentration the PES complexation exhibits pearl-necklace to agglomerated double spherical structures with a PE chain decorating the surfactant micelles. The counterions do not condense on the complex, but are released in the medium with a random distribution. The relaxation dynamics for three different length scales, polymer chain, segmental and monomer, show distinct features of the charge and neutral species; the counterions are fastest followed by the PE chain andmore » surfactants. The surfactant heads and tails have the slowest relaxation due to their restricted movement inside the agglomerated structure. At the shortest length scale, all the charge and neutral species show similar relaxation dynamics confirming Rouse behavior at monomer length scales. Overall, the present study highlights the structure-property relationship for polymer-surfactant complexation. These results will help improve the understanding of PES complex and should aid in the design of better materials for future applications.« less

  6. New synthetic surfactant - how and when?

    PubMed

    Curstedt, Tore; Johansson, Jan

    2006-01-01

    Animal-derived surfactant preparations are very effective in the treatment of premature infants with respiratory distress syndrome but they are expensive to produce and supplies are limited. In order to widen the indications for surfactant treatment there is a need for synthetic preparations, which can be produced in large quantities and at a reasonable cost. However, development of clinically active synthetic surfactants has turned out to be more complicated than initially anticipated. The hydrophobic surfactant proteins, SP-B and SP-C, which are involved in the adsorption of surface-active lipids to the air-liquid interface of the alveoli and increase alveolar stability, are either too big to synthesize, structurally complex or unstable in pure form. A new generation of synthetic surfactants containing simplified phospholipid mixtures and small amounts of peptides replacing the hydrophobic proteins is currently under development and will in the near future be introduced into the market. However, more trials need to be performed before any conclusions can be drawn about the effectiveness of these synthetic surfactants in relation to natural animal-derived preparations. Copyright (c) 2006 S. Karger AG, Basel.

  7. Lung surfactant as a drug delivery system.

    PubMed

    Vermehren, C; Frokjaer, S; Aurstad, T; Hansen, J

    2006-01-03

    Lung surfactant is a complex mixture of mainly phospholipids and proteins. The composition leads to a unique spreading effect of the surfactant as well as spontaneous vesicle formation, which may be favourable characteristics of a drug delivery system for pulmonary delivery. The aim of study was to investigate the potential use of the surfactant extract, HL10 (LeoPharma, DK) as a drug delivery system. Studies involved incorporation of hydrophilic- and amphipathic model drugs (sucrose and acylated peptides) into HL10 and elucidation of the influence of surfactant proteins on the HL10 behaviour. Results showed that HL10 vesicles did not retain sucrose indicating formation of leaky vesicles. Studying the influence of surfactant proteins on release from DPPC-liposomes showed tendencies toward a protein-induced release. Hence, the surfactant proteins may influence the membrane lipid packing and characteristics resulting in leakiness of the membranes. Incorporation of acylated peptides into HL10 depended on the chain length rendering a successful incorporation of the peptide acylated with C14-acyl chains. This study suggests that HL10 may be a promising drug delivery system for the pulmonary delivery of amphipathic drug substances, e.g. therapeutically active acylated peptides (e.g. acylated insulin).

  8. [Deficiency of surfactant protein: Case report].

    PubMed

    Milet, María Beatriz; Mena N, Patricia; Pérez, Héctor I; Espinoza, Tatiana

    Congenital surfactant deficiency is a condition infrequently diagnosed in newborns. A clinical case is presented of surfactant protein B deficiency. A review is performed on the study, treatment and differential diagnosis of surfactant protein deficiencies and infant chronic interstitial lung disease. The case is presented of a term newborn that developed respiratory distress, recurrent pulmonary opacification, and a transient response to the administration of surfactant. Immunohistochemical and genetic studies confirmed the diagnosis of surfactant protein B deficiency. Pulmonary congenital anomalies require a high index of suspicion. Surfactant protein B deficiency is clinically progressive and fatal in the majority of the cases, similar to that of ATP binding cassette subfamily A member 3 (ABCA3) deficiency. Protein C deficiency is insidious and may present with a radiological pulmonary interstitial pattern. Due to the similarity in the histological pattern, genetic studies help to achieve greater certainty in the prognosis and the possibility of providing adequate genetic counselling. Copyright © 2016 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2004-01-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. Anionic surfactants (SS-6656, Alfoterra 35, 38, 63,65,68) have been identified which can change the wettability of the calcite surface to intermediate/water-wet condition as well or better than the cationic surfactant DTAB with a West Texas crude oil in the presence of Na{sub 2}CO{sub 3}. All the carbonate surfaces (Lithographic Limestone, Marble, Dolomite and Calcite) show similar behavior with respect to wettability alteration with surfactant 4-22. Anionic surfactants (5-166, Alfoterra-33 and Alfoterra-38 and Alfoterra-68), which lower the interfacial tension with a West Texas crude oil to very low values (<10{sup -2} nM/m), have also been identified. Plans for the next quarter include conducting wettability, mobilization, and imbibition studies.

  10. DNA interaction with cis- and trans- isomers of photosensitive surfactant

    NASA Astrophysics Data System (ADS)

    Unksov, I. N.; Kasyanenko, N. A.

    2014-12-01

    Interaction between DNA and photosensitive cationic surfactant in a solution is studied. Studies were conducted to examine the impact of the surfactant in its cis- conformation on the size of DNA molecule and also to investigate the phase behavior of the system depending on DNA and surfactant concentration. We conclude that trans- isomer of surfactant requires its smaller concentration to reach the DNA compaction compared with cis- isomer received by UV radiation of solutions. Studies of DNA-surfactant systems were performed by means of spectrophotometry and viscometry. Variation of surfactant concentration enables us to determine the precipitation zone on phase diagram. From the viscosity study it can be indicated that precipitation zone is narrower for UV-radiated surfactant and it shifts to higher surfactant concentration. Also we examine the reversibility of DNA compaction in systems with the surfactant in its trans- form.

  11. Interactions of organic contaminants with mineral-adsorbed surfactants.

    PubMed

    Zhu, Lizhong; Chen, Baoliang; Tao, Shu; Chiou, Cary T

    2003-09-01

    Sorption of organic contaminants (phenol, p-nitrophenol, and naphthalene) to natural solids (soils and bentonite) with and without myristylpyridinium bromide (MPB) cationic surfactant was studied to provide novel insightto interactions of contaminants with the mineral-adsorbed surfactant. Contaminant sorption coefficients with mineral-adsorbed surfactants, Kss, show a strong dependence on surfactant loading in the solid. At low surfactant levels, the Kss values increased with increasing sorbed surfactant mass, reached a maximum, and then decreased with increasing surfactant loading. The Kss values for contaminants were always higher than respective partition coefficients with surfactant micelles (Kmc) and natural organic matter (Koc). At examined MPB concentrations in water the three organic contaminants showed little solubility enhancement by MPB. At low sorbed-surfactant levels, the resulting mineral-adsorbed surfactant via the cation-exchange process appears to form a thin organic film, which effectively "adsorbs" the contaminants, resulting in very high Kss values. At high surfactant levels, the sorbed surfactant on minerals appears to form a bulklike medium that behaves essentially as a partition phase (rather than an adsorptive surface), with the resulting Kss being significantly decreased and less dependent on the MPB loading. The results provide a reference to the use of surfactants for remediation of contaminated soils/sediments or groundwater in engineered surfactant-enhanced washing.

  12. Interactions of organic contaminants with mineral-adsorbed surfactants

    USGS Publications Warehouse

    Zhu, L.; Chen, B.; Tao, S.; Chiou, C.T.

    2003-01-01

    Sorption of organic contaminants (phenol, p-nitrophenol, and naphthalene) to natural solids (soils and bentonite) with and without myristylpyridinium bromide (MPB) cationic surfactant was studied to provide novel insight to interactions of contaminants with the mineral-adsorbed surfactant. Contaminant sorption coefficients with mineral-adsorbed surfactants, Kss, show a strong dependence on surfactant loading in the solid. At low surfactant levels, the Kss values increased with increasing sorbed surfactant mass, reached a maximum, and then decreased with increasing surfactant loading. The Kss values for contaminants were always higher than respective partition coefficients with surfactant micelles (Kmc) and natural organic matter (Koc). At examined MPB concentrations in water the three organic contaminants showed little solubility enhancement by MPB. At low sorbed-surfactant levels, the resulting mineral-adsorbed surfactant via the cation-exchange process appears to form a thin organic film, which effectively "adsorbs" the contaminants, resulting in very high Kss values. At high surfactant levels, the sorbed surfactant on minerals appears to form a bulklike medium that behaves essentially as a partition phase (rather than an adsorptive surface), with the resulting Kss being significantly decreased and less dependent on the MPB loading. The results provide a reference to the use of surfactants for remediation of contaminated soils/sediments or groundwater in engineered surfactant-enhanced washing.

  13. Structure and dynamics of polyelectrolyte surfactant mixtures under conditions of surfactant excess

    NASA Astrophysics Data System (ADS)

    Hoffmann, Ingo; Simon, Miriam; Farago, Bela; Schweins, Ralf; Falus, Peter; Holderer, Olaf; Gradzielski, Michael

    2016-09-01

    Oppositely charged polyelectrolyte (PE) surfactant mixtures can self-assemble into a large variety of mesoscopic structures, so-called polyelectrolyte surfactant complexes (PESCs). These structures directly affect the macroscopic behavior of such solutions. In this study, we investigated mixtures of the cationically charged PE JR 400 and the anionic surfactant SDS with the help of different neutron scattering and fluorescence methods. While an excess of PE charges in semi-dilute solutions causes an increase of viscosity, it has been observed that an excess of surfactant charges reduces the viscosity while precipitation is observed at charge equilibrium. The increase in viscosity had been investigated before and was attributed to the formation of cross links between PE chains. In this publication we focus our attention on the reduction of viscosity which is observed with an excess of surfactant charges. It is found that the PE chains form relatively large and densely packed clusters near the phase boundary on the surfactant rich side, thereby occupying less space and reducing the viscosity. For even higher surfactant concentrations, individual surfactant decorated PE chains are observed and their viscosity is found to be similar to that of the pure PE.

  14. Pseudomonas aeruginosa protease IV degrades surfactant proteins and inhibits surfactant host defense and biophysical functions.

    PubMed

    Malloy, Jaret L; Veldhuizen, Ruud A W; Thibodeaux, Brett A; O'Callaghan, Richard J; Wright, Jo Rae

    2005-02-01

    Pulmonary surfactant has two distinct functions within the lung: reduction of surface tension at the air-liquid interface and participation in innate host defense. Both functions are dependent on surfactant-associated proteins. Pseudomonas aeruginosa is primarily responsible for respiratory dysfunction and death in cystic fibrosis patients and is also a leading pathogen in nosocomial pneumonia. P. aeruginosa secretes a number of proteases that contribute to its virulence. We hypothesized that P. aeruginosa protease IV degrades surfactant proteins and results in a reduction in pulmonary surfactant host defense and biophysical functions. Protease IV was isolated from cultured supernatant of P. aeruginosa by gel chromatography. Incubation of cell-free bronchoalveolar lavage fluid with protease IV resulted in degradation of surfactant proteins (SP)-A, -D, and -B. SPs were degraded in a time- and dose-dependent fashion by protease IV, and degradation was inhibited by the trypsin-like serine protease inhibitor Nalpha-p-tosyl-L-lysine-chloromethyl ketone (TLCK). Degradation by protease IV inhibited SP-A- and SP-D-mediated bacterial aggregation and uptake by macrophages. Surfactant treated with protease IV was unable to reduce surface tension as effectively as untreated surfactant, and this effect was inhibited by TLCK. We speculate that protease IV may be an important contributing factor to the development and propagation of acute lung injury associated with P. aeruginosa via loss of surfactant function within the lung.

  15. Surfactant Delivery into the Lung

    NASA Astrophysics Data System (ADS)

    Grotberg, James; Filoche, Marcel

    2014-11-01

    We have developed a multiscale, compartmentalized model of surfactant and liquid delivery into the lung. Assuming liquid plug propagation, the airway compartment accounts for the plug's volume deposition (coating) on the airway wall, while the bifurcation compartment accounts for plug splitting from the parent airway to the two daughter airways. Generally the split is unequal due to gravity and geometry effects. Both the deposition ratio RD (deposition volume/airway volume), and the splitting ratio, RS, of the daughters volumes are solved independently from one another. Then they are used in a 3D airway network geometry to achieve the distribution of delivery into the lung. The airway geometry is selected for neonatal as well as adult applications, and can be advanced from symmetric, to stochastically asymmetric, to personalized. RD depends primarily on the capillary number, Ca, while RS depends on Ca, the Reynolds number, Re, the Bond number, Bo, the dose volume, VD, and the branch angles. The model predicts the distribution of coating on the airway walls and the remaining plug volume delivered to the alveolar region at the end of the tree. Using this model, we are able to simulate and test various delivery protocols, in order to optimize delivery and improve the respiratory function.

  16. Dilute Surfactant Methods for Carbonate Formations

    SciTech Connect

    Kishore K. Mohanty

    2006-02-01

    There are many fractured carbonate reservoirs in US (and the world) with light oil. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). The process of using dilute anionic surfactants in alkaline solutions has been investigated in this work for oil recovery from fractured oil-wet carbonate reservoirs both experimentally and numerically. This process is a surfactant-aided gravity drainage where surfactant diffuses into the matrix, lowers IFT and contact angle, which decrease capillary pressure and increase oil relative permeability enabling gravity to drain the oil up. Anionic surfactants have been identified which at dilute concentration of 0.05 wt% and optimal salinity can lower the interfacial tension and change the wettability of the calcite surface to intermediate/water-wet condition as well or better than the cationic surfactant DTAB with a West Texas crude oil. The force of adhesion in AFM of oil-wet regions changes after anionic surfactant treatment to values similar to those of water-wet regions. The AFM topography images showed that the oil-wetting material was removed from the surface by the anionic surfactant treatment. Adsorption studies indicate that the extent of adsorption for anionic surfactants on calcite minerals decreases with increase in pH and with decrease in salinity. Surfactant adsorption can be minimized in the presence of Na{sub 2}CO{sub 3}. Laboratory-scale surfactant brine imbibition experiments give high oil recovery (20-42% OOIP in 50 days; up to 60% in 200 days) for initially oil-wet cores through wettability alteration and IFT reduction. Small (<10%) initial gas saturation does not affect significantly the rate of oil recovery in the imbibition process, but larger gas saturation decreases the oil recovery rate. As the core permeability decreases, the rate of oil recovery reduces

  17. Microemulsion-based lycopene extraction: Effect of surfactants, co-surfactants and pretreatments.

    PubMed

    Amiri-Rigi, Atefeh; Abbasi, Soleiman

    2016-04-15

    Lycopene is a potent antioxidant that has received extensive attention recently. Due to the challenges encountered with current methods of lycopene extraction using hazardous solvents, industry calls for a greener, safer and more efficient process. The main purpose of present study was application of microemulsion technique to extract lycopene from tomato pomace. In this respect, the effect of eight different surfactants, four different co-surfactants, and ultrasound and enzyme pretreatments on lycopene extraction efficiency was examined. Experimental results revealed that application of combined ultrasound and enzyme pretreatments, saponin as a natural surfactant, and glycerol as a co-surfactant, in the bicontinuous region of microemulsion was the optimal experimental conditions resulting in a microemulsion containing 409.68±0.68 μg/glycopene. The high lycopene concentration achieved, indicates that microemulsion technique, using a low-cost natural surfactant could be promising for a simple and safe separation of lycopene from tomato pomace and possibly from tomato industrial wastes.

  18. Selection of surfactant in remediation of DDT-contaminated soil by comparison of surfactant effectiveness.

    PubMed

    Guo, Ping; Chen, Weiwei; Li, Yueming; Chen, Tao; Li, Linhui; Wang, Guanzhu

    2014-01-01

    With an aim to select the most appropriate surfactant for remediation of DDT-contaminated soil, the performance of nonionic surfactants Tween80, TX-100, and Brij35 and one anionic surfactant sodium dodecyl benzene sulfonate (SDBS) in enhancement of DDT water solubility and desorption of DDT from contaminated soil and their adsorption onto soil and ecotoxicities were investigated in this study. Tween80 had the highest solubilizing and soil-washing ability for DDT among the four experimental surfactants. The adsorption loss of surfactants onto soil followed the order of TX-100 > Tween80 > Brij35 > SDBS. The ecotoxicity of Tween80 to ryegrass (Lolium perenne L.) was lowest. The overall performance considering about the above four aspects suggested that Tween80 should be selected for the remediation of DDT-contaminated soil, because Tween80 had the greatest solubilizing and soil-washing ability for DDT, less adsorption loss onto soil, and the lowest ecotoxicity in this experiment.

  19. A Review on Progress in QSPR Studies for Surfactants

    PubMed Central

    Hu, Jiwei; Zhang, Xiaoyi; Wang, Zhengwu

    2010-01-01

    This paper presents a review on recent progress in quantitative structure-property relationship (QSPR) studies of surfactants and applications of various molecular descriptors. QSPR studies on critical micelle concentration (cmc) and surface tension (γ) of surfactants are introduced. Studies on charge distribution in ionic surfactants by quantum chemical calculations and its effects on the structures and properties of the colloids of surfactants are also reviewed. The trends of QSPR studies on cloud point (for nonionic surfactants), biodegradation potential and some other properties of surfactants are evaluated. PMID:20479997

  20. Surfactant-enhanced low-pH alkaline flooding

    SciTech Connect

    Peru, D.A. and Co., Columbia, MD . Research Div.); Lorenz, P.B. )

    1990-08-01

    This paper reports sodium bicarbonate investigated as a potential alkaline agent in surfactant-enhanced alkaline flooding because it has very little tendency to dissolve silicate minerals. In experiments performed with Wilmington, CA, crude oil and three types of surfactants, the bicarbonate/surfactant combination caused a marked lowering of interfacial tension (IFT). Bicarbonate protected the surfactant against divalent cations and reduced adsorption of surfactant and polymer on various minerals. Coreflood test confirm that sodium bicarbonate plus surfactant can be an effective alternative to the high-pH flooding process.

  1. Growing Characteristics of Fine Ice Particles in Surfactant Solution

    NASA Astrophysics Data System (ADS)

    Suzuki, Hiroshi; Nakayama, Kosuke; Komoda, Yoshiyuki; Usui, Hiromoto; Okada, Kazuto; Fujisawa, Ryo

    Time variation characteristics of ice particles in a surfactant solution have been investigated. The effect of surfactants on corrosion characteristics was also studied. The results were compared with those treated with poly(vinyl alcohol). From the results, the present surfactant, cetyl dimethyl betaine was not found to be effective on preventing Ostward ripening of ice particles as poly(vinyl alcohol) showed. Then, it was concluded some effective technology has to be installed with surfactants when this surfactant treatment is realized. On the corrosion characteristics, it was found that the present surfactant shows the same level as tap water.

  2. The use of surfactant in lung transplantation.

    PubMed

    Amital, Anat; Shitrit, David; Raviv, Yael; Saute, Milton; Medalion, Benjamin; Bakal, Llana; Kramer, Mordechai R

    2008-12-15

    Lung transplantation impairs surfactant activity, which may contribute to primary graft dysfunction (PGD). Prompted by studies in animals and a few reports in humans, this study sought to determine if the administration of surfactant during transplantation serves as an effective preventive measure. An open, randomized, controlled prospective design was used. Forty-two patients scheduled for single (n=38) or double (n=4) lung transplantation at a major tertiary medical center were randomly assigned to receive, or not, intraoperative surfactant treatment. In the treated group, bovine surfactant was administered at a dose of 20 mg phospholipids/kg through bronchoscope after the establishment of bronchial anastomosis. The groups were compared for oxygenation (PaO2/FiO2), chest X-ray findings, PGD grade, and outcome. Compared with the untreated group, the patients who received surfactant were characterized by better postoperative oxygenation mean PaO2/FiO2 (418.8+/-123.8 vs. 277.9+/-165 mm Hg, P=0.004), better chest radiograph score, a lower PGD grade (0.66 vs. 1.86, P=0.005), fewer cases of severe PGD (1 patient vs. 12, P<0.05), earlier extubation (by 2.2 hr; 95% CI 1.1-4.3 hr, P=0.027), shorter intensive care unit stay (by 2.3 days; 95% CI 1.47-3.74 days, P=0.001), and better vital capacity at 1 month (61% vs. 50%, P=0.022). One treated and 2 untreated patients died during the first postoperative month. Surfactant instillation during lung transplantation improves oxygenation, prevents PGD, shortens intubation time, and enhances early posttransplantation recovery. Further, larger studies are needed to assess whether surfactant should be used routinely in lung transplantation.

  3. Surfactants and the Mechanics of Respiration

    NASA Astrophysics Data System (ADS)

    Jbaily, Abdulrahman; Szeri, Andrew J.

    2016-11-01

    Alveoli are small sacs found at the end of terminal bronchioles in human lungs with a mean diameter of 200 μm. A thin layer of fluid (hypophase) coats the inner face of an alveolus and is in contact with the air in the lungs. The thickness of this layer varies among alveoli, but is in the range of 0.1 to 0.5 μm for many portions of the alveolar network. The interfacial tension σ at the air-hypophase interface tends to favor collapse of the alveolus, and resists its expansion during inhalation. Type II alveolar cells synthesize and secrete a mixture of phospholipids and proteins called pulmonary surfactant. These surfactant molecules adsorb to the interface causing σ of water at body temperature is 70 mN/m and falls to an equilibrium value of 25 mN/m when surfactants are present. Also, in a dynamic sense, it is known that σ is reduced to near 0 during exhalation when the surfactant film compresses. In this work, the authors develop a mechanical and transport model of the alveolus to study the effect of surfactants on various aspects of respiration. The model is composed of three principal parts: (i) air movement into and out of the alveolus; (ii) a balance of linear momentum across the two-layered membrane of the alveolus (hypophase and elastic wall); and (iii) a pulmonary surfactant transport problem in the hypophase. The goal is to evaluate the influence of pulmonary surfactant on respiratory mechanics.

  4. Influence of clay mineral structure and surfactant nature on the adsorption capacity of surfactants by clays.

    PubMed

    Sánchez-Martín, M J; Dorado, M C; del Hoyo, C; Rodríguez-Cruz, M S

    2008-01-15

    Adsorption of three surfactants of different nature, Triton X-100 (TX100) (non-ionic), sodium dodecylsulphate (SDS) (anionic) and octadecyltrimethylammonium bromide (ODTMA) (cationic) by four layered (montmorillonite, illite, muscovite and kaolinite) and two non-layered (sepiolite and palygorskite) clay minerals was studied. The objective was to improve the understanding of surfactant behaviour in soils for the possible use of these compounds in remediation technologies of contaminated soils by toxic organic compounds. Adsorption isotherms were obtained using surfactant concentrations higher and lower than the critical micelle concentration (cmc). These isotherms showed different adsorption stages of the surfactants by the clay minerals, and were classified in different subgroups of the L-, S- or H-types. An increase in the adsorption of SDS and ODTMA by all clay minerals is observed up to the cmc of the surfactant in the equilibrium solution is reached. However, there was further TX100 adsorption when the equilibrium concentration was well above the cmc. Adsorption constants from Langmuir and Freundlich equations (TX100 and ODTMA) or Freundlich equation (SDS) were used to compare adsorption of different surfactants by clay minerals studied. These constants indicated the surfactant adsorption by clay minerals followed this order ODTMA>TX100>SDS. The adsorption of TX100 and ODTMA was higher by montmorillonite and illite, and the adsorption of SDS was found to be higher by kaolinite and sepiolite. Results obtained show the influence of clay mineral structure and surfactant nature on the adsorption capacity of surfactants by clays, and they indicate the interest to consider the soil mineralogical composition when one surfactant have to be selected in order to establish more efficient strategies for the remediation of soils and water contaminated by toxic organic pollutants.

  5. Adsorption and adsolubilization of polymerizable surfactants on aluminum oxide.

    PubMed

    Attaphong, Chodchanok; Asnachinda, Emma; Charoensaeng, Ampira; Sabatini, David A; Khaodhiar, Sutha

    2010-04-01

    Surfactant-based adsorption processes have been widely investigated for environmental applications. A major problem facing surfactant-modified adsorbents is surfactant loss from the adsorbent due to loss of monomers from solution and subsequent surfactant desorption. For this study, a bilayer of anionic polymerizable surfactant (Hitenol BC 05, Hitenol BC 10 and Hitenol BC 20) and non-polymerizable surfactant (Hitenol N 08) was adsorbed onto alumina. The results of adsorption studies showed that as the number of ethylene oxide (EO) groups of the surfactants increased, the area per molecule increased and the maximum adsorption decreased. The lowest maximum adsorption onto alumina was for Hitenol BC 20 (20 EO groups) corresponding to 0.08 mmol/g or 0.34 molecule/nm(2) while the highest level of adsorption was 0.30 mmol/g or 1.28 molecule/nm(2) for Hitenol BC 05 (5 EO groups). This variation in adsorption was attributed to the increased bulkiness of the head group with increasing number of EO groups. Relative to the adsolubilization capacity of organic solutes, ethylcyclohexane adsolubilizes more than styrene. Styrene and ethylcyclohexane adsolubilization were both independent of the number of EO groups of the surfactant. For surfactant desorption studies, the polymerization of polymerizable surfactants increased the stability of surfactants adsorbed onto the alumina surface and reduced surfactant desorption from the alumina surface. These results provide useful information on surfactant-based surface modification to enhance contaminant remediation and industrial applications.

  6. Oil recovery performances of surfactant solutions by capillary imbibition.

    PubMed

    Babadagli, Tayfun; Boluk, Yaman

    2005-02-01

    Critical parameters playing a role in oil recovery by capillary imbibition of surfactant solutions were studied. Experiments conducted on sandstone and carbonate samples using different oil and surfactant types were evaluated for surfactant selection. In this evaluation interfacial tension (IFT), surfactant type, solubility characteristics of surfactants, rock type, initial water (pre-wet rock), and surfactant concentration were considered. In addition to these, a new technique was adopted to facilitate the surfactant screening process. This technique is based on assigning inorganic and organic property values and plotting organic conception diagrams (OCD) for surfactants. OCD defines the property of a compound in terms of physical chemistry in such a way that the property that depends much on the van der Waals force is called "organic" and the one that depends much on electric affinity is called "inorganic." Correlations between the capillary imbibition recovery performance and the properties of surfactant and oil (organic value (OV), inorganic value (IV), and IFT of surfactant solutions, oil viscosity, and surfactant type) were obtained. These correlations are expected to be useful in selecting the proper surfactant for improved oil recovery as well as identifying the effects of surfactant properties on the capillary imbibition performance.

  7. Surface shear inviscidity of soluble surfactants

    PubMed Central

    Zell, Zachary A.; Nowbahar, Arash; Mansard, Vincent; Leal, L. Gary; Deshmukh, Suraj S.; Mecca, Jodi M.; Tucker, Christopher J.; Squires, Todd M.

    2014-01-01

    Foam and emulsion stability has long been believed to correlate with the surface shear viscosity of the surfactant used to stabilize them. Many subtleties arise in interpreting surface shear viscosity measurements, however, and correlations do not necessarily indicate causation. Using a sensitive technique designed to excite purely surface shear deformations, we make the most sensitive and precise measurements to date of the surface shear viscosity of a variety of soluble surfactants, focusing on SDS in particular. Our measurements reveal the surface shear viscosity of SDS to be below the sensitivity limit of our technique, giving an upper bound of order 0.01 μN·s/m. This conflicts directly with almost all previous studies, which reported values up to 103–104 times higher. Multiple control and complementary measurements confirm this result, including direct visualization of monolayer deformation, for SDS and a wide variety of soluble polymeric, ionic, and nonionic surfactants of high- and low-foaming character. No soluble, small-molecule surfactant was found to have a measurable surface shear viscosity, which seriously undermines most support for any correlation between foam stability and surface shear rheology of soluble surfactants. PMID:24563383

  8. Surfactant remediation of diesel fuel polluted soil.

    PubMed

    Khalladi, Razika; Benhabiles, Ouassila; Bentahar, Fatiha; Moulai-Mostefa, Naji

    2009-05-30

    Soil contamination with petroleum hydrocarbons has caused critical environmental and health defects and increasing attention has been paid for developing innovative technology for cleaning up this contamination. In this work, the washing process of a soil column by ionic surfactant sodium dodecyl sulfate (SDS) was investigated. Water flow rate and the contamination duration (age) have been studied. The performance of water in the removal of diesel fuel was found to be non-negligible, while water contributed by 24.7% in the global elimination of n-alkanes. The effect of SDS is significant beyond a concentration of 8mM. After 4h of treatment with surfactant solution, the diesel soil content remains constant, which shows the existence of a necessary contact time needed to the surfactant to be efficient. The soil washing process at a rate of 3.2 mL/min has removed 97% of the diesel fuel. This surfactant soil remediation process was shown to be governed by the first-order kinetics. These results are of practical interest in developing effective surfactant remediation technology of diesel fuel contaminated soils.

  9. Rheology of Natural Lung Surfactant Films

    NASA Astrophysics Data System (ADS)

    Alonso, Coralie; Waring, Alan; Zsadzinski, Joseph

    2004-03-01

    The lung surfactant (LS) is a lipoprotein mixture lining the inside of the pulmonary alveoli which has the ability to lower the surface tension of the air-liquid hypophase interface to value near zero thus reducing the work of breathing and which also prevents the alveolar collapse. A lack or malfunction of lung surfactant, as it is often the case for premature infants, leads to respiratory distress syndrome. RDS can be treated by supplying replacement LS to the infants and several medications derived from natural sources, are now widely used. The lung surfactant is adsorbed at the air-liquid interface and is subjected to incessant compression expansion cycles therefore Langmuir monolayers provide a suitable model to investigate the physical properties of lung surfactant films. Using a magnetic needle rheometer, we measured the shear viscosity of natural lung surfactant spread at the air-liquid interface upon compression and expansion cycles for three different formulations. The shear viscosity of Survanta changes by orders of magnitude along one cycle while for Curosurf samples it changes only slightly and for Infasurf films it remains constant. These different behaviors can be explained by differences in composition between the three formulations leading to different organizations on the molecular scale.

  10. 2-DE using hemi-fluorinated surfactants.

    PubMed

    Starita-Geribaldi, Mireille; Thebault, Pascal; Taffin de Givenchy, Elisabeth; Guittard, Frederic; Geribaldi, Serge

    2007-07-01

    The synthesis of hemi-fluorinated zwitterionic surfactants was realized and assessed for 2-DE, a powerful separation method for proteomic analysis. These new fluorinated amidosulfobetaine (FASB-p,m) were compared to their hydrocarbon counterparts amidosulfobetaine (ASB-n) characterized by a hydrophilic polar head, a hydrophobic and lipophilic tail, and an amido group as connector. The tail of these FASB surfactants was in part fluorinated resulting in the modulation of its lipophilicity (or oleophobicity). Their effect on the red blood cell (RBC) membrane showed a specific solubilization depending on the length of the hydrophobic part. A large number of polypeptide spots appeared in the 2-DE patterns by using FASB-p,m. The oleophobic character of these surfactants was confirmed by the fact that Band 3, a highly hydrophobic transmembrane protein, was not solubilized by these fluorinated structures. The corresponding pellet was very rich in Band 3 and could then be solubilized by using a strong detergent such as amidosulfobetaine with an alkyl tail containing 14 carbon atoms (ASB-14). Thus, these hemi-fluorinated surfactants appeared as powerful tools when used at the first step of a two-step solubilization strategy using a hydrocarbon homologous surfactant in the second step.

  11. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2004-10-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. Simulation studies indicate that both wettability alteration and gravity-driven flow play significant role in oil recovery from fractured carbonates. Anionic surfactants (Alfoterra 35, 38) recover about 55% of the oil in about 150 days by imbibition driven by wettability alteration and low tension in the core-scale. Anionic surfactant, Alfoterra-68, recovers about 40% of the oil by lower tension aided gravity-driven imbibition in the core-scale. Cationic surfactant, DTAB recovers about 35% of the oil. Plans for the next quarter include conducting simulation and imbibition studies.

  12. Dilute Surfactant Methods for Carbonate Formations

    SciTech Connect

    Kishore K. Mohanty

    2004-03-31

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. Anionic surfactants (Alfoterra 35, 38) recover more than 40% of the oil in about 50 days by imbibition driven by wettability alteration in the core-scale. Anionic surfactant, Alfoterra-68, recovers about 28% of the oil by lower tension aided gravity-driven imbibition in the core-scale. Residual oil saturation showed little capillary number dependence between 10{sup -5} and 10{sup -2}. Wettability alteration increases as the number of ethoxy groups increases in ethoxy sulfate surfactants. Plans for the next quarter include conducting mobilization, and imbibition studies.

  13. Electrical surface potential of pulmonary surfactant.

    PubMed

    Leonenko, Zoya; Rodenstein, Mathias; Döhner, Jana; Eng, Lukas M; Amrein, Matthias

    2006-11-21

    Pulmonary surfactant is a mixed lipid protein substance of defined composition that self-assembles at the air-lung interface into a molecular film and thus reduces the interfacial tension to close to zero. A very low surface tension is required for maintaining the alveolar structure. The pulmonary surfactant film is also the first barrier for airborne particles entering the lung upon breathing. We explored by frequency modulation Kelvin probe force microscopy (FM-KPFM) the structure and local electrical surface potential of bovine lipid extract surfactant (BLES) films. BLES is a clinically used surfactant replacement and here served as a realistic model surfactant system. The films were distinguished by a pattern of molecular monolayer areas, separated by patches of lipid bilayer stacks. The stacks were at positive electrical potential with respect to the surrounding monolayer areas. We propose a particular molecular arrangement of the lipids and proteins in the film to explain the topographic and surface potential maps. We also discuss how this locally variable surface potential may influence the retention of charged or polar airborne particles in the lung.

  14. Analysis of supercooling activities of surfactants.

    PubMed

    Kuwabara, Chikako; Terauchi, Ryuji; Tochigi, Hiroshi; Takaoka, Hisao; Arakawa, Keita; Fujikawa, Seizo

    2014-08-01

    Supercooling-promoting activities (SCAs) of 25 kinds of surfactants including non-ionic, anionic, cationic and amphoteric types were examined in solutions (buffered Milli-Q water, BMQW) containing the ice nucleation bacterium (INB) Erwinia ananas, silver iodide (AgI) or BMQW alone, which unintentionally contained unidentified ice nucleators, by a droplet freezing assay. Most of the surfactants exhibited SCA in solutions containing AgI but not in solutions containing the INB E. ananas or BMQW alone. SCAs of many surfactants in solutions containing AgI were very high compared with those of previously reported supercooling-promoting substances. Cationic surfactants, hexadecyltrimethylammonium bromide (C16TAB) and hexadecyltrimethylammonium chloride (C16TAC), at concentrations of 0.01% (w/v) exhibited SCA of 11.8 °C, which is the highest SCA so far reported. These surfactants also showed high SCAs at very low concentrations in solutions containing AgI. C16TAB exhibited SCA of 5.7 °C at a concentration of 0.0005% (w/v).

  15. Surfactants with colloids: adsorption or absorption?

    PubMed

    Smith, Gregory N; Grillo, Isabelle; Rogers, Sarah E; Eastoe, Julian

    2015-07-01

    The interaction of Aerosol OT (AOT) surfactant with systems of model colloids in nonaqueous solvents (water-in-oil microemulsions, surfactant-stabilized silica organosols, and sterically-stabilized PMMA latexes) is expected to be system specific. Two limiting cases are expected: adsorption, with surfactant located at the particle surfaces, or absorption, with surfactant incorporated into the particle cores. Two approaches have been used to determine how AOT is distributed in the colloidal systems. The stability of the colloids in different alkanes (heptane to hexadecane, including mixtures) has been studied to determine any effects on the colloid surfaces. Contrast-variation small-angle neutron scattering (SANS) measurements of the colloid cores and of AOT-colloid mixtures in colloid-matched solvent have also been performed. Normalization to account for the different scattering intensities and different particle radii have been used to enable a system-independent comparison. AOT in water-in-oil microemulsions and surfactant-stabilized silica organosols is determined to be adsorbed, whereas, surprisingly, AOT in sterically-stabilized PMMA latexes is found to be absorbed. Possible origins of these differences are discussed. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Foaming behaviour of polymer surfactant solutions

    NASA Astrophysics Data System (ADS)

    Cervantes-Martínez, Alfredo; Maldonado, Amir

    2007-06-01

    We study the effect of a non-ionic amphiphilic polymer (PEG-100 stearate also called Myrj 59) on the foaming behaviour of aqueous solutions of an anionic surfactant (sodium dodecyl sulfate or SDS). The SDS concentration was kept fixed while the Myrj 59 concentration was varied. Measurements of foamability, surface tension and electrical conductivity were carried out. The results show two opposite effects depending on the polymer concentration: foamability is higher when the Myrj 59 concentration is low; however, it decreases considerably when the polymer concentration is increased. This behaviour is due to the polymer adsorption at the air/liquid interface at lower polymer concentrations, and to the formation of a polymer-surfactant complex in the bulk at higher concentrations. The results are confirmed by surface tension and electrical conductivity measurements, which are interpreted in terms of the microstructure of the polymer-surfactant solutions. The observed behaviour is due to the amphiphilic nature of the studied polymer. The increased hydrophobicity of Myrj 59, compared to that of water-soluble polymers like PEG or PEO, increases its 'reactivity' towards SDS, i.e. the strength of its interaction with this anionic surfactant. Our results show that hydrophobically modified polymers have potential applications as additives in order to control the foaming properties of surfactant solutions.

  17. SURFACTANT - POLYMER INTERACTION FOR IMPROVED OIL RECOVERY

    SciTech Connect

    Unknown

    1997-09-01

    The goal of this research is to use the interaction between a surfactant and a polymer for efficient displacement of tertiary oil by improving slug integrity, adsorption and mobility control. Surfactant--polymer flooding has been shown to be highly effective in laboratory-scale linear floods. The focus of this proposal is to design an inexpensive surfactant-polymer mixture that can efficiently recover tertiary oil by avoiding surfactant slug degradation, high adsorption and viscous/heterogeneity fingering. This report contains data concerning selection of appropriate fluids for use in laboratory experiments and numerical simulations. A mixture comprising a ''pseudo oil'' with appropriate surfactant and polymer is proposed. The properties of this system has been determined. The experimental set-up has been conditioned for use and experiments involving the aforementioned system have already started. A commercial simulator has been acquired for use in reproducing the experiments. A graduate student has been trained in its use. Linear stability analysis equations have been developed and phase maps for one and two-dimensions are currently computed.

  18. Surfactant apoprotein in nonmalignant pulmonary disorders.

    PubMed Central

    Singh, G.; Katyal, S. L.

    1980-01-01

    Formalin-fixed, paraffin-embedded lungs exhibiting a variety of nonmalignant disorders were studied by immunoperoxidase staining using antibodies specific for surfactant apoprotein, IgG, IgM, IgA, albumin, fibrinogen, and lysozyme. Normal Type II pneumocytes showed staining for surfactant apoprotein in the perinuclear region only. The extent and intensity of staining for apoprotein was markedly increased in reactive Type II pneumocytes. This increase appeared to be a nonspecific reaction to lung injury. The intra-alveolar material in pulmonary alveolar proteinosis stained intensely for surfactant apoprotein, indicating that the accumulated proteinaceous material contained pulmonary surfactant. Type II pneumocytes in pulmonary alveolar proteinosis exhibited hyperplasia as well as hypertrophy. The few macrophages in lung affected by pulmonary alveolar proteinosis stained intensely for lysozyme. The excessive intraalveolar accumulation of proteinaceous material in pulmonary alveolar proteinosis may be the result of both an over-production as well as a deficient removal of pulmonary surfactant. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 p[57]-a PMID:7004201

  19. Surfactant effects on SF6 hydrate formation.

    PubMed

    Lee, Bo Ram; Lee, Ju Dong; Lee, Hyun Ju; Ryu, Young Bok; Lee, Man Sig; Kim, Young Seok; Englezos, Peter; Kim, Myung Hyun; Kim, Yang Do

    2009-03-01

    Sulfur hexafluoride (SF(6)) has been widely used in a variety of industrial processes, but it is one of the most potent greenhouse gases. For this reason, it is necessary to separate or collect it from waste gas streams. One separation method is through hydrate crystal formation. In this study, SF(6) hydrate was formed in aqueous surfactant solutions of 0.00, 0.01, 0.05, 0.15 and 0.20 wt% to investigate the effects of surfactants on the hydrate formation rates. Three surfactants, Tween 20 (Tween), sodium dodecyl sulfate (SDS) and linear alkyl benzene sulfonate (LABS), were tested in a semi-batch stirred vessel at the constant temperature and pressures of 276.2 K and 0.78 MPa, respectively. All surfactants showed kinetic promoter behavior for SF(6) hydrate formation. It was also found that SF(6) hydrate formation proceeded in two stages with the second stage being the most rapid. In situ Raman spectroscopy analysis revealed that the increased gas consumption rate with the addition of surfactant was possibly due to the increased gas filling rate in the hydrate cavity.

  20. Surfactant treatment for acute respiratory distress syndrome

    PubMed Central

    Lopez-Herce, J.; de Lucas, N.; Carrillo, A.; Bustinza, A.; Moral, R.

    1999-01-01

    OBJECTIVE—To determine prospectively the efficacy of surfactant in acute respiratory distress syndrome.
STUDY DESIGN—Twenty patients, 1 month to 16 years of age, diagnosed with an acute pulmonary disease with severe hypoxaemia (PaO2/FiO2 < 100) (13 with systemic or pulmonary disease and seven with cardiac disease) were treated with one to six doses of 50-200 mg/kg of porcine surfactant administered directly into the trachea. The surfactant was considered to be effective when the PaO2/FiO2 improved by > 20%.
RESULTS—After initial surfactant administration the PaO2/FiO2 increased significantly in patients with systemic or pulmonary disease from 68 to 111, and the oxygenation index (OI) diminished significantly from 36.9 to 27.1. The PaO2/FiO2 and OI did not improve in children with cardiac disease. The improvement of the patients who survived was greater than that of those who died.
CONCLUSIONS—Surfactant moderately improves oxygenation in some children with severe acute respiratory distress syndrome secondary to pulmonary or systemic disease.

 PMID:10325705

  1. Synthesis of mesoporous nano-hydroxyapatite by using zwitterions surfactant

    EPA Science Inventory

    Mesoporous nano-hydroxyapatite (mn-HAP) was successfully synthesized via a novel micelle-templating method using lauryl dimethylaminoacetic acid as zwitterionic surfactant. The systematic use of such a surfactant in combination with microwave energy inputenables the precise contr...

  2. Chemomechanical behaviors of polymer gels by surfactant binding

    NASA Astrophysics Data System (ADS)

    Narita, Tetsuharu; Gong, Jianping; Osada, Yoshihito

    1999-05-01

    A weakly crosslinked poly(2-acrylamido-2-methylpropanesulfonic acid) immersed in cationic surfactant (N-n-alkylpyridinium chloride) shows biomimetic chemomechanical movement under dc current. The principle of the movement is based on an electrokinetic molecular assembly reaction of the surfactant onto the polymer network. In order to analyze the diffusion and binding processes which are both of importance for understanding the alkyl size dependence of the chemomechanical behavior, kinetic studies of the surfactants binding were made systematically changing the alkyl size and concentration of the surfactants and ionic strength. It was found that the driving force of the surfactant diffusion is the electrochemical potential gradient, while the surfactant binding enhances the diffusion proces. A mathematical model for the surfactant diffusion was developed taking account of the surfactant binding process and obtained results were well explained the experimental observations.

  3. Surfactant ionic liquid-based microemulsions for polymerization.

    PubMed

    Yan, Feng; Texter, John

    2006-07-05

    Surfactants based on imidazolium ionic liquids (ILs), including polymerizable surfactant ILs, have been synthesized and used to stabilize polymerizable microemulsions useful for producing polymer nanoparticles, gels, and open-cell porous materials.

  4. Synthesis of mesoporous nano-hydroxyapatite by using zwitterions surfactant

    EPA Science Inventory

    Mesoporous nano-hydroxyapatite (mn-HAP) was successfully synthesized via a novel micelle-templating method using lauryl dimethylaminoacetic acid as zwitterionic surfactant. The systematic use of such a surfactant in combination with microwave energy inputenables the precise contr...

  5. Fullerene surfactants and their use in polymer solar cells

    SciTech Connect

    Jen, Kwan-Yue; Yip, Hin-Lap; Li, Chang-Zhi

    2015-12-15

    Fullerene surfactant compounds useful as interfacial layer in polymer solar cells to enhance solar cell efficiency. Polymer solar cell including a fullerene surfactant-containing interfacial layer intermediate cathode and active layer.

  6. Simulation of surfactant-enhanced aquifer remediation

    SciTech Connect

    Brown, C.L.; Pope, G.A.; Sepehrnoori, K.; Abriola, L.M.

    1994-11-01

    This paper demonstrates that surfactant-enhanced aquifer remediation (SEAR) can be modeled in two and three dimensions using a finite-difference simulator and incorporating realistic heterogenieties in aquifer properties and complex surfactant chemistry based upon a multicomponent, multiphase compositional description of the experimental chemistry. The presented simulations provide significant new insights into the SEAR process. The effectiveness of SEAR is sensitive to many variables including the initial infiltration rate of DNAPL, the natural hydraulic gradient, well locations, well pumping and injection rates, aquifer heterogenieties, and properties such as cappillary pressure, relative permeability, and surfactant chemistry. In this paper a comprehensive model for SEAR is presented and applied to explore the potential performance of this technology on an aquifer scale. This study illustrates the value of modeling in SEAR design, how this modeling can be accomplished, what information is necessary, and what kinds of results modeling can be expected to produce.

  7. Surfactant studies for bench-scale operation

    NASA Technical Reports Server (NTRS)

    Hickey, Gregory S.; Sharma, Pramod K.

    1992-01-01

    A phase 2 study was initiated to investigate surfactant-assisted coal liquefaction, with the objective of quantifying the enhancement in liquid yields and product quality. This publication covers the first quarter of work. The major accomplishments were: the refurbishment of the high-pressure, high-temperature reactor autoclave, the completion of four coal liquefaction runs with Pittsburgh #8 coal, two each with and without sodium lignosulfonate surfactant, and the development of an analysis scheme for the product liquid filtrate and filter cake. Initial results at low reactor temperatures show that the addition of the surfactant produces an improvement in conversion yields and an increase in lighter boiling point fractions for the filtrate.

  8. Recent Food Applications of Microbial Surfactants.

    PubMed

    Nitschke, Marcia; Silva, Sumária Sousa E

    2016-07-20

    During last years the interest on microbial surfactants or biosurfactants has gained attention due to their natural origin and environmental compatibility. These characteristics fulfill the demand of regulatory agencies and society to use of more sustained and green chemicals. Microbial-derived surfactants can replace synthetic surfactants in a great variety of industrial applications as detergents, foaming, emulsifiers, solubilizers and wetting agents. Change in trend of consumers to natural from synthetic additives and also the increasing health and environmental concerns creating demand for new "green" additives in food. Apart from their inherent surface-active properties, BS have been shown antimicrobial and antibiofilm activity against food pathogens; therefore, BS can be versatile additives or ingredients for food processing. These interesting applications will be discussed in this review.

  9. Nanotube Dispersions Made With Charged Surfactant

    NASA Technical Reports Server (NTRS)

    Kuper, Cynthia; Kuzma, Mike

    2006-01-01

    Dispersions (including monodispersions) of nanotubes in water at relatively high concentrations have been formulated as prototypes of reagents for use in making fibers, films, and membranes based on single-walled carbon nanotubes (SWNTs). Other than water, the ingredients of a dispersion of this type include one or more charged surfactant(s) and carbon nanotubes derived from the HiPco(TradeMark) (or equivalent) process. Among reagents known to be made from HiPco(TradeMark)(or equivalent) SWNTs, these are the most concentrated and are expected to be usable in processing of bulk structures and materials. Test data indicate that small bundles of SWNTs and single SWNTs at concentrations up to 1.1 weight percent have been present in water plus surfactant. This development is expected to contribute to the growth of an industry based on applied carbon nanotechnology. There are expected to be commercial applications in aerospace, avionics, sporting goods, automotive products, biotechnology, and medicine.

  10. Natural surfactants used in cosmetics: glycolipids.

    PubMed

    Lourith, N; Kanlayavattanakul, M

    2009-08-01

    Cosmetic surfactant performs detergency, wetting, emulsifying, solubilizing, dispersing and foaming effects. Adverse reactions of chemical synthesis surfactant have an effect on environment and humans, particularly severe in long term. Biodegradability, low toxicity and ecological acceptability which are the benefits of naturally derived surfactant that promises cosmetic safety are, therefore, highly on demand. Biosurfactant producible from microorganisms exhibiting potential surface properties suitable for cosmetic applications especially incorporate with their biological activities. Sophorolipids, rhamnolipids and mannosylerythritol lipids are the most widely used glycolipids biosurfactant in cosmetics. Literatures and patents relevant to these three glycolipids reviewed were emphasizing on the cosmetic applications including personal care products presenting the cosmetic efficiency, efficacy and economy benefits of glycolipids biosurfactant.

  11. Surfactant mediated liquid phase exfoliation of graphene.

    PubMed

    Narayan, Rekha; Kim, Sang Ouk

    2015-01-01

    Commercialization of graphene based applications inevitably requires cost effective mass production. From the early days of research on graphene, direct liquid phase exfoliation (LPE) of graphite has been considered as the most promising strategy to produce high-quality mono or few-layer graphene sheets in solvent dispersion forms. Substantial success has been achieved thus far in the LPE of graphene employing numerous solvent systems and suitable surfactants. This invited review article principally showcase the recent research progress as well as shortcomings of surfactant assisted LPE of graphene. In particular, a comprehensive assessment of the quality and yield of the graphene sheets produced by different categories of the surfactants are summarized. Future direction of LPE methods is also proposed for the eventual success of commercial applications.

  12. Surfactant mediated liquid phase exfoliation of graphene

    NASA Astrophysics Data System (ADS)

    Narayan, Rekha; Kim, Sang Ouk

    2015-10-01

    Commercialization of graphene based applications inevitably requires cost effective mass production. From the early days of research on graphene, direct liquid phase exfoliation (LPE) of graphite has been considered as the most promising strategy to produce high-quality mono or few-layer graphene sheets in solvent dispersion forms. Substantial success has been achieved thus far in the LPE of graphene employing numerous solvent systems and suitable surfactants. This invited review article principally showcase the recent research progress as well as shortcomings of surfactant assisted LPE of graphene. In particular, a comprehensive assessment of the quality and yield of the graphene sheets produced by different categories of the surfactants are summarized. Future direction of LPE methods is also proposed for the eventual success of commercial applications.

  13. Surfactant studies for bench-scale operation

    NASA Technical Reports Server (NTRS)

    Hickey, Gregory S.; Sharma, Pramod K.

    1993-01-01

    A phase 2 study has been initiated to investigate surfactant-assisted coal liquefaction, with the objective of quantifying the enhancement in liquid yields and product quality. This report covers the second quarter of work. The major accomplishments were: completion of coal liquefaction autoclave reactor runs with Illinois number 6 coal at processing temperatures of 300, 325, and 350 C, and pressures of 1800 psig; analysis of the filter cake and the filtrate obtained from the treated slurry in each run; and correlation of the coal conversions and the liquid yield quality to the surfactant concentration. An increase in coal conversions and upgrading of the liquid product quality due to surfactant addition was observed for all runs.

  14. Exogenous surfactant restores lung function but not peripheral immunosuppression in ventilated surfactant-deficient rats.

    PubMed

    Vreugdenhil, Harriet A; Lachmann, Burkhard; Haitsma, Jack J; Zijlstra, Jitske; Heijnen, Cobi J; Jansen, Nicolaas J; van Vught, Adrianus J

    2006-01-01

    The authors have previously shown that mechanical ventilation can result in increased pulmonary inflammation and suppressed peripheral leukocyte function. In the present study the effect of surfactant therapy on pulmonary inflammation and peripheral immune function in ventilated surfactant-deficient rats was assessed. Surfactant deficiency was induced by repeated lung lavage, treated rats with surfactant or left them untreated, and ventilated the rats during 2 hours. Nonventilated rats served as healthy control group. Expression of macrophage inflammatory protein (MIP)-2 was measured in bronchoalveolar lavage (BAL), interleukin (IL)-1beta, and heat shock protein 70 (HSP70) were measured in total lung homogenates. Outside the lung phytohemagglutinin (PHA)-induced lymphocyte proliferation, interferon (IFN)-gamma and IL-10 production, and natural killer activity were measured in splenocytes. After 2 hours of mechanical ventilation, expression of MIP-2, IL-1beta, and HSP70 increased significantly in the lungs of surfactant-deficient rats. Outside the lung, mitogen-induced proliferation and production of IFN-gamma and IL-10 reduced significantly. Only natural killer cell activity remained unaffected. Surfactant treatment significantly improved lung function, but could not prevent increased pulmonary expression of MIP-2, IL-1beta, and HSP70 and decreased peripheral mitogen-induced lymphocyte proliferation and IFN-gamma and IL-10 production in vitro. In conclusion, 2 hours of mechanical ventilation resulted in increased lung inflammation and partial peripheral leukocyte suppression in surfactant-deficient rats. Surfactant therapy ameliorated lung function but could not prevent or restore peripheral immunosuppression. The authors postulate that peripheral immunosuppression may occur in ventilated surfactant deficient patients, which may enhance susceptibility for infections.

  15. Preparation and characterization of zwitterionic surfactant-modified montmorillonites.

    PubMed

    Zhu, Jianxi; Qing, Yanhong; Wang, Tong; Zhu, Runliang; Wei, Jingming; Tao, Qi; Yuan, Peng; He, Hongping

    2011-08-15

    A series of zwitterionic surfactant-modified montmorillonites (ZSMMs) were synthesized using montmorillonite and three zwitterionic surfactants with different alkyl chain lengths at different concentrations [0.2-4.0 cation exchange capacity (CEC)]. These ZSMMs were characterized by X-ray diffraction (XRD), thermo-gravimetric analysis and differential thermo-gravimetric (TG/DTG) analyses. The zwitterionic surfactant could be intercalated into the interlayer spaces of montmorillonites and causing interlayer space-swelling. From XRD measurements, the amount of the surfactants loaded and the basal spacing increased with surfactant concentration and alkyl chain length. One endothermic DTG peak occurred at ~390 °C, which was assigned to the decomposition of the zwitterionic surfactant on the organo-montmorillonites from 0.2 to 0.6 CEC. When the surfactant loading was increased, a new endothermic peak appeared at ~340 °C. From the microstructures of these ZSMMs, the mechanism of zwitterionic surfactant adsorption was proposed. At relatively low loadings of the zwitterionic surfactant, most of surfactants enter the spacing by an ion-exchange mechanism and are adsorbed onto the interlayer cation sites. When the concentration of the zwitterionic surfactant exceeds the CEC of montmorillonite, the surfactant molecules then adhere to the surface-adsorbed surfactant. Some surfactants enter the interlayers, whereas the others are attached to the clay surface. When the concentration of surfactant increases further beyond 2.0 CEC, the surfactants may occupy the inter-particle space within the house-of-cards aggregate structure. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Surfactant-Polymer Interaction for Improved Oil Recovery

    SciTech Connect

    Gabitto, Jorge; Mohanty, Kishore K.

    2002-01-07

    The goal of this research was to use the interaction between a surfactant and a polymer for efficient displacement of tertiary oil by improving slug integrity, oil solubility in the displacing fluid and mobility control. Surfactant-polymer flooding has been shown to be highly effective in laboratory-scale linear floods. The focus of this proposal is to design an inexpensive surfactant-polymer mixture that can efficiently recover tertiary oil by avoiding surfactant slug degradation and viscous/heterogeneity fingering.

  17. Effect of surfactants on properties of soap-based greases

    SciTech Connect

    Fuks, I.G.

    1983-07-01

    Surfactants often influence the susceptibility of the grease to additives. This paper considers ways to improve the effectiveness of surfactant additives by the use of additive packages. The mechanism of surfactant action in forming grease structures are elucidated, and methods for preventing grease softening are established. The softening effect of surfactants is explained in part by retardation of the initial stages of the structurization i.e., association and micelle formation.

  18. Adhesion of latex films. Influence of surfactants

    SciTech Connect

    Charmeau, J.Y.; Kientz, E.; Holl, Y.

    1996-12-31

    In the applications of film forming latexes in paint, paper, coating, adhesive, textile industries, one of the most important property of latex films is adhesion onto a support. From the point of view of adhesion, latex films have two specificities. The first one arises from the particular structure of the film which is usually not homogeneous but retains to a certain extent the memory of the particles it was made from. These structure effects are clearly apparent when one compares mechanical or adhesion properties of pure latex films and of films of the same polymers but prepared from a solution. Latex films show higher Young`s moduli and lower adhesion properties than solution films. The second specificity of latex films comes from the presence of the surfactant which was used in the synthesis and as stabilizer for the latex. Most industrial latexes contain low amounts of surfactant, typically in the range 0.1 to 2-3 wt%. However, being usually incompatible with the polymer, the surfactant is not homogeneously distributed in the film. It tends to segregate towards the film-air or film-support interfaces or to form domains in the bulk of the film. Distribution of surfactants in latex films has been studied by several authors. The influence of the surfactant on adhesion, as well as on other properties, is thus potentially very important. This article presents the results of the authors investigation of surfactant effects on adhesion properties of latex films. To the authors knowledge, there is no other example, in the open literature, of this kind of study.

  19. Novel surfactant-selective membrane electrode based on polyelectrolyte-surfactant complex.

    PubMed

    Zorin, Ivan; Scherbinina, Tatiana; Fetin, Petr; Makarov, Ivan; Bilibin, Alexander

    2014-12-01

    Novel class of active ionophores for surfactant selective electrodes is proposed. PVC membrane doped with polyelectrolyte-surfactant stoichiometric complex is used for ion-selective electrode construction responsive to cetyltrimethyl ammonium bromide and related surfactants. New ionophore is quite stable and completely insoluble in aqueous media in wide range of pH. The electrode displays nearly Nernstian slope in CTAB concentration range 10(-6)-10(-3)M. Polyelectrolyte platform allows to design wide range of different ionophores responsive to cationic organic substances. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Control of acid mine drainage using surfactants

    SciTech Connect

    Not Available

    1983-02-01

    This news sheet describes US Bureau of Mines work on the reduction or prevention of acid mine drainage from coal refuse piles and surface mines by inhibiting the growth of Thiobacillus ferrooxidans. It has been found that the direct application of a dilute surfactant or detergent solution to coal refuse piles or overburden can be an effective preventive measure or can reduce water treatment costs by controlling acid drainage at its source. Of the anionic surfactants tested to date, sodium lauryl sulphate appears to be the most effective. Alpha olefin sulphonate and alkyl benzene sulphonate are acceptable alternatives. The results of field trials are presented.

  1. Two-dimensional photonic crystal surfactant detection.

    PubMed

    Zhang, Jian-Tao; Smith, Natasha; Asher, Sanford A

    2012-08-07

    We developed a novel two-dimensional (2-D) crystalline colloidal array photonic crystal sensing material for the visual detection of amphiphilic molecules in water. A close-packed polystyrene 2-D array monolayer was embedded in a poly(N-isopropylacrylamide) (PNIPAAm)-based hydrogel film. These 2-D photonic crystals placed on a mirror show intense diffraction that enables them to be used for visual determination of analytes. Binding of surfactant molecules attaches ions to the sensor that swells the PNIPAAm-based hydrogel. The resulting increase in particle spacing red shifts the 2-D diffracted light. Incorporation of more hydrophobic monomers increases the sensitivity to surfactants.

  2. Effects of selected surfactants on soil microbial activity

    USDA-ARS?s Scientific Manuscript database

    Surfactants (surface-active agents) facilitate and accentuate the emulsifying, dispersing, spreading, and wetting properties of liquids. Surfactants are used in industry to reduce the surface tension of liquid and to solubilize compounds. For agricultural pest management, surfactants are an import...

  3. Reuse of surfactants and cosolvents for NAPL remediation

    SciTech Connect

    Lowe, D.F.; Oubre, C.L.; Ward, C.H.

    2000-07-01

    Recovery and reuse of surfactants used in site remediation can substantially improve the overall economics. Prior to this project, it has not been demonstrated that a surfactant recovery process could be reliably designed and operated at field conditions. Nor had the question of the most cost effective surfactant recovery scheme been addressed. This book highlights innovative and cost effective technologies for ground water remediation.

  4. Effect of surfactant alkyl chain length on soil cadmium desorption using surfactant/ligand systems.

    PubMed

    Shin, Mari; Barrington, Suzelle F; Marshall, William D; Kim, Jin-Woo

    2005-02-01

    The effect of surfactant alkyl chain length on soil Cd desorption was studied using nonionic surfactants of polyethylene oxide (PEO) of PEO chain lengths of 7.5 (Triton X-114), 9.5 (Triton X-100), 30 (Triton X-305), or 40 units (Triton X-405) in combination with the I- ligand. Triplicate 1 g soil samples were equilibrated with 15 ml of surfactant-ligand mixture, at concentrations of 0.025, 0.50 or 0.10, and 0.0, 0.168 or 0.336 mol/l, respectively. After shaking the samples for 24 h, the supernatant fraction was analyzed for Cd content to determine the percent of Cd desorbed from the soil. After five successive washings, 53%, 40% and 25% of Cd had been desorbed by 0.025, 0.050 or 0.10 mol/l of Triton X-114, respectively, in the presence of 0.336 mol/l of I-, whereas with the same conditions, Triton X-100 desorbed 61%, 57% and 56% Cd and either Triton X-305 or Triton X-405 desorbed 51, 40 and 14 to 16% Cd. The most efficient Cd desorption was obtained using 0.025 mol/l Triton X-100 in admixture with 0.336 mol/l I-. Increased surfactant concentration was detrimental to Cd desorption consistent with a process that blocked ligand access to the soil particle surface. After 5 washings,the cumulative cadmium desorption decreased with increasing surfactant alkyl chain length, indicating that the metal-ligand complexes are preferably stabilized by the micelles' hydrophobic octyl phenyl (OP) group rather than by the hydrophilic PEO group. In the absence of ligand, the surfactants alone desorbed less than 1% Cd from the contaminated soil, suggesting that the ligand, rather than the surfactant, extracts the metal, to be subsequently stabilized within the surfactant micelles.

  5. SIMULATION OF SURFACTANT-ENHANCED AQUIFER REMEDIATION

    EPA Science Inventory

    Surfactant-enhanced aquifer remediation (SEAR) is currently under active investigation as one of the most promising alternatives to conventional pump-and-treat remediation for aquifers contaminated by dense nonaqueous phase organic liquids. An existing three-dimensional finite-di...

  6. SURFACTANT FLUSH: HOW WELL DID IT WORK?

    EPA Science Inventory

    The Oklahoma Corporation Commission through a contract with Surbec-Art, Inc. of Norman Oklahoma has remediated TPH contamination at a gasoline spill at Golden, Oklahoma. Residual gasoline was removed from the subsurface using a flush of surfactant, followed by in situ bioremedia...

  7. Dilute Surfactant Methods for Carbonate Formations

    SciTech Connect

    Kishore K. Mohanty

    2005-10-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the best hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. Laboratory-scale surfactant brine imbibition experiments give high oil recovery (35-62% OOIP) for initially oil-wet cores through wettability alteration and IFT reduction. Core-scale simulation results match those of the experiments. Initial capillarity-driven imbibition gives way to a final gravity-driven process. As the matrix block height increases, surfactant alters wettability to a lesser degree, or permeability decreases, oil production rate decreases. The scale-up to field scale will be further studied in the next quarter.

  8. Nanoparticle interaction with model lung surfactant monolayers

    PubMed Central

    Harishchandra, Rakesh Kumar; Saleem, Mohammed; Galla, Hans-Joachim

    2010-01-01

    One of the most important functions of the lung surfactant monolayer is to form the first line of defence against inhaled aerosols such as nanoparticles (NPs), which remains largely unexplored. We report here, for the first time, the interaction of polyorganosiloxane NPs (AmorSil20: 22 nm in diameter) with lipid monolayers characteristic of alveolar surfactant. To enable a better understanding, the current knowledge about an established model surface film that mimics the surface properties of the lung is reviewed and major results originating from our group are summarized. The pure lipid components dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol have been used to study the biophysical behaviour of their monolayer films spread at the air–water interface in the presence of NPs. Film balance measurements combined with video-enhanced fluorescence microscopy have been used to investigate the formation of domain structures and the changes in the surface pattern induced by NPs. We are able to show that NPs are incorporated into lipid monolayers with a clear preference for defect structures at the fluid–crystalline interface leading to a considerable monolayer expansion and fluidization. NPs remain at the air–water interface probably by coating themselves with lipids in a self-assembly process, thereby exhibiting hydrophobic surface properties. We also show that the domain structure in lipid layers containing surfactant protein C, which is potentially responsible for the proper functioning of surfactant material, is considerably affected by NPs. PMID:19846443

  9. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2003-01-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. We have acquired field oil and core samples and field brine compositions from Marathon. We have conducted preliminary adsorption and wettability studies. Addition of Na{sub 2}CO{sub 3} decreases anionic surfactant adsorption on calcite surface. Receding contact angles increase with surfactant adsorption. Plans for the next quarter include conducting adsorption, phase behavior and wettability studies.

  10. SIMULATION OF SURFACTANT-ENHANCED AQUIFER REMEDIATION

    EPA Science Inventory

    Surfactant-enhanced aquifer remediation (SEAR) is currently under active investigation as one of the most promising alternatives to conventional pump-and-treat remediation for aquifers contaminated by dense nonaqueous phase organic liquids. An existing three-dimensional finite-di...

  11. Photosensitive surfactants: micellization and interaction with DNA.

    PubMed

    Zakrevskyy, Yuriy; Roxlau, Julian; Brezesinski, Gerald; Lomadze, Nino; Santer, Svetlana

    2014-01-28

    Recently, photosensitive surfactants have re-attracted considerable attention. It has been shown that their association with oppositely charged biologically important polyelectrolytes, such as DNA or microgels, can be efficiently manipulated simply by light exposure. In this article, we investigate the self-assembly of photosensitive surfactants as well as their interactions with DNA by calorimetric and spectroscopic methods. Critical micelle concentration (CMC), standard micellization enthalpy, entropy, and Gibbs energy were determined in different conditions (ionic strengths and temperatures) for a series of cationic surfactants with an azobenzene group in their tail. It is shown, that aggregation forces of photosensitive units play an important role in the micellization giving the major contribution to the micellization enthalpy. The onset of the aggregation can be traced from shift of the absorption peak position in the UV-visible spectrum. Titration UV-visible spectroscopy is used as an alternative, simple, and sensitive approach to estimate CMC. The titration UV-visible spectroscopy was also employed to investigate interactions (CAC: critical aggregation concentration, precipitation, and colloidal stabilization) in the DNA-surfactant complex.

  12. SURFACTANT FLUSH: HOW WELL DID IT WORK?

    EPA Science Inventory

    The Oklahoma Corporation Commission through a contract with Surbec-Art, Inc. of Norman Oklahoma has remediated TPH contamination at a gasoline spill at Golden, Oklahoma. Residual gasoline was removed from the subsurface using a flush of surfactant, followed by in situ bioremedia...

  13. Average molecular weight of surfactants in aerosols

    NASA Astrophysics Data System (ADS)

    Latif, M. T.; Brimblecombe, P.

    2007-09-01

    Surfactants in atmospheric aerosols determined as methylene blue active substances (MBAS) and ethyl violet active substances (EVAS). The MBAS and EVAS concentrations can be correlated with surface tension as determined by pendant drop analysis. The effect of surface tension was more clearly indicated in fine mode aerosol extracts. The concentration of MBAS and EVAS was determined before and after ultrafiltration analysis using AMICON centrifuge tubes that define a 5000 Da (5 K Da) nominal molecular weight fraction. Overall, MBAS and to a greater extent EVAS predominates in fraction with molecular weight below 5 K Da. In case of aerosols collected in Malaysia the higher molecular fractions tended to be a more predominant. The MBAS and EVAS are correlated with yellow to brown colours in aerosol extracts. Further experiments showed possible sources of surfactants (e.g. petrol soot, diesel soot) in atmospheric aerosols to yield material having molecular size below 5 K Da except for humic acid. The concentration of surfactants from these sources increased after ozone exposure and for humic acids it also general included smaller molecular weight surfactants.

  14. Photosensitive surfactants: Micellization and interaction with DNA

    NASA Astrophysics Data System (ADS)

    Zakrevskyy, Yuriy; Roxlau, Julian; Brezesinski, Gerald; Lomadze, Nino; Santer, Svetlana

    2014-01-01

    Recently, photosensitive surfactants have re-attracted considerable attention. It has been shown that their association with oppositely charged biologically important polyelectrolytes, such as DNA or microgels, can be efficiently manipulated simply by light exposure. In this article, we investigate the self-assembly of photosensitive surfactants as well as their interactions with DNA by calorimetric and spectroscopic methods. Critical micelle concentration (CMC), standard micellization enthalpy, entropy, and Gibbs energy were determined in different conditions (ionic strengths and temperatures) for a series of cationic surfactants with an azobenzene group in their tail. It is shown, that aggregation forces of photosensitive units play an important role in the micellization giving the major contribution to the micellization enthalpy. The onset of the aggregation can be traced from shift of the absorption peak position in the UV-visible spectrum. Titration UV-visible spectroscopy is used as an alternative, simple, and sensitive approach to estimate CMC. The titration UV-visible spectroscopy was also employed to investigate interactions (CAC: critical aggregation concentration, precipitation, and colloidal stabilization) in the DNA-surfactant complex.

  15. Surfactant loss: Effects of temperature, salinity, and wettability

    SciTech Connect

    Noll, L.A.; Gall, B.L.; Crocker, M.E.; Olsen, D.K.

    1989-05-01

    Adsorption of sodium dodecylsulfate, Triton X-100, decyltrimethylammonium bromide surfactants onto silica gel and Berea sandstone mineral surfaces has been studied as a function of temperature, solution salt concentration, and mineral surface wettability. Adsorption studies using a flow calorimeter were conducted using pure surfactants and minerals. The studies were then extended to the adsorption of one type of commercial surfactant onto both consolidated and crushed Berea sandstone using column techniques. This has allowed the comparison of different methods to evaluate surfactant losses from flowing rather than static surfactant solutions. 20 refs., 15 figs., 37 tabs.

  16. Thermally stable surfactants and compositions and methods of use thereof

    DOEpatents

    Chaiko, David J.

    2008-09-02

    There are provided novel thermally stable surfactants for use with fillers in the preparation of polymer composites and nanocomposites. Typically, surfactants of the invention are urethanes, ureas or esters of thiocarbamic acid having a hydrocarbyl group of from 10 to 50 carbons and optionally including an ionizable or charged group (e.g., carboxyl group or quaternary amine). Thus, there are provided surfactants having Formula I: ##STR00001## wherein the variables are as defined herein. Further provided are methods of making thermally stable surfactants and compositions, including composites and nanocomposites, using fillers coated with the surfactants.

  17. Palm oil based surfactant products for petroleum industry

    NASA Astrophysics Data System (ADS)

    Permadi, P.; Fitria, R.; Hambali, E.

    2017-05-01

    In petroleum production process, many problems causing reduced production are found. These include limited oil recovery, wax deposit, asphaltene deposit, sludge deposit, and emulsion problem. Petroleum-based surfactant has been used to overcome these problems. Therefore, innovation to solve these problems using surfactant containing natural materials deserves to be developed. Palm oil-based surfactant is one of the potential alternatives for this. Various types of derivative products of palm oil-based surfactant have been developed by SBRC IPB to be used in handling problems including surfactant flooding, well stimulation, asphaltene dissolver, well cleaning, and wax removal found in oil and gas industry.

  18. Surfactant-laden drops rising in a stratified ambient

    NASA Astrophysics Data System (ADS)

    Blanchette, Francois; Martin, David

    2015-11-01

    We present results of a numerical study of the dynamics of rising drops in the presence of both surfactants and stratification. Our simulations model oil drops rising in the oceans, where naturally occurring or man-made surfactants are present. We study surfactant covered drops in uniform and density-stratified ambients, as well as clean drops entering a dissolved surfactant layer. We quantify the effects of entrainment for various Reynolds and Marangoni numbers. We also report a brief acceleration followed by a significant deceleration as a clean drop enters a surfactant layer, and describe how the adsorption rate affects those dynamics.

  19. Structural study of surfactant-dependent interaction with protein

    SciTech Connect

    Mehan, Sumit; Aswal, Vinod K.; Kohlbrecher, Joachim

    2015-06-24

    Small-angle neutron scattering (SANS) has been used to study the complex structure of anionic BSA protein with three different (cationic DTAB, anionic SDS and non-ionic C12E10) surfactants. These systems form very different surfactant-dependent complexes. We show that the structure of protein-surfactant complex is initiated by the site-specific electrostatic interaction between the components, followed by the hydrophobic interaction at high surfactant concentrations. It is also found that hydrophobic interaction is preferred over the electrostatic interaction in deciding the resultant structure of protein-surfactant complexes.

  20. Intratracheal atomized surfactant provides similar outcomes as bolus surfactant in preterm lambs with respiratory distress syndrome.

    PubMed

    Milesi, Ilaria; Tingay, David G; Zannin, Emanuela; Bianco, Federico; Tagliabue, Paolo; Mosca, Fabio; Lavizzari, Anna; Ventura, Maria Luisa; Zonneveld, C Elroy; Perkins, Elizabeth J; Black, Don; Sourial, Magdy; Dellacá, Raffaele L

    2016-07-01

    Aerosolization of exogenous surfactant remains a challenge. This study is aimed to evaluate the efficacy of atomized poractant alfa (Curosurf) administered with a novel atomizer in preterm lambs with respiratory distress syndrome. Twenty anaesthetized lambs, 127 ± 1 d gestational age, (mean ± SD) were instrumented before birth and randomized to receive either (i) positive pressure ventilation without surfactant (Control group), (ii) 200 mg/kg of bolus instilled surfactant (Bolus group) at 10 min of life or (iii) 200 mg/kg of atomized surfactant (Atomizer group) over 60 min from 10 min of life. All lambs were ventilated for 180 min with a standardized protocol. Lung mechanics, regional lung compliance (electrical impedance tomography), and carotid blood flow (CBF) were measured with arterial blood gas analysis. Dynamic compliance and oxygenation responses were similar in the Bolus and Atomizer groups, and both better than Control by 180 min (all P < 0.05; two-way ANOVA). Both surfactant groups demonstrated more homogeneous regional lung compliance throughout the study period. There were no differences in CBFConclusion:In a preterm lamb model, atomized surfactant resulted in similar gas exchange and mechanics as bolus administration. This study suggests evaluation of supraglottic atomization with this system when noninvasive support is warranted.

  1. Organised surfactant assemblies in analytical atomic spectrometry

    NASA Astrophysics Data System (ADS)

    Sanz-Medel, Alfredo; Fernandez de la Campa, Maria del Rosario; Gonzalez, Elisa Blanco; Fernandez-Sanchez, Maria Luisa

    1999-02-01

    The use of surfactant-based organised assemblies in analytical atomic spectroscopy is extensively and critically reviewed along three main lines: first, the ability of organised media to enhance detection of atomic spectroscopic methods by favourable manipulation of physical and chemical properties of the sample solution second, the extension of separation mechanisms by resorting to organised media and third a discussion of synergistic combinations of liquid chromatography separations and atomic detectors via the use of vesicular mobile phases. Changes in physical properties of sample solutions aspirated in atomic spectrometry by addition of surfactants can be advantageously used in at least four different ways: (i) to improve nebulisation efficiency; (ii) to enhance wettability of solid surfaces used for atomisation; (iii) to improve compatibility between aqueous and organic phases; and (iv) to achieve good dispersion of small particles in "slurry" techniques. Controversial results and statements published so far are critically discussed. The ability of surfactant-based organised assemblies, such as micelles and vesicles, to organise reactants at the molecular level has also been applied to enhance the characteristics of chemical generation of volalite species of metals and semi-metals (e.g., hydride or ethylide generation of As, Pb, Cd, Se, Sn, and cold vapour Hg generation) used in atomic methods. Enhancements in efficiency/transport of volatile species, increases in the reaction kinetics, stabilisation of some unstable species and changes in the selectivity of the reactions by surfactants are dealt with. Non-chromatographic cloud-point separations to design pre-concentration procedures with subsequent metal determination by atomic methods are addressed along with chromatographic separations of expanded scope by addition of surfactants to the conventional aqueous mobile phases of reversed-phase high-performance liquid chromatography. Finally, the synergistic

  2. Adsorption of surfactants and polymers at interfaces

    NASA Astrophysics Data System (ADS)

    Rojas, Orlando Jose

    Surface tension and high-resolution laser light scattering experiments were used to investigate the adsorption of isomeric sugar-based surfactants at the air/liquid interface in terms of surfactant surface packing and rheology. Soluble monolayers of submicellar surfactant solutions exhibited a relatively viscous behavior. It was also proved that light scattering of high-frequency thermally-induced capillary waves can be utilized to study surfactant exchange between the surface and the bulk solution. Such analysis revealed the existence of a diffusional relaxation mechanism. A procedure based on XPS was developed for quantification, on an absolute basis, of polymer adsorption on mica and Langmuir-Blodgett cellulose films. The adsorption of cationic polyelectrolytes on negatively-charged solid surfaces was highly dependent on the polymer ionicity. It was found that the adsorption process is driven by electrostatic mechanisms. Charge overcompensation (or charge reversal) of mica occurred after adsorption of polyelectrolytes of ca. 50% charge density, or higher. It was demonstrated that low-charge-density polyelectrolytes adsorb on solid surfaces with an extended configuration dominated by loops and tails. In this case the extent of adsorption is limited by steric constraints. The conformation of the polyelectrolyte in the adsorbed layer is dramatically affected by the presence of salts or surfactants in aqueous solution. The phenomena which occur upon increasing the ionic strength are consistent with the screening of the electrostatic attraction between polyelectrolyte segments and solid surface. This situation leads to polyelectrolyte desorption accompanied by both an increase in the layer thickness and the range of the steric force. Adsorbed polyelectrolytes and oppositely charged surfactants readily associate at the solid/liquid interface. Such association induces polyelectrolyte desorption at a surfactant concentration which depends on the polyelectrolyte charge

  3. Surfactant changes during experimental pneumocystosis are related to Pneumocystis development.

    PubMed

    Aliouat, E M; Escamilla, R; Cariven, C; Vieu, C; Mullet, C; Dei-Cas, E; Prévost, M C

    1998-03-01

    Pneumocystosis-related surfactant changes have been reported in both humans and corticosteroid-treated experimental hosts. As corticosteroids induce an increase in pulmonary surfactant, some findings could be considered as controversial. The aim of this study was to investigate whether the surfactant composition changes during experimental pneumocystosis were related to the Pneumocystis development. In this work two corticosteroid-untreated animal models were used: rabbits, which develop spontaneous pneumocystosis at weaning; and severe combined immunodeficiency mice, which were intranasally inoculated with Pneumocystis carinii. Surfactant phospholipid and protein content was explored by bronchoalveolar lavage. The in vitro effect of surfactant on P. carinii growth was also explored. In the two models, the surfactant phospholipid/protein ratio was significantly increased, whereas parasite rates were low. This ratio decreases with the slope increase of the parasite growth curve. These early surfactant changes suggested that Pneumocystis proliferation requires alveolar lining fluid changes, and that normal surfactant is not suitable for parasite development. In this way, in vitro experiments presented here have revealed an inhibitory effect of synthetic or seminatural surfactants on the P. carinii growth. Further studies are needed to determine how Pneumocystis induces the reported early modifications of the surfactant, and why the parasite development is inhibited by pulmonary surfactant.

  4. Surfactant therapy: the current practice and the future trends

    PubMed Central

    Altirkawi, Khalid

    2013-01-01

    The efficacy of surfactant preparations used in the prevention and treatment of respiratory distress syndrome (RDS) is a well known fact; however, many controversies remain. The debate over which surfactant to be used, when and what is the best mode of delivery is still raging. Currently, animal-derived surfactants are preferred and clearly recommended by various practice guidelines, but new synthetic surfactants containing peptides that mimic the action of surfactant proteins are emerging and they seem to have a comparable efficacy profile to the natural surfactants. It is hoped that with further improvements, they will outperform their natural counterparts in terms of reliability and cost-effectiveness. Early surfactant administration was shown to further reduce the risk of RDS and its complications. However, as nasal continuous positive airway pressure (nCPAP) is becoming increasingly the preferred first-line therapy for RDS, the less invasive approaches of respiratory support along with early selective surfactant administration (e.g. INSURE) appears to provide a better option. Although neonatal RDS is still the main indication of surfactant therapy, other pathological processes received considerable attention and major research has been dedicated to explore the role of surfactant in their management, Meconium aspiration syndrome (MAS) and congenital pneumonia are two worthy examples. The most updated practice guidelines do recommend the use of endotracheal instillation as the preferred mode of surfactant delivery. However, aerosolization and other non-invasive methods are being investigated with some success; nonetheless, further improvements are very much in need. PMID:27493353

  5. Comparative study of clinical pulmonary surfactants using atomic force microscopy

    PubMed Central

    Zhang, Hong; Fan, Qihui; Wang, Yi E.; Neal, Charles R.; Zuo, Yi Y.

    2016-01-01

    Clinical pulmonary surfactant is routinely used to treat premature newborns with respiratory distress syndrome, and has shown great potential in alleviating a number of neonatal and adult respiratory diseases. Despite extensive study of chemical composition, surface activity, and clinical performance of various surfactant preparations, a direct comparison of surfactant films is still lacking. In this study, we use atomic force microscopy to characterize and compare four animal-derived clinical surfactants currently used throughout the world, i.e., Survanta, Curosurf, Infasurf and BLES. These modified-natural surfactants are further compared to dipalmitoyl phosphatidylcholine (DPPC), a synthetic model surfactant of DPPC:palmitoyl-oleoyl phosphatidylglycerol (POPG) (7:3), and endogenous bovine natural surfactant. Atomic force microscopy reveals significant differences in the lateral structure and molecular organization of these surfactant preparations. These differences are discussed in terms of DPPC and cholesterol contents. We conclude that all animal-derived clinical surfactants assume a similar structure of multilayers of fluid phospholipids closely attached to an interfacial monolayer enriched in DPPC, at physiologically relevant surface pressures. This study provides the first comprehensive survey of the lateral structure of clinical surfactants at various surface pressures. It may have clinical implications on future application and development of surfactant preparations. PMID:21439262

  6. Pulmonary surfactants and their role in pathophysiology of lung disorders.

    PubMed

    Akella, Aparna; Deshpande, Shripad B

    2013-01-01

    Surfactant is an agent that decreases the surface tension between two media. The surface tension between gaseous-aqueous interphase in the lungs is decreased by the presence of a thin layer of fluid known as pulmonary surfactant. The pulmonary surfactant is produced by the alveolar type-II (AT-II) cells of the lungs. It is essential for efficient exchange of gases and for maintaining the structural integrity of alveoli. Surfactant is a secretory product, composed of lipids and proteins. Phosphatidylcholine and phosphatidylglycerol are the major lipid constituents and SP-A, SP-B, SP-C, SP-D are four types of surfactant associated proteins. The lipid and protein components are synthesized separately and are packaged into the lamellar bodies in the AT-II cells. Lamellar bodies are the main organelle for the synthesis and metabolism of surfactants. The synthesis, secretion and recycling of the surfactant lipids and proteins is regulated by complex genetic and metabolic mechanisms. The lipid-protein interaction is very important for the structural organization of surfactant monolayer and its functioning. Alterations in surfactant homeostasis or biophysical properties can result in surfactant insufficiency which may be responsible for diseases like respiratory distress syndrome, lung proteinosis, interstitial lung diseases and chronic lung diseases. The biochemical, physiological, developmental and clinical aspects of pulmonary surfactant are presented in this article to understand the pathophysiological mechanisms of these diseases.

  7. Lung surfactants and different contributions to thin film stability.

    PubMed

    Hermans, Eline; Bhamla, M Saad; Kao, Peter; Fuller, Gerald G; Vermant, Jan

    2015-11-07

    The surfactant lining the walls of the alveoli in the lungs increases pulmonary compliance and prevents collapse of the lung at the end of expiration. In premature born infants, surfactant deficiency causes problems, and lung surfactant replacements are instilled to facilitate breathing. These pulmonary surfactants, which form complex structured fluid-fluid interfaces, need to spread with great efficiency and once in the alveolus they have to form a thin stable film. In the present work, we investigate the mechanisms affecting the stability of surfactant-laden thin films during spreading, using drainage flows from a hemispherical dome. Three commercial lung surfactant replacements Survanta, Curosurf and Infasurf, along with the phospholipid dipalmitoylphosphatidylcholine (DPPC), are used. The surface of the dome can be covered with human alveolar epithelial cells and experiments are conducted at the physiological temperature. Drainage is slowed down due to the presence of all the different lung surfactant replacements and therefore the thin films show enhanced stability. However, a scaling analysis combined with visualization experiments demonstrates that different mechanisms are involved. For Curosurf and Infasurf, Marangoni stresses are essential to impart stability and interfacial shear rheology does not play a role, in agreement with what is observed for simple surfactants. Survanta, which was historically the first natural surfactant used, is rheologically active. For DPPC the dilatational properties play a role. Understanding these different modes of stabilization for natural surfactants can benefit the design of effective synthetic surfactant replacements for treating infant and adult respiratory disorders.

  8. Comparative study of clinical pulmonary surfactants using atomic force microscopy.

    PubMed

    Zhang, Hong; Fan, Qihui; Wang, Yi E; Neal, Charles R; Zuo, Yi Y

    2011-07-01

    Clinical pulmonary surfactant is routinely used to treat premature newborns with respiratory distress syndrome, and has shown great potential in alleviating a number of neonatal and adult respiratory diseases. Despite extensive study of chemical composition, surface activity, and clinical performance of various surfactant preparations, a direct comparison of surfactant films is still lacking. In this study, we use atomic force microscopy to characterize and compare four animal-derived clinical surfactants currently used throughout the world, i.e., Survanta, Curosurf, Infasurf and BLES. These modified-natural surfactants are further compared to dipalmitoyl phosphatidylcholine (DPPC), a synthetic model surfactant of DPPC:palmitoyl-oleoyl phosphatidylglycerol (POPG) (7:3), and endogenous bovine natural surfactant. Atomic force microscopy reveals significant differences in the lateral structure and molecular organization of these surfactant preparations. These differences are discussed in terms of DPPC and cholesterol contents. We conclude that all animal-derived clinical surfactants assume a similar structure of multilayers of fluid phospholipids closely attached to an interfacial monolayer enriched in DPPC, at physiologically relevant surface pressures. This study provides the first comprehensive survey of the lateral structure of clinical surfactants at various surface pressures. It may have clinical implications on future application and development of surfactant preparations. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Droplet impact on liquid films in the presence of surfactants

    NASA Astrophysics Data System (ADS)

    Jais, Khadijah; Yip, Natalie; Che, Zhizhao; Matar, Omar

    2016-11-01

    In this study of droplet impact on liquid films, surfactants are added to the droplet, the liquid film or both, and the effects of different surfactant concentrations are investigated using high-speed imaging. The results show that surfactants suppress partial coalescence, due to damping of the capillary waves. Rebounding occurs more frequently when surfactants are added, as the surfactant molecules resist the drainage of the intervening air layer. When the droplet deforms the surfactant film, there is an uneven distribution of surfactant molecules along the interface, resulting in a surface tension gradient and a Marangoni stress. The Marangoni stress acts to even out the surface tension gradient and to aid rebounding. Surfactant droplet ruptures the film with a much lower surfactant concentration, leaving an apparent dry region on the substrate at the impact point. This is likely due to Marangoni stresses where the film pulls the droplet apart. As the film thickness is increased, a Worthington jet is formed, with secondary droplet(s) ejected from the jet only when surfactants are present. This study reveals that the presence of surfactants can significantly alter the impact process of droplets on liquid films. EPSRC UK Programme Grant MEMPHIS (EP/K003976/1).

  10. Synthesis and properties evaluation of sulfobetaine surfactant with double hydroxyl

    NASA Astrophysics Data System (ADS)

    Zhou, Ming; Luo, Gang; Zhang, Ze; Li, Sisi; Wang, Chengwen

    2017-09-01

    A series of sulfobetaine surfactants {N-[(3-alkoxy-2-hydroxyl)propoxy] ethyl-N,N-dimethyl-N-(2-hydroxyl)propyl sulfonate} ammonium chloride were synthesized with raw materials containing linear saturated alcohol, N,N-dimethylethanolamine, sodium 3-chloro-2-hydroxyl propane sulfonic acid and epichlorohydrin. The molecule structures of sulfobetaine surfactants were characterized by FTIR, 1HNMR and elemental analysis. Surface tension measurements can provide us information about the surface tension at the CMC (γCMC), pC20, Γmax and Amin. The pC20 values of sulfobetaine surfactants increase with the hydrophobic chain length increasing. Amin values of the surfactants decrease with increasing hydrophobic chain length from 10 to 14. The critical micelle concentration (CMC) and surface tension (γCMC) values of the sulfobetaine surfactants decrease with increasing hydrophobic chain length from 10 to 16. The lipophilicity of surfactant was enhanced with the increase of the carbon chain, however, the ability of anti-hard water was weakened. The minimum oil/water interfacial tension of four kinds of sulfobetaine surfactants is 10-2-10-3 mN/m magnitude, which indicates that the synthesized bis-hydroxy sulfobetaine surfactants have a great ability to reduce interfacial tension in the surfactant flooding system. The surface tension (γCMC) values of synthesized surfactants were lower compared with conventional anionic surfactant sodium dodecyl sulfonate.

  11. Surfactant-enhanced alkaline flooding field project

    SciTech Connect

    French, T.R.

    1991-10-01

    The Tucker sand of Helper (KS) field is a candidate for surfactant-enhanced alkaline flooding. The geology of the Helper site is typical of many DOE Class I reservoirs. The Tucker sand of Helper field was deposited in a fluvial dominated deltaic environment. Helper oil can be mobilized with either chemical system 2 or chemical system 3, as described in this report. Oil fields in the Gulf Coast region are also good candidates for surfactant-enhanced alkaline flooding. The results from laboratory tests conducted in Berea sandstone cores with oil brine from Helper (KS) field are encouraging. The crude oil is viscous and non-acidic and, yet, was mobilized by the chemical formulations described in this report. Significant amounts of the oil were mobilized under simulated reservoir conditions. The results in Berea sandstone cores were encouraging and should be verified by tests with field core. Consumption of alkali, measured with field core, was very low. Surfactant loss appeared to be acceptable. Despite the good potential for mobilization of Helper oil, certain reservoir characteristics such as low permeability, compartmentalization, and shallow depth place constraints on applications of any chemical system in the Tucker sand. These constraints are typical of many DOE Class I reservoirs. Although Hepler field is not a perfect reservoir in which to apply surfactant- enhanced alkaline flooding, Hepler oil is particularly amenable to mobilization by surfactant-enhanced alkaline systems. A field test is recommended, dependent upon final evaluation of well logs and cores from the proposed pilot area. 14 refs., 21 figs., 10 tabs.

  12. SURFACTANT BASED ENHANCED OIL RECOVERY AND FOAM MOBILITY CONTROL

    SciTech Connect

    George J. Hirasaki; Clarence A. Miller; Gary A. Pope; Richard E. Jackson

    2004-02-01

    Surfactant flooding has the potential to significantly increase recovery over that of conventional waterflooding. The availability of a large number of surfactant structures makes it possible to conduct a systematic study of the relation between surfactant structure and its efficacy for oil recovery. Also, the addition of an alkali such as sodium carbonate makes possible in situ generation of surfactant and significant reduction of surfactant adsorption. In addition to reduction of interfacial tension to ultra-low values, surfactants and alkali can be designed to alter wettability to enhance oil recovery. An alkaline surfactant process is designed to enhance spontaneous imbibition in fractured, oil-wet, carbonate formations. It is able to recover oil from dolomite core samples from which there was no oil recovery when placed in formation brine.

  13. Evolution of pulmonary surfactants for the treatment of neonatal respiratory distress syndrome and paediatric lung diseases.

    PubMed

    Mazela, Jan; Merritt, T Allen; Gadzinowski, Janusz; Sinha, Sunil

    2006-09-01

    This review documents the evolution of surfactant therapy, beginning with observations of surfactant deficiency in respiratory distress syndrome, the basis of exogenous surfactant treatment and the development of surfactant-containing novel peptides patterned after SP-B. We critically analyse the molecular interactions of surfactant proteins and phospholipids contributing to surfactant function. Peptide-containing surfactant provides clinical efficacy in the treatment of respiratory distress syndrome and offers promise for treating other lung diseases in infancy.

  14. Natural vs synthetic surfactants in neonatal respiratory distress syndrome.

    PubMed

    Halliday, H L

    1996-02-01

    This review examines the 11 randomised clinical trials that have compared different surfactant preparations. Seven trials, enrolling 2488 infants with respiratory distress syndrome (RDS), compared the natural surfactant beractant (Survanta) with the synthetic surfactant colfosceril palmitate (Exosurf Neonatal). Infants treated with beractant had lower oxygen requirements for at least 3 days than those treated with colfosceril palmitate. The infants treated with beractant also had lower risks of neonatal mortality [odds ratio (OR) 0.81; 95% confidence interval (CI) 0.65 to 1.01], retinopathy of prematurity (OR 0.81; 95% CI 0.66 to 0.99), and the combined endpoint of death or bronchopulmonary dysplasia (OR 0.86; 95% CI 0.75 to 0.99), compared with those treated with colfosceril palmitate. Calf lung surfactant extract (CLSE; Infasurf), another natural surfactant, has been compared with colfosceril palmitate in 2 studies: in one as prophylaxis and in the other as rescue therapy. Similar, although nonsignificant, advantages were found for the natural surfactant compared with the synthetic surfactant. In 6 of these 9 trials there was a significant reduction in the odds of pulmonary air leaks (OR 0.53; 95% CI 0.41 to 0.64) for infants treated with natural compared with synthetic surfactants. In 7 trials (3554 infants) comparing natural and synthetic surfactants to treat RDS (6 comparing beractant and colfosceril palmitate, and one CLSE and colfosceril palmitate), there was a significantly reduced risk of neonatal mortality (OR 0.80; 95% CI 0.66 to 0.97) with natural compared with synthetic surfactant treatment. In 2 further trials, different natural surfactant preparations have been compared. Reduced oxygen needs for 24 hours after treatment were found for CLSE and Curosurf (porcine-derived lung surfactant, PLS) when each was compared with beractant. Apparent longer term benefits from these surfactants were not statistically proven. Further trials are needed to be certain

  15. Influence of Surfactants on Sodium Chloride Crystallization in Confinement.

    PubMed

    Qazi, Mohsin J; Liefferink, Rinse W; Schlegel, Simon J; Backus, Ellen H G; Bonn, Daniel; Shahidzadeh, Noushine

    2017-05-02

    We study the influence of different surfactants on NaCl crystallization during evaporation of aqueous salt solutions. We found that at concentrations of sodium chloride close to saturation, only the cationic surfactant CTAB and the nonionic surfactant Tween 80 remain stable. For the nonionic surfactant, the high concentration of salt does not significantly change either the critical micellar concentration (CMC) or the surface tension at the CMC; for the cationic surfactant, the CMC is reduced by roughly 2 orders of magnitude upon adding the salt. The presence of both types of surfactants in the salt solution delays the crystallization of sodium chloride with evaporation. This, in turn, leads to high supersaturation which induces the rapid precipitation of a hopper crystal in the bulk. The crystallization inhibitor role of these surfactants is shown to be mainly due to the passivation of nucleation sites at both liquid/air and solid/liquid interfaces rather than a change in the evaporation rate which is found not to be affected by the presence of the surfactants. The adsorption of surfactants at the liquid/air interface prevents the crystallization at this location which is generally the place where the precipitation of sodium chloride is observed. Moreover, sum frequency generation spectroscopy measurements show that the surfactants are also present at the solid/liquid interface. The incorporation of the surfactants into the salt crystals is investigated using a novel, but simple, method based on surface tension measurements. Our results show that the nonionic surfactant Tween 80 is incorporated in the NaCl crystals but the cationic surfactant CTAB is not. Taken together, these results therefore allow us to establish the effect of the presence of surfactants on sodium chloride crystallization.

  16. Influence of Surfactants on Sodium Chloride Crystallization in Confinement

    PubMed Central

    2017-01-01

    We study the influence of different surfactants on NaCl crystallization during evaporation of aqueous salt solutions. We found that at concentrations of sodium chloride close to saturation, only the cationic surfactant CTAB and the nonionic surfactant Tween 80 remain stable. For the nonionic surfactant, the high concentration of salt does not significantly change either the critical micellar concentration (CMC) or the surface tension at the CMC; for the cationic surfactant, the CMC is reduced by roughly 2 orders of magnitude upon adding the salt. The presence of both types of surfactants in the salt solution delays the crystallization of sodium chloride with evaporation. This, in turn, leads to high supersaturation which induces the rapid precipitation of a hopper crystal in the bulk. The crystallization inhibitor role of these surfactants is shown to be mainly due to the passivation of nucleation sites at both liquid/air and solid/liquid interfaces rather than a change in the evaporation rate which is found not to be affected by the presence of the surfactants. The adsorption of surfactants at the liquid/air interface prevents the crystallization at this location which is generally the place where the precipitation of sodium chloride is observed. Moreover, sum frequency generation spectroscopy measurements show that the surfactants are also present at the solid/liquid interface. The incorporation of the surfactants into the salt crystals is investigated using a novel, but simple, method based on surface tension measurements. Our results show that the nonionic surfactant Tween 80 is incorporated in the NaCl crystals but the cationic surfactant CTAB is not. Taken together, these results therefore allow us to establish the effect of the presence of surfactants on sodium chloride crystallization. PMID:28425711

  17. CHARACTERIZATION OF PHASE AND EMULSION BEHAVIOR, SURFACTANT RETENTION, AND OIL RECOVERY FOR NOVEL ALCOHOL ETHOXYCARBOXYLATE SURFACTANTS

    SciTech Connect

    Lebone T. Moeti; Ramanathan Sampath

    2001-09-28

    This final technical report describes work performed under DOE Grant No. DE-FG26-97FT97278 during the period October 01, 1997 to August 31, 2001 which covers the total performance period of the project. During this period, detailed information on optimal salinity, temperature, emulsion morphologies, effectiveness for surfactant retention and oil recovery was obtained for an Alcohol Ethoxycarboxylate (AEC) surfactant to evaluate its performance in flooding processes. Tests were conducted on several AEC surfactants and NEODOX (23-4) was identified as the most suitable hybrid surfactant that yielded the best proportion in volume for top, middle, and bottom phases when mixed with oil and water. Following the selection of this surfactant, temperature and salinity scans were performed to identify the optimal salinity and temperature, and the temperature and salinity intervals in which all three phases coexisted. NEODOX 23-4 formed three phases between 4 and 52.5 C. It formed an aqueous rich microemulsion phase at high temperatures and an oleic rich microemulsion phase at low temperatures--a characteristic of the ionic part of the surfactant. The morphology measurement system was set-up successfully at CAU. The best oil/water/surfactant system defined by the above phase work was then studied for emulsion morphologies. Electrical conductivities were measured for middle and bottom phases of the NEODOX 23-4/dodecane/10mM water system and by mixing measured volumes of the middle phase into a fixed volume of the bottom phase and vice versa at room temperature. Electrical conductivity of the mixture decreased as the fraction of volume of the middle phase was increased and vice versa. Also inversion phenomena was observed. These experiments were then repeated for bottom/middle (B/M) and middle/bottom (M/B) conjugate pair phases at 10, 15, 25, 30, 35, 40, and 45 C. Electrical conductivity measurements were then compared with the predictions of the conductivity model developed in

  18. Reverse micellar extraction of bovine serum albumin - a comparison between the effects of gemini surfactant and its corresponding monomeric surfactant.

    PubMed

    Xiao, Jing; Cai, Juan; Guo, Xia

    2013-01-15

    Gemini surfactant displayed distinct advantages over monomeric surfactant in the liquid-liquid reverse micellar extraction process. First, less amount of gemini surfactant than monomeric surfactant was needed for transferring almost complete bovine serum albumin (BSA) into organic phase from aqueous phase. Second, the loading capacity of gemini surfactant reverse micelle phase was much higher than that of the corresponding monomeric surfactant reverse micelle. Third, efficient backward extraction (75-92%) of BSA could be effected in a wide pH range from 4 to 9 with gemini surfactant reverse micelle while a pH of ca. 4.3 is prerequisite to the recovery of BSA from monomeric surfactant reverse micelle. So far, the reports about the effect of surfactant structure on protein extraction have been limited. This study indicates the important role of the spacer of gemini surfactant in protein extraction process and may provide more knowledge on how to optimise surfactant structure. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Structure and Conformational Dynamics of DMPC/Dicationic Surfactant and DMPC/Dicationic Surfactant/DNA Systems

    PubMed Central

    Pietralik, Zuzanna; Krzysztoń, Rafał; Kida, Wojciech; Andrzejewska, Weronika; Kozak, Maciej

    2013-01-01

    Amphiphilic dicationic surfactants, known as gemini surfactants, are currently studied for gene delivery purposes. The gemini surfactant molecule is composed of two hydrophilic “head” groups attached to hydrophobic chains and connected via molecular linker between them. The influence of different concentrations of 1,5-bis (1-imidazolilo-3- decyloxymethyl) pentane chloride (gemini surfactant) on the thermotropic phase behaviour of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) bilayers with and without the presence of DNA was investigated using Fourier transformed infrared (FTIR) and circular dichroism (CD) spectroscopies, small angle scattering of synchrotron radiation and differential scanning calorimetry. With increasing concentration of surfactant in DMPC/DNA systems, a disappearance of pretransition and a decrease in the main phase transition enthalpy and temperature were observed. The increasing intensity of diffraction peaks as a function of surfactant concentration also clearly shows the ability of the surfactant to promote the organisation of lipid bilayers in the multilayer lamellar phase. PMID:23571492

  20. Application of peptide gemini surfactants as novel solubilization surfactants for photosystems I and II of cyanobacteria.

    PubMed

    Koeda, Shuhei; Umezaki, Katsunari; Noji, Tomoyasu; Ikeda, Atsushi; Kawakami, Keisuke; Kondo, Masaharu; Yamamoto, Yasushi; Shen, Jian-Ren; Taga, Keijiro; Dewa, Takehisa; Ito, Shigeru; Nango, Mamoru; Tanaka, Toshiki; Mizuno, Toshihisa

    2013-09-17

    We designed novel peptide gemini surfactants (PG-surfactants), DKDKC12K and DKDKC12D, which can solubilize Photosystem I (PSI) of Thermosynecoccus elongatus and Photosystem II (PSII) of Thermosynecoccus vulcanus in an aqueous buffer solution. To assess the detailed effects of PG-surfactants on the original supramolecular membrane protein complexes and functions of PSI and PSII, we applied the surfactant exchange method to the isolated PSI and PSII. Spectroscopic properties, light-induced electron transfer activity, and dynamic light scattering measurements showed that PSI and PSII could be solubilized not only with retention of the original supramolecular protein complexes and functions but also without forming aggregates. Furthermore, measurement of the lifetime of light-induced charge-separation state in PSI revealed that both surfactants, especially DKDKC12D, displayed slight improvement against thermal denaturation below 60 °C compared with that using β-DDM. This degree of improvement in thermal resistance still seems low, implying that the peptide moieties did not interact directly with membrane protein surfaces. By conjugating an electron mediator such as methyl viologen (MV(2+)) to DKDKC12K (denoted MV-DKDKC12K), we obtained derivatives that can trap the generated reductive electrons from the light-irradiated PSI. After immobilization onto an indium tin oxide electrode, a cathodic photocurrent from the electrode to the PSI/MV-DKDKC12K conjugate was observed in response to the interval of light irradiation. These findings indicate that the PG-surfactants DKDKC12K and DKDKC12D provide not only a new class of solubilization surfactants but also insights into designing other derivatives that confer new functions on PSI and PSII.

  1. Surfactant Based Enhanced Oil Recovery and Foam Mobility Control

    SciTech Connect

    George J. Hirasaki; Clarence A. Miller

    2006-09-09

    Surfactant flooding has the potential to significantly increase recovery over that of conventional waterflooding. The availability of a large number of surfactant structures makes it possible to conduct a systematic study of the relation between surfactant structure and its efficacy for oil recovery. A mixture of two surfactants was found to be particularly effective for application in carbonate formations at low temperature. The mixture is single phase for higher salinity or calcium concentrations than that for either surfactant used alone. This makes it possible to inject the surfactant slug with polymer close to optimal conditions and yet be single phase. A formulation has been designed for a particular field application. It uses partially hydrolyzed polyacrylamide for mobility control. The addition of an alkali such as sodium carbonate makes possible in situ generation of naphthenic soap and significant reduction of synthetic surfactant adsorption. The design of the process to maximize the region of ultra-low IFT takes advantage of the observation that the ratio of soap to synthetic surfactant is a parameter in the conditions for optimal salinity. Even for a fixed ratio of soap to surfactant, the range of salinity for low IFT was wider than that reported for surfactant systems in the literature. Low temperature, forced displacement experiments in dolomite and silica sandpacks demonstrate that greater than 95% recovery of the waterflood remaining oil is possible with 0.2% surfactant concentration, 0.5 PV surfactant slug, with no alcohol. Compositional simulation of the displacement process demonstrates the role of soap/surfactant ratio on passage of the profile through the ultralow IFT region, the importance of a wide salinity range of low IFT, and the importance of the viscosity of the surfactant slug. Mobility control is essential for surfactant EOR. Foam is evaluated to improve the sweep efficiency of surfactant injected into fractured reservoirs as well as a

  2. The effects of surfactant formulation on nonequilibrium NAPL solubilization

    NASA Astrophysics Data System (ADS)

    Zhong, Lirong; Mayer, Alex S.; Pope, Gary A.

    2003-01-01

    Surfactant-enhanced aquifer remediation (SEAR) involves the injection of surfactant solutions into aquifers contaminated with nonaqueous phase liquids (NAPL). Batch and column experiments were used to assess the effect of surfactant formulation on the rate of NAPL solubilization. The experimental variables were surfactant type, surfactant concentration, electrolyte concentration, and cosolvent concentration. Model equations were proposed and solved to describe solubilization under the conditions of each type of experiment. Using these models, a solubilization rate constant, kb, and an overall mass transfer rate coefficient, k, were estimated from the batch and column experiments, respectively. The solubilization rate constant was consistently sensitive to surfactant type, surfactant concentration, and electrolyte concentration. The estimated solubilization rate constants varied over two orders of magnitude. The results of the column experiments also were sensitive to the surfactant formulation. Variations in the fitted mass transfer rate coefficient parameter, β0, were related to variations in the surfactant formulations. A comparison between the results of the batch and column experiments yields an apparent relationship between β0 and kb. This relationship suggests that the mass transfer rate coefficient is directly related to the formulation of the surfactant solution.

  3. Kinematic viscosity of therapeutic pulmonary surfactants with added polymers

    PubMed Central

    Lu, Karen W.; Pérez-Gil, Jesús; Taeusch, H. William

    2009-01-01

    The addition of various polymers to pulmonary surfactants improves surface activity in experiments both in vitro and in vivo. Although the viscosity of surfactants has been investigated, the viscosity of surfactant polymer mixtures has not. In this study, we have measured the viscosities of Survanta and Infasurf with and without the addition of polyethylene glycol, dextran or hyaluronan. The measurements were carried out over a range of surfactant concentrations using two concentrations of polymers at two temperatures. Our results indicate that at lower surfactant concentrations, the addition of any polymers increased the viscosity. However, the addition of polyethylene glycol and dextran to surfactants at clinically used concentrations can substantially lower viscosity. Addition of hyaluronan at clinical surfactant concentrations slightly increased Infasurf viscosity and produced little change in Survanta viscosity. Effects of polymers on viscosity correlate with changes in size and distribution of surfactant aggregates and the apparent free volume of liquid as estimated by light microscopy. Aggregation of surfactant vesicles caused by polymers may therefore not only improve surface activity as previously shown, but may also affect viscosity in ways that could improve surfactant distribution in vivo. PMID:19366601

  4. SURFACTANT BASED ENHANCED OIL RECOVERY AND FOAM MOBILITY CONTROL

    SciTech Connect

    George J. Hirasaki; Clarence A. Miller; Gary A. Pope; Richard E. Jackson

    2004-07-01

    Surfactant flooding has the potential to significantly increase recovery over that of conventional waterflooding. The availability of a large number of surfactants makes it possible to conduct a systematic study of the relation between surfactant structure and its efficacy for oil recovery. Also, the addition of an alkali such as sodium carbonate makes possible in situ generation of surfactant and significant reduction of surfactant adsorption. In addition to reduction of interfacial tension to ultra-low values, surfactants and alkali can be designed to alter wettability to enhance oil recovery. An alkaline surfactant process is designed to enhance spontaneous imbibition in fractured, oil-wet, carbonate formations. It is able to recover oil from dolomite core samples from which there was no oil recovery when placed in formation brine. Mobility control is essential for surfactant EOR. Foam is evaluted to improve the sweep efficiency of surfactant injected into fractured reservoirs. UTCHEM is a reservoir simulator specially designed for surfactant EOR. A dual-porosity version is demonstrated as a potential scale-up tool for fractured reservoirs.

  5. The effects of surfactant formulation on nonequilibrium NAPL solubilization.

    PubMed

    Zhong, Lirong; Mayer, Alex S; Pope, Gary A

    2003-01-01

    Surfactant-enhanced aquifer remediation (SEAR) involves the injection of surfactant solutions into aquifers contaminated with nonaqueous phase liquids (NAPL). Batch and column experiments were used to assess the effect of surfactant formulation on the rate of NAPL solubilization. The experimental variables were surfactant type, surfactant concentration, electrolyte concentration, and cosolvent concentration. Model equations were proposed and solved to describe solubilization under the conditions of each type of experiment. Using these models, a solubilization rate constant, kappa(b), and an overall mass transfer rate coefficient, kappa, were estimated from the batch and column experiments, respectively. The solubilization rate constant was consistently sensitive to surfactant type, surfactant concentration, and electrolyte concentration. The estimated solubilization rate constants varied over two orders of magnitude. The results of the column experiments also were sensitive to the surfactant formulation. Variations in the fitted mass transfer rate coefficient parameter, beta(0), were related to variations in the surfactant formulations. A comparison between the results of the batch and column experiments yields an apparent relationship between beta(0) and kappa(b). This relationship suggests that the mass transfer rate coefficient is directly related to the formulation of the surfactant solution.

  6. Pulmonary surfactant adsorption is increased by hyaluronan or polyethylene glycol.

    PubMed

    Taeusch, H William; Dybbro, Eric; Lu, Karen W

    2008-04-01

    In acute lung injuries, inactivating agents may interfere with transfer (adsorption) of pulmonary surfactants to the interface between air and the aqueous layer that coats the interior of alveoli. Some ionic and nonionic polymers reduce surfactant inactivation in vitro and in vivo. In this study, we tested directly whether an ionic polymer, hyaluronan, or a nonionic polymer, polyethylene glycol, enhanced adsorption of a surfactant used clinically. We used three different methods of measuring adsorption in vitro: a modified pulsating bubble surfactometer; a King/Clements device; and a spreading trough. In addition we measured the effects of both polymers on surfactant turbidity, using this assay as a nonspecific index of aggregation. We found that both hyaluronan and polyethylene glycol significantly increased the rate and degree of surfactant material adsorbed to the surface in all three assays. Hyaluronan was effective in lower concentrations (20-fold) than polyethylene glycol and, unlike polyethylene glycol, hyaluronan did not increase apparent aggregation of surfactant. Surfactant adsorption in the presence of serum was also enhanced by both polymers regardless of whether hyaluronan or polyethylene glycol was included with serum in the subphase or added to the surfactant applied to the surface. Therefore, endogenous polymers in the alveolar subphase, or exogenous polymers added to surfactant used as therapy, may both be important for reducing inactivation of surfactant that occurs with various lung injuries.

  7. Kinematic viscosity of therapeutic pulmonary surfactants with added polymers.

    PubMed

    Lu, Karen W; Pérez-Gil, Jesús; Taeusch, H William

    2009-03-01

    The addition of various polymers to pulmonary surfactants improves surface activity in experiments both in vitro and in vivo. Although the viscosity of surfactants has been investigated, the viscosity of surfactant polymer mixtures has not. In this study, we have measured the viscosities of Survanta and Infasurf with and without the addition of polyethylene glycol, dextran or hyaluronan. The measurements were carried out over a range of surfactant concentrations using two concentrations of polymers at two temperatures. Our results indicate that at lower surfactant concentrations, the addition of any polymers increased the viscosity. However, the addition of polyethylene glycol and dextran to surfactants at clinically used concentrations can substantially lower viscosity. Addition of hyaluronan at clinical surfactant concentrations slightly increased Infasurf viscosity and produced little change in Survanta viscosity. Effects of polymers on viscosity correlate with changes in size and distribution of surfactant aggregates and the apparent free volume of liquid as estimated by light microscopy. Aggregation of surfactant vesicles caused by polymers may therefore not only improve surface activity as previously shown, but may also affect viscosity in ways that could improve surfactant distribution in vivo.

  8. [ANTIMICROBIAL ACTION OF NOCARDIA VACCINII IMV B-7405 SURFACTANTS].

    PubMed

    Pirog, T P; Beregova, K A; Savenko, I V; Shevchuk, T A; Iutynska, G O

    2015-01-01

    To study the effect of Nocardia vaccinii IMV B-7405 surfactants on some bacteria (including pathogens of genera Proteus, Staphylococcus, Enterobacter), yeast of Candida species and fungi (Aspergillus niger R-3, Fusarium culmorum T-7). The antimi- crobial properties of surfactant were determined in suspension culture by Koch method and also by index of the minimum inhibitory concentration. Surfactants were extracted from supernatant of cultural liquid by mixture of chloroform and methanol (2:1). It is shown that the antimicrobial properties of N. vaccinii IMV B-7405 surfactant depended on the degree of purification (supernatant, solution of surfactant), concentration and exposure. Survival of Escherichia coli IEM-1 and Bacillus subtilis BT-2 (both vegetative cells and spores) after treatment for 1-2 hours with surfactants solution and the supernatant (the surfactant concentration 21 µg/ml) was 3-28%. Minimum inhibitory concentrations of N. vaccinii IMV B-7405 surfactants on studied bacteria, yeast and micromycetes were 11.5-85.0; 11.5-22.5 and 165.0-325.0 µ/ml respectively. Minimum inhibitory concentrations of N. vaccinii IMV B-7405 surfactants are comparable to those of the known microbial surfactants. The possibility of using the supernatant of culture liquid as an effective antimicrobial agent noticeably simplifies and reduces the cost of the technology of its obtaining.

  9. LNAPL Removal from Unsaturated Porous Media using Surfactant Infiltration

    SciTech Connect

    Zhong, Lirong; Oostrom, Martinus

    2012-11-19

    A series of unsaturated column experiments was performed to evaluate light non-aqueous phase liquid (LNAPL) fate and removal during surfactant solution infiltration. Surfactant-LNAPL phase behavior tests were conducted to optimize the remedial solutions. Packed sand and site sediment columns were first processed to establish representative LNAPL smear zone under unsaturated conditions. Infiltration of low-concentration surfactant was then applied in a stepwise flush mode, with 0.3 column pore volume (PV) of solution in each flush. The influence of infiltrated surfactant solution volume and pH on LNAPL removal was assessed. A LNAPL bank was observed at the very front of the first surfactant infiltration in each column, indicating that a very low surfactant concentration is needed to reduce the LNAPL-water interfacial tension sufficiently enough to mobilize trapped LNAPL under unsaturated conditions. More LNAPL was recovered as additional steps of surfactant infiltration were applied. Up to 99% LNAPL was removed after six infiltration steps, with less than 2.0 PV of total surfactant solution application, suggesting surfactant infiltration may be an effective method for vadose zone LNAPL remediation. The influence of pH tested in this study (3.99~10.85) was insignificant because the buffering capacity of the sediment kept the pH in the column higher than the zero point charge, pHzpc, of the sediment and therefore the difference between surfactant sorption was negligible.

  10. Molecular simulation of surfactant-assisted protein refolding

    NASA Astrophysics Data System (ADS)

    Lu, Diannan; Liu, Zheng; Liu, Zhixia; Zhang, Minlian; Ouyang, Pingkai

    2005-04-01

    Protein refolding to its native state in vitro is a challenging problem in biotechnology, i.e., in the biomedical, pharmaceutical, and food industry. Protein aggregation and misfolding usually inhibit the recovery of proteins with their native states. These problems can be partially solved by adding a surfactant into a suitable solution environment. However, the process of this surfactant-assisted protein refolding is not well understood. In this paper, we wish to report on the first-ever simulations of surfactant-assisted protein refolding. For these studies, we defined a simple model for the protein and the surfactant and investigated how a surfactant affected the folding behavior of a two-dimensional lattice protein molecule. The model protein and model surfactant were chosen such that we could capture the important features of the folding process and the interaction between the protein and the surfactant, namely, the hydrophobic interaction. It was shown that, in the absence of surfactants, a protein in an "energy trap" conformation, i.e., a local energy minima, could not fold into the native form, which was characterized by a global energy minimum. The addition of surfactants created folding pathways via the formation of protein-surfactant complexes and thus enabled the conformations that fell into energy trap states to escape from these traps and to form the native proteins. The simulation results also showed that it was necessary to match the hydrophobicity of surfactant to the concentration of denaturant, which was added to control the folding or unfolding of a protein. The surfactants with different hydrophobicity had their own concentration range on assisting protein refolding. All of these simulations agreed well with experimental results reported elsewhere, indicating both the validity of the simulations presented here and the potential application of the simulations for the design of a surfactant on assisting protein refolding.

  11. Evaluation of mixed surfactants for improved chemical flooding

    SciTech Connect

    Llave, F.M.; French, T.R.; Lorenz, P.B.

    1993-02-01

    Phase behavior studies were conducted using combinations of a primary surfactant component and several ethoxylated surfactants. The objective of the study is to evaluate combinations of surfactants, anionic-nonionic and anionic-anionic mixtures, that would yield favorable phase behavior and solubilization capacity. The dependence of the solution behavior on the additive surfactant structure, surfactant type, oil, surfactant proportion, salinity, HLB, and temperature was observed. The results showed that the ethoxylated surfactants can improve the solution behavior of the overall system. The increase in optimum salinity range of these solutions corresponded to an increase in the degree of ethoxylation of additive surfactant, up to a certain limit. The nonionic surfactant additives yielded much higher salinities compared to the results from the ethoxylated anionics tested. The proportion of surfactant component in solution was critical in achieving a balance between the solubilization capacity and the enhancement in the system's salinity tolerance. Some combinations of these types of surfactants showed improved solution behavior with favorable solubilization capacity. The phase inversion temperature (PIT) method has been shown to be a relatively fast method for screening candidate surfactant systems. Comparisons were made using both the conventional salinity scan and the PIT method on selected chemical systems. The results showed good agreement between the salinity regions determined using both methods. A difference in the dependence of optimal salinity on HLB was observed for the different nonionics tested. The linear alkyl alcohol ethoxylates exhibited a behavior distinct from the dialkyl phenols at similar HLB levels with and without the primary sulfonate component in the solution. Other experiments performed at NIPER have shown that surfactant-enhanced alkaline flooding has good potential for the recovery of oil from Naval Petroleum Reserve Number 3 (NPR No. 3).

  12. Evaluation of mixed surfactants for improved chemical flooding

    SciTech Connect

    Llave, F.M.; French, T.R.; Lorenz, P.B.

    1993-02-01

    Phase behavior studies were conducted using combinations of a primary surfactant component and several ethoxylated surfactants. The objective of the study is to evaluate combinations of surfactants, anionic-nonionic and anionic-anionic mixtures, that would yield favorable phase behavior and solubilization capacity. The dependence of the solution behavior on the additive surfactant structure, surfactant type, oil, surfactant proportion, salinity, HLB, and temperature was observed. The results showed that the ethoxylated surfactants can improve the solution behavior of the overall system. The increase in optimum salinity range of these solutions corresponded to an increase in the degree of ethoxylation of additive surfactant, up to a certain limit. The nonionic surfactant additives yielded much higher salinities compared to the results from the ethoxylated anionics tested. The proportion of surfactant component in solution was critical in achieving a balance between the solubilization capacity and the enhancement in the system`s salinity tolerance. Some combinations of these types of surfactants showed improved solution behavior with favorable solubilization capacity. The phase inversion temperature (PIT) method has been shown to be a relatively fast method for screening candidate surfactant systems. Comparisons were made using both the conventional salinity scan and the PIT method on selected chemical systems. The results showed good agreement between the salinity regions determined using both methods. A difference in the dependence of optimal salinity on HLB was observed for the different nonionics tested. The linear alkyl alcohol ethoxylates exhibited a behavior distinct from the dialkyl phenols at similar HLB levels with and without the primary sulfonate component in the solution. Other experiments performed at NIPER have shown that surfactant-enhanced alkaline flooding has good potential for the recovery of oil from Naval Petroleum Reserve Number 3 (NPR No. 3).

  13. Next Generation Surfactants for Improved Chemical Flooding Technology

    SciTech Connect

    Laura Wesson; Prapas Lohateeraparp; Jeffrey Harwell; Bor-Jier Shiau

    2012-05-31

    The principle objective of this project was to characterize and test current and next generation high performance surfactants for improved chemical flooding technology, focused on reservoirs in the Pennsylvanian-aged (Penn) sands. In order to meet this objective the characteristic curvatures (Cc) of twenty-eight anionic surfactants selected for evaluation for use in chemical flooding formulations were determined. The Cc values ranged from -6.90 to 2.55 with the majority having negative values. Crude oil samples from nine Penn sand reservoirs were analyzed for several properties pertinent to surfactant formulation for EOR application. These properties included equivalent alkane carbon numbers, total acid numbers, and viscosity. The brine samples from these same reservoirs were analyzed for several cations and for total dissolved solids. Surfactant formulations were successfully developed for eight reservoirs by the end of the project period. These formulations were comprised of a tertiary mixture of anionic surfactants. The identities of these surfactants are considered proprietary, but suffice to say the surfactants in each mixture were comprised of varying chemical structures. In addition to the successful development of surfactant formulations for EOR, there were also two successful single-well field tests conducted. There are many aspects that must be considered in the development and implementation of effective surfactant formulations. Taking into account these other aspects, there were four additional studies conducted during this project. These studies focused on the effect of the stability of surfactant formulations in the presence of polymers with an associated examination of polymer rheology, the effect of the presence of iron complexes in the brine on surfactant stability, the potential use of sacrificial agents in order to minimize the loss of surfactant to adsorption, and the effect of electrolytes on surfactant adsorption. In these last four studies

  14. Surfactant protein B inhibits secretory phospholipase A2 hydrolysis of surfactant phospholipids

    PubMed Central

    Grier, Bonnie L.; Waite, B. Moseley; Veldhuizen, Ruud A.; Possmayer, Fred; Yao, Li-Juan; Seeds, Michael C.

    2012-01-01

    Hydrolysis of surfactant phospholipids (PL) by secretory phospholipases A2 (sPLA2) contributes to surfactant damage in inflammatory airway diseases such as acute lung injury/acute respiratory distress syndrome. We and others have reported that each sPLA2 exhibits specificity in hydrolyzing different PLs in pulmonary surfactant and that the presence of hydrophilic surfactant protein A (SP-A) alters sPLA2-mediated hydrolysis. This report tests the hypothesis that hydrophobic SP-B also inhibits sPLA2-mediated surfactant hydrolysis. Three surfactant preparations were used containing varied amounts of SP-B and radiolabeled tracers of phosphatidylcholine (PC) or phosphatidylglycerol (PG): 1) washed ovine surfactant (OS) (pre- and postorganic extraction) compared with Survanta (protein poor), 2) Survanta supplemented with purified bovine SP-B (1–5%, wt/wt), and 3) a mixture of dipalmitoylphosphatidylcholine (DPPC), 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC), and 1-palmitoyl-2-oleoyl-phosphatidylglycerol (POPG) (DPPC:POPC:POPG, 40:40:20) prepared as vesicles and monomolecular films in the presence or absence of SP-B. Hydrolysis of PG and PC by Group IB sPLA2 (PLA2G1A) was significantly lower in the extracted OS, which contains SP-B, compared with Survanta (P = 0.005), which is SP-B poor. Hydrolysis of PG and PC in nonextracted OS, which contains all SPs, was lower than both Survanta and extracted OS. When Survanta was supplemented with 1% SP-B, PG and PC hydrolysis by PLA2G1B was significantly lower (P < 0.001) than in Survanta alone. When supplemented into pure lipid vesicles and monomolecular films composed of PG and PC mixtures, SP-B also inhibited hydrolysis by both PLA2G1B and Group IIA sPLA2 (PLA2G2A). In films, PLA2G1B hydrolyzed surfactant PL monolayers at surface pressures ≤30 mN/m (P < 0.01), and SP-B lowered the surface pressure range at which hydrolysis can occur. These results suggest the hydrophobic SP, SP-B, protects alveolar surfactant PL from

  15. Bioavailability enhancement by addition of surfactant and surfactant-like compounds

    SciTech Connect

    Strong-Gunderson, J.M.; Palumbo, A.V.

    1995-12-31

    The bioavailability and microbial degradation of contaminant compounds (e.g., toluene and naphthalene) were enhanced by adding synthetic surfactants, biosurfactants, and nutrients with surfactant like properties. In addition to enhanced contaminant degradation, these surfactant compounds have the potential to change the availability of natural organic matter (NOM), and thus may affect overall site bioremediation. Two bacterial bioreporter strains that are induced by toluene or naphthalene were used to directly measure contaminant bioavailability. A cell-free biosurfactant product, Tween-80, and an oleophilic fertilizer were added to aqueous suspensions and soil slurries containing toluene or naphthalene. The addition of these surfactant compounds at or below the critical micelle concentration (CMC) enhanced bioavailability as measured by increased levels of bioluminescence. Bioluminescence data were coupled with gas chromatographic analyses. The addition of Tween-80 increased not only the bioavailability of the contaminants but also, in a separate assay, the bioavailability of recalcitrant NOM. The enhanced NOM bioavailability was inferred from measurements of biomass by optical density increases and plate counts. Thus, adding surfactant compounds for enhanced contaminant degradation has the potential to introduce additional competition for nutrients and microbial metabolism, a significant area of concern for in situ site remediation.

  16. Interfacial reactions of ozone with surfactant protein B in a model lung surfactant system.

    PubMed

    Kim, Hugh I; Kim, Hyungjun; Shin, Young Shik; Beegle, Luther W; Jang, Seung Soon; Neidholdt, Evan L; Goddard, William A; Heath, James R; Kanik, Isik; Beauchamp, J L

    2010-02-24

    Oxidative stresses from irritants such as hydrogen peroxide and ozone (O(3)) can cause dysfunction of the pulmonary surfactant (PS) layer in the human lung, resulting in chronic diseases of the respiratory tract. For identification of structural changes of pulmonary surfactant protein B (SP-B) due to the heterogeneous reaction with O(3), field-induced droplet ionization (FIDI) mass spectrometry has been utilized. FIDI is a soft ionization method in which ions are extracted from the surface of microliter-volume droplets. We report structurally specific oxidative changes of SP-B(1-25) (a shortened version of human SP-B) at the air-liquid interface. We also present studies of the interfacial oxidation of SP-B(1-25) in a nonionizable 1-palmitoyl-2-oleoyl-sn-glycerol (POG) surfactant layer as a model PS system, where competitive oxidation of the two components is observed. Our results indicate that the heterogeneous reaction of SP-B(1-25) at the interface is quite different from that in the solution phase. In comparison with the nearly complete homogeneous oxidation of SP-B(1-25), only a subset of the amino acids known to react with ozone are oxidized by direct ozonolysis in the hydrophobic interfacial environment, both with and without the lipid surfactant layer. Combining these experimental observations with the results of molecular dynamics simulations provides an improved understanding of the interfacial structure and chemistry of a model lung surfactant system subjected to oxidative stress.

  17. Hydrogels of sodium alginate in cationic surfactants: Surfactant dependent modulation of encapsulation/release toward Ibuprofen.

    PubMed

    Jabeen, Suraya; Chat, Oyais Ahmad; Maswal, Masrat; Ashraf, Uzma; Rather, Ghulam Mohammad; Dar, Aijaz Ahmad

    2015-11-20

    The interaction of cetyltrimethylammoium bromide (CTAB) and its gemini homologue (butanediyl-1,4-bis (dimethylcetylammonium bromide), 16-4-16 with biocompatible polymer sodium alginate (SA) has been investigated in aqueous medium. Addition of K2CO3 influences viscoelastic properties of surfactant impregnated SA via competition between electrostatic and hydrophobic interactions. Viscosity of these polymer-surfactant systems increases with increase in concentration of K2CO3, and a cryogel is formed at about 0.5M K2CO3 concentration. The thermal stability of gel (5% SA+0.5M K2CO3) decreases with increase in surfactant concentration, a minimum is observed with increase in 16-4-16 concentration. The impact of surfactant addition on the alginate structure vis-à-vis its drug loading capability and release thereof was studied using Ibuprofen (IBU) as the model drug. The hydrogel with 16-4-16 exhibits higher IBU encapsulation and faster release in comparison to the one containing CTAB. This higher encapsulation-cum-faster release capability has been related to micelle mediated solubilization and greater porosity of the hydrogel with gemini surfactant.

  18. Ultrafiltration of surfactant and aromatic/surfactant solutions using ceramic membranes

    SciTech Connect

    Gadelle, F.; Koros, W.J.; Schechter, R.S.

    1996-10-01

    Rejection and permeate flux taken together establish the efficiency of an ultrafiltration separation. The controllable factors that may influence the efficiency are systematically studied. These factors include transmembrane pressure, recirculation rate, membrane pore size, and solute and surfactant structure and concentration. Experiments carried out using both cationic and nonionic surfactants show that rejection decreases and permeate flux increases with membranes of increasing pore sizes. However, for the large pore size membrane (200 {angstrom}), it is also observed that rejection increases and permeate flux decreases as the filtration proceeds. These unexpected results suggest that micelles penetrate and accumulate into the larger pores, thereby reducing the effective membrane pore size. Depending on the molecular structure and concentration of the surfactant, rejection as high as 99.9% is achieved with a ceramic membrane having 65 {angstrom} pores. Permeate fluxes between 30 and 70% of pure water are observed. The addition of a solute tends to improve surfactant rejection and to decrease the permeate flux. Solute rejection increases with surfactant concentration and hydrophobicity. Solubilization isotherms determined here by ultrafiltration are shown to be in agreement with isotherms obtained with head space gas chromatography.

  19. Interfacial Reactions of Ozone with Surfactant Protein B in a Model Lung Surfactant System

    PubMed Central

    Kim, Hugh I.; Kim, Hyungjun; Shin, Young Shik; Beegle, Luther W.; Jang, Seung Soon; Neidholdt, Evan L.; Goddard, William A.; Heath, James R.; Kanik, Isik; Beauchamp, J. L.

    2010-01-01

    Oxidative stresses from irritants such as hydrogen peroxide and ozone (O3) can cause dysfunction of the pulmonary surfactant (PS) layer in the human lung, resulting in chronic diseases of the respiratory tract. For identification of structural changes of pulmonary surfactant protein B due to the heterogeneous reaction with O3, field induced droplet ionization (FIDI) mass spectrometry is utilized. FIDI is a soft ionization method in which ions are extracted from the surface of microliter-volume droplets. We report the structurally specific oxidative changes of SP-B1-25 (a shortened version of human surfactant protein B) at the air-liquid interface. We also present studies of the interfacial oxidation of SP-B1-25 in a non-ionizable 1-palmitoyl-2-oleoyl-sn-glycerol (POG) surfactant layer as a model PS system, where the competitive oxidation of the two components is observed. Our results indicate that the heterogeneous reaction of SP-B1-25 at the interface is quite different from that in the solution phase. Compared to the nearly complete homogeneous oxidation of SP-B1-25, only a subset of the amino acids known to react with ozone is oxidized by direct ozonolysis in the hydrophobic interfacial environment, both with and without the lipid monolayer. Combining these experimental observations with the results of molecular dynamics simulations provides an improved understanding of the interfacial structure and chemistry of a model lung surfactant system when subject to oxidative stress. PMID:20121208

  20. The effects of alkylammonium counterions on the aggregation of fluorinated surfactants and surfactant ionic liquids.

    PubMed

    Pottage, Matthew J; Greaves, Tamar L; Garvey, Christopher J; Tabor, Rico F

    2016-08-01

    The effects of organic counterions with varying carbon number on surfactant aggregation have been analysed by coupling perfluorooctanoate surfactant anions with various alkylammonium counterions. Both the degree of substitution (primary to tertiary) and alkyl chain length (0-3 carbons) of the counterions were varied to provide a comprehensive matrix of geometries and lipophilicities. Surface activity was measured using pendant drop tensiometry, while temperature-controlled small-angle neutron scattering was used to probe changes in aggregation morphology. It was found that the use of such alkylammonium counterions resulted in a strong preference for bilayer formation even at low surfactant concentration (<2wt%), when compared to simple inorganic counterions such as sodium which favour near-spherical micelles. At increased temperatures, some counterions led to unique phase behaviour wherein a transition between two structurally different lamellar phases is seen, rationalised as a transition into a microscopic phase separation wherein a surfactant-rich lamellar phase coexists with a dilute micellar phase. The results indicate that aggregation is controlled by a delicate balance of counterion size, hydrophilicity and diffuseness of charge, providing new methods for the subtle control of surfactant solutions.

  1. Polymer enrichment decelerates surfactant membranes near interfaces

    NASA Astrophysics Data System (ADS)

    Lipfert, F.; Frielinghaus, H.; Holderer, O.; Mattauch, S.; Monkenbusch, M.; Arend, N.; Richter, D.

    2014-04-01

    Close to a planar surface, lamellar structures are imposed upon otherwise bulk bicontinuous microemulsions. Thermally induced membrane undulations are modified by the presence of the rigid interface. While it has been shown that a pure membrane's dynamics are accelerated close to the interface, we observed nearly unchanged relaxation rates for membranes spiked with large amphiphilic diblock copolymers. An increase of the polymer concentration by a factor of 2-3 for the first and second surfactant membrane layers was observed. We interpret the reduced relaxation times as the result of an interplay between the bending rigidity and the characteristic distance of the first surfactant membrane to the rigid interface, which causes the hydrodynamic and steric interface effects described in Seifert's theory. The influence of these effects on decorated membranes yields a reduction of the frequencies and an amplification of the amplitudes of long-wavelength undulations, which are in accordance to our experimental findings.

  2. Simulation of surfactant-enhanced aquifer remediation

    NASA Astrophysics Data System (ADS)

    Brown, Chris L.; Pope, Gary A.; Abriola, Linda M.; Sepehrnoori, Kamy

    1994-11-01

    Surfactant-enhanced aquifer remediation (SEAR) is currently under active investigation as one of the most promising alternatives to conventional pump-and-treat remediation for aquifers contaminated by dense nonaqueous phase organic liquids. An existing three-dimensional finite-difference enhanced oil recovery simulator is adapted to model the SEAR process. This simulator incorporates the complex chemistry and multiphase transport behavior of surfactant/water/organic mixtures in permeable media. Model governing equations and parameter requirements are discussed, and simulations are employed to illustrate some important issues potentially affecting SEAR performance at the field scale. Simulations suggest that the total time for remediation could be reduced by more than an order of magnitude over conventional remediation approaches by employing SEAR. The assumptions, approximations, and conditions required to achieve such a favorable result are identified, and the importance of modeling as a quantitative tool for the assessment of SEAR is highlighted.

  3. Amphipols: Polymeric surfactants for membrane biology research.

    SciTech Connect

    Popot, J.-L.; Berry, E.A.; Charvolin, D.; Creuzenet, C.; Ebel, C.; Engelman, D.M.; Flotenmeyer, M.; Giusti, F.; Gohon, Y.; Hong, Q.; Lakey, J.H.; Leonard, K.; Shuman, H.A.; Timmins, P.; Warschawski, D.E.; Zito, F.; Zoonens, M.; Pucci, B.; Tribet, C.

    2003-06-20

    Membrane proteins classically are handled in aqueous solutions as complexes with detergents. The dissociating character of detergents, combined with the need to maintain an excess of them, frequently results in more or less rapid inactivation of the protein under study. Over the past few years, we have endeavored to develop a novel family of surfactants, dubbed amphipols (APs). APs are amphiphilic polymers that bind to the transmembrane surface of the protein in a noncovalent but, in the absence of a competing surfactant, quasi-irreversible manner. Membrane proteins complexed by APs are in their native state, stable, and they remain water soluble in the absence of detergent or free APs. An update is presented of the current knowledge about these compounds and their demonstrated or putative uses in membrane biology.

  4. Penetration of surfactant solutions into hydrophobic capillaries.

    PubMed

    Bain, Colin D

    2005-08-21

    The initial rise velocity of surfactant solutions in hydrophobic capillaries is independent of time (F. Tiberg, B. Zhmud, K. Hallstensson and M. von Bahr, Phys. Chem. Chem. Phys., 2000, 2, 5189). By analogy with the hydrodynamics of an overflowing cylinder, we present a steady-state solution for capillary penetration in which the velocity is determined by the adsorption kinetics at the air-water interface. Good agreement between the model predictions and experimental data of Tiberg and coworkers is obtained for the non-ionic surfactant C10E6 under the assumption of diffusion-controlled adsorption. The longer chain homologue, C14E6, shows evidence of kinetic barriers to adsorption.

  5. Liquid and surfactant delivery into pulmonary airways

    PubMed Central

    Halpern, David; Fujioka, Hideki; Takayama, Shuichi; Grotberg, James B.

    2008-01-01

    We describe the mechanisms by which liquids and surfactants can be delivered into the pulmonary airways. These are instilled and transported throughout the lung in clinical therapies such as surfactant replacement therapy, partial liquid ventilation and drug delivery. The success of these treatments is contingent on the liquid distribution and the delivery to targeted regions of the lung. The targeting of a liquid plug can be influenced by a variety of factors such as the physical properties of the liquid, the interfacial activity, the gravitational orientation, instillation method and propagation speed. We provide a review of experimental and theoretical studies that examine these effects in single tubes or channels, in tubes with single bifurcations and in the whole lung. PMID:18585985

  6. Surfactant-driven fracture of gels: Growth

    NASA Astrophysics Data System (ADS)

    Daniels, Karen; Schillaci, Mark; Bostwick, Joshua

    2012-11-01

    A droplet of surfactant spreading on a gel substrate can produce fractures on the gel surface, which originate at the contact-line and propagate outwards in a star-burst pattern. Fractures have previously been observed to initiate through a thermal process, with the number of fractures controlled by the ratio of surface tension differential to gel shear modulus. After the onset of fracture, experiments show the arm length grows with universal power law L =t 3 / 4 that does not scale with any material parameters (Daniels et al. 2007, PRL), including super-spreading surfactants (Spandangos et al. 2012, Langmuir). We develop a model for crack growth controlled by the transport of an inviscid fluid into the fracture tip. While treating the gel as a linear material correctly predicts power-law growth, we find that only by considering a Neo-Hookean (incompressible) material do we obtain agreement with the experiments.

  7. Biosurfactants: a sustainable replacement for chemical surfactants?

    PubMed

    Marchant, Roger; Banat, Ibrahim M

    2012-09-01

    Glycolipid biosurfactants produced by bacteria and yeasts provide significant opportunities to replace chemical surfactants with sustainable biologically produced alternatives in bulk commercial products such as laundry detergents and surface cleaners. Sophorolipids are already available in sufficient yield to make their use feasible while rhamnolipids and mannosylerythritol lipids require further development. The ability to tailor the biosurfactant produced to the specific needs of the product formulation will be an important future step.

  8. Surfactant-Enhanced In Situ Soils Washing

    DTIC Science & Technology

    1987-09-01

    technology . Several shortfa-- were observed and have been documented in this report. The report also contains. information on the operation of a groundwater...is 5.5 to 6.0. Atomic absorbtion analysis indicated dissolved iron levels as high as 24 mg/L in areas of high organic contamination. This iron...percent surfactant, consisting of a 50/50 mix of an ethoxylated alkyl phenol and ethoxylated fatty acid were passed through each column. Leachates from

  9. Pulmonary surfactant: phase behavior and function.

    PubMed

    Piknova, Barbora; Schram, Vincent; Hall, Stephen B

    2002-08-01

    Pulmonary surfactant functions by first flowing rapidly into the alveolar air/water interface, but then resisting collapse from the surface when the adsorbed interfacial film is compressed during exhalation. Widely accepted models emphasize the importance of phase behavior in both processes. Recent studies show, however, that fluidity is a relatively minor determinant of adsorption and that solid films, which resist collapse, can form by kinetic processes unrelated to equilibrium phase behavior.

  10. Rhamnolipid surfactants: alternative substrates, new strategies.

    PubMed

    Benincasa, Maria; Marqués, AnaM; Pinazo, Aurora; Manresa, Angels

    2010-01-01

    This chapter concentrates on the various possibilities of using alternative substrates and new strategies. Such strategies include an integrated production system to reduce the environmental impact and an attempt to minimize residues, which reinforces socio-economic and region-structural development. Additionally, we offer an overview of the physicochemical and biological properties of rhamnolipid surfactants associated with the applications of these molecules in different circumstances.

  11. O/W emulsions stabilised by both low molecular weight surfactants and colloidal particles: The effect of surfactant type and concentration.

    PubMed

    Pichot, R; Spyropoulos, F; Norton, I T

    2010-12-01

    The stability against coalescence of O/W emulsions in the presence of both surfactants and colloidal particles was investigated. In particular the effect of the surfactant type and concentration in these emulsifier mixtures on the O/W emulsions' stability was studied. Two types of surfactants were selected; those that have the ability to stabilise O/W emulsions on their own (O/W surfactants) and those that cannot (W/O surfactants). Tween 60 and Sodium Caseinate were selected as the O/W surfactants and lecithin as the W/O surfactant. Oil-in-water emulsions prepared with both particles and any of the three surfactants were stable against coalescence but, depending on the type of surfactant, the behaviour of the systems was found to depend on surfactant concentration. The droplet sizes of emulsions stabilised by mixed emulsifier systems containing low concentrations of O/W surfactants (Tween 60 or Sodium Caseinate) were smaller than those solely stabilised by either the surfactant or particles alone. At intermediate O/W surfactants concentrations, the droplet sizes of the emulsions increased. Further increases in the O/W surfactants' concentration, resulted in the complete removal of particles from the interface with the system now behaving as a surfactant-only stabilised emulsion. The behaviour of emulsions stabilised by emulsifier mixtures containing W/O surfactants was not dependent on the concentration of surfactant: no removal of particles was observed. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Use of micellar-enhanced ultrafiltration at low surfactant concentrations and with anionic-nonionic surfactant mixtures

    SciTech Connect

    Fillipi, B.R.; Brant, L.W.; Scamehorn, J.F.; Christian, S.D.

    1999-05-01

    Micellar-enhanced ultrafiltration is a separation technique which can be used to remove metal ions or dissolved organics from water. Metal ions bind to the surface of negatively charged micelles of an anionic surfactant while organic solutes tend to dissolve or solubilized within the micelles. The mixture is then forced through an ultrafiltration membrane with pore sizes small enough to block passage of the micelles and associated metal ions and/or dissolved organics. Monomeric or unassociated surfactant passes through the membrane and does not contribute to the separation. This paper considers advantages of addition of small concentrations of nonionic surfactant to an anionic surfactant; the resulting anionic-nonionic mixed micelles exhibit negative deviation from ideality of mixing which leads to a smaller fraction of the surfactant being present as monomer and a subsequently larger fraction present in the micellar form. The addition of nonionic surfactant improved the separation of divalent zinc substantially at total concentrations above the critical micelle concentration (cmc) of the anionic surfactant. Both zinc and tert-butylphenol (a nonionic organic solute) show unexpected rejection at surfactant concentrations moderately below the cmc, where micelles are absent. This is considered as due to a higher surfactant concentration in the gel layer adjacent to the membrane where micelles are present. Reduction of this rejection at lower transmembrane pressure drops supports this mechanism. Some rejection of zinc was observed in the absence of surfactant but not of tert-butylphenol, indicating an additional effect of membrane charge for ionic solutes.

  13. Effects of less-invasive surfactant administration on oxygenation, pulmonary surfactant distribution, and lung compliance in spontaneously breathing preterm lambs.

    PubMed

    Niemarkt, Hendrik J; Kuypers, Elke; Jellema, Reint; Ophelders, Daan; Hütten, Matthias; Nikiforou, Maria; Kribs, Angela; Kramer, Boris W

    2014-08-01

    A new technique was proposed to administer surfactant to spontaneous breathing preterm infants by placing a thin catheter through the vocal cords. This technique was not studied with respect to oxygenation, gas exchange, surfactant distribution, and lung mechanics. We tested the technique of less-invasive surfactant administration (LISA) in a spontaneous breathing preterm lamb model. Preterm lambs (n = 12) of 133-134 d gestational age were randomized to the following three groups: (i) continuous positive airway pressure (CPAP) only, (ii) CPAP + LISA, and (iii) intubation and mechanical ventilation with surfactant administration. Surfactant was labeled with samarium oxide. During the next 180 min, blood gas analyses were performed. Postmortem, lungs were removed and surfactant distribution was assessed, and pressure-volume curves were performed. Pao2 in the LISA-treated lambs was significantly higher than in the lambs that exclusively received CPAP. Moreover, Pao2 values were similar between the LISA-treated and the intubated lambs. Overall, surfactant deposition was less in the LISA lambs, with significantly less surfactant distributed to the right upper lobe. Lung compliance was better in the intubated lambs compared with the LISA-treated lambs, although this did not reach significance. LISA improved oxygenation, similar to conventional surfactant application techniques, despite lower surfactant deposition and lung compliance.

  14. Surfactant-enhanced remediation of organic contaminated soil and water.

    PubMed

    Paria, Santanu

    2008-04-21

    Surfactant based remediation technologies for organic contaminated soil and water (groundwater or surface water) is of increasing importance recently. Surfactants are used to dramatically expedite the process, which in turn, may reduce the treatment time of a site compared to use of water alone. In fact, among the various available remediation technologies for organic contaminated sites, surfactant based process is one of the most innovative technologies. To enhance the application of surfactant based technologies for remediation of organic contaminated sites, it is very important to have a better understanding of the mechanisms involved in this process. This paper will provide an overview of the recent developments in the area of surfactant enhanced soil and groundwater remediation processes, focusing on (i) surfactant adsorption on soil, (ii) micellar solubilization of organic hydrocarbons, (iii) supersolubilization, (iv) density modified displacement, (v) degradation of organic hydrocarbon in presence surfactants, (vi) partitioning of surfactants onto soil and liquid organic phase, (vii) partitioning of contaminants onto soil, and (viii) removal of organics from soil in presence of surfactants. Surfactant adsorption on soil and/or sediment is an important step in this process as it results in surfactant loss reduced the availability of the surfactants for solubilization. At the same time, adsorbed surfactants will retained in the soil matrix, and may create other environmental problem. The biosurfactants are become promising in this application due to their environmentally friendly nature, nontoxic, low adsorption on to soil, and good solubilization efficiency. Effects of different parameters like the effect of electrolyte, pH, soil mineral and organic content, soil composition etc. on surfactant adsorption are discussed here. Micellar solubilization is also an important step for removal of organic contaminants from the soil matrix, especially for low aqueous

  15. Water repellency induced by pulmonary surfactants.

    PubMed

    Hills, B A

    1982-04-01

    1. Pure cotton fabric was partially carboxylated to produce a tough, porous, hydrophilic sub-phase to stimulate the epithelial membrane of the alveolar wall from a permeability standpoint. 2. Two of the predominant pulmonary surfactants, dipalmitoyl lecithin (DPL) and dipalmitoyl phosphatidylethanolamine (DPPE), were found to inhibit wetting of this synthetic membrane and of human cutaneous epithelium as manifest by a large contact angle. 3. When treated with DPL at physiological concentrations, the porous synthetic membrane was found to support a head of saline well in excess of systolic pulmonary artery pressure with no penetration and could do so for periods well in excess of 1 hr; untreated control samples allowed almost immediate fluid filtration. 4. Filtration could be initiated in the DPL-treated membranes by wetting the reverse side, confirming that the threshold pressure for fluid penetration was afforded by capillarity and, hence, by water repellency induced by the surfactant. 5. Water repellency induced by the amphoteric surfactants occurring naturally in the lung is discussed as a possible factor contributing to the pressure threshold to be exceeded for alveolar oedema to form. 6. Evidence is reviewed and several advantages discussed for the implied concept of an essentially dry lining to the alveolus with a discontinuous liquid layer largely confined to convex corners which could slowly resolve any oedema by surface forces.

  16. Water repellency induced by pulmonary surfactants.

    PubMed Central

    Hills, B A

    1982-01-01

    1. Pure cotton fabric was partially carboxylated to produce a tough, porous, hydrophilic sub-phase to stimulate the epithelial membrane of the alveolar wall from a permeability standpoint. 2. Two of the predominant pulmonary surfactants, dipalmitoyl lecithin (DPL) and dipalmitoyl phosphatidylethanolamine (DPPE), were found to inhibit wetting of this synthetic membrane and of human cutaneous epithelium as manifest by a large contact angle. 3. When treated with DPL at physiological concentrations, the porous synthetic membrane was found to support a head of saline well in excess of systolic pulmonary artery pressure with no penetration and could do so for periods well in excess of 1 hr; untreated control samples allowed almost immediate fluid filtration. 4. Filtration could be initiated in the DPL-treated membranes by wetting the reverse side, confirming that the threshold pressure for fluid penetration was afforded by capillarity and, hence, by water repellency induced by the surfactant. 5. Water repellency induced by the amphoteric surfactants occurring naturally in the lung is discussed as a possible factor contributing to the pressure threshold to be exceeded for alveolar oedema to form. 6. Evidence is reviewed and several advantages discussed for the implied concept of an essentially dry lining to the alveolus with a discontinuous liquid layer largely confined to convex corners which could slowly resolve any oedema by surface forces. Images Fig. 2 Fig. 3 PMID:6896727

  17. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2003-10-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. We have conducted adsorption, phase behavior, interfacial tension (IFT) and wettability studies. Alfoterra-38 (0.05 wt%), Alfoterra-35 (0.05 wt%), SS-6656 (0.05 wt%), and DTAB (1 wt%) altered the wettability of the initially oil-wet calcite plate to an intermediate/water-wet state. Low IFT ({approx}10{sup -3} dynes/cm) is obtained with surfactants 5-166, Alfoterra-33 and Alfoterra-38. Plans for the next quarter include conducting wettability and mobilization studies.

  18. Probing Nanoscale Thermal Transport in Surfactant Solutions

    PubMed Central

    Cao, Fangyu; Liu, Ying; Xu, Jiajun; He, Yadong; Hammouda, B.; Qiao, Rui; Yang, Bao

    2015-01-01

    Surfactant solutions typically feature tunable nanoscale, internal structures. Although rarely utilized, they can be a powerful platform for probing thermal transport in nanoscale domains and across interfaces with nanometer-size radius. Here, we examine the structure and thermal transport in solution of AOT (Dioctyl sodium sulfosuccinate) in n-octane liquids using small-angle neutron scattering, thermal conductivity measurements, and molecular dynamics simulations. We report the first experimental observation of a minimum thermal conductivity occurring at the critical micelle concentration (CMC): the thermal conductivity of the surfactant solution decreases as AOT is added till the onset of micellization but increases as more AOT is added. The decrease of thermal conductivity with AOT loading in solutions in which AOT molecules are dispersed as monomers suggests that even the interfaces between individual oleophobic headgroup of AOT molecules and their surrounding non-polar octane molecules can hinder heat transfer. The increase of thermal conductivity with AOT loading after the onset of micellization indicates that the thermal transport in the core of AOT micelles and across the surfactant-oil interfaces, both of which span only a few nanometers, are efficient. PMID:26534840

  19. Therapeutic surfactant-stripped frozen micelles

    NASA Astrophysics Data System (ADS)

    Zhang, Yumiao; Song, Wentao; Geng, Jumin; Chitgupi, Upendra; Unsal, Hande; Federizon, Jasmin; Rzayev, Javid; Sukumaran, Dinesh K.; Alexandridis, Paschalis; Lovell, Jonathan F.

    2016-05-01

    Injectable hydrophobic drugs are typically dissolved in surfactants and non-aqueous solvents which can induce negative side-effects. Alternatives like `top-down' fine milling of excipient-free injectable drug suspensions are not yet clinically viable and `bottom-up' self-assembled delivery systems usually substitute one solubilizing excipient for another, bringing new issues to consider. Here, we show that Pluronic (Poloxamer) block copolymers are amenable to low-temperature processing to strip away all free and loosely bound surfactant, leaving behind concentrated, kinetically frozen drug micelles containing minimal solubilizing excipient. This approach was validated for phylloquinone, cyclosporine, testosterone undecanoate, cabazitaxel and seven other bioactive molecules, achieving sizes between 45 and 160 nm and drug to solubilizer molar ratios 2-3 orders of magnitude higher than current formulations. Hypertonic saline or co-loaded cargo was found to prevent aggregation in some cases. Use of surfactant-stripped micelles avoided potential risks associated with other injectable formulations. Mechanistic insights are elucidated and therapeutic dose responses are demonstrated.

  20. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2005-07-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. Laboratory imbibition tests show that imbibition rate is not very sensitive to the surfactant concentration (in the range of 0.05-0.2 wt%) and small amounts of trapped gas saturation. It is however very sensitive to oil permeability and water-oil-ratio. Less than 0.5 M Na2CO3 is needed for in situ soap generation and low adsorption; NaCl can be added to reach the necessary total salinity. The simulation result matches the laboratory imbibition experimental data. Small fracture spacing and high permeability would be needed for high rate of recovery.

  1. How surfactants influence evaporation-driven flows

    NASA Astrophysics Data System (ADS)

    Liepelt, Robert; Marin, Alvaro; Rossi, Massimiliano; Kähler, Christian J.

    2014-11-01

    Capillary flows appear spontaneously in sessile evaporating drops and give rise to particle accumulation around the contact lines, commonly known as coffee-stain effect (Deegan et al., Nature, 1997). On the other hand, out-of-equilibrium thermal effects may induce Marangoni flows in the droplet's surface that play an important role in the flow patterns and in the deposits left on the substrate. Some authors have argued that contamination or the presence of surfactants might reduce or eventually totally annul the Marangoni flow (Hu & Larson, J. Phys. Chem. B, 2006). On the contrary, others have shown an enhancement of the reverse surface flow (Sempels et al., Nat. Commun., 2012). In this work, we employ Astigmatic Particle Tracking Velocimetry (APTV) to obtain the 3D3C evaporation-driven flow in both bulk and droplet's surface, using surfactants of different ionic characters and solubility. Our conclusions lead to a complex scenario in which different surfactants and concentrations yield very different surface-flow patterns, which eventually might influence the colloidal deposition patterns.

  2. Surfactant-enhanced bicarbonate flooding. Final report

    SciTech Connect

    Peru, D.A.

    1986-10-01

    Coalescence rate constants were calculated for systems containing alcohol ethoxysulfate both with and without TRONACRAB (sodium bicarbonate). All systems containing TRONACRAB above 3.8% total salinity had higher coalescence rate constants than systems not containing TRONACARB. The results indicate that TRONACARB promotes faster coalescence of crude oil-surfactant brine emulsions. Additions of TRONACARB to preflush brine was found to be more economical than chloride brine in reducing divalent ion concentration. Silicon (Si) concentrations did not exceed 24 ppm after TRONACARB was in contact with Berea sandstone for 1 week at 42/sup 0/C. The occurrence of silica scales is expected to be minimal when using TRONACARB in chemical flooding or in a preflush. A chemical slug containing TRONACARB, petroleum sulfate, and polymer recovered from 6 to 20% more residual oil than did systems containing either: TRONACARB plus polymer or surfactant plus polymer. The results from the oil-displacement tests indicate that a synergistic relationship exists between TRONACARB and low concentrations of surfactant and polymer whereby the oil-recovery efficiency was improved, and the chemical cost per barrel of oil recovered was decreased when the three chemicals were used together. 8 refs., 9 figs., 5 tabs.

  3. Environmentally compatible surfactants for the cosmetic industry.

    PubMed

    Berger, H

    1997-10-01

    From the application pattern of surfactant-containing cosmetic products, it is inevitable that the major part of the chemicals will be discharged into waste water and eventually will enter the environment. Because the environmental compatibility of the products is based on the ecological properties of their raw meterials, the biodegradability and ecotoxicological behaviour of the product components and particularly the surfactants, form the central elements of the environmental compatibility assessment. The tools for this evaluation are standardized test systems, which are described and discussed on the basis of the ecological data of selected surfactants. De par le type d'application des produits cosmetiques contenant des tensioactifs, il est inevitable que la plus grande partie des substances chimiques soit evacuee dans les eaux usees et finisse par arriver dans l'environnement. Puisque la compatibilite environnementale des produits est basee sur les proprietes ecologiques de leurs matieres premieres, la biodegradabilite et le comportement ecotoxicologique des composants des produits, et en particulier des tensioactifs, forment les elements majeurs de l'evaluation de la compatibilite environnementale. Les outils de cette evaluation sont des systemes d'essai normalises, qui sont decrits et commentes d'apres les donnees ecologiques de tensioactifs choisis.

  4. The Accelerated Late Adsorption of Pulmonary Surfactant

    PubMed Central

    2011-01-01

    Adsorption of pulmonary surfactant to an air−water interface lowers surface tension (γ) at rates that initially decrease progressively, but which then accelerate close to the equilibrium γ. The studies here tested a series of hypotheses concerning mechanisms that might cause the late accelerated drop in γ. Experiments used captive bubbles and a Wilhelmy plate to measure γ during adsorption of vesicles containing constituents from extracted calf surfactant. The faster fall in γ reflects faster adsorption rather than any feature of the equation of state that relates γ to surface concentration (Γ). Adsorption accelerates when γ reaches a critical value rather than after an interval required to reach that γ. The hydrophobic surfactant proteins (SPs) represent key constituents, both for reaching the γ at which the acceleration occurs and for producing the acceleration itself. The γ at which rates of adsorption increase, however, is unaffected by the Γ of protein in the films. In the absence of the proteins, a phosphatidylethanolamine, which, like the SPs, induces fusion of the vesicles with the interfacial film, also causes adsorption to accelerate. Our results suggest that the late acceleration is characteristic of adsorption by fusion of vesicles with the nascent film, which proceeds more favorably when the Γ of the lipids exceeds a critical value. PMID:21417351

  5. Dynamics of surfactants spreading on gel layers

    NASA Astrophysics Data System (ADS)

    Spandagos, Constantine; Luckham, Paul; Matar, Omar

    2009-11-01

    Gel-like materials are of central importance to a large number of engineering, biological, biomedical and day-life applications. This work attempts to investigate the spreading of droplets of surfactant solutions on agar gels, which is accompanied by cracking of the gel layers. The cracking progresses via the formation of patterns that resemble ``starbursts,'' which have been reported recently in the literature by Daniels et al. Marangoni stresses generated by surface tension gradients between the surfactant droplet and the uncontaminated gel layer are identified to be the driving force behind these phenomena. The morphology and dynamics of the starburst patterns are investigated for droplets of different surfactant solutions, including sodiumdodecylsulphate, spreading on gel layers of different strengths. The instability is characterised in terms of the number of arms that form, and their mean width and length as a function of time. In addition, photoelasticity is used to provide information about the stress field of the material, which, combined with the results from our direct visualisation, can elucidate further the mechanisms underlying the pattern formation and the nature of the interactions between the liquid and the gel.

  6. Therapeutic surfactant-stripped frozen micelles

    PubMed Central

    Zhang, Yumiao; Song, Wentao; Geng, Jumin; Chitgupi, Upendra; Unsal, Hande; Federizon, Jasmin; Rzayev, Javid; Sukumaran, Dinesh K.; Alexandridis, Paschalis; Lovell, Jonathan F.

    2016-01-01

    Injectable hydrophobic drugs are typically dissolved in surfactants and non-aqueous solvents which can induce negative side-effects. Alternatives like ‘top-down' fine milling of excipient-free injectable drug suspensions are not yet clinically viable and ‘bottom-up' self-assembled delivery systems usually substitute one solubilizing excipient for another, bringing new issues to consider. Here, we show that Pluronic (Poloxamer) block copolymers are amenable to low-temperature processing to strip away all free and loosely bound surfactant, leaving behind concentrated, kinetically frozen drug micelles containing minimal solubilizing excipient. This approach was validated for phylloquinone, cyclosporine, testosterone undecanoate, cabazitaxel and seven other bioactive molecules, achieving sizes between 45 and 160 nm and drug to solubilizer molar ratios 2–3 orders of magnitude higher than current formulations. Hypertonic saline or co-loaded cargo was found to prevent aggregation in some cases. Use of surfactant-stripped micelles avoided potential risks associated with other injectable formulations. Mechanistic insights are elucidated and therapeutic dose responses are demonstrated. PMID:27193558

  7. Micellar electrokinetic chromatography with acid labile surfactant.

    PubMed

    Stanley, Bob; Lucy, Charles A

    2012-02-24

    We present a study of a degradable surfactant, sodium 4-[(2-methyl-2-undecyl-1,3-dioxolan-4-yl)methoxy]-1-propane sulfonate that is also known as an acid-labile surfactant (ALS). The performance of ALS as a pseudostationary phase is assessed and compared with established pseudostationary phases such as sodium dodecyl sulphate (SDS), volatile surfactants and polymeric micelles. ALS achieves separation efficiency of 100,000-145,000 theoretical plates and relative standard deviation (RSD) of electrophoretic mobility (n=5) of less than 3%. Retention factors with ALS are strongly correlated with those with SDS. This is shown by the R2=0.79 for all eleven analytes and an R2=0.992 for specifically the non-hydrogen bonding (NHB) analytes. However, ALS displays different selectivity than SDS for hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA) solutes (R2 of 0.74 and 0.88, respectively). ALS is degraded to less surface active compounds in acidic solution. These less surface-active compounds are more compatible with the electrospray ionization mass spectrometry (ESI-MS). ALS has a half-life of 48 min at pH 4. ALS has the potential to couple micellar electrokinetic chromatography (MEKC) with the ESI-MS. ALS can be used as a pseudostationary phase for a high efficiency separation and later acid hydrolyzed to enable an ESI-MS analysis. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Distribution of surfactants in latex films: a Rutherford Backscattering study.

    PubMed

    Lee, Wai Peng; Gundabala, Venkata R; Akpa, Belinda S; Johns, Michael L; Jeynes, Chris; Routh, Alexander F

    2006-06-06

    Uneven distribution of surfactant in dried latex films can affect the final film properties such as its water-resistance, gloss, and adhesiveness. Therefore, it is important to understand the driving force for surfactant transport during drying. In this paper, the accumulation of surfactant on the surface of poly(styrene-co-butyl acrylate) latex is studied using Rutherford Backscattering (RBS) and compared with results from a model that is based on the diffusive transport of particles and surfactant. Experimentally, a 30-50 nm thick surface layer, rich in surfactant, is seen and the concentration in the bulk of the film, obtained from RBS, agrees, at least qualitatively, with the model predictions for two of the surfactants tested.

  9. Rheological properties of ovalbumin hydrogels as affected by surfactants addition.

    PubMed

    Hassan, Natalia; Messina, Paula V; Dodero, Veronica I; Ruso, Juan M

    2011-04-01

    The gel properties of ovalbumin mixtures with three different surfactants (sodium perfluorooctanoate, sodium octanoate and sodium dodecanoate) have been studied by rheological techniques. The gel elasticities were determined as a function of surfactant concentration and surfactant type. The fractal dimension of the formed structures was evaluated from plots of storage modulus against surfactant concentration. The role of electrostatic, hydrophobic and disulfide SS interactions in these systems has been demonstrated to be the predominant. The viscosity of these structures tends to increase with surfactant concentration, except for the fluorinated one. Unfolded ovalbumin molecules tend to form fibrillar structures that tend to increase with surfactant concentration, except for the fluorinated one. This fact has been related to the particular nature of this molecule. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Enhancement of enzymatic hydrolysis of cellulose by surfactant

    SciTech Connect

    Ooshima, H.; Sakata, M.; Harano, Y.

    1986-01-01

    Effects of surfactants on enzymatic saccharification of cellulose have been studied. Nonionic, amphoteric, and cationic surfactants enhanced the saccharification, while anionic surfactant did not. Cationic and anionic surfactants denatured cellulase in their relatively low concentrations, namely, more than 0.008 and 0.001%, respectively. Using nonionic surfactant Tween 20, which is most effective to the enhancement (e.g., the fractional conversion attained by 72 h saccharification of 5 wt % Avicel in the presence of 0.05 wt % Tween 20 is increased by 35%), actions of surfactant have been examined. As the results, it was suggested that Tween 20 plays an important role in the hydrolysis of crystalline cellulose and that Tween 20 disturbs the adsorption of endoglucanase on cellulose, i.e., varies the adsorption balance of endo- and exoglucanase, resulting in enhancing the reaction. The influence of Tween 20 to the saccharification was found to remain in simultaneous saccharification and fermentation of Avicel.

  11. Gemini imidazolium surfactants: synthesis and their biophysiochemical study.

    PubMed

    Kamboj, Raman; Singh, Sukhprit; Bhadani, Avinash; Kataria, Hardeep; Kaur, Gurcharan

    2012-08-21

    New gemini imidazolium surfactants 9-13 have been synthesized by a regioselective epoxy ring-opening reaction under solvent-free conditions. The surface properties of these new gemini surfactants were evaluated by surface tension and conductivity measurements. These surfactants have been found to have low critical micelle concentration (cmc) values as compared to other categories of gemini cationic surfactants and also showed the tendency to form premicellar aggregates in solution at sufficiently low concentration below their cmc values. The thermal degradation of these surfactants was determined by thermograviometry analysis (TGA). These new cationic surfactants have a good DNA binding capability as determined by agarose gel electrophoresis and ethidium bromide exclusion experiments. They have also been found to have low cytotoxicity by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay on the C6 glioma cell line.

  12. Estimation hydrophilic-lipophilic balance number of surfactants

    SciTech Connect

    Pawignya, Harsa; Prasetyaningrum, Aji Kusworo, Tutuk D.; Pramudono, Bambang; Dyartanti, Endah R.

    2016-02-08

    Any type of surfactant has a hydrophilic-lipophilic balance number (HLB number) of different. There are several methods for determining the HLB number, with ohysical properties of surfactant (solubility cloud point and interfacial tension), CMC methods and by thermodynamics properties (Free energy Gibbs). This paper proposes to determined HLB numbers from interfelation methods. The result of study indicated that the CMC method described by Hair and Moulik espesially for nonionic surfactant. The application of exess Gibbs free energy and by implication activity coefficient provides the ability to predict the behavior of surfactants in multi component mixtures of different concentration. Determination of HLB number by solubility and cloud point parameter is spesific for anionic and nonionic surfactant but this methods not available for cationic surfactants.

  13. [Pulmonary surfactant homeostasis associated genetic abnormalities and lung diseases].

    PubMed

    Jiang, Xiaojing; Sun, Xiuzhu; Du, Weihua; Hao, Haisheng; Zhao, Xueming; Wang, Dong; Zhu, Huabin; Liu, Yan

    2016-08-01

    Pulmonary surfactant (PS) is synthesized and secreted by alveolar epithelial type II (AEII) cells, which is a complex compound formed by proteins and lipids. Surfactant participates in a range of physiological processes such as reducing the surface tension, keeping the balance of alveolar fluid, maintaining normal alveolar morphology and conducting host defense. Genetic disorders of the surfactant homeostasis genes may result in lack of surfactant or cytotoxicity, and lead to multiple lung diseases in neonates, children and adults, including neonatal respiratory distress syndrome, interstitial pneumonia, pulmonary alveolar proteinosis, and pulmonary fibrosis. This paper has provided a review for the functions and processes of pulmonary surfactant metabolism, as well as the connection between disorders of surfactant homeostasis genes and lung diseases.

  14. Numerical simulation of drop and bubble dynamics with soluble surfactant

    NASA Astrophysics Data System (ADS)

    Wang, Qiming; Siegel, Michael; Booty, Michael R.

    2014-05-01

    Numerical computations are presented to study the effect of soluble surfactant on the deformation and breakup of an axisymmetric drop or bubble stretched by an imposed linear strain flow in a viscous fluid. At the high values of bulk Peclet number Pe in typical fluid-surfactant systems, there is a thin transition layer near the interface in which the surfactant concentration varies rapidly. The large surfactant gradients are resolved using a fast and accurate "hybrid" numerical method that incorporates a separate, singular perturbation analysis of the dynamics in the transition layer into a full numerical solution of the free boundary problem. The method is used to investigate the dependence of drop deformation on parameters that characterize surfactant solubility. We also compute resolved examples of tipstreaming, and investigate its dependence on parameters such as flow rate and bulk surfactant concentration.

  15. Surfactant effects on environmental behavior of pesticides.

    PubMed

    Katagi, Toshiyuki

    2008-01-01

    The potential effects of adjuvants, including surfactants used in pesticide formulation, have been extensively studied for many small organic chemicals, but similar investigation on pesticides is limited in most cases. Solubilizing effects leading to the apparently increased water solubility of a pesticide are commonly known through the preparation of formulations, but fundamental profiles, especially for a specific monodisperse surfactant, are not fully studied. Reduced volatilization of a pesticide from the formulation can be explained by analogy of a very simple organic chemical, but the actual mechanism for the pesticide is still obscure. In contrast, from the point of view of avoiding groundwater contamination with a pesticide, adsorption/desorption profiles in the presence of surfactants and adjuvants have been examined extensively as well as pesticide mobility in the soil column. The basic mechanism in micelle-catalyzed hydrolysis is well known, and theoretical approaches including the PPIE model have succeeded in explaining the observed effects of surfactants, but its application to pesticides is also limited. Photolysis, especially in an aqueous phase, is in the same situation. The dilution effect in the real environment would show these effects on hydrolysis and photolysis to be much less than expected from the laboratory basic studies, but more information is necessary to examine the practical extent of the effects in an early stage of applying a pesticide formulation to crops and soil. Many adjuvants, including surfactants, are biodegradable in the soil environment, and thus their effects on the biodegradation of a pesticide in soil and sediment may be limited, as demonstrated by field trials. Not only from the theoretical but also the practical aspect, the foliar uptake of pesticide in the presence of adjuvants has been investigated extensively and some prediction on the ease of foliar uptake can be realized in relation to the formulation technology

  16. Surfactant Based Enhanced Oil Recovery and Foam Mobility Control

    SciTech Connect

    George J. Hirasaki; Clarence A. Miller; Gary A. Pope

    2005-07-01

    Surfactant flooding has the potential to significantly increase recovery over that of conventional waterflooding. The availability of a large number of surfactant structures makes it possible to conduct a systematic study of the relation between surfactant structure and its efficacy for oil recovery. A combination of two surfactants was found to be particularly effective for application in carbonate formations at low temperature. A formulation has been designed for a particular field application. The addition of an alkali such as sodium carbonate makes possible in situ generation of surfactant and significant reduction of surfactant adsorption. In addition to reduction of interfacial tension to ultra-low values, surfactants and alkali can be designed to alter wettability to enhance oil recovery. The design of the process to maximize the region of ultra-low IFT is more challenging since the ratio of soap to synthetic surfactant is a parameter in the conditions for optimal salinity. Compositional simulation of the displacement process demonstrates the interdependence of the various components for oil recovery. An alkaline surfactant process is designed to enhance spontaneous imbibition in fractured, oil-wet, carbonate formations. It is able to recover oil from dolomite core samples from which there was no oil recovery when placed in formation brine. Mobility control is essential for surfactant EOR. Foam is evaluated to improve the sweep efficiency of surfactant injected into fractured reservoirs. UTCHEM is a reservoir simulator specially designed for surfactant EOR. It has been modified to represent the effects of a change in wettability. Simulated case studies demonstrate the effects of wettability.

  17. Surfactant development for enhanced oil recover. Final report

    SciTech Connect

    1996-07-01

    The general objective of the project is to develop novel surfactants for tertiary recovery of light oil at elevated temperatures and high brine concentrations. Specific objectives are: to design, synthesize and characterize new surfactants capable of forming microemulsions of high stability at high temperatures and high salinity; to select microemulsions that will yield optimum efficiency and effectiveness in oil solubilization; to characterize the physico-chemical properties of selected microemulsion; to correlate surfactant efficacy with physico-chemical variables of selected reservoirs.

  18. The Pulmonary Surfactant: Impact of Tobacco Smoke and Related Compounds on Surfactant and Lung Development

    PubMed Central

    Scott, J Elliott

    2004-01-01

    Cigarette smoking, one of the most pervasive habits in society, presents many well established health risks. While lung cancer is probably the most common and well documented disease associated with tobacco exposure, it is becoming clear from recent research that many other diseases are causally related to smoking. Whether from direct smoking or inhaling environmental tobacco smoke (ETS), termed secondhand smoke, the cells of the respiratory tissues and the lining pulmonary surfactant are the first body tissues to be directly exposed to the many thousands of toxic chemicals in tobacco. Considering the vast surface area of the lung and the extreme attenuation of the blood-air barrier, it is not surprising that this organ is the primary route for exposure, not just to smoke but to most environmental contaminants. Recent research has shown that the pulmonary surfactant, a complex mixture of phospholipids and proteins, is the first site of defense against particulates or gas components of smoke. However, it is not clear what effect smoke has on the surfactant. Most studies have demonstrated that smoking reduces bronchoalveolar lavage phospholipid levels. Some components of smoke also appear to have a direct detergent-like effect on the surfactant while others appear to alter cycling or secretion. Ultimately these effects are reflected in changes in the dynamics of the surfactant system and, clinically in changes in lung mechanics. Similarly, exposure of the developing fetal lung through maternal smoking results in postnatal alterations in lung mechanics and higher incidents of wheezing and coughing. Direct exposure of developing lung to nicotine induces changes suggestive of fetal stress. Furthermore, identification of nicotinic receptors in fetal lung airways and corresponding increases in airway connective tissue support a possible involvement of nicotine in postnatal asthma development. Finally, at the level of the alveoli of the lung, colocalization of nicotinic

  19. The Pulmonary Surfactant: Impact of Tobacco Smoke and Related Compounds on Surfactant and Lung Development

    PubMed Central

    Scott, J Elliott

    2004-01-01

    Cigarette smoking, one of the most pervasive habits in society, presents many well established health risks. While lung cancer is probably the most common and well documented disease associated with tobacco exposure, it is becoming clear from recent research that many other diseases are causally related to smoking. Whether from direct smoking or inhaling environmental tobacco smoke (ETS), termed secondhand smoke, the cells of the respiratory tissues and the lining pulmonary surfactant are the first body tissues to be directly exposed to the many thousands of toxic chemicals in tobacco. Considering the vast surface area of the lung and the extreme attenuation of the blood-air barrier, it is not surprising that this organ is the primary route for exposure, not just to smoke but to most environmental contaminants. Recent research has shown that the pulmonary surfactant, a complex mixture of phospholipids and proteins, is the first site of defense against particulates or gas components of smoke. However, it is not clear what effect smoke has on the surfactant. Most studies have demonstrated that smoking reduces bronchoalveolar lavage phospholipid levels. Some components of smoke also appear to have a direct detergent-like effect on the surfactant while others appear to alter cycling or secretion. Ultimately these effects are reflected in changes in the dynamics of the surfactant system and, clinically in changes in lung mechanics. Similarly, exposure of the developing fetal lung through maternal smoking results in postnatal alterations in lung mechanics and higher incidents of wheezing and coughing. Direct exposure of developing lung to nicotine induces changes suggestive of fetal stress. Furthermore, identification of nicotinic receptors in fetal lung airways and corresponding increases in airway connective tissue support a possible involvement of nicotine in postnatal asthma development. Finally, at the level of the alveoli of the lung, colocalization of nicotinic

  20. Infrared investigation of organo-montmorillonites prepared from different surfactants.

    PubMed

    Ma, Yuehong; Zhu, Jianxi; He, Hongping; Yuan, Peng; Shen, Wei; Liu, Dong

    2010-07-01

    In this paper, a series of organoclays were prepared from montmorillonites with different CEC and surfactants with different alkyl chain numbers and chain length. Then, FTIR spectroscopy using ATR, DRIFT and KBr pressed disk techniques was used to characterize the local environments of surfactant and host clays in various surfactants modified montmorillonites under wet and dry states. The present study demonstrates that the alkyl chain length and chain number have significant influences on the local environment of the intercalated surfactants. Also, this study indicates that the surface property of the resulting organoclays is affected by the loading and configuration of the intercalated surfactants. In wet state, more gauche conformers are introduced into the alkyl chains in the organoclays with low surfactant loading, evidenced by the shift of CH(2) vibration to higher frequency. Meanwhile, in the case of the organo-montmorillonites with high surfactant loading, the interaction between the surfactant and silicate surface results in a re-arrangement of SiO(4) tetrahedral sheets and a splitting of Si-O stretching vibration. The KBr pressed disk technique is suitable to probe the conformational ordering of the confined amine chains and the reflectance spectroscopy with ATR and/or DRIFT technique is more suitable to probe the water in organoclays. These findings are of high importance to the preparation of organoclays with proper surfactants and investigation of the microstructure of the resulting organoclays using suitable techniques.

  1. Solution properties and electrospinning of phosphonium gemini surfactants.

    PubMed

    Hemp, Sean T; Hudson, Amanda G; Allen, Michael H; Pole, Sandeep S; Moore, Robert B; Long, Timothy E

    2014-06-14

    Bis(diphenylphosphino)alkanes quantitatively react with excess 1-bromododecane to prepare novel phosphonium gemini surfactants with spacer lengths ranging from 2 to 4 methylenes (12-2/3/4-12P). Dodecyltriphenylphosphonium bromide (DTPP), a monomeric surfactant analog, was readily water soluble, however, in sharp contrast, phosphonium gemini surfactants were poorly soluble in water due to two hydrophobic tails and relatively hydrophobic cationic head groups containing phenyl substituents. Isothermal titration calorimetry did not reveal a measurable critical micelle concentration for the 12-2-12P phosphonium gemini surfactant in water at 25 °C. Subsequent studies in 50/50 v/v water-methanol at 25 °C showed a CMC of 1.0 mM for 12-2-12P. All phosphonium gemini surfactants effectively complexed nucleic acids, but failed to deliver nucleic acids in vitro to HeLa cells. The solution behavior of phosphonium gemini surfactants was investigated in chloroform, which is an organic solvent where reverse micellar structures are favored. Solution rheology in chloroform explored the solution behavior of the phosphonium gemini surfactants compared to DTPP. The 12-2-12P and 12-3-12P gemini surfactants were successfully electrospun from chloroform to generate uniform fibers while 12-4-12P gemini surfactant and DTPP only electrosprayed to form droplets.

  2. Surfactants and cosolvents for NAPL remediation. A technologies practices manual

    SciTech Connect

    Lowe, D.F.; Oubre, C.L.; Ward, C.H.

    1999-11-01

    This book gives you tools to provide assistance in the application of surfactant- and cosolvent-based flushing technologies to subsurface remediation. Written for the field practitioners, the book covers important aspects--from design to operation--of this unique remediation technique. Topics of discussion include the following: technology description and current status; geology and contaminant distribution; surfactant/cosolvent enhanced recovery of NAPL; produced fluids and management and surfactant/cosolvent flushing; cost considerations; field project case studies; literature summary database; cost worksheets/design worksheets; surfactant cost estimates; and future research.

  3. Effect of budesonide and salbutamol on surfactant properties.

    PubMed

    Palmer, D; Schürch, S; Belik, J

    2000-09-01

    The objective of this study was to evaluate the in vitro effect of budesonide and salbutamol on the surfactant biophysical properties. The surface-tension properties of two bovine lipid extracts [bovine lipid extract surfactant (BLES) and Survanta] and a rat lung lavage natural surfactant were evaluated in vitro by the captive bubble surfactometer. Measurements were obtained before and after the addition of a low and high concentration of budesonide and salbutamol. Whereas salbutamol had no significant effect, budesonide markedly reduced the surface-tension-lowering properties of all surfactant preparations. Surfactant adsorption (decrease in surface tension vs. time) was significantly reduced (P < 0.01) at a high budesonide concentration with BLES, both concentrations with Survanta, and a low concentration with natural surfactant. At both concentrations, budesonide reduced (P < 0.01) Survanta film stability (minimal surface vs. time at minimum bubble volume), whereas no changes were seen with BLES. The minimal surface tension obtained for all surfactant preparations was significantly higher (P < 0.01), and the percentage of film area compression required to reach minimum surface tension was significantly lower after the addition of budesonide. In conclusion, budesonide, at concentrations used therapeutically, adversely affects the surface-tension-lowering properties of surfactant. We speculate that it may have the same adverse effect on the human surfactant.

  4. Molecular origins of surfactant-mediated stabilization of protein drugs.

    PubMed

    Lee, Hyo Jin; McAuley, Arnold; Schilke, Karl F; McGuire, Joseph

    2011-10-01

    Loss of activity through aggregation and surface-induced denaturation is a significant problem in the production, formulation and administration of therapeutic proteins. Surfactants are commonly used in upstream and downstream processing and drug formulation. However, the effectiveness of a surfactant strongly depends on its mechanism(s) of action and properties of the protein and interfaces. Surfactants can modulate adsorption loss and aggregation by coating interfaces and/or participating in protein-surfactant associations. Minimizing protein loss from colloidal and interfacial interaction requires a fundamental understanding of the molecular factors underlying surfactant effectiveness and mechanism. These concepts provide direction for improvements in the manufacture and finishing of therapeutic proteins. We summarize the roles of surfactants, proteins, and surfactant-protein complexes in modulating interfacial behavior and aggregation. These events depend on surfactant properties that may be quantified using a thermodynamic model, to provide physical/chemical direction for surfactant selection or design, and to effectively reduce aggregation and adsorption loss. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Surfactant-enhanced sodium bicarbonate flooding. Project OE6

    SciTech Connect

    Peru, D.A.

    1986-08-01

    Three anionic and four nonionic surfactants were tested for their emulsification behavior with TRONACRAB (sodium bicarbonate) and Wilmington crude oil. Three of the surfactants were found to enhance the solubilization of oil in the brine phase in the presence of TRONACARB according to the screening guide established in this study. Interfacial tension measurements were made on the most promising systems. The results support the hypothesis that a synergistic relationship can exist between low concentrations of synthetic surfactant and TRONACRAB. In batch experiments using kaolinite and in a linear coreflood using consolidated Berea sandstone, TRONACRAB reduced adsorption of surfactant by up to 93%. TRONACARB was less effective in preventing adsorption onto crushed Berea sandstone probably due to an unusually high amount of ferrodolomite (calcium magnesium carbonate with iron impurities). The following conclusion have been made from the results of this work. (1) Addition of water-soluble synthetic surfactants to brines containing TRONACARB enhances the aqueous solubility of surfactants formed in situ. (2) The greatest solubilization of oil into the brine phase occurs when TRONACARB is used with synthetic surfactant. (3) The use of TRONACARB in combination with synthetic surfactants results in ultralow interfacial tension upon contact with the oil phase. (4) TRONACARB decreases the temperature at which ninionics can solubilize oil effectively (lower IFT). The use of nonionics at lower temperatures will reduce adsorption significantly. (5) TRONACARB is as useful as higher pH alkaline agents in preventing adsoprtion of anionic surfactants. 12 refs., 10 figs., 4 tabs.

  6. Surfactants have multi-fold effects on skin barrier function.

    PubMed

    Lemery, Emmanuelle; Briançon, Stéphanie; Chevalier, Yves; Oddos, Thierry; Gohier, Annie; Boyron, Olivier; Bolzinger, Marie-Alexandrine

    2015-01-01

    The stratum corneum (SC) is responsible for the barrier properties of the skin and the role of intercorneocyte skin lipids, particularly their structural organization, in controlling SC permeability is acknowledged. Upon contacting the skin, surfactants interact with the SC components leading to barrier damage. To improve knowledge of the effect of several classes of surfactant on skin barrier function at three different levels. The influence of treatments of human skin explants with six non-ionic and four ionic surfactant solutions on the physicochemical properties of skin was investigated. Skin surface wettability and polarity were assessed through contact angle measurements. Infrared spectroscopy allowed monitoring the SC lipid organization. The lipid extraction potency of surfactants was evaluated thanks to HPLC-ELSD assays. One anionic and one cationic surfactant increased the skin polarity by removing the sebaceous and epidermal lipids and by disturbing the organization of the lipid matrix. Another cationic surfactant displayed a detergency effect without disturbing the skin barrier. Several non-ionic surfactants disturbed the lipid matrix organization and modified the skin wettability without any extraction of the skin lipids. Finally two non-ionic surfactants did not show any effect on the investigated parameters or on the skin barrier. The polarity, the organization of the lipid matrix and the lipid composition of the skin allowed describing finely how surfactants can interact with the skin and disturb the skin barrier function.

  7. Inactivation of Herpes Simplex Viruses by Nonionic Surfactants

    PubMed Central

    Asculai, Samuel S.; Weis, Margaret T.; Rancourt, Martha W.; Kupferberg, A. B.

    1978-01-01

    Nonionic surface-active agents possessing ether or amide linkages between the hydrophillic and hydrophobic portions of the molecule rapidly inactivated the infectivity of herpes simplex viruses. The activity stemmed from the ability of nonionic surfactants to dissolve lipid-containing membranes. This was confirmed by observing surfactant destruction of mammalian cell plasma membranes and herpes simplex virus envelopes. Proprietary vaginal contraceptive formulations containing nonionic surfactants also inactivated herpes simplex virus infectivity. This observation suggests that nonionic surfactants in appropriate formulation could effectively prevent herpes simplex virus transmission. Images PMID:208460

  8. Multicentre patch test study of air-oxidized ethoxylated surfactants.

    PubMed

    Matura, Mihaly; Bodin, Anna; Skare, Lizbet; Nyrén, Miruna; Hovmark, Anders; Lindberg, Magnus; Lundeberg, Lena; Wrangsjö, Karin; Karlberg, Ann-Therese

    2004-10-01

    Frequent exposure to water and surfactants is considered to be the main cause of hand eczema from wet work. Ethoxylated surfactants are susceptible to oxidation and some of the oxidation products formed have proved to be contact sensitizers in guinea pigs. The question of human sensitization to oxidized surfactants was addressed in a multicentre study in the Stockholm region. 528 consecutive dermatitis patients were patch tested with widely used ethoxylated surfactants in oxidized and non-oxidized form as well as certain identified oxidation compounds. 61 patients presented with mild, clearly irritant reactions to some of the surfactants tested. 18 patients showed not only erythema but also oedema and/or papules and vesicles, using a morphologic descriptive system for reading the patch test reactions. These reactions occurred mostly to oxidized surfactants and oxidation products. When retesting 9 of these 18 patients only an allergic reaction to acetaldehyde was confirmed. We conclude that oxidized ethoxylated surfactants have increased irritant potential compared to non-oxidized material. Our working hypothesis is that oxidized surfactants of technical quality exert a lower risk of sensitization than do oxidized homologous pure surfactants. Among the potential allergens formed during autoxidation, formaldehyde and acetaldehyde must be considered as a source of unexpected exposure.

  9. Surfactant-mediated Biodegradation of Polycyclic Aromatic Hydrocarbons

    PubMed Central

    Li, Jing-Liang; Chen, Bing-Hung

    2009-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are toxic environmental pollutants that are known or suspected carcinogens or mutagens. Bioremediation has been used as a general way to eliminate them from the contaminated sites or aquifers, but their biodegradation is rather limited due to their low bioavailability because of their sparingly soluble nature. Surfactant-mediated biodegradation is a promising alternative. The presence of surfactants can increase the solubility of PAHs and hence potentially increase their bioavailability. However, inconclusive results have been reported on the effects of surfactant on the biodegradation of PAHs. In this work, surfactant-mediated biodegradation of PAHs is reviewed.

  10. Removal of vaporous naphthalene using polyoxyethylenated nonionic surfactants.

    PubMed

    Huang, Hsiao-Lin; Lee, Whei-May Grace

    2003-08-01

    Previous research has demonstrated that an anionic surfactant can increase the solubility of the vapor phases of both naphthalene and sulfur dioxide in water. This study examines the feasibility of removing polycyclic aromatic hydrocarbons (PAHs) during gas absorption by adding the polyoxyethylenated nonionic surfactants tetraethylene glycol monodecyl ether (C10E4), octaethylene glycol monodecyl ether (C10E8), and octaethylene glycol monotetradecyl ether (C14E8), to water. The apparent solubility and absorption rates of naphthalene in surfactant solution were slightly higher than in pure water at a concentration lower than the critical micelle concentration (CMC). However, the apparent equilibrium naphthalene solubility increased linearly in proportion to the concentrations of nonionic surfactants because of the solubilization effect of micelles at concentrations above the CMC. The solubilization effect exceeded that of the reduced mass transfer coefficient, increasing the rate of absorption of vaporous naphthalene. For the four surfactants, the capacity to solubilize naphthalene was in the order C10E4 > C14E8 > C10E8 > sodium dodecyl sulfate (SDS) and was related to the hydrophile-lipophile balance values of the surfactants. The enrichment factors, which can express the degree of naphthalene solubility in solution, were 6.09-14.2 at a surfactant concentration of 0.01 M for the three polyoxyethylenated nonionic surfactants. Empirical findings confirm that adding nonionic surfactants increases the absorption efficiency of hydrophobic organic compounds (HOCs) using spray or packed tower.

  11. HENRY'S LAW CONSTANTS AND MICELLAR PARTITIONING OF VOLATILE ORGANIC COMPOUNDS IN SURFACTANT SOLUTIONS

    EPA Science Inventory

    Partitioning of volatile organic compounds (VOCs) into surfactant micelles affects the apparent vapor-liquid equilibrium of VOCs in surfactant solutions. This partitioning will complicate removal of VOCs from surfactant solutions by standard separation processes. Headspace expe...

  12. TOXICITY COMPARISON OF BIOSURFACTANTS AND SYNTHETIC SURFACTANTS USED IN OIL SPILL REMEDIATION TO TWO ESTUARINE SPECIES

    EPA Science Inventory

    The relative environmental toxicities of synthetic and biogenic surfactants used in oil spill remediation efforts are not well understood. Acute and chronic toxicities of three synthetic surfactants and three microbially produced surfactants were determined and compared in this s...

  13. PROPERTIES OF FOOD GRADE (EDIBLE) SURFACTANTS AFFECTING SUBSURFACE REMEDIATION OF CHLORINATED SOLVENTS

    EPA Science Inventory

    In this research, several food grade (edible) surfactants are systematically evaluated for various loss mechanisms: precipitation, adsorption, and coacervation (for nonionic surfactants). Cloud points for the polyethoxylate sorbitan (T-MAZ) surfactants are much higher than aquife...

  14. PROPERTIES OF FOOD GRADE (EDIBLE) SURFACTANTS AFFECTING SUBSURFACE REMEDIATION OF CHLORINATED SOLVENTS

    EPA Science Inventory

    In this research, several food grade (edible) surfactants are systematically evaluated for various loss mechanisms: precipitation, adsorption, and coacervation (for nonionic surfactants). Cloud points for the polyethoxylate sorbitan (T-MAZ) surfactants are much higher than aquife...

  15. TOXICITY COMPARISON OF BIOSURFACTANTS AND SYNTHETIC SURFACTANTS USED IN OIL SPILL REMEDIATION TO TWO ESTUARINE SPECIES

    EPA Science Inventory

    The relative environmental toxicities of synthetic and biogenic surfactants used in oil spill remediation efforts are not well understood. Acute and chronic toxicities of three synthetic surfactants and three microbially produced surfactants were determined and compared in this s...

  16. HENRY'S LAW CONSTANTS AND MICELLAR PARTITIONING OF VOLATILE ORGANIC COMPOUNDS IN SURFACTANT SOLUTIONS

    EPA Science Inventory

    Partitioning of volatile organic compounds (VOCs) into surfactant micelles affects the apparent vapor-liquid equilibrium of VOCs in surfactant solutions. This partitioning will complicate removal of VOCs from surfactant solutions by standard separation processes. Headspace expe...

  17. Environmental and human safety of major surfactants. Volume 1. Anionic surfactants. Part 1. Linear alkylbenzene sulfonates. Final report

    SciTech Connect

    Not Available

    1991-02-01

    The report discusses critical reviews of published literature and unpublished company data on major surfactants. Part 1 of Vol. 1 discusses the chemistry, biodegradation, environmental effects and safety and human safety of linear alkylbenzene sulfonates. The information presented updates and supplements similar data included in two predecessor studies, Human Safety and Environmental Aspects of Major Surfactants (1977) NTIS Accession Number PB-301193 and Human and Environmental Aspects of Major Surfactants (Supplement) (1981) NTIS Accession Number PB-81-182453.

  18. Environmental and human safety of major surfactants. Volume 1. Anionic surfactants. Part 2. Alcohol ethoxy sulfates. Final report

    SciTech Connect

    Not Available

    1991-02-01

    The report discusses critical reviews of published literature and unpublished company data on major surfactants. Part 2 of Vol. 1 discusses the chemistry, biodegradation, environmental effects and safety and human safety of alcohol ethoxy sulfates. The information presented updates and supplements similar data included in two predecessor studies, Human Safety and Environmental Aspects of Major Surfactants (1977) NTIS Accession Number PB301193 and Human and Environmental Aspects of Major Surfactants (Supplement) (1981) NTIS Accessiion Number PB81-182453.

  19. Environmental and human safety of major surfactants. Volume 1. Anionic surfactants. Part 3. Alkyl sulfates. Final report

    SciTech Connect

    Not Available

    1991-02-01

    The report discusses critical reviews of published literature and unpublished company data on major surfactants. Part 3 of Vol. 1 discusses the chemistry, biodegradation, environmental effects and safety and human safety of alkyl sulfates. The information presented updates and supplements similar data included in two predecessor studies, Human Safety and Environmental Aspects of Major Surfactants (1977) NTIS Accession Number PB301193 and Human and Environmental Aspects of Major Surfactants (Supplement) (1981) NTIS Accession Number PB81-182453.

  20. The effect of polymer-surfactant interaction on the rheological properties of surfactant enhanced alkaline flooding formulations

    SciTech Connect

    French, T.R.; Josephson, C.B.

    1993-02-01

    Surfactant-enhanced, lower pH (weak) alkaline chemicals are effective for mobilizing residual oil. Polymer is used for mobility control because if mobility control is lost, then oil recovery is reduced. The ability to maintain mobility control during surfactant-alkaline flooding can be adversely affected by chemical interaction. In this work, interaction between polymers and surfactants was shown to be affected by pH, ionic strength, crude oil, and the properties of the polymers and surfactants. Polymer-surfactant interaction (phase separation, precipitation, and viscosity loss) occurred between most of the polymers and surfactants that were tested. Polymer-surfactant interaction is difficult to eliminate, and no method was found for completely eliminating interaction. Polymer-surfactant interaction occurred at optimal salinity and below optimal salinity. Polymer-surfactant interaction had an adverse effect on polymer rheology; however, the adverse effect of interaction on polymer rheology was lessened when oil was present. Increasing the pH of chemical systems further reduced the adverse effects of interaction on polymer rheology.

  1. Adsorption of polyoxyethylenic surfactants on quartz, kaolin, and dolomite: A correlation between surfactant structure and solid surface nature

    SciTech Connect

    Nevskaia, D.M.; Guerrero-Ruiz, A.; Lopez-Gonzalez, J.deD.

    1996-08-10

    Adsorption of a surfactant at a liquid-solid interface makes up the basis of many technological processes such as detergency, flotation, water treatment, and enhanced oil recovery. The influence of variables such as adsorption temperature, polar chain length, and nature of functional groups on the adsorption, from aqueous solutions, of various surfactants (TX-114, TX-100, TX-165, TX-305, NP1P4E, NP4P1E, NP4S, NP10S, and NP25S) has been investigated. Several nonporous solids, including various samples of quartz, kaolin, and dolomite, were studied. Conformational changes of adsorbed surfactant molecules on one quartz, when the oxyethylenic length of Tritons increases, have been detected. For all the other solid samples the surface is not completely covered by Tritons. On quartz, the surfactants are adsorbed by hydrogen bonds between the surfactant`s ether groups and the silanol groups of the solid surface. These hydroxyl groups must be free and sufficiently separated from other hydroxyls of the solid surface. When the number of propoxy groups increases (from NP1P4E to NP4P1E) the adsorbed amount of surfactant on the solid studied decreases. Anionic surfactants are adsorbed on quartz in lower amounts than the corresponding nonionic surfactants. However, the adsorbed amounts of Tritons and sulfated Tritons on kaolin are similar, probably due to the positive charges on the edges of this material.

  2. Surfactant therapy for meconium aspiration syndrome: current status.

    PubMed

    Dargaville, Peter A; Mills, John F

    2005-01-01

    Meconium aspiration syndrome (MAS) is an important cause of respiratory distress in the term infant. Therapy for the disease remains problematic, and newer treatments such as high-frequency ventilation and inhaled nitric oxide are being applied with increasing frequency. There is a significant disturbance of the pulmonary surfactant system in MAS, with a wealth of experimental data indicating that inhibition of surfactant function in the alveolar space is an important element of the pathophysiology of the disease. This inhibition may be mediated by meconium, plasma proteins, haemoglobin and oedema fluid, and, at least in vitro, can be overcome by increasing surfactant phospholipid concentration. These observations have served as the rationale for administration of exogenous surfactant preparations in MAS, initially as standard bolus therapy and, more recently, in association with therapeutic lung lavage. Bolus surfactant therapy in ventilated infants with MAS has been found to improve oxygenation in most studies, although there are a significant proportion of nonresponders and in many cases the effect is transient. Pooled data from randomised controlled trials of surfactant therapy suggest a benefit in terms of a reduction in the requirement for extracorporeal membrane oxygenation (relative risk 0.48 in surfactant-treated infants) but no diminution of air leak or ventilator days. Current evidence would support the use of bolus surfactant therapy on a case by case basis in nurseries with a relatively high mortality associated with MAS, or the lack of availability of other forms of respiratory support such as high-frequency ventilation or nitric oxide. If used, bolus surfactant should be administered as early as practicable to infants who exhibit significant parenchymal disease, at a phospholipid dose of at least 100 mg/kg, rapidly instilled into the trachea. Natural surfactant or a third-generation synthetic surfactant should be used and the dosage repeated every 6

  3. Nucleate pool boiling heat transfer in aqueous surfactant solutions

    NASA Astrophysics Data System (ADS)

    Wasekar, Vivek Mahadeorao

    Saturated, nucleate pool boiling in aqueous surfactant solutions is investigated experimentally. Also, the role of Marangoni convection, driven both by temperature and surfactant concentration gradients at the vapor-liquid interface of a nucleating bubble is computationally explored. Experimental measurements of dynamic and equilibrium sigma using the maximum bubble pressure method indicate dynamic sigma to be higher than the corresponding equilibrium value, both at room and elevated temperatures. Also, nonionic surfactants (Triton X-100, Triton X-305) show larger sigma depression than anionic surfactants (SDS, SLES), and a normalized representation of their dynamic adsorption isotherms is shown to be helpful in generalizing the surfactant effectiveness to reduce surface tension. The dynamic sigma has a primary role in the modification of bubble dynamics and associated heat transfer, and is dictated by the adsorption kinetics of the surfactant molecules at boiling temperatures. In general, an enhancement in heat transfer is observed, which is characterized by an early incipience and an optimum boiling performance at or around the critical micelle concentration of the surfactant. The optimum performances, typically in the fully developed boiling regime ( q''w > 100 kW/m2), show a reverse trend with respect to surfactant molecular weights M, i.e., higher molecular weight additives promote lower enhancement. Normalized boiling performance using the respective solution's dynamic sigma correlates heat transfer coefficient by M-0.5 for anionics and M 0 for nonionics. This has been shown to be brought about by the surfactant concentration and its interfacial activity in a concentration sublayer around the growing vapor bubble, which governs the bubble growth behavior through the mechanism of dynamic sigma. The ionic nature of the surfactant influences the thickness and molecular makeup of the enveloping sublayer, thereby affecting the bubble dynamics and boiling heat

  4. Surfactant-enhanced control of track-etch pore morphology

    NASA Astrophysics Data System (ADS)

    Apel, P. Yu; Blonskaya, I. V.; Didyk, A. Yu; Dmitriev, S. N.; Orelovitch, O. L.; Root, D.; Samoilova, L. I.; Vutsadakis, V. A.

    2001-06-01

    The influence of surfactants on the process of chemical development of ion tracks in polymers is studied. Based on the experimental data, a mechanism of the surfactant effect on the track-etch pore morphology is proposed. In the beginning of etching the surfactant is adsorbed on the surface and creates a layer that is quasi-solid and partially protects the surface from the etching agent. However, some etchant molecules diffuse through the barrier and react with the polymer surface. This results in the formation of a small hole at the entrance to the ion track. After the hole has attained a few nanometers in diameter, the surfactant molecules penetrate into the track and cover its walls. Further diffusion of the surfactant into the growing pore is hindered. The adsorbed surfactant layer is not permeable for large molecules. In contrast, small alkali molecules and water molecules diffuse into the track and provide the etching process enlarging the pore. At this stage the transport of the surfactant into the pore channel can proceed only due to the lateral diffusion in the adsorbed layer. The volume inside the pore is free of surfactant molecules and grows at a higher rate than the pore entrance. After a more prolonged etching the bottle-like (or "cigar-like") pore channels are formed. The bottle-like shape of the pore channels depends on the etching conditions such as alkali and surfactant concentration, temperature, and type of the surfactant. The use of surfactants enables one to produce track-etch membranes with improved flow rate characteristics compared with those having cylindrical pores with the same nominal pore diameters.

  5. Biodegradation of phenanthrene in soils in the presence of surfactants

    SciTech Connect

    Jahan, K.

    1993-01-01

    This research addresses the effect of low surfactant concentrations on the biodegradation of slightly soluble organic compounds in the presence and absence of soil. Biodegradation of phenanthrene in excess of its aqueous solubility by an acclimated mixed culture was studied in the presence of nonionic surfactants. Nonionic surfactants were selected over other types of surfactants because of their higher hydrocarbon solubilizing power, weaker adsorption to charged sites, less toxicity to bacteria, and poor foaming properties. Surfactants were tested to measure their effectiveness for increasing the solubility of phenanthrene, their adsorption on the soil matrix, their biodegradability, their effect on the adsorption of phenanthrene and on the rates of biodegradation of phenanthrene. Solubility enhancement studies of phenanthrene by the surfactants indicated relatively small effects at sub-micellar surfactant concentrations. Batch biodegradation studies in which phenanthrene was available as particulates and as a surface coating on sand were carried out in closed BOD bottles in the Hach manometric system. Addition of surfactants at 25 mg/L enhanced biodegradation rates as measured by oxygen uptake, protein production and disappearance of phenanthrene. A dynamic model which couples dissolution and biodegradation processes could adequately represent the experimental batch data. Modelling studies suggest that biodegradation was accelerated because the dissolution rates of phenanthrene increased in presence of the surfactants. Continuous flow column studies with phenanthrene coated Jordan sand was carried out to simulate groundwater flow conditions. Sorption studies on Jordan aquifer sand indicated that this low-carbon aquifer material adsorbs small amounts of phenanthrene as well as surfactants. The tests show that low surfactant concentrations were marginally beneficial in washing phenanthrene from precoated sand.

  6. Identifying the Imprint of Surfactant Stabilisation in Whitecap Foam Evolution

    NASA Astrophysics Data System (ADS)

    Callaghan, A. H.; Deane, G. B.; Stokes, D.

    2016-02-01

    Surfactants are ubiquitous in the world's oceans and can affect climatically-relevant processes such as air-sea gas exchange, sea spray aerosol (SSA) flux, and air-sea momentum transfer. Surfactants are amphiphilic and help form the physically and chemically distinct ocean surface microlayer (SML), however, the spatial distribution, concentration and composition of the SML is not well understood, especially under conditions of vigorous wave breaking. Like the SML, breaking waves also influence physical exchange processes at the air-sea interface, and oceanic whitecap foam coverage is commonly used to quantify bubble-mediated exchange processes. However, surfactants can increase the lifetime of foam over clean water conditions, potentially complicating the use of whitecap coverage to parameterise air-sea gas exchange and SSA production flux. A better understanding of how surfactants affect the evolution of whitecap foam is needed to improve whitecap parameterisations of bubble-mediated processes, and may also provide a remote sensing approach to map the spatial distribution of surfactants at the water surface. Here we present results from a laboratory study that looked at whitecap foam evolution in "clean" and "surfactant-added" seawater regimes. We find that the whitecap foam area growth timescale is largely insensitive to the presence of surfactants, but that surfactant stabilization of whitecap foam becomes important during the whitecap foam area decay phase. The timescale at which this occurs appears to be consistent for breaking waves of different scale and intensity. A simple method is then used to isolate the surfactant signal and derive an equivalent "clean" seawater foam decay time for the whitecaps in the "surfactant-added" regime. The method is applied to oceanic whitecaps and results compared to the laboratory whitecaps from the "clean" and "surfactant-added" regimes.

  7. Effect of salt and surfactant concentration on the structure of polyacrylate gel/surfactant complexes.

    PubMed

    Nilsson, Peter; Unga, Johan; Hansson, Per

    2007-09-20

    Small-angle X-ray scattering was used to elucidate the structure of crosslinked polyacrylate gel/dodecyltrimethylammonium bromide complexes equilibrated in solutions of varying concentrations of surfactant and sodium bromide (NaBr). Samples were swollen with no ordering (micelle free), or they were collapsed with either several distinct peaks (cubic Pm3n) or one broad correlation peak (disordered micellar). The main factor determining the structure of the collapsed complexes was found to be the NaBr concentration, with the cubic structure existing up to approximately 150 mM NaBr and above which only the disordered micellar structure was found. Increasing the salt concentration decreases the polyion mediated attractive forces holding the micelles together causing swelling of the gel. At sufficiently high salt concentration the micelle-micelle distance in the gel becomes too large for the cubic structure to be retained, and it melts into a disordered micellar structure. As most samples were above the critical micelle concentration, the bulk of the surfactant was in the form of micelles in the solution and the surfactant concentration thereby had only a minor influence on the structure. However, in the region around 150 mM NaBr, increasing the surfactant concentration, at constant NaBr concentration, was found to change the structure from disordered micellar to ordered cubic and back to disordered again.

  8. Surfactant enhanced disinfection of the human norovirus surrogate, tulane virus with organic acids and surfactant

    USDA-ARS?s Scientific Manuscript database

    Human infection with foodborne viruses can occur following consumption of contaminated food, person-to-person body contact, or release of aerosols. Combinatorial treatments of surfactants and organic acids may have synergistic or additive mechanisms to inactivate foodborne viruses and prevent outbr...

  9. Characterization of Phase and Emulsion Behavior, Surfactant Retention, and Oil Recovery for Novel Alcohol Ethoxycarboxylate Surfactants

    SciTech Connect

    Lebone T. Moeti; Ramanathan Sampath

    1998-05-01

    This semi-annual technical progress report describes work performed at Clark Atlanta University under DOE Grant No. DE-FG26-97FT97278 during the period October 01, 1997 to April 01, 1998 which covers the first six months of the project. During this reporting period, laboratory space to set up the surfactant characterization measurement system in the Research Science Center was made available. A Ph.D. student in Chemistry was identified and is supported as a Graduate Research Assistant in this project. Her contribution towards this project will form her Ph.D. thesis. The test matrix to perform salinity and temperature scans was established. Supply requests to obtain refined hydrocarbon, surfactant, and crude were processed and supplies obtained. A temperature bath with a control unit to perform temperature scans was obtained on loan from Federal Energy Technology Center, Morgantown, WV. The setting up of the temperature control unit, and associated chiller with water circulation lines is in progress. Tests were conducted on several hybrid surfactants to identify the best surfactants for future experimental work that yield almost equal volumes of top, middle, and bottom phases when mixed with oil and water. The student reviewed the current literature in the subject area, and modeling efforts that were established in previous studies to predict electrical conductivities and inversion phenomena. These activities resulted in one published conference paper, and one student poster paper during this reporting period.

  10. Size separation of analytes using monomeric surfactants

    DOEpatents

    Yeung, Edward S.; Wei, Wei

    2005-04-12

    A sieving medium for use in the separation of analytes in a sample containing at least one such analyte comprises a monomeric non-ionic surfactant of the of the general formula, B-A, wherein A is a hydrophilic moiety and B is a hydrophobic moiety, present in a solvent at a concentration forming a self-assembled micelle configuration under selected conditions and having an aggregation number providing an equivalent weight capable of effecting the size separation of the sample solution so as to resolve a target analyte(s) in a solution containing the same, the size separation taking place in a chromatography or electrophoresis separation system.

  11. Synthesis of surfactants based on pentaerythritol. I. Cationic and zwitterionic gemini surfactants.

    PubMed

    Jahan, Nusrat; Paul, Nawal; Petropolis, Christian J; Marangoni, D Gerrard; Grindley, T Bruce

    2009-10-16

    Simple strategies for the synthesis of five series of cationic gemini surfactants and one series of zwitterionic gemini surfactants from pentaerythritol have been developed. Two lipophilic groups were introduced onto pentaerythritol by alkylation of the known compound, O-benzylidenepentaerythritol, with 1-bromooctane, 1-bromodecane, 1-bromododecane, and 1-bromotetradecane. Hydrogenolysis of the benzylidene acetals gave diols which were converted into three different series of trimethylammonium derivatives. The diiodides derived from the diols could be displaced by dimethylamine, even though they are adjacent to a quaternary carbon atom. Alkylation with methyl iodide gave the first series. The iodides were easily displaced by cyanide ion and the resulting dinitriles were hydrolyzed, converted to N,N-dimethylamides, and reduced to give a second series. Oxidation of the diols to dialdehydes under Swern conditions followed by Horner-Wadsworth-Emmons reactions with diethyl N,N-dimethylcarbamoylmethylphosphonate followed by two-stage reduction gave a third series. The dialkoxides derived from the four di-O-alkylpentaerthritol diols were reacted with 2-dimethylaminoethyl chloride and 3-dimethylaminopropyl chloride in neighboring-group assisted double Williamson ether syntheses to give precursors to two more series. As expected because the neighboring group participation occurs through a four-membered-ring intermediate, considerably more vigorous conditions were required for the reactions with 3-dimethylaminopropyl chloride. 2-Diethylaminoethyl bromide was found to be less reactive than 2-dimethylaminoethyl chloride. The products were alkylated with methyl iodide and, in some cases, other alkyl halides to give cationic gemini surfactants. Alkylation of one series with ethyl bromoacetate followed by anion exchange resin catalyzed ester hydrolysis gave zwitterionic gemini surfactants. The members of all series have superior surfactant properties.

  12. Solubilization of DNAPLs by mixed surfactant: reduction in partitioning losses of nonionic surfactant.

    PubMed

    Zhao, Baowei; Zhu, Lizhong; Yang, Kun

    2006-02-01

    Efforts to remediate the dense nonaqueous phase liquids (DNAPLs) by mobilizing them face with risks of driving the contaminants deeper into aquifer zones. This spurs research for modifying the approach for in situ remediation. In this paper, a novel solubilization of DNAPLs by mixed nonionic and anionic surfactant, Triton X-100 (TX100) and sodium dodecylbenzene sulfonate (SDBS), was presented and compared with those by single ones. Given 1:40 phase ratio of DNAPL:water (v/v) and the total surfactant concentration from 0.2 to 10gl(-1), mixed TX100-SDBS at the total mass ratios of 3:1, 1:1 and 1:3 exhibited significant solubilization for the DNAPLs, trichloroethene (TCE), chlorobenzene (CB) and 1,2-dichlorobenzene (1,2-DCB). The solubilization extent by mixed TX100-SDBS was much larger than by single TX100 and even larger than by single SDBS at the ratios of 1:1 and 1:3, respectively. TX100 partitioning into the organic phase dictated the solubilization extent. The TX100 losses into TCE, CB and 1,2-DCB phases were more than 99%, 97% and 97% when single TX100 was used. With SDBS alone, no SDBS partitioned into DNAPLs was observed and in mixed systems, SDBS decreased greatly the partition loss of TX100 into DNAPLs. The extent of TX100 partition decreased with increasing the amount of SDBS. The mechanism for reduction of TX100 partition was discussed. TX100 and SDBS formed mixed micelles in the solution phase. The inability of SDBS to partition into DNAPLs and the mutual affinity of SDBS and TX100 in the mixed micelle controlled the partitioning of TX100 into DNAPL phase. The work presented here demonstrates that mixed nonionic-anionic surfactants would be preferred over single surfactants for solubilization remediation of DNAPLs, which could avoid risks of driving the contaminants deeper into aquifers and decrease the surfactant loss and remediation cost.

  13. Study of surfactant-skin interactions by skin impedance measurements.

    PubMed

    Lu, Guojin; Moore, David J

    2012-02-01

    The stratum corneum (SC) plays a very critical physiological role as skin barrier in regulating water loss through the skin and protects the body from a wide range of physical and chemical exogenous insults. Surfactant-containing formulations can induce skin damage and irritation owing to surfactant absorption and penetration. It is generally accepted that reduction in skin barrier properties occurs only after surfactants have penetrated/permeated into the skin barrier. To mitigate the harshness of surfactant-based cleansing products, penetration/permeation of surfactants should be reduced. Skin impedance measurements have been taken in vitro on porcine skin using vertical Franz diffusion cells to investigate the impact of surfactants, temperature and pH on skin barrier integrity. These skin impedance results demonstrate excellent correlation with other published methods for assessing skin damage and irritation from different surfactant chemistry, concentration, pH, time of exposure and temperature. This study demonstrates that skin impedance can be utilized as a routine approach to screen surfactant-containing formulations for their propensity to compromise the skin barrier and hence likely lead to skin irritation.

  14. New Y-shaped surfactants from renewable resources.

    PubMed

    Ali, Tammar Hussein; Hussen, Rusnah Syahila Duali; Heidelberg, Thorsten

    2014-11-01

    A series of sugar-based surfactants, involving a single hydrophobic chain (C12) and two side-by-side arranged head groups, was prepared form simple glucose precursors. All surfactants were highly water soluble and exhibited exclusively micellar assemblies. This behavior makes them interesting candidates for oil in water emulsifiers. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Modification of Wyoming montmorillonite surfaces using a cationic surfactant.

    PubMed

    Xi, Yunfei; Frost, Ray L; He, Hongping; Kloprogge, Theo; Bostrom, Thor

    2005-09-13

    Surfaces of Wyoming SWy-2-Na-montmorillonite were modified using ultrasonic and hydrothermal methods through the intercalation and adsorption of the cationic surfactant octadecyltrimethylammonium bromide (ODTMA). Changes in the surfaces and structure were characterized using X-ray diffraction (XRD), thermal analysis (TG), and electron microscopy. The ultrasonic preparation method results in a higher surfactant concentration within the montmorillonite interlayer when compared with that from the hydrothermal method. Three different molecular environments for surfactants within the surface-modified montmorillonite are proposed upon the basis of their different decomposition temperatures. Both XRD patterns and TEM images demonstrate that SWy-2-Na-montmorillonite contains superlayers. TEM images of organoclays prepared at high surfactant concentrations show alternate basal spacings between neighboring layers. SEM images show that modification with surfactant reduces the clay particle size and aggregation. Organoclays prepared at low surfactant concentration display curved flakes, whereas they become flat with increasing intercalated surfactant. Novel surfactant-modified montmorillonite results in the formation of new nanophases with the potential for the removal of organic impurities from aqueous media.

  16. Enrichment of surfactant from its aqueous solution using ultrasonic atomization.

    PubMed

    Takaya, Haruko; Nii, Susumu; Kawaizumi, Fumio; Takahashi, Katsuroku

    2005-08-01

    Dilute aqueous solutions of dodecyl-benzenesulfonic acid sodium salt (DBS-Na) and polyoxyethylenenonylphenyl ethers (PONPEs) were ultrasonically atomized. The surfactants were concentrated in collected mist droplets. The enrichment ratio increased with decreasing surfactant concentration. Depending on the surfactant's molecular weight and affinity to water, different enrichment ratio was observed in the range of low feed concentrations. For anionic surfactant, DBS-Na, the enrichment ratio was significantly improved by KCl addition and a peak appeared on the plot of the ratio against KCl concentration. Addition of NaCl or CaCl2 . 2H2O to the surfactant solution also enhanced the enrichment ratio; however, the effect was relatively small. Such behaviors of the ratio were interpreted as enhanced interfacial adsorption of the surfactant and a lack of supply of surfactant monomers from liquid bulk because of slow breaking of surfactant micelles. Time required for collecting an amount of mist was also observed. Among the three salt systems, the time for KCl system was twice as long as others. This fact suggested that the formation of smaller droplets in KCl system.

  17. Interaction of photosensitive surfactant with DNA and poly acrylic acid

    SciTech Connect

    Zakrevskyy, Yuriy Paasche, Jens; Lomadze, Nino; Santer, Svetlana; Cywinski, Piotr; Cywinska, Magdalena; Reich, Oliver; Löhmannsröben, Hans-Gerd

    2014-01-28

    In this paper, we investigate interactions and phase transitions in polyelectrolyte-surfactant complexes formed between a cationic azobenzene-containing surfactant and two types of polyelectrolytes: natural (DNA) or synthetic (PAA: poly acrylic acid). The construction of a phase diagram allowed distancing between four major phases: extended coil conformation, colloidally stable compacted globules, colloidal instability range, and surfactant-stabilized compact state. Investigation on the complexes’ properties in different phases and under irradiation with UV light provides information about the role of the surfactant's hydrophobic trans isomers both in the formation and destruction of DNA and PAA globules as well as in their colloidal stabilization. The trans isomer shows much stronger affinity to the polyelectrolytes than the hydrophilic cis counterpart. There is no need for complete compensation of the polyelectrolyte charges to reach the complete compaction. On contrary to the findings previously reported in the literature, we demonstrate – for the first time – complete polyelectrolyte compaction which occurs already at 20% of DNA (and at 50% of PAA) charge compensation. The trans isomer plays the main role in the compaction. The aggregation between azobenzene units in the photosensitive surfactant is a driving force of this process. The decompaction can be realized during UV light irradiation and is strongly influenced by the interplay between surfactant-surfactant and surfactant-DNA interactions in the compacted globules.

  18. PHASE BEHAVIOR OF WATER/PERCHLOROETHYLENE/ANIONIC SURFACTANT SYSTEMS

    EPA Science Inventory

    Winsor Type I (o/w), Type II (w/o), and Type III (middle phase) microemulsions have been generated for water and perchloroethylene (PCE) in combination with anionic surfactants and the appropriate electrolyte concentration. The surfactant formulation was a combination of sodium d...

  19. Competitive Adsorption: A Physical Model for Lung Surfactant Inactivation

    PubMed Central

    Fernsler, Jonathan G.; Zasadzinski, Joseph A.

    2009-01-01

    Charged, surface-active serum proteins can severely reduce or eliminate the adsorption of lung surfactant from the subphase to the alveolar air-liquid interface via a kinetically controlled competitive adsorption process. The decreased surfactant concentration at the interface leads to higher surface tensions during the compression of the interface during breathing. The correspondence between the factors governing colloid stability and competitive adsorption is validated via a new method of measuring surfactant and serum protein adsorption rates to the air-water interface using quantitative Brewster Angle Microscopy (BAM). Competitive adsorption from a 10 mg/mL albumin subphase prevents the adsorption of lung surfactant from even high subphase concentrations due to the fast diffusion of the water-soluble proteins to the interface. The formation of an albumin film causes an electrostatic and steric barrier to subsequent surfactant adsorption, which can destroy the necessary properties of functional lung surfactant: low surface tension during compression and rapid respreading after film collapse. Surfactant inactivation is at least partially due to decreased surfactant adsorption; such decreased adsorption due to the presence of serum proteins may play a role in the development and severity of Acute Respiratory Distress Syndrome. PMID:19534502

  20. Microbial surfactants and their potential applications: an overview.

    PubMed

    Mukherjee, Ashis K; Das, Kishore

    2010-01-01

    Biosurfactant or microbial surfactants produced by microbes are structurally diverse and heterogeneous groups of surface-active amphipathic molecules. They are capable of reducing surface and interfacial tension and have a wide range of industrial and environmental applications. The present chapter reviews the biochemical properties of different classes of microbial surfactants and their potential application in different industrial sectors.

  1. The Influence of Surfactants on the Zeta Potential of Coals

    SciTech Connect

    Marsalek, R.

    2009-07-01

    The surface of three different kinds of coal was modified by three surfactants (cationic, anionic, and non-ionic). Changes on coal surface were examined by the zeta potential technique. The influence of the dispersion of pH, concentration of surfactants, and contact time were investigated. The most significant change in zeta potential resulting from adding surfactants was observed in activated coal (hydrophobic surface, largest BET surface area). Adding the cationic surfactant led to an increase of the zeta potential, contrary to measuring done in water. The anionic surfactant decreased the value of the zeta potential; however, this change was not too remarkable. The results proved that even a very low concentration of the cationic surfactant (0.01 mmol/L) causes a remarkable change of the zeta potential. On the other hand, a similar effect was observed until the concentration of the anionic surfactant reached about 10 mmol/L. The mechanism of binding surfactants is not simple, but preferential hydrophobic interactions were discovered.

  2. Surfactant-assisted liquefaction of particulate carbonaceous substances

    NASA Technical Reports Server (NTRS)

    Hsu, G. C. (Inventor)

    1978-01-01

    A slurry of carbonaceous particles such as coal containing an oil soluble polar substituted oleophilic surfactant, suitably an amine substituted long chain hydrocarbon, is liquefied at high temperature and high hydrogen presence. The pressure of surfactant results in an increase in yield and the conversion product contains a higher proportion of light and heavy oils and less asphaltene than products from other liquefaction processes.

  3. Ultrastructure of exogenous surfactants using cryogenic scanning electron microscopy.

    PubMed

    Banerjee, R; Bellare, J R

    2001-01-01

    Therapy with specialised biomaterials, exogenous surfactants, is known to significantly decrease the mortality rates in Respiratory Distress Syndrome (RDS). Surfactants available commercially vary widely in composition and biophysical properties. The present paper studies the ultrastructure of three exogenous surfactants used for the treatment of Respiratory Distress Syndrome, namely, Survanta, ALEC and Exosurf Neonatal with respect to their ability to form liposomes using cryogenic scanning electron microscopy. Liposomal organisation is more obvious in Exosurf than in Survanta and is most pronounced in ALEC. ALEC forms closed regular liposomes with an onion-ring-like internal bilayer arrangement. Survanta forms open membranous structures with wavy ribbon-like membranes. The complex membrane-like structures seen with Survanta may be due to the interaction of lipids with surfactant-specific proteins present in this surfactant which is derived from natural lung extracts and might indicate superior spreading at the lipid-water interface. Artificial protein-free surfactants (ALEC and Exosurf) did not appear to form these open membranous structures. Further study of the ultrastructure of possible biomaterials as surfactants could help in the development of new, improved artificial protein-free surfactants with open membranous structures that might facilitate spreading at the air-liquid interface of lungs.

  4. PHASE BEHAVIOR OF WATER/PERCHLOROETHYLENE/ANIONIC SURFACTANT SYSTEMS

    EPA Science Inventory

    Winsor Type I (o/w), Type II (w/o), and Type III (middle phase) microemulsions have been generated for water and perchloroethylene (PCE) in combination with anionic surfactants and the appropriate electrolyte concentration. The surfactant formulation was a combination of sodium d...

  5. Aggregation Behavior of Mixed-Counterion Double-Chained Surfactants

    DTIC Science & Technology

    1991-01-01

    Cryofixation of colloidal dispersions with the controlled environment vitrification system allows vicrostructural detail of surfactant aggregates as small ...surfactant mixtures. Thus, in the dialkyldimethylammonium system, the small , unhydrated bromide counterion sits close to the aggregate surface and...head group repulsions are high, a is large and curvatures are small . Thus, the optimal aggregate of ditetradecyldimethylammonium acetate is a small

  6. Hyperbranched hydrocarbon surfactants give fluorocarbon-like low surface energies.

    PubMed

    Sagisaka, Masanobu; Narumi, Tsuyoshi; Niwase, Misaki; Narita, Shioki; Ohata, Atsushi; James, Craig; Yoshizawa, Atsushi; Taffin de Givenchy, Elisabeth; Guittard, Frédéric; Alexander, Shirin; Eastoe, Julian

    2014-06-03

    Two series of Aerosol-OT-analogue surfactants (sulfosuccinate-type di-BCnSS and sulfoglutarate-type di-BCnSG) with hyperbranched alkyl double tails (so-called "hedgehog" groups, carbon number n = 6, 9, 12, and 18) have been synthesized and shown to demonstrate interfacial properties comparable to those seen for related fluorocarbon (FC) systems. Critical micelle concentration (CMC), surface tension at the CMC (γCMC), and minimum area per molecule (Amin) were obtained from surface tension measurements of aqueous surfactant solutions. The results were examined for relationships between the structure of the hedgehog group and packing density at the interface. To evaluate A and B values in the Klevens equation for these hedgehog surfactants, log(CMC) was plotted as a function of the total carbon number in the surfactant double tail. A linear relationship was observed, producing B values of 0.20-0.25 for di-BCnSS and di-BCnSG, compared to a value of 0.31 for standard double-straight-tail sulfosuccinate surfactants. The lower B values of these hedgehog surfactants highlight their lower hydrophobicity compared to double-straight-tail surfactants. To clarify how hydrocarbon density in the surfactant-tail layer (ρ(layer)) affects γCMC, the ρ(layer) of each double-tail surfactant was calculated and the relationship between γCMC and ρ(layer) examined. As expected for the design of low surface energy surfactant layers, ρ(layer) was identified as an important property for controlling γCMC with higher ρ(layer), leading to a lower γCMC. Interestingly, surfactants with BC9 and BC12 tails achieved much lower γCMC, even at low ρ(layer) values of <0.55 g cm(-3). The lowest surface energy surfactant studied here was di-BC6SS, which had a γCMC of only 23.8 mN m(-1). Such a low γCMC is comparable to those obtained with short FC-tail surfactants (e.g., 22.0 mN m(-1) for the sulfosuccinate-type FC-surfactant with R = F(CF2)6CH2CH2-).

  7. Aqueous Gemini Surfactant Self-Assembly into Complex Lyotropic Phases

    NASA Astrophysics Data System (ADS)

    Mahanthappa, Mahesh; Sorenson, Gregory

    2012-02-01

    In spite of the potentially wide-ranging applications of aqueous bicontinuous lyotropic liquid crystals (LLCs), the discovery of amphiphiles that reliably form these non-constant mean curvature morphologies over large phase windows remains largely serendipitous. Recent work has established that cationic gemini surfactants exhibit a pronounced tendency to form bicontinuous cubic (e.g. gyroid) phases as compared to their parent single-tail amphiphiles. The universality of this phenomenon in other surfactant systems remains untested. In this paper, we will report the aqueous LLC phase behavior of a new class of anionic gemini surfactants derived from long chain carboxylic acids. Our studies show that these new surfactants favor the formation of non-constant mean curvature gyroid and primitive (``Plumber's Nightmare'') structures over amphiphile concentration windows up to 20 wt% wide. Based on these observations, we will discuss insights gained into the delicate force balance governing the self-assembly of these surfactants into aqueous bicontinuous LLCs.

  8. Permeability modification of porous media by surfactant solutions

    SciTech Connect

    Kalpakci, B.; Klaus, E.E.; Duda, J.L.; Nagarajan, R.

    1981-01-01

    Results are presented of a study on the flow properties of surfactant solutions in porous media, using the Penn State Porous Media Viscometer. The effects of permeability, shear rate, and surface characteristics of the porous media on the flow of oil-external, and water-external type microemulsions as well as surfactant solutions with lamellar structures have been examined. Flow studies have been carried out in untreated Bradford and Berea sandstones, oil-wet and water-wet treated sandstones, and filter papers. This study shows that the flow of surfactant solutions causes a decrease in permeability which reaches a stable value after the flow of several hundred pore volumes of the surfactant solution. This work is pertinent to flooding with surfactants. 33 refs.

  9. Low-surface energy surfactants with branched hydrocarbon architectures.

    PubMed

    Alexander, Shirin; Smith, Gregory N; James, Craig; Rogers, Sarah E; Guittard, Frédéric; Sagisaka, Masanobu; Eastoe, Julian

    2014-04-01

    Surface tensiometry and small-angle neutron scattering have been used to characterize a new class of low-surface energy surfactants (LSESs), "hedgehog" surfactants. These surfactants are based on highly branched hydrocarbon (HC) chains as replacements for environmentally hazardous fluorocarbon surfactants and polymers. Tensiometric analyses indicate that a subtle structural modification in the tails and headgroup results in significant effects on limiting surface tensions γcmc at the critical micelle concentration: a higher level of branching and an increased counterion size promote an effective reduction of surface tension to low values for HC surfactants (γcmc ∼ 24 mN m(-1)). These LSESs present a new class of potentially very important materials, which form lamellar aggregates in aqueous solutions independent of dilution.

  10. Surface tension profiles of nanofluid containing surfactant during microwave irradiation

    NASA Astrophysics Data System (ADS)

    Tanaka, K.; Asakuma, Y.; Saptoro, A.; Phan, C.

    2017-06-01

    Manipulation of the surface tension is useful in improving heat and mass transfer performances of nanofluids in thermal systems. In our previous study, the effect of microwave irradiation on the reduction of surface tension of nanofluids (Fe2O3) was found even after it was turned off. In this study, a synergistic effect of microwave irradiation and surfactant addition (SDS) was investigated to obtain further surface tension reduction of nanofluid. Experimental results indicate that surfactant addition is effective for wider particle number density in reducing surface tension, and the reduction level strongly depends on the surfactant concentration. On the other hand, effect of the number density on the surface tension reduction is less significant for the same concentration of surfactant. From the obtained data, a combination of microwave irradiation and surfactant addition shows potential to be used as a promising method to manipulate surface tension of nanofluids.

  11. Structural rearrangements in self-assembled surfactant layers at surfaces

    SciTech Connect

    Sushko, Maria L.; Liu, Jun

    2010-03-25

    The transition from compact to extended configuration in ionic surfactant layers under the influence of salt, surfactant surface density and temperature is studied using the classical density functional theory (cDFT). The increase in ionic strength of aqueous salt solution or in surfactant surface density leads to the transition from the hemicylindrical to the perpendicular monolayer configuration of the molecules. Although producing the same structural rearrangement in the surfactant layer the origin of the effect of salt and surface density is different. While the addition of salt increases the out-of-plane attractive interactions with the solvent, the increase in density results in the increase in the in-plane repulsion in surfactant layer. The temperature effects are subtler and are mainly manifested in the reduction of the solution structuring at elevated temperatures.

  12. Surfactant Effects on Microemulsion-Based Nanoparticle Synthesis

    PubMed Central

    Tojo, Concha; de Dios, Miguel; Barroso, Fernando

    2010-01-01

    The effect of the surfactant on the size, polydispersity, type of size distribution and structure of nanoparticles synthesized in microemulsions has been studied by computer simulation. The model simulates the surfactant by means of two parameters: the intermicellar exchange parameter, kex, related to dimer life time, and film flexibility parameter, f, related to interdroplet channel size. One can conclude that an increase in surfactant flexibility leads to bigger and polydisperse nanoparticle sizes. In addition, at high concentrations, the same reaction gives rise to a unimodal distribution using a flexible surfactant, and a bimodal distribution using a rigid one. In relation to bimetallic nanoparticles, if the nanoparticle is composed of two metals with a moderate difference in reduction potentials, increasing the surfactant flexibility modifies the nanoparticle structure, giving rise to a transition from a nanoalloy (using a rigid film) to a core-shell structure (using a flexible one).

  13. Effects of surfactants on extraction of phenanthrene in spiked sand.

    PubMed

    Chang, M C; Huang, C R; Shu, H Y

    2000-10-01

    Problems associated with polynuclear aromatic hydrocarbon (PAH) contaminated site in environmental media have received increasing attention. To resolve such problems, innovative in situ methods are urgently required. This work investigated the feasibility of using surfactants to extract phenanthrene on spiked sand in a batch system. Phenanthrene was spiked into Ottawa sand to simulate contaminated soil. Six surfactants, Brij 30 (BR), Triton X-100 (TR), Tergitol NP-10 (TE), Igepal CA-720 (IG), sodium dodecyl sulfate (SDS) and hexadecyl trimethyl ammonium bromide (HTAB) were used. Adjusting the extraction time, mixing speed and surfactant concentration yielded the optimum extracting conditions. The concentration of phenanthrene was identified with HPLC. Under the experimental conditions, results indicated that those surfactants were highly promising on site remediation since the residual phenanthrene concentration was effectively reduced. The optimum operating conditions were obtained at 30 min, 125 rpm and surfactant concentrations in 4%.

  14. NMR diffusion analysis of surfactant-humic substance interactions.

    PubMed

    Otto, William H; Britten, Danny J; Larive, Cynthia K

    2003-05-15

    Surfactants can be introduced into the environment through wastewater or by direct contamination. Understanding the fate and transport of surfactants in the environment is important in assessing their role as pollutants. Humic substances are complex heterogeneous mixtures of decomposition products of natural organic materials. They are environmentally important because they are known to solubilize and transport organic pollutants. Therefore humic substances are likely to affect the environmental fate of surfactants. Diffusion coefficients measured with pulsed-field gradient nuclear magnetic resonance spectroscopy are used in this study to examine the intermolecular interactions of the surfactants sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) in the presence of various humic substances. These results indicate that humic substances enhance the aggregation of SDS prior to micellization with a more pronounced effect observed for the more hydrophobic humic materials. The positively charged surfactant CTAB forms stable ion pairs with the humic substances.

  15. Enhanced solubilization of curcumin in mixed surfactant vesicles.

    PubMed

    Kumar, Arun; Kaur, Gurpreet; Kansal, S K; Chaudhary, Ganga Ram; Mehta, S K

    2016-05-15

    Self-assemblies of equimolar double and single chain mixed ionic surfactants, with increasing numbers of carbon atoms of double chain surfactant, were analyzed on the basis of fluorescence and conductivity results. Attempts were also made to enhance the solubilization of curcumin in aqueous equimolar mixed surfactant systems. Mixed surfactant assembly was successful in retarding the degradation of curcumin in alkaline media (only 25-28 40% degraded in 10h at pH 13). Fluorescence spectroscopy and fluorescence quenching methods were employed to predict the binding position and mechanism of curcumin with self-assemblies. Results indicate that the interactions take place according to both dynamic and static quenching mechanisms and curcumin was distributed in a palisade layer of mixed aggregates. Antioxidant activity (using DPPH radical) and biocompatibility (using calf-thymus DNA) of curcumin-loaded mixed surfactant formulations were also evaluated. The prepared systems improved the stability, solubility and antioxidant activity of curcumin and additionally are biocompatible.

  16. Theory of interfacial phase transitions in surfactant systems

    NASA Astrophysics Data System (ADS)

    Shukla, K. P.; Payandeh, B.; Robert, M.

    1991-06-01

    The spin-1 Ising model, which is equivalent to the three-component lattice gas model, is used to study wetting transitions in three-component surfactant systems consisting of an oil, water, and a nonionic surfactant. Phase equilibria, interfacial profiles, and interfacial tensions for three-phase equilibrium are determined in mean field approximation, for a wide range of temperature and interaction parameters. Surfactant interaction parameters are found to strongly influence interfacial tensions, reducing them in some cases to ultralow values. Interfacial tensions are used to determine whether the middle phase, rich in surfactant, wets or does not wet the interface between the oil-rich and water-rich phases. By varying temperature and interaction parameters, a wetting transition is located and found to be of the first order. Comparison is made with recent experimental results on wetting transitions in ternary surfactant systems.

  17. Delivery and performance of surfactant replacement therapies to treat pulmonary disorders

    PubMed Central

    El-Gendy, Nashwa; Kaviratna, Anubhav; Berkland, Cory; Dhar, Prajnaparamita

    2013-01-01

    Lung surfactant is crucial for optimal pulmonary function throughout life. An absence or deficiency of surfactant can affect the surfactant pool leading to respiratory distress. Even if the coupling between surfactant dysfunction and the underlying disease is not always well understood, using exogenous surfactants as replacement is usually a standard therapeutic option in respiratory distress. Exogenous surfactants have been extensively studied in animal models and clinical trials. The present article provides an update on the evolution of surfactant therapy, types of surfactant treatment, and development of newer-generation surfactants. The differences in the performance between various surfactants are highlighted and advanced research that has been conducted so far in developing the optimal delivery of surfactant is discussed. PMID:23919474

  18. Delivery and performance of surfactant replacement therapies to treat pulmonary disorders.

    PubMed

    El-Gendy, Nashwa; Kaviratna, Anubhav; Berkland, Cory; Dhar, Prajnaparamita

    2013-08-01

    Lung surfactant is crucial for optimal pulmonary function throughout life. An absence or deficiency of surfactant can affect the surfactant pool leading to respiratory distress. Even if the coupling between surfactant dysfunction and the underlying disease is not always well understood, using exogenous surfactants as replacement is usually a standard therapeutic option in respiratory distress. Exogenous surfactants have been extensively studied in animal models and clinical trials. The present article provides an update on the evolution of surfactant therapy, types of surfactant treatment, and development of newer-generation surfactants. The differences in the performance between various surfactants are highlighted and advanced research that has been conducted so far in developing the optimal delivery of surfactant is discussed.

  19. 3D Model of Surfactant Replacement Therapy

    NASA Astrophysics Data System (ADS)

    Grotberg, James; Tai, Cheng-Feng; Filoche, Marcel

    2015-11-01

    Surfactant Replacement Therapy (SRT) involves instillation of a liquid-surfactant mixture directly into the lung airway tree. Though successful in neonatal applications, its use in adults had early success followed by failure. We present the first mathematical model of 3D SRT where a liquid plug propagates through the tree from forced inspiration. In two separate modeling steps, the plug first deposits a coating film on the airway wall which subtracts from its volume, a ``coating cost''. Then the plug splits unevenly at the airway bifurcation due to gravity. The steps are repeated until a plug ruptures or reaches the tree endpoint alveoli/acinus. The model generates 3D images of the resulting acinar distribution and calculates two global indexes, efficiency and homogeneity. Simulating published literature, the earlier successful adult SRT studies show comparatively good index values, while the later failed studies do not. Those unsuccessful studies used smaller dose volumes with higher concentration mixtures, apparently assuming a well mixed compartment. The model shows that adult lungs are not well mixed in SRT due to the coating cost and gravity effects. Returning to the higher dose volume protocols could save many thousands of lives annually in the US. Supported by NIH Grants HL85156, HL84370 and Agence Nationale de la Recherche, ANR no. 2010-BLAN-1119-05.

  20. [Lung surfactant changes in acute destructive pancreatitis].

    PubMed

    Uchikov, A; Khristov, Zh; Murdzhev, K; Tar'lov, Z

    2000-01-01

    Severe acute pancreatitis (SAP), with mortality rate ranging from 15 to 40 per cent, continues to be a serious challenge to emergency surgeons. Not infrequently, in such cases lesions to the respiratory system develop, with the changes in pulmonary surfactant (PS) occurring during SAP considered as one of the major factors implicated. Alterations in structural phospholipids of PS (lecithin and sphyngomyelin) are assessed under experimental conditions in 26 dogs with modulated SAP at 1, 3, 6, 12 and 24 hours, and the obtained results compared to the ones prior to pancreatitis triggering. The animals are divided up into two groups--untreated and given Sandostatin treatment. In either group a reduction of PS fractions is documented, with a statistically significant lesser reduction of the indicators under study being established in the Sandostatin-treated group by comparison with the untreated one. Modulated SAP in dogs accounts for a significant reduction of the surfactant phospholipid values--lecithin and sphyngomyelin--in bronchoalveolar lavage (BAL).

  1. DILUTE SURFACTANT METHODS FOR CARBONATE FORMATIONS

    SciTech Connect

    Kishore K. Mohanty

    2005-04-01

    There are many carbonate reservoirs in US (and the world) with light oil and fracture pressure below its minimum miscibility pressure (or reservoir may be naturally fractured). Many carbonate reservoirs are naturally fractured. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). Thermal and miscible tertiary recovery techniques are not effective in these reservoirs. Surfactant flooding (or huff-n-puff) is the only hope, yet it was developed for sandstone reservoirs in the past. The goal of this research is to evaluate dilute (hence relatively inexpensive) surfactant methods for carbonate formations and identify conditions under which they can be effective. Laboratory imbibition tests show about 61% oil recovery in the case of Alf-38 and 37% in the case of DTAB. A numerical model has been developed that fits the rate of imbibition of the laboratory experiment. Field-scale fracture block simulation shows that as the fracture spacing increases, so does the time of recovery. Plans for the next quarter include simulation studies.

  2. Performed surfactant-optimized aqueous alkaline flood

    SciTech Connect

    Thigpen, D.R.; Lawson, J.B.; Nelson, R.C.

    1991-11-26

    This paper describes improvement in a process for recovering oil from an acidic oil reservoir by injecting an aqueous alkaline solution comprising water, sodium chloride, and alkaline material for reacting with the reservoir oil forming a petroleum acid soap to form an in-situ surfactant system. The improvement comprises: selecting a preformed cosurfactant which is soluble in both the aqueous solution and the reservoir oil and has a solubility ratio which is grater than the solubility ratio of the petroleum acid soap where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; combining with the alkaline solution an amount of the preformed cosurfactant which will result in the in-situ surfacant system having a salinity about equal to a salinity which results in minimal interfacial tension between the oil in the reservoir and the in-situ surfactant system at reservoir temperature, wherein the amount of the preformed cosurfactant is about 0.3 percent by weight in the aqueous alkaline solution; and injecting the cosurfactant-aqueous alkaline solution mixture into the reservoir to displace oil toward a fluid production location.

  3. Surfactants for Bubble Removal against Buoyancy.

    PubMed

    Raza, Md Qaisar; Kumar, Nirbhay; Raj, Rishi

    2016-01-08

    The common phenomenon of buoyancy-induced vapor bubble lift-off from a heated surface is of importance to many areas of science and technology. In the absence of buoyancy in zero gravity of space, non-departing bubbles coalesce to form a big dry patch on the heated surface and heat transfer deteriorates despite the high latent heat of vaporization of water. The situation is worse on an inverted heater in earth gravity where both buoyancy and surface tension act upwards to oppose bubble removal. Here we report a robust passive technique which uses surfactants found in common soaps and detergents to avoid coalescence and remove bubbles downwards, away from an inverted heater. A force balance model is developed to demonstrate that the force of repulsion resulting from the interaction of surfactants adsorbed at the neighboring liquid-vapor interfaces of the thin liquid film contained between bubbles is strong enough to overcome buoyancy and surface tension. Bubble removal frequencies in excess of ten Hz resulted in more than twofold enhancement in heat transfer in comparison to pure water. We believe that this novel bubble removal mechanism opens up opportunities for designing boiling-based systems for space applications.

  4. Surfactants for Bubble Removal against Buoyancy

    PubMed Central

    Raza, Md. Qaisar; Kumar, Nirbhay; Raj, Rishi

    2016-01-01

    The common phenomenon of buoyancy-induced vapor bubble lift-off from a heated surface is of importance to many areas of science and technology. In the absence of buoyancy in zero gravity of space, non-departing bubbles coalesce to form a big dry patch on the heated surface and heat transfer deteriorates despite the high latent heat of vaporization of water. The situation is worse on an inverted heater in earth gravity where both buoyancy and surface tension act upwards to oppose bubble removal. Here we report a robust passive technique which uses surfactants found in common soaps and detergents to avoid coalescence and remove bubbles downwards, away from an inverted heater. A force balance model is developed to demonstrate that the force of repulsion resulting from the interaction of surfactants adsorbed at the neighboring liquid-vapor interfaces of the thin liquid film contained between bubbles is strong enough to overcome buoyancy and surface tension. Bubble removal frequencies in excess of ten Hz resulted in more than twofold enhancement in heat transfer in comparison to pure water. We believe that this novel bubble removal mechanism opens up opportunities for designing boiling-based systems for space applications. PMID:26743179

  5. Identification of surfactants emerged in aerobic granulation.

    PubMed

    Wang, Zhiping; Li, Bing; Zhang, Tong

    2011-01-01

    In this study, aerobic granules were cultivated in sequencing batch reactors with activated sludge as the seed. The reactors were operated for 12 h per cycle with the organic loading rate (OLR) increasing in double stepwise from 0.5 to 4.0 g COD L⁻¹d⁻¹. Within the 40 d running, black granules with regular and smooth morphology were cultivated, which had high wet density and high settling velocity. During the granulation process, foams emerged and disappeared in the reactor, coinciding with the proliferation of filamentous microorganisms in the granules, implying that surfactants might exist and play an important role in the granulation. Using ultra performance liquid chromatography-tandem mass spectrometry, the surfactants were identified as homologous compounds of polyethylene glycol (PEG) with molecular weights ranging mainly from 100 to 500 Da. Their general formulas were proposed as HO-[CH₂-CH₂-O](n)-H. The source of PEG still needs further investigation. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Reversal of multidrug resistance by surfactants.

    PubMed Central

    Woodcock, D. M.; Linsenmeyer, M. E.; Chojnowski, G.; Kriegler, A. B.; Nink, V.; Webster, L. K.; Sawyer, W. H.

    1992-01-01

    Cremophor EL, a pharmacologically inactive solubilising agent, has been shown to reverse multidrug resistance (MDR). Using flow cytometric evaluation of equilibrium intracellular levels of daunorubicin (DNR), we found that eight other surface active agents will also reverse MDR. All the active detergents contain polyethoxylated moieties but have no similarities in their hydrophobic components. The properties of three polyethoxylated surfactants that showed the lowest toxicities, Cremophor, Tween 80 and Solutol HS15, were examined in more detail. The concentrations of Tween 80 and Solutol required to reverse DNR exclusion were 10-fold lower than for Cremophor. However while concentrations greater than or equal to 1:10(2) of the former two surfactants resulted in breakdown of cells, even 1:10 of Cremophor did not lyse cells. Studies of the effects of Cremophor on the uptake and efflux of DNR in normal and MDR cell types showed that Cremophor increases intracellular DNR primarily by locking the rapid efflux from the cells. This blockage of drug efflux may be mediated by a substantial alteration in the fluidity of cell membranes induced by Cremophor, as shown by decreased fluorescence anisotropy of a membrane probe. Consistent with these data, coinjection of adriamycin plus Cremophor into mice carrying a multidrug resistant P388 transplantable tumour significantly increased the survival time of the mice compared with adriamycin treatment alone. PMID:1637678

  7. Surfactants for Bubble Removal against Buoyancy

    NASA Astrophysics Data System (ADS)

    Raza, Md. Qaisar; Kumar, Nirbhay; Raj, Rishi

    2016-01-01

    The common phenomenon of buoyancy-induced vapor bubble lift-off from a heated surface is of importance to many areas of science and technology. In the absence of buoyancy in zero gravity of space, non-departing bubbles coalesce to form a big dry patch on the heated surface and heat transfer deteriorates despite the high latent heat of vaporization of water. The situation is worse on an inverted heater in earth gravity where both buoyancy and surface tension act upwards to oppose bubble removal. Here we report a robust passive technique which uses surfactants found in common soaps and detergents to avoid coalescence and remove bubbles downwards, away from an inverted heater. A force balance model is developed to demonstrate that the force of repulsion resulting from the interaction of surfactants adsorbed at the neighboring liquid-vapor interfaces of the thin liquid film contained between bubbles is strong enough to overcome buoyancy and surface tension. Bubble removal frequencies in excess of ten Hz resulted in more than twofold enhancement in heat transfer in comparison to pure water. We believe that this novel bubble removal mechanism opens up opportunities for designing boiling-based systems for space applications.

  8. Competitive substrate biodegradation during surfactant-enhanced remediation

    SciTech Connect

    Goudar, C.; Strevett, K.; Grego, J.

    1999-12-01

    The impact of synthetic surfactants on the aqueous phase biodegradation of benzene, toluene, and p-xylene (BTpX) was studied using two anionic surfactants, sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS), and two nonionic surfactants, POE(20) sorbitan monooleate (T-maz-80) and octyl-phenolpoly(ethyleneoxy) ethanol (CA-620). Batch biodegradation experiments were performed to evaluate surfactant biodegradability using two different microbial cultures. Of the four surfactants used in this study, SDS and T-maz-80 were readily degraded by a microbial consortium obtained from an activated sludge treatment system, whereas only SDS was degraded by a microbial culture that was acclimated to BTpX. Biodegradation kinetic parameters associated with SDS and T-maz-80 degradation by the activated sludge consortium were estimated using respirometric data in conjunction with a nonlinear parameter estimation technique as {mu}{sub max} = 0.93 h{sup {minus}1}, K{sub s}= 96.18 mg/L and {mu}{sub max} = 0.41 h{sup {minus}1}, K{sub s} = 31.92 mg/L, respectively. When both BTpX and surfactant were present in the reactor along with BTpX-acclimated microorganisms, two distinct biodegradation patterns were seen. SDS was preferentially utilized inhibiting hydrocarbon biodegradation, whereas, the other three surfactants had no impact on BTpX biodegradation. None of the four surfactants were toxic to the microbial cultures used in this study. Readily biodegradable surfactants are not very effective for subsurface remediation applications as they are rapidly consumed, and also because of their potential inhibitory effects on intrinsic hydrocarbon biodegradation. This greatly increases treatment costs as surfactant recovery and reuse are adversely affected.

  9. Mechanisms of Particle Charging by Surfactants in Nonpolar Dispersions.

    PubMed

    Lee, Joohyung; Zhou, Zhang-Lin; Alas, Guillermo; Behrens, Sven Holger

    2015-11-10

    Electric charging of colloidal particles in nonpolar solvents plays a crucial role for many industrial applications and products, including rubbers, engine oils, toners, or electronic displays. Although disfavored by the low solvent permittivity, particle charging can be induced by added surfactants, even nonionic ones, but the underlying mechanism is poorly understood, and neither the magnitude nor the sign of charge can generally be predicted from the particle and surfactant properties. The conclusiveness of scientific studies has been limited partly by a traditional focus on few surfactant types with many differences in their chemical structure and often poorly defined composition. Here we investigate the surface charging of poly(methyl methacrylate) particles dispersed in hexane-based solutions of three purified polyisobutylene succinimide polyamine surfactants with "subtle" structural variations. We precisely vary the surfactant chemistry by replacing only a single electronegative atom located at a fixed position within the polar headgroup. Electrophoresis reveals that these small differences between the surfactants lead to qualitatively different particle charging. In the respective particle-free surfactant solutions we also find potentially telling differences in the size of the surfactant aggregates (inverse micelles), the residual water content, and the electric solution conductivity as well as indications for a significant size difference between oppositely charged inverse micelles of the most hygroscopic surfactant. An analysis that accounts for the acid/base properties of all constituents suggests that the observed particle charging is better described by asymmetric adsorption of charged inverse micelles from the liquid bulk than by charge creation at the particle surface. Intramicellar acid-base interaction and intermicellar surfactant exchange help rationalize the formation of micellar ions pairs with size asymmetry.

  10. NMR study of the dynamics of cationic gemini surfactant 14-2-14 in mixed solutions with conventional surfactants.

    PubMed

    Jiang, Yan; Lu, Xing-Yu; Chen, Hong; Mao, Shi-Zhen; Liu, Mai-Li; Luo, Ping-Ya; Du, You-Ru

    2009-06-18

    Three kinds of conventional surfactants, namely, two nonionic surfactants [polyethylene glycol (23) lauryl ether (Brij-35) and Triton X-100 (TX-100)], one cationic surfactant [n-tetradecyltrimethyl ammonium bromide (TTAB)], and an anionic surfactant [sodium n-dodecyl sulfate (SDS)}, were mixed into the quaternary ammonium gemini surfactant [C(14)H(29)N(+)(CH(3))(2)](2)(CH(2))(2).2Br(-) (14-2-14) in aqueous solution. The exchange rate constants between 14-2-14 molecules in the mixed micelles and those in the bulk solution were detected using two nuclear magnetic resonance (NMR) methods: one-dimensional (1D) line shape analysis and two-dimensional (2D) exchange spectroscopy (EXSY). The results obtained from these two methods were consistent. Both showed that mixing a nonionic conventional surfactant, either Brij-35 or TX-100, enhanced the exchange process between the 14-2-14 molecules in the mixed micelles and those in the bulk solution. In contrast, the anionic surfactant SDS and the cationic surfactant TTAB slowed the process slightly.

  11. Low potential ocular irritation of arginine-based gemini surfactants and their mixtures with nonionic and zwitterionic surfactants.

    PubMed

    Mitjans, Montserrat; Martínez, Verónica; Clapés, Pere; Pérez, Lourdes; Infante, M Rosa; Vinardell, M Pilar

    2003-10-01

    The aim of this study was to find new biocompatible surfactants and mixtures with low ocular irritant action for application in pharmaceutical formulations and to establish a relationship between their structure and their potential ocular irritant activity. An alternative method to the Draize in vivo test, based on the adverse effects of surfactants on the cytoplasmic membrane of red blood cell, was used to evaluate the potential ocular irritation of the surfactants. It was found that the hemolytic activity of arginine-based gemini surfactants increased with the aliphatic alkyl chain lengths of the hydrophobic tail. The addition of the surfactant with an alkyl chain length of 10 carbon atoms to cocoamidopropilbetaina (TB), decylglucoside (APG), and Nalpha-lauroyl-arginine ethyl ester (LAE) increases the hemolytic activity moderately for the mixtures with TB and LAE (1.1- and 1.5-fold, respectively) and strongly for APG (five-fold). The new arginine-based gemini surfactants constitute a suitable alternative to commercial surfactants because of their natural origins, which make them biocompatible and renewable products. Based on their hemolytic activity as an alternative to the Draize test, these new arginine-based gemini surfactants and their mixtures can be classified as mild irritants. This fact constitutes an advantage, especially for pharmaceutical and cosmetic applications.

  12. Identification of phases of various oil, surfactant/ co-surfactants and water system by ternary phase diagram.

    PubMed

    Syed, Haroon K; Peh, Kok K

    2014-01-01

    The objective of this study was to select appropriate surfactants or blends of surfactants and oil to study the ternary phase diagram behavior and identify various phases obtained from the oil and surfactant/surfactant mixture combinations of different HLB. The phases include conventional emulsion, gel/viscous and transparent/translucent microemulsion. Pseudoternary phase diagrams of water, oil and S/Smix of various HLB values range of 9.65-15 were constructed by using water titration method at room temperature. Visual analysis, conductivity and dye dilution test (methylene blue) were performed after each addition and mixing of water, to identify phases as microemulsion, o/w or w/o emulsion (turbid/milky) and transparent gel/turbid viscous. High gel or viscous area was obtained with Tween 80 and surfactant mixture of Tween 80 and Span 80 with all oils. The results indicated that non-ionic surfactants and PG of different HLB values exhibited different pseudoternary phase diagram characteristics but no microemulsions originated from mineral and olive oils. The w/o emulsion occupied a large area in the ternary phase triangle when HLB value of the surfactant/Smix decreased. The o/w emulsion area was large with increasing HLB value of surfactant/Smix.

  13. The binding and insertion of imidazolium-based ionic surfactants into lipid bilayers: the effects of the surfactant size and salt concentration.

    PubMed

    Lee, Hwankyu; Jeon, Tae-Joon

    2015-02-28

    Imidazolium-based ionic surfactants with hydrocarbon tails of different sizes were simulated with lipid bilayers at different salt concentrations. Starting with the random position of ionic surfactants outside the bilayer, surfactants with long tails mostly insert into the bilayer, while those with short tails show the insertion of fewer surfactant molecules, indicating the effect of the tail length. In particular, surfactants with a tail of two or four hydrocarbons insert and reversibly detach from the bilayer, while the inserted longer surfactants cannot be reversibly detached because of the strong hydrophobic interaction with lipid tails, in quantitative agreement with experiments. Longer surfactants insert more deeply and irreversibly into the bilayer and thus increase lateral diffusivities of the bilayer, indicating that longer surfactants more significantly disorder lipid bilayers, which also agrees with experiments regarding the effect of the tail length of ionic surfactants on membrane permeability and toxicity. Addition of NaCl ions weakens the electrostatic interactions between headgroups of surfactants and lipids, leading to the binding of fewer surfactants into the bilayer. In particular, our simulation findings indicate that insertion of ionic surfactants can be initiated by either the hydrophobic interaction between tails of surfactants and lipids or the electrostatic binding between imidazolium heads and lipid heads, and the strength of hydrophobic and electrostatic interactions depends on the tail length of surfactants.

  14. High Oxygen Concentrations Adversely Affect the Performance of Pulmonary Surfactant.

    PubMed

    Smallwood, Craig D; Boloori-Zadeh, Parnian; Silva, Maricris R; Gouldstone, Andrew

    2017-08-01

    Although effective in the neonatal population, exogenous pulmonary surfactant has not demonstrated a benefit in pediatric and adult subjects with hypoxic lung injury despite a sound physiologic rationale. Importantly, neonatal surfactant replacement therapy is administered in conjunction with low fractional FIO2 while pediatric/adult therapy is administered with high FIO2 . We suspected a connection between FIO2 and surfactant performance. Therefore, we sought to assess a possible mechanism by which the activity of pulmonary surfactant is adversely affected by direct oxygen exposure in in vitro experiments. The mechanical performance of pulmonary surfactant was evaluated using 2 methods. First, Langmuir-Wilhelmy balance was utilized to study the reduction in surface area (δA) of surfactant to achieve a low bound value of surface tension after repeated compression and expansion cycles. Second, dynamic light scattering was utilized to measure the size of pulmonary surfactant particles in aqueous suspension. For both experiments, comparisons were made between surfactant exposed to 21% and 100% oxygen. The δA of surfactant was 21.1 ± 2.0% and 35.8 ± 2.0% during exposure to 21% and 100% oxygen, respectively (P = .02). Furthermore, dynamic light-scattering experiments revealed a micelle diameter of 336.0 ± 12.5 μm and 280.2 ± 11.0 μm in 21% and 100% oxygen, respectively (P < .001), corresponding to a ∼16% decrease in micelle diameter following exposure to 100% oxygen. The characteristics of pulmonary surfactant were adversely affected by short-term exposure to oxygen. Specifically, surface tension studies revealed that short-term exposure of surfactant film to high concentrations of oxygen expedited the frangibility of pulmonary surfactant, as shown with the δA. This suggests that reductions in pulmonary compliance and associated adverse effects could begin to take effect in a very short period of time. If these findings can be demonstrated in vivo, a role for

  15. A Noninvasive Surfactant Adsorption Test Predicting the Need for Surfactant Therapy in Preterm Infants Treated with Continuous Positive Airway Pressure.

    PubMed

    Autilio, Chiara; Echaide, Mercedes; Benachi, Alexandra; Marfaing-Koka, Anne; Capoluongo, Ettore D; Pérez-Gil, Jesús; De Luca, Daniele

    2017-03-01

    To determine the diagnostic accuracy of the surfactant adsorption test (SAT) as a predictor for the need for surfactant replacement therapy in neonates with respiratory distress syndrome (RDS). Amniotic fluid samples were collected from 41 preterm neonates with RDS treated with continuous positive airway pressure (CPAP) and 15 healthy control term neonates. Purified porcine surfactant served as a further control. Lamellar bodies and lung ultrasound score were also measured in a subset of the neonates treated with CPAP. Surfactant was administered according to the European guidelines, and clinical data were collected prospectively. Surfactant activity was measured as adsorption at the air/liquid interface and given in relative fluorescent units (RFU). Surfactant activity differed among native porcine surfactant (median, 4863 RFU; IQR, 4405-5081 RFU), healthy term neonates (median, 2680 RFU; IQR, 2069-3050 RFU), and preterm neonates with RDS (median, 442 RFU; IQR, 92-920 RFU; P <.0001). The neonates who failed CPAP had lower surfactant activity compared with those who did not fail CPAP (median, 92 RFU; IQR, 0-315 RFU vs 749 RFU; IQR, 360-974 RFU; P = .0002). Differences between groups were more evident beyond 20-30 minutes of fluorescence; the 30-minute time point showed the highest area under the curve (0.84; P <.001) and the best cutoff level (170 RFU; specificity, 72%; sensitivity, 96%) for the prediction of CPAP failure. Surfactant activity at 30 minutes was significantly correlated with lamellar bodies (r = 0.51, P = .006) and lung ultrasound score (r = -0.39, P = .013). This technique has the potential to be developed into a fast, simple-to-interpret clinical test. The SAT can reliably identify preterm infants with subsequent CPAP failure and shows promise as a screening test for surfactant replacement in preterm neonates. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Perfluorinated surfactants in surface and drinking waters.

    PubMed

    Skutlarek, Dirk; Exner, Martin; Färber, Harald

    2006-09-01

    In this paper recent results are provided of an investigation on the discovery of 12 perfluorinated surfactants (PS) in different surface and drinking waters (Skutlarek et al. 2006 a, Skutlarek et al. 2006 b). In the last years, many studies have reported ubiquitous distribution of this group of perfluorinated chemicals, especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in the environment, particularly in wildlife animal and human samples (Giesy and Kannan 2001, Houde et al. 2006, Prevedouros et al. 2006). Perfluorinated surfactants (e.g. PFOS and PFOA) have shown different potentials for reproductory interference and carcinogenity in animal experiments as well as partly long half-lives in humans (Guruge et al. 2006, FSA UK 2006a, FSA UK 2006b, 3M 2005, OECD 2002, Yao and Zhong 2005). They possess compound-dependent extreme recalcitrance against microbiological and chemical degradation and, in addition, they show variable potentials for bioaccumulation in animals and humans (Houde et al. 2006). Surface and drinking water samples were collected from different sampling sites: Surface waters: samples taken from the rivers Rhine, Ruhr, Moehne and some of their tributaries. Further samples were taken from the Rhine-Herne-Canal and the Wesel-Datteln-Canal. Drinking waters: samples taken in public buildings of the Rhine-Ruhr area. After sample clean-up and concentration by solid-phase extraction, the perfluorinated surfactants were determined using HPLC-MS/MS. All measured concentrations (sum of seven mainly detected components) in the Rhine river and its main tributaries (mouths) were determined below 100 ng/L. The Ruhr river (tributary of the Rhine) showed the highest concentration (94 ng/L), but with a completely different pattern of components (PFOA as major component), as compared with the other tributaries and the Rhine river. Further investigations along the Ruhr river showed remarkably high concentrations of PS in the upper reaches of

  17. Characterization of Phase and Emulsion Behavior, Surfactant Retention, and Oil Recovery for Novel Alcohol Ethoxycarboxylate Surfactant

    SciTech Connect

    Moeti, Lebone T.; Sampath, Ramanathan

    2002-03-13

    Electrical conductivity measurements for middle, bottom, and top phases, as well as bottom/middle, and middle/bottom conjugate pair phases of the NEODOX 23-4/dodecane/10mM water system were continued from the previous reporting period. Electrical conductivity of the mixture decreased as the fraction of volume of the middle phase was increased and vice versa. Also inversion phenomena was observed. Following this, more emulsion studies at various temperatures were progresses. A theoretical model to predict the conductivity measurements using Maxwell equations was developed and sensitivity analyses to test the performance of the model was completed. Surtek, Golden, CO, our industrial partner in this project, investigated the suitability of the surfactant for enhanced oil recovery employing coreflooding techniques and observed lower surfactant and hydrocarbon recovery for NEODOX 23-4.

  18. Simultaneous determination of cationic surfactants and nonionic surfactants by ion-association titration.

    PubMed

    Sakai, Tadao; Teshima, Norio; Takatori, Yasufumi

    2003-09-01

    A simultaneous determination of cationic and nonionic surfactants has been developed using ion-association titration. Tetrabromophenolphthalein ethyl ester (TBPE) was used as an indicator. Benzalkonium reacted with TBPE to form a blue ion-associate in the organic phase. When tetrakis(4-fluorophenyl)borate was added dropwise to the solution, the color of the organic phase turned to yellow at the equivalence point. In addition, when a large amount of potassium ion was added to a solution including Triton X-100, Triton X-100 could be determined by the same technique as described above because of formation of the K+-Triton X-100 cation. The proposed method is available for the stepwise determination of cationic and nonionic surfactants in mixtures.

  19. Surfactant and nonlinear drop dynamics in microgravity

    NASA Astrophysics Data System (ADS)

    Jankovsky, Joseph Charles

    2000-11-01

    Large amplitude drop dynamics in microgravity were conducted during the second United States Microgravity Laboratory mission carried onboard the Space Shuttle Columbia (20 October-5 November 1995). Centimeter- sized drops were statically deformed by acoustic radiation pressure and released to oscillate freely about a spherical equilibrium. Initial aspect ratios of up to 2.0 were achieved. Experiments using pure water and varying aqueous concentrations of Triton-X 100 and bovine serum albumin (BSA) were performed. The axisymmetric drop shape oscillations were fit using the degenerate spherical shape modes. The frequency and decay values of the fundamental quadrupole and fourth order shape mode were analyzed. Several large amplitude nonlinear oscillation dynamics were observed. Shape entrainment of the higher modes by the fundamental quadrupole mode occurred. Amplitude- dependent effects were observed. The nonlinear frequency shift, where the oscillation frequency is found to decrease with larger amplitudes, was largely unaffected by the presence of surfactants. The percentage of time spent in the prolate shape over one oscillation cycle was found to increase with oscillation amplitude. This prolate shape bias was also unaffected by the addition of surfactants. These amplitude-dependent effects indicate that the nonlinearities are a function of the bulk properties and not the surface properties. BSA was found to greatly enhance the surface viscoelastic properties by increasing the total damping of the oscillation, while Triton had only a small influence on damping. The surface concentration of BSA was found to be diffusion-controlled over the time of the experiments, while the Triton diffusion rate was very rapid. Using the experimental frequency and decay values, the suface viscoelastic properties of surface dilatational viscosity ( ks ) and surface shear viscosity ( ms ) were found for varying surfactant concentrations using the transcendental equation of Lu

  20. Surfactant remediation field demonstration using a vertical circulation well

    SciTech Connect

    Knox, R.C.; Sabatini, D.A.; Harwell, J.H.; Brown, R.E.; West, C.C.; Blaha, F.; Griffin, C.

    1997-11-01

    A field demonstration of surfactant-enhanced solubilization was completed in a shallow unconfined aquifer located at a Coast Guard Station in Traverse City, Michigan. The primary objectives of the study were: (1) to assess the ability of the vertical circulation well (VCW) system for controlling chemical extractants added to the subsurface; and (2) to assess the behavior of the surfactant solution in the subsurface, with a goal of maximum surfactant recovery. A secondary objective was to demonstrate enhanced removal of PCE and recalcitrant components of a jet fuel. The analytical results showed that the surfactant increased the contaminant mass extracted by 40-fold and 90-fold for the PCE and jet fuel constituents, respectively. The surfactant solution demonstrated minimal sorption (retardation) and did not precipitate in the subsurface formation. In addition, the VCW system was able to capture in excess of 95% of the injected surfactant solution. Additional field testing and full-scale implementation of surfactant-enhanced subsurface remediation should be performed.

  1. Cloud point of nonionic surfactants: modulation with pharmaceutical excipients.

    PubMed

    Na, G C; Yuan, B O; Stevens, H J; Weekley, B S; Rajagopalan, N

    1999-04-01

    To determine the cloud point of a variety of nonionic surfactants and to search for means to raise the surfactant cloud point in liquid formulations. Cloud points of nonionic surfactants were determined visually in a water bath. Organic compounds, many of which have been used as pharmaceutical excipients, were tested initially for effect on the cloud point of poloxamine 908. Four effective cloud point boosters (CPBs) from different structural classes were further tested on additional surfactants. A number of compounds can raise the cloud point of nonionic surfactants. These cloud point boosters are classified into two categories: nonionic and ionic. The nonionic CPBs include poly(ethylene glycols), propylene glycol, methanol, ethanol, isopropanol, and 2-hydroxypropyl-beta-cyclodextrin. They are effective at molar concentrations. The ionic CPBs include anionic and cationic surfactants, charged phospholipids, long chain fatty acids, and bile salts. They are effective at millimolar concentrations. The cloud point of nonionic surfactants used in liquid formulations can be modulated through the proper choice of excipient.

  2. Extensive intraalveolar pulmonary hemorrhage in infants dying after surfactant therapy.

    PubMed

    Pappin, A; Shenker, N; Hack, M; Redline, R W

    1994-04-01

    To assess the possible relationship between exogenous surfactant therapy and pulmonary hemorrhage in premature infants, we compared autopsy findings in 15 infants treated with exogenous surfactant and in 29 who died before the introduction of surfactant therapy. Infants who met the following criteria were included: birth weight 501 to 1500 gm, survival 4 hours to 7 days, and no congenital anomalies. Average birth weight, gestational age, and age at death were equivalent for the two groups. High rates of pulmonary hemorrhage were present in both groups (treated 80% vs untreated 83%). The untreated group had higher incidences of interstitial hemorrhage and lung hematomas and significantly more large interstitial hemorrhages: 31% untreated versus 0% treated (p < 0.05). The overall rate of intraalveolar hemorrhage was similar in the two groups, but surfactant-treated infants were more likely to have extensive intraalveolar hemorrhage: 53% versus 14% (p < 0.05). Most surfactant-treated infants who survived more than 24 hours had extensive intraalveolar hemorrhage (8/9). Patients who had extensive intraalveolar hemorrhage, with or without prior surfactant therapy, frequently had clinically significant pulmonary hemorrhage (7/12). These findings indicate that infants who die after surfactant therapy have higher rates of a specific type of pulmonary hemorrhage--extensive intraalveolar hemorrhage.

  3. Viscosity of Aqueous Polyelectrolyte Solutions with Oppositely Charged Surfactant

    NASA Astrophysics Data System (ADS)

    Eggert, Matthew; Colby, Ralph

    2006-03-01

    The viscosity of polyelectrolyte solutions with oppositely charged surfactants is measured for a series of anionic polyelectrolytes of variable hydrophobicity (alternating copolymers of sodium maleate with hydrocarbon comonomers) in the presence of cationic trimethyl ammonium bromides with various alkyl tail lengths. These results are compared with a simple model that modifies the scaling theory for unentangled semidilute polyelectrolyte solutions to account for the addition of oppositely charged surfactant. The surfactant lowers the viscosity of these solutions through two means. The polyelectrolyte binds to the surface of the surfactant micelle, reducing the effective chain length of the polymer. The binding also causes counterions of the polyelectrolyte and the surfactant to be released into solution, acting as a salt that screens the repulsion between charges of the polyelectrolyte, causing the chains to have smaller size. The fraction of effectively charged monomers (i.e., free counterions) on the polyelectrolyte is measured via an ion-selective electrode, meaning the simple model has no adjustable parameters. Additional electrodes are used to measure the amount of free surfactant in solution in order to estimate the amount of surfactant associated with each polyelectrolyte chain.

  4. Surfactants in atmospheric aerosols and rainwater around lake ecosystem.

    PubMed

    Razak, Intan Suraya; Latif, Mohd Talib; Jaafar, Shoffian Amin; Khan, Md Firoz; Mushrifah, Idris

    2015-04-01

    This study was conducted to determine the composition of surfactants in atmospheric aerosols and rainwater in the vicinity of Lake Chini, Malaysia. Samples of atmospheric aerosol and rainwater were collected between March and September 2011 using a high volume air sampler (HVAS) and glass bottles equipped with funnel. Colorimetric analysis was undertaken to determine the concentration of anionic surfactants as methylene blue active substances (MBAS) and cationic surfactants as disulphine blue active substances (DBAS). The water-soluble ionic compositions were determined using inductively coupled plasma mass spectrometry for cations (Na, K, Mg and Ca) and ion chromatography equipped with a conductivity detector for anions (F(-), Cl(-), NO3(-), and SO4(2-)) and the Nessler Method was used to obtain the NH4(+) concentrations. The source apportionment of MBAS and DBAS in atmospheric aerosols was identified using a combination of principal component analysis (PCA) and multiple linear regression (MLR). The results revealed that the concentrations of surfactants in atmospheric aerosols and rainwater were dominated by anionic surfactants as MBAS. The concentration of surfactants as MBAS and DBAS was dominated in fine mode compared to coarse mode aerosols. Using PCA/MLR analysis, two major sources of atmospheric surfactants to Lake Chini were identified as soil dust (75 to 93%) and biomass burning (2 to 22%).

  5. New serine-derived gemini surfactants as gene delivery systems.

    PubMed

    Cardoso, Ana M; Morais, Catarina M; Cruz, A Rita; Silva, Sandra G; do Vale, M Luísa; Marques, Eduardo F; de Lima, Maria C Pedroso; Jurado, Amália S

    2015-01-01

    Gemini surfactants have been extensively used for in vitro gene delivery. Amino acid-derived gemini surfactants combine the special aggregation properties characteristic of the gemini surfactants with high biocompatibility and biodegradability. In this work, novel serine-derived gemini surfactants, differing in alkyl chain lengths and in the linker group bridging the spacer to the headgroups (amine, amide and ester), were evaluated for their ability to mediate gene delivery either per se or in combination with helper lipids. Gemini surfactant-based DNA complexes were characterized in terms of hydrodynamic diameter, surface charge, stability in aqueous buffer and ability to protect DNA. Efficient formulations, able to transfect up to 50% of the cells without causing toxicity, were found at very low surfactant/DNA charge ratios (1/1-2/1). The most efficient complexes presented sizes suitable for intravenous administration and negative surface charge, a feature known to preclude potentially adverse interactions with serum components. This work brings forward a new family of gemini surfactants with great potential as gene delivery systems. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. The effect of surfactants on drop deformation, collisions and breakup

    NASA Astrophysics Data System (ADS)

    Cristini, Vittorio; Zhou, Hua; Lowengrub, John; Macosko, Chris

    2001-11-01

    The dynamics of deformable drops in viscous flows are investigated via numerical simulations. A novel finite-element/sharp-interface algorithm based on adaptive tetrahedra (Hooper et al. 2001) for simulations is used. Three-dimensional drop deformation is studied in the presence of a surfactant coating of the drop interface. Under these conditions, flow-driven surfactant redistribution induces Marangoni stresses at the interface that modify the hydrodynamics and thus affect the rheology of emulsions and polymer blends. The effects of the equation of state that relates the concentration of surfactant on the interface to the surface tension, and of diffusion and solubility of surfactant molecules are included in our model. Results of simulations under strong-flow conditions are presented that describe the effect of surfactants on the development of lamellar microstructures in emulsions (Wetzel and Tucker 2001; Cristini et al. 2001). More stable drop lamellae with larger interfacial area are predicted in the presence of surfactants, in agreement with recent experimental observations (Jeon and Macosko 2000). In addition, the feasibility of accurate simulations of drop collisions and breakup is demonstrated using our model, and preliminary results on the effects of surfactants on these phenomena are presented.

  7. Surfactants in microbiology and biotechnology: Part 2. Application aspects.

    PubMed

    Singh, Ajay; Van Hamme, Jonathan D; Ward, Owen P

    2007-01-01

    Surfactants are amphiphilic compounds which can reduce surface and interfacial tensions by accumulating at the interface of immiscible fluids and increase the solubility, mobility, bioavailability and subsequent biodegradation of hydrophobic or insoluble organic compounds. Chemically synthesized surfactants are commonly used in the petroleum, food and pharmaceutical industries as emulsifiers and wetting agents. Biosurfactants produced by some microorganisms are becoming important biotechnology products for industrial and medical applications due to their specific modes of action, low toxicity, relative ease of preparation and widespread applicability. They can be used as emulsifiers, de-emulsifiers, wetting and foaming agents, functional food ingredients and as detergents in petroleum, petrochemicals, environmental management, agrochemicals, foods and beverages, cosmetics and pharmaceuticals, and in the mining and metallurgical industries. Addition of a surfactant of chemical or biological origin accelerates or sometimes inhibits the bioremediation of pollutants. Surfactants also play an important role in enhanced oil recovery by increasing the apparent solubility of petroleum components and effectively reducing the interfacial tensions of oil and water in situ. However, the effects of surfactants on bioremediation cannot be predicted in the absence of empirical evidence because surfactants sometimes stimulate bioremediation and sometimes inhibit it. For medical applications, biosurfactants are useful as antimicrobial agents and immunomodulatory molecules. Beneficial applications of chemical surfactants and biosurfactants in various industries are discussed in this review.

  8. Autophilic effect: wetting of hydrophobic surfaces by surfactant solutions.

    PubMed

    Milne, Andrew J B; Amirfazli, A

    2010-04-06

    This paper resolves questions in the literature regarding the autophilic effect (i.e., movement of surfactant past the advancing contact line-leading to an increase in drop radius beyond that due to the advance) and its importance to quasi-static sessile drop wetting. Various systems (SDS, HTAB, and MEGA 10 surfactant solutions at three concentrations each and pure water and ethylene glycol on hydrophobic Teflon and OTS-coated silicon) are probed to determine the existence, time constant, and magnitude of the autophilic effect, using quasi-static advancing and receding sessile drops. From spreading results and advancing contact angle measurements, it is inferred that the autophilic effect does not occur for our systems (in contradiction of some literature) for the following reasons. First, no relation exists between the time constant for spreading and surfactant concentration, meaning the spreading seen is likely inertial in cause and not due to surfactants. Second, advancing contact angle decreases between tests on clean surfaces and those pre-exposed to surfactant, ruling out the possibility that the autophilic effect is faster than the advance. Third, spreading is seen after the end of the advance over both clean and pre-exposed surfaces, ruling out the possibility that the autophilic effect is slower than the advance. Finally, the pure liquids spread in a similar fashion to surfactant solutions on Teflon and similar contact angle measurements are seen for surfactant solutions and pure liquids of similar surface tension.

  9. Molecular dynamics for surfactant-assisted protein refolding

    NASA Astrophysics Data System (ADS)

    Lu, Diannan; Liu, Zheng; Wu, Jianzhong

    2007-02-01

    Surfactants are widely used to refold recombinant proteins that are produced as inclusion bodies in E. Coli. However, the microscopic details of the surfactant-assisted protein refolding processes are yet to be uncovered. In the present work, the authors aim to provide insights into the effect of hydrophobic interactions of a denatured protein with surfactant molecules on the refolding kinetics and equilibrium by using the Langevin dynamics for coarse-grained models. The authors have investigated the folding behavior of a β-barrel protein in the presence of surfactants of different hydrophobicities and concentrations. It is shown that the protein folding process follows a "collapse-rearrangement" mechanism, i.e., the denatured protein first falls into a collapsed state before acquiring the native conformation. In comparison with the protein folding without surfactants, the protein-surfactant hydrophobic interactions promote the collapse of a denatured protein and, consequently, the formation of a hydrophobic core. However, the surfactants must be released from the hydrophobic core during the rearrangement step, in which the native conformation is formed. The simulation results can be qualitatively reproduced by experiments.

  10. Rheology of cellulose nanofibrils in the presence of surfactants.

    PubMed

    Quennouz, Nawal; Hashmi, Sara M; Choi, Hong Sung; Kim, Jin Woong; Osuji, Chinedum O

    2016-01-07

    Cellulose nanofibrils (CNFs) present unique opportunities for rheology modification in complex fluids. Here we systematically consider the effect of ionic and non-ionic surfactants on the rheology of dilute CNF suspensions. Neat suspensions are transparent yield-stress fluids which display strong shear thinning and power-law dependence of modulus on concentration, G' ∼ c(2.1). Surfactant addition below a critical mass concentration cc produces an increase in the gel modulus with retention of optical clarity. Larger than critical concentrations induce significant fibril aggregation leading to the loss of suspension stability and optical clarity, and to aggregate sedimentation. The critical concentration was the lowest for a cationic surfactant (DTAB), cc ≈ 0.08%, while suspension stability was retained for non-ionic surfactants (Pluronic F68, TX100) at concentrations up to 8%. The anionic surfactant SDS led to a loss of stability at cc ≈ 1.6% whereas suspension stability was not compromised by anionic SLES up to 8%. Dynamic light scattering data are consistent with a scenario in which gel formation is driven by micelle-nanofibril bridging mediated by associative interactions of ethoxylated surfactant headgroups with the cellulose fibrils. This may explain the strong difference between the properties of SDS and SLES-modified suspensions. These results have implications for the use of CNFs as a rheology modifier in surfactant-containing systems.

  11. Effects of smoke inhalation on alveolar surfactant subtypes in mice.

    PubMed Central

    Oulton, M. R.; Janigan, D. T.; MacDonald, J. M.; Faulkner, G. T.; Scott, J. E.

    1994-01-01

    The effects of smoke inhalation on alveolar surfactant subtypes were examined in mice exposed for 30 minutes to smoke generated from the burning of a flexible polyurethane foam. At 4 or 12 hours after the exposure, three surfactant pellets, P10, P60, and P100, and a supernatant, S100, were prepared by sequential centrifugation of lavage fluids at 10,000 g for 30 minutes (P10), 60,000 g for 60 minutes (P60), and 100,000 g for 15 hours (P100 and S100). Phospholipid analysis and electron microscopy were performed on each fraction. Smoke exposure dramatically altered the normal distributions of these fractions: it significantly increased the phospholipid content of the heavier subtype, P10, which is thought to represent newly secreted surfactant; had no effect on the intermediate form, P60; and dramatically increased the phospholipid content (approximately fivefold) of the lighter subtypes, P100 and S100, which are believed to represent catabolic end-products of alveolar surfactant. Only P100 was structurally altered by the smoke. These results represent alterations of the normal metabolic processing of alveolar surfactant. Whereas the mechanism is yet to be defined, it seems to involve a small but significant increase in the newly secreted surfactant, as well as an excessively high accumulation of the structurally altered catabolic forms of the secreted surfactant. Images Figure 3 PMID:7943183

  12. The effect of surfactant on pollutant biosorption of Trametes versicolor

    NASA Astrophysics Data System (ADS)

    Gül, Ülküye Dudu; Silah, Hülya; Akbaş, Halide; Has, Merve

    2016-04-01

    The major problem concerning industrial wastewater is treatment of dye and heavy metal containing effluents. Industrial effluents are also contained surfactants that are used as levelling, dispersing and wetting agents. The purpose of this study was to investigate the effect of surfactant on textile dye biosorption properties of a white rot fungus named Trametes versicolor. Reactive dyes are commonly used in textile industry because of their advantages such as brightness and excellent color fastness. A recative textile dye, called Everzol Black, was used in this study. The low-cost mollasses medium is used for fungal growth. The usage of mollases, the sugar refinery effluent as a source of energy and nutrients, gained importance because of reducing the cost and also reusing another waste. In biosorption process the effect of surfactant on dye removal properties of T. versicolor was examined as a function of pH, dye consentration and surfactant concentration. The results of this study showed that the surfactant enhanced the dye removal capacity of Trametes versicolor. The dye and surfactant molecules were interacted electrostatically and these electrostatic interactions improved dye removal properties of filamentous fungus T. versicolor. The results of this study recommended the use of surfactants as an inducer in textile wastewater treatment technologies.

  13. Characterization and Control of Surfactant-Mediated Norovirus Interactions

    PubMed Central

    Mertens, Brittany S.; Velev, Orlin D.

    2015-01-01

    Understanding of the colloidal interactions of Norovirus particles in aqueous medium could provide insights on the origins of the notorious stability and infectivity of these widespread viral agents. We characterized the effects of solution pH and surfactant type and concentration on the aggregation, dispersion, and disassembly of Norovirus virus-like particles (VLPs) using dynamic light scattering, electrophoretic light scattering, and transmission electron microscopy. Owing to net negative surface charge of the VLPs at neutral pH, low concentrations of cationic surfactant tend to aggregate the VLPs, whereas low concentrations of anionic surfactant tend to disperse the particles. Increasing the concentration of these surfactants beyond their critical micelle concentration leads to virus capsid disassembly and breakdown of aggregates. Non-ionic surfactants, however, had little effect on virus interactions and likely stabilized them additionally in suspension. The data were interpreted on the basis of simple models for surfactant binding and re-charging of the virus capsid. We used zeta potential data to characterize virus surface charge and interpret the mechanisms behind these demonstrated surfactant-virus interactions. The fundamental understanding and control of these interactions will aid in practical formulations for virus inactivation and removal from contaminated surfaces. PMID:26378627

  14. Treatment of the Thylakoid Membrane with Surfactants 1

    PubMed Central

    Markwell, John P.; Thornber, J. Philip

    1982-01-01

    Treatment of higher plant (Nicotiana tabacum L. var. Samsun) chloroplast thylakoid membranes with surfactants results in a shift of the chlorophyll a absorption maximum in the red spectral region from its in vivo value of 678.5 nanometers to shorter wavelengths. The magnitude of this shift is correlated with membrane disruption, and is not necessarily due to the release of pigment from pigment-protein complexes present in the membrane. Membrane disruption has been measured by the amount of pigment in the supernatant fraction after centrifugation of surfactant treated membranes. For an equivalent amount of disruption, the extent of the blue-shift is influenced by the ionic nature of the surfactant: anionic surfactants cause small shifts, cationic surfactants cause the largest (∼10 nanometers) shifts, and nonionic surfactants produce intermediate shifts. The wavelength of maximum absorbance of chlorophyll a in the red region is a convenient criterion for assessing the potential utility of different surfactants for studies on the structure, composition and function of higher plant thylakoid membranes. PMID:16662547

  15. Optimization of metalworking fluid microemulsion surfactant concentrations for microfiltration recycling.

    PubMed

    Zhao, Fu; Clarens, Andres; Skerlos, Steven J

    2007-02-01

    Microfiltration can be used as a recycling technology to increase metalworking fluid (MWF) life span, decrease procurement and disposal costs, and reduce occupational health risks and environmental impacts. The cost-effectiveness of the process can be increased by minimizing fouling interactions between MWFs and membranes. This paper reports on the development of a microfiltration model that establishes governing relationships between MWF surfactant system characteristics and microfiltration recycling performance. The model, which is based on surfactant adsorption/desorption kinetics, queueing theory, and coalescence kinetics of emulsion droplets, is verified experimentally. An analysis of the model and supporting experimental evidence indicates that the selection of surfactant systems minimally adsorb to membranes and lead to a high activation energy of coalescence results in a higher MWF flux through microfiltration membranes. The model also yields mathematical equations that express the optimal concentrations of anionic and nonionic surfactants with which microfiltration flux is maximized for a given combination of oil type, oil concentration, and surfactant types. Optimal MWF formulations are demonstrated for a petroleum oil MWF using a disulfonate/ ethoxylated alcohol surfactant package and for several vegetable oil MWFs using a disulfonate/ethoxylated glyceryl ester surfactant package. The optimization leads to flux increases ranging from 300 to 800% without impact on manufacturing performance. It is further shown that MWF reformulation efforts directed toward increasing microfiltration flux can have the beneficial effect of increasing MWF robustness to deterioration and flux decline in the presence of elevated concentrations of hardwater ions.

  16. Effects of fixatives on function of pulmonary surfactant.

    PubMed

    Bachofen, H; Gerber, U; Schürch, S

    2002-09-01

    The structure of pulmonary surfactant films remains ill defined. Although plausible film fragments have been imaged by electron microscopy, questions about the significance of the findings and even about the true fixability of surfactant films by the usual fixatives glutaraldehyde (GA), osmium tetroxide (OsO(4)), and uranyl acetate (UA) have not been settled. We exposed functioning natural surfactant films to fixatives within a captive bubble surfactometer and analyzed the effect of fixatives on surfactant function. The capacity of surfactant to reach near-zero minimum surface tension on film compression was barely impaired after exposure to GA or OsO(4). Although neither GA nor OsO(4) prevented the surfactant from forming a surface active film, GA increased the equilibrium surface tension to above 30 mN/m, and both GA and OsO(4) decreased film stability as seen in the slowly rising minimum surface tension from 1 to ~5 mN/m in 10 min. In contrast, the effect of UA seriously impaired surface activity in that both adsorption and minimum surface tension were substantially increased. In conclusion, the fixatives tested in this study are not suitable to fix, i.e., to solidify, surfactant films. Evidently, however, OsO(4) and UA may serve as staining agents.

  17. Remediation of contaminated soil by a solvent/surfactant system.

    PubMed

    Chu, W; Kwan, C Y

    2003-10-01

    This study investigates a new approach using a solvent/surfactant-aided soil-washing process to improve the performance of conventional surfactant-aided soil remediation. Three surfactants (Brij 35, Tween 80, and SDS) and three organic solvents (acetone, triethylamine, and squalane) were used to evaluate the desorption performances of 4,4'-dichlorobiphenyl (DCB) out of three soils with different sorption characteristics. The performance improvement is likely due to better dissolution of the hydrophobic contaminants from the soil assisted by the solvent, and the formation of solvent-incorporated surfactant micelles, which increases both the size (i.e. capacity) and affinity of micelles for more effective contaminant extraction. The foc of soils were found to be important in determining the performance of a solvent/surfactant-aided soil-washing process. Judging from the experimental data and as verified by the two constants in the proposed soil-washing model, as the organic solvent is coexisting with the surfactant micelles, both the marginal soil-washing performance (right after the use of a very small amount of solvent compared to that of none) and the final soil-washing capacity are increased compared to those of a pure surfactant-aided washing process.

  18. Effect of surfactant addition on phenanthrene biodegradation in sediments

    SciTech Connect

    Tsomides, H.J.; Hughes, J.B.; Thomas, J.M.; Ward, C.H.

    1995-12-31

    A laboratory study was conducted to determine whether commercial surfactants enhance the bioremediation of PAH-contaminated sediments. Phenanthrene was chosen as a representative PAH. An inoculum of PAH-degrading microorganisms, enriched from an aquatic sediment, was used in sediment-water slurry microcosm biodegradation experiments. Of seven nonionic surfactants tested, only one (Triton X-100) did not inhibit phenanthrene mineralization at concentrations above the critical micelle concentration (CMC). Temporal studies on Triton X-100 revealed that while it initially inhibited mineralization in sediment-free microcosms, after 1 week Triton X-100 slightly improved phenanthrene biotransformation and mineralization in microcosms with and without sediment. For all treatments, phenanthrene disappearance was complete after 9 d. and mineralization reached 50 to 65% after 12 d. Sorption to the sediment appears to have reduced the free aqueous surfactant concentration, thereby reducing surfactant toxicity to the microorganisms. These results suggest that many surfactants are toxic to PAH-degrading microorganisms, and while surfactant addition may not always have adverse effects on biodegradation, the use of surfactants might not be necessary to achieve complete contaminant removal.

  19. Effect of surfactant addition on phenanthrene biodegradation in sediments

    SciTech Connect

    Tsomides, H.J.; Hughes, J.B.; Thomas, J.M.; Ward, C.H.

    1995-06-01

    A laboratory study was conducted to determine whether commercial surfactants enhance the bioremediation of PAH-contaminated sediments. Phenanthrene was chosen as a representative PAH; an inoculum of PAH-degrading microorganisms, enriched from an aquatic sediment, was used in sediment-water slurry microcosm biodegradation experiments. Of seven non-ionic surfactants tested, only one (Triton X-100) did not inhibit phenanthrene mineralization at concentrations above the critical micelle concentration (CMC). Temporal studies on Triton X-100 revealed that while it initially inhibited mineralization in sediment-free microcosms, after 1 week Triton X-100 slightly improved phenanthrene biotransformation and mineralization in microcosms with and without sediment. For all treatments, phenanthrene disappearance was complete after 9 d, and mineralization reached 50 to 65% after 12 d. Sorption to the sediment appears to have reduced the free aqueous surfactant concentration, thereby reducing surfactant toxicity to the microorganisms. These results suggest that many surfactants are toxic to PAH-degrading microorganisms, and while surfactant addition may not always have adverse effects on biodegradation, the use of surfactants might not be desirable to achieve complete contamination removal.

  20. Sublethal effect of agronomical surfactants on the spider Pardosa agrestis.

    PubMed

    Niedobová, Jana; Hula, Vladimír; Michalko, Radek

    2016-06-01

    In addition to their active ingredients, pesticides contain also additives - surfactants. Use of surfactants has been increasing over the past decade, but their effects on non-target organisms, especially natural enemies of pests, have been studied only very rarely. The effect of three common agrochemical surfactants on the foraging behavior of the wolf spider Pardosa agrestis was studied in the laboratory. Differences in short-term, long-term, and overall cumulative predatory activities were investigated. We found that surfactant treatment significantly affected short-term predatory activity but had no effect on long-term predatory activity. The surfactants also significantly influenced the cumulative number of killed prey. We also found the sex-specific increase in cumulative kills after surfactants treatment. This is the first study showing that pesticide additives have a sublethal effect that can weaken the predatory activity of a potential biological control agent. More studies on the effects of surfactants are needed to understand how they affect beneficial organisms in agroecosystems.

  1. CHARACTERIZATION OF PHASE AND EMULSION BEHAVIOR, SURFACTANT RETENTION, AND OIL RECOVERY FOR NOVEL ALCOHOL ETHOXYCARBOXYLATE SURFACTANTS

    SciTech Connect

    LEBONE MOETI; RAMANATHAN SAMPATH

    1998-11-01

    This semi-annual technical progress report describes work performed at Clark Atlanta University under DOE Grant No. DE-FG26-97FT97278 during the period April 01, 1998 to October 01, 1998 which covers the second six months of the project. Presently work is in progress at the EOR Laboratory, Clark Atlanta University (CAU), to characterize phase and emulsion behavior for a novel, hybrid (ionic/non-ionic), alcohol ethoxycarboxylate surfactant (NEODOX 23-4 from Shell Chemical Company). During this reporting period, salinity scans were completed for 0, 5, 10, 20, 50, 100, 250, 500, 1000, 2000, 3000, 4000, 5000, and 6000 mM salt concentrations at 20, 25, and 30 °C to identify optimal salinity intervals in which all three phases coexist for this surfactant. Temperature scans were also performed at 20 mM salt concentration for various surfactant concentrations ranging from 0 to 60 weight percent at temperatures ranging from 5 to 50 °C to identify optimal surfactant concentration and temperature intervals in which all three phases coexist. This resulted in an "alpha" curve with an interval of temperature in which all three phases coexisted. Presently, temperature scans are being repeated at 100, 250, 500, 1000, and 5000 mM salt concentrations to see whether increase in salt concentration has any effect on the temperature interval. This will provide us better understanding and experimental control of the many variables involved in this research in the future. Following completion of the temperature scans, phase studies will be conducted at CAU, and coreflooding experiments at the facility of our industrial partner, Surtek, Golden, CO.

  2. A study of surfactant adsorption with applications in surfactant assisted enhanced oil recovery processes

    SciTech Connect

    Hankins, N.P.

    1989-01-01

    A study is presented to assess the feasibility of high-pH preflushing to reduce surfactant adsorption in micellar flooding. Under static or dynamic flow conditions, adsorption of a pure anionic surfactant on Berea is eliminated at mild electrolyte above pH 8, 2 pH units above the experimental determined pzc. Static and dynamic studies of hydroxide consumption by Berea indicate mild dissolution at the pH range of interest. The effect of pH on the adsorption isotherm for Berea indicate a large increase in logarithmic slope at high pH. Similar studies are presented for kaolinite and alumina. A patch-wise, phase separation model is presented to quantify the relationship between adsorption, and bulk pH and salinity. The concept of the site-binding model is incorporated into the development of surface aggregates (both admicelles and hemimicelles), and it is confirmed that the aggregates are stabilized at high pH by the abstraction of positive charge to the surface beneath the aggregate, and by high counterion binding, allowing physical adsorption above the pzc. A novel sweep improvement process, surfactant assisted waterflooding, is presented. The chromatographic and phase separation behavior of dissimilar surfactants and their mixtures allows a selective and controllable blocking of watered-out zones of a reservoir. A mathematical model is developed, and the theory of coherence is extended to multidimensional, multiphase, multicomponent flow, allowing the development of a novel simulator, which is then applied. The results indicate that the blocking mechanism is very selective in markedly heterogeneous reservoir. Shorter reservoirs have the highest potential for application; high oil recoveries are then possible since blocking can be controlled to occur deep inside the watered out zones.

  3. Solubilization of pentanol by cationic surfactants and binary mixtures of cationic surfactants

    SciTech Connect

    Morgan, M.E.

    1993-12-31

    The research reported here has included studies of the solubilization of pentanol in hexadecylpyridinium chloride (CPC), trimethyletetradecylammonium chloride (C{sub 14}Cl), benzyldimethyltetradecylammonium chloride (C{sub 14}BzCl), benzyldimethylhexadecylpyridinium chloride (C{sub 16}BzCl), hexadecyltrimethylammonium bromide (CTAB), and binary mixtures of CPC + C{sub 16}BzCl and C{sub 14}Cl + C{sub 14}BzCl. Rather than using calorimetric methods, this project will employ headspace chromatography to measure solubilization of pentanol over a wide range of solute concentrations. While not yielding as much thermodynamic data as calorimetry, headspace chromatography is a more direct measure of the extent of solubilization. Using headspace chromatography, is a more direct measure of the extent of solubilization. Using headspace chromatography, this study will seek to determine whether strongly synergistic mixture ratios exist in the case of binary cationic surfactant systems. There are two equilibria in the pentanol-water-surfactant system: (1) The pentanol solubilized in micelles is in equilibrium with the monomeric pentanol in solution, and (2) the monomeric pentanol is in equilibrium with the pentanol in the vapor above the solution. To establish the link between the two equilibria, a sample of the vapor above pure liquid pentanol must be collected, in order to find the activity of pentanol in solution. Also, a calibration curve for various concentrations of pentanol in solution. From this type of data it is possible to infer both the concentration of pentanol solubilized in micelles and the concentrations of pentanol in the ``bulk`` solution outside the micelles. The method is equally applicable to systems containing a single surfactant as well as mixtures of surfactants.

  4. Beneficial effects of synthetic KL₄ surfactant in experimental lung transplantation.

    PubMed

    Sáenz, A; Alvarez, L; Santos, M; López-Sánchez, A; Castillo-Olivares, J L; Varela, A; Segal, R; Casals, C

    2011-04-01

    The aim of this study was to investigate whether intratracheal administration of a new synthetic surfactant that includes the cationic, hydrophobic 21-residue peptide KLLLLKLLLLKLLLLKLLLLK (KL₄), might be effective in reducing ischaemia-reperfusion injury after lung transplantation. Single left lung transplantation was performed in Landrace pigs 22 h post-harvest. KL₄ surfactant at a dose of 25 mg total phospholipid·kg body weight⁻¹ (2.5 mL·kg body weight⁻¹) was instilled at 37°C to the donor left lung (n = 8) prior to explantation. Saline (2.5 mL·kg body weight⁻¹; 37°C) was instilled into the donor left lung of the untreated group (n = 6). Lung function in recipients was measured during 2 h of reperfusion. Recipient left lung bronchoalveolar lavage (BAL) provided native cytometric, inflammatory marker and surfactant data. KL(4) surfactant treatment recovered oxygen levels in the recipient blood (mean ± sd arterial oxygen tension/inspiratory oxygen fraction 424 ± 60 versus 263 ± 101 mmHg in untreated group; p=0.01) and normalised alveolar-arterial oxygen tension difference. Surfactant biophysical function was also recovered in KL₄ surfactant-treated lungs. This was associated with decreased C-reactive protein levels in BAL, and recovery of surfactant protein A content, normalised protein/phospholipid ratios, and lower levels of both lipid peroxides and protein carbonyls in large surfactant aggregates. These findings suggest an important protective role for KL₄ surfactant treatment in lung transplantation.

  5. Gemini ester quat surfactants and their biological activity.

    PubMed

    Łuczyński, Jacek; Frąckowiak, Renata; Włoch, Aleksandra; Kleszczyńska, Halina; Witek, Stanisław

    2013-03-01

    Cationic gemini surfactants are an important class of surface-active compounds that exhibit much higher surface activity than their monomeric counterparts. This type of compound architecture lends itself to the compound being easily adsorbed at interfaces and interacting with the cellular membranes of microorganisms. Conventional cationic surfactants have high chemical stability but poor chemical and biological degradability. One of the main approaches to the design of readily biodegradable and environmentally friendly surfactants involves inserting a bond with limited stability into the surfactant molecule to give a cleavable surfactant. The best-known example of such a compound is the family of ester quats, which are cationic surfactants with a labile ester bond inserted into the molecule. As part of this study, a series of gemini ester quat surfactants were synthesized and assayed for their biological activity. Their hemolytic activity and changes in the fluidity and packing order of the lipid polar heads were used as the measures of their biological activity. A clear correlation between the hemolytic activity of the tested compounds and their alkyl chain length was established. It was found that the compounds with a long hydrocarbon chain showed higher activity. Moreover, the compounds with greater spacing between their alkyl chains were more active. This proves that they incorporate more easily into the lipid bilayer of the erythrocyte membrane and affect its properties to a greater extent. A better understanding of the process of cell lysis by surfactants and of their biological activity may assist in developing surfactants with enhanced selectivity and in widening their range of application.

  6. Novel fluorinated gemini surfactants with γ-butyrolactone segments.

    PubMed

    Kawase, Tokuzo; Okada, Kazuyuki; Oida, Tatsuo

    2015-01-01

    In this work, novel γ-butyrolactone-type monomeric and dimeric (gemini) surfactants with a semifluoroalkyl group [Rf- (CH2)3-; Rf = C4F9, C6F13, C8F17] as the hydrophobic group were successfully synthesized. Dimethyl malonate was dimerized or connected using Br(CH2)sBr (s = 0, 1, 2, 3) to give tetraesters, and they were bis-allylated. Radical addition of fluoroalkyl using Rf-I and an initiator, i.e., 2,2'-azobisisobutyronitrile for C4F9 or di-t-butyl peroxide for C6F13 and C8F17, was perform at high temperature, with prolonged heating, to obtain bis(semifluoroalkyl)-dilactone diesters. These dilactone diesters were hydrolyzed using KOH/EtOH followed by decarboxylation in AcOH to afford γ-butyrolactonetype gemini surfactants. Common 1 + 1 semifluoroalkyl lactone surfactants were synthesized using the same method. Their surfactant properties [critical micelle concentration (CMC), γCMC, pC20, ΓCMC, and AG] were investigated by measuring the surface tension of the γ-hydroxybutyrate form prepared in aqueous tetrabutylammonium hydroxide solution. As expected, the CMC values of the gemini surfactants were more than one order of magnitude smaller than those of the corresponding 1 + 1 surfactants. Other properties also showed the excellent ability of the gemini structure to reduce the surface tension. These surfactants were easily and quantitatively recovered by acidification. The monomeric surfactant was recovered in the γ-hydroxybutyric acid form, and the gemini surfactant as a mixture of γ-butyrolactone and γ-hydroxybutyric acid forms.

  7. Bacterial Adhesion to Soil Contaminants in the Presence of Surfactants

    PubMed Central

    Stelmack, Patricia L.; Gray, Murray R.; Pickard, Michael A.

    1999-01-01

    It has been proposed that addition of surfactants to contaminated soil enhances the solubility of target compounds; however, surfactants may simultaneously reduce the adhesion of bacteria to hydrophobic surfaces. If the latter mechanism is important for the biodegradation of virtually insoluble contaminants, then the use of surfactants may not be beneficial. The adhesion of a Mycobacterium strain and a Pseudomonas strain, isolated from a creosote-contaminated soil, to the surfaces of highly viscous non-aqueous-phase liquids (NAPLs) was measured. The NAPLs were organic material extracted from soils from two creosote-contaminated sites and two petroleum-contaminated sites. Cells suspended in media with and without surfactant were placed in test tubes coated with an NAPL, and the percentages of cells that adhered to the surface of the NAPL in the presence and absence of surfactant were compared by measuring optical density. Test tubes without NAPLs were used as controls. The presence of either Triton X-100 or Dowfax 8390 at a concentration that was one-half the critical micelle concentration (CMC) inhibited adhesion of both species of bacteria to the NAPLs. Both surfactants, when added at concentrations that were one-half the CMCs to test tubes containing previously adhered bacteria, also promoted the removal of the cells from the surfaces of the NAPL-coated test tubes. Neither surfactant was toxic to the bacteria. Further investigation showed that a low concentration of surfactant also inhibited the growth of both species on anthracene, indicating that the presence of a surfactant resulted in a reduction in the uptake of the solid carbon source. PMID:9872775

  8. Bacterial adhesion to soil contaminants in the presence of surfactants

    SciTech Connect

    Stelmack, P.L.; Gray, M.R.; Pickard, M.A.

    1999-01-01

    It has been proposed that addition of surfactants to contaminated soil enhances the solubility of target compounds; however, surfactants may simultaneously reduce the adhesion of bacteria to hydrophobic surfaces. If the latter mechanism is important for the biodegradation of virtually insoluble contaminants, then the use of surfactants may not be beneficial. The adhesion of a Mycobacterium strain and a Pseudomonas strain, isolated from a creosote-contaminated soil, to the surfaces of highly viscous non-aqueous-phase liquids (NAPLs) was measured. The NAPLs were organic material extracted from soils from two creosote-contaminated sites and two petroleum-contaminated sites. Cells suspended in media with and without surfactant were placed in test tubes coated with an NAPL, and the percentages of cells that adhered to the surface of the NAPL in the presence and absence of surfactant were compared by measuring optical density. Test tubes without NAPLs were used as controls. The presence of either Triton X-100 or Dowfax 8390 at a concentration that was one-half the critical micelle concentration (CMC) inhibited adhesion of both species of bacteria to the NAPLs. Both surfactants, when added at concentrations that were one-half the CMCs to test tubes containing previously adhered bacteria, also promoted the removal of the cells from the surfaces of the NAPL-coated test tubes. Neither surfactant was toxic to the bacteria. Further investigation showed that a low concentration of surfactant also inhibited the growth of both species on anthracene, indicating that the presence of a surfactant resulted in a reduction in the uptake of the solid carbon source.

  9. Single well surfactant test to evaluate surfactant floods using multi tracer method

    DOEpatents

    Sheely, Clyde Q.

    1979-01-01

    Data useful for evaluating the effectiveness of or designing an enhanced recovery process said process involving mobilizing and moving hydrocarbons through a hydrocarbon bearing subterranean formation from an injection well to a production well by injecting a mobilizing fluid into the injection well, comprising (a) determining hydrocarbon saturation in a volume in the formation near a well bore penetrating formation, (b) injecting sufficient mobilizing fluid to mobilize and move hydrocarbons from a volume in the formation near the well bore, and (c) determining the hydrocarbon saturation in a volume including at least a part of the volume of (b) by an improved single well surfactant method comprising injecting 2 or more slugs of water containing the primary tracer separated by water slugs containing no primary tracer. Alternatively, the plurality of ester tracers can be injected in a single slug said tracers penetrating varying distances into the formation wherein the esters have different partition coefficients and essentially equal reaction times. The single well tracer method employed is disclosed in U.S. Pat. No. 3,623,842. This method designated the single well surfactant test (SWST) is useful for evaluating the effect of surfactant floods, polymer floods, carbon dioxide floods, micellar floods, caustic floods and the like in subterranean formations in much less time and at much reduced cost compared to conventional multiwell pilot tests.

  10. Soluble aggregates in aqueous solutions of polyion-surfactant ion complex salts and a nonionic surfactant.

    PubMed

    Janiak, John; Tomšič, Matija; Lundberg, Dan; Olofsson, Gerd; Piculell, Lennart; Schillén, Karin

    2014-08-14

    Water-soluble aggregates based on two polyion-surfactant ion "complex salts", consisting of hexadecyltrimethylammonium (C16TA(+)) and polyacrylate (PA(-)) with either 25 or 6000 repeating units, with added nonionic surfactant octaethylene glycol monododecyl ether (C12E8) have been investigated. A previous phase study has shown that added C12E5 or C12E8 can solubilize complex salts in aqueous systems, and that increasing the poly(ethylene oxide) chain length of the nonionic surfactant and/or decreasing the polyion length favors dissolution. In this work we report on dynamic light scattering, NMR diffusometry, small-angle X-ray scattering, and isothermal titration calorimetry measurements performed to characterize the solubilized composite aggregates in dilute aqueous solution in terms of size and stoichiometry. It was found that mixed aggregates of polyacrylate, C16TA(+) ions, and C12E8, with almost constant stoichiometry, coexist with free micelles of C12E8 at all investigated mixing ratios. The length of the polyion only weakly affects the stoichiometry of the mixed aggregates while strongly affecting their size and water solubility.

  11. Random bilayer phases of dilute surfactant solutions

    NASA Astrophysics Data System (ADS)

    Cates, M. E.; Roux, D.

    1990-12-01

    Surfactant molecules in dilute solution may aggregate reversibly into extended structures. For suitably chosen molecules, the preferred packing involves a locally flat bilayer which tends to wander entropically at large distances. At low temperatures (and/or high concentrations) the system forms a stack of flat sheets with one-dimensional quasi-long range order (a smectic liquid crystal), but at high temperatures or low concentrations, the stack can melt into a random surface structure that resembles a multiply connected labyrinth or 'sponge' of bilayer in a sea of solvent. Recent theoretical and experimental progress in understanding the properties of the sponge is reviewed. The authors argue that the sponge phase may provide a good system for the study of various liquid-state critical phenomena.

  12. New multifunctional surfactants from natural phenolic acids.

    PubMed

    Centini, Marisanna; Rossato, Maria Sole; Sega, Alessandro; Buonocore, Anna; Stefanoni, Sara; Anselmi, Cecilia

    2012-01-11

    Several new multifunctional molecules derived from natural sources such as amino acids and hydroxycinnamic acids were synthesized. They exhibit various activities such as emulsifying, UV-protecting, and radical scavenging, thereby conforming to the latest requirements for cosmetic ingredients. The synthesis comprises only a few steps: (i) the amino acid, the acid groups of which are protected by esterification, is coupled with ferulic or caffeic acid; (ii) the p-hydroxyl group of the cinnamic derivative reacts with dodecyl bromide in the presence of potassium carbonate (the resulting compounds are highly lipophilic and tested as water/oil (W/O) emulsifiers); (iii) these molecules, by deprotonating the acid groups of the amino acids, with successive salification, are more hydrophilic, with stronger O/W emulsifying properties. The new multifunctional surfactants might prove useful for the treatment of multiple skin conditions, including loss of cellular antioxidants, damage from free radicals, damage from UV, and others.

  13. Biodegradation of the anionic surfactant dialkyl sulphosuccinate

    SciTech Connect

    Hales, S.G. . Port Sunlight Lab.)

    1993-10-01

    A range of Organization for Economic Cooperation and Development (OECD) guideline test systems was used to determine the extent and possible mechanisms of biodegradation of dialkyl sulphosuccinate (DASS, C[sub 6]/C[sub 8]). Primary biodegradation of DASS was virtually complete in OECD guideline tests and in simulations of activated sludge sewage treatment systems under both optimal and adverse conditions, and of an anaerobic digester. Ultimate biodegradation increased form about 50% in ready tests to 94% in more powerful inherent tests. [[sup 14]C]DASS was used to determine the fate of the surfactant in activated sludge and in surface waters. Mechanistic studies were performed to ascertain the biodegradative pathway of [[sup 14]C]DASS. A putative degradation pathway for DASS is proposed.

  14. Functionally polymerized surfactant vesicles: synthesis and characterization

    SciTech Connect

    Tundo, P.; Kippenberger, D.J.; Klahn, P.L.; Prieto, N.E.; Fendler, J.H.

    1982-01-27

    Bis(2-(10-undecenoyloxycarbony bromide, bis(2-(10-undecenoyloxycarbony (2-hydroxyethyl)methylammonium bromide, bis(2-(10-undecenoyloxycarbony acid, bis(2-(10-undecenoyloxycarbony allylbis(2-dodecanoyloxycarbon bromide, and dimethyl-n-hexadecyl (10-(p-vin decyl)ammonium bromide have been synthesized. The predominantly single compartment bilayer vesicles formed from these surfactants could be polymerized either by exposure to ultraviolet irradiation or by the use of azoisobutyronitrile as an initiator. The presence of vesicles (unpolymerized and polymeric) has been demonstrated by electron micrography, H/sup 1/ NMR, gel filtration, phase transition, turbidity changes, substrate entrapment, and permeability. Polymerized vesicles are considerably more stable and less permeable and have reduced rates of turbidity changes compared to their unpolymerized counterparts. 19 references.

  15. Surfactant-based critical phenomena in microgravity

    NASA Technical Reports Server (NTRS)

    Kaler, Eric W.; Paulaitis, Michael E.

    1994-01-01

    The objective of this research project is to characterize by experiment and theoretically both the kinetics of phase separation and the metastable structures produced during phase separation in a microgravity environment. The particular systems we are currently studying are mixtures of water, nonionic surfactants, and compressible supercritical fluids at temperatures and pressures where the coexisting liquid phases have equal densities (isopycnic phases). In this report, we describe experiments to locate equilibrium isopycnic phases and to determine the 'local' phase behavior and critical phenomena at nearby conditions of temperature, pressure, and composition. In addition, we report the results of preliminary small angle neutron scattering (SANS) experiments to characterize microstructures that exist in these mixtures at different fluid densities.

  16. Theory of surfactant-mediated growth on semiconductor surfaces

    NASA Astrophysics Data System (ADS)

    Kaxiras, Efthimios; Kandel, Daniel

    1996-08-01

    The surfactant effect, first demonstrated by Copel et al. [Phys. Rev. Lett. 63 (1989) 632] by using As to promote epitaxial growth of Ge on Si(100), has now been studied in a wide variety of systems, thus making systematic studies possible. We present theoretical models that account for the observed behavior of various surfactants on semiconductor surfaces, including homo-epitaxial and hetero-epitaxial growth. The theoretical models include first-principles calculations of the relative energy of different structures associated with surfactant layers and the activation energies for diffusion and exchange mechanisms, as well as solid-on-solid Monte Carlo simulations.

  17. Key interactions of surfactants in therapeutic protein formulations: A review.

    PubMed

    Khan, Tarik A; Mahler, Hanns-Christian; Kishore, Ravuri S K

    2015-11-01

    Proteins as amphiphilic, surface-active macromolecules, demonstrate substantial interfacial activity, which causes considerable impact on their multifarious applications. A commonly adapted measure to prevent interfacial damage to proteins is the use of nonionic surfactants. Particularly in biotherapeutic formulations, the use of nonionic surfactants is ubiquitous in order to prevent the impact of interfacial stress on drug product stability. The scope of this review is to convey the current understanding of interactions of nonionic surfactants with proteins both at the interface and in solution, with specific focus to their effects on biotherapeutic formulations.

  18. Amino acid–based surfactants: New antimicrobial agents.

    PubMed

    Pinazo, A; Manresa, M A; Marques, A M; Bustelo, M; Espuny, M J; Pérez, L

    2016-02-01

    The rapid increase of drug resistant bacteria makes necessary the development of new antimicrobial agents. Synthetic amino acid-based surfactants constitute a promising alternative to conventional antimicrobial compounds given that they can be prepared from renewable raw materials. In this review, we discuss the structural features that promote antimicrobial activity of amino acid-based surfactants. Monocatenary, dicatenary and gemini surfactants that contain different amino acids on the polar head and show activity against bacteria are revised. The synthesis and basic physico-chemical properties have also been included.

  19. Biodegradation kinetics of phenanthrene solubilized in surfactant micelles

    SciTech Connect

    Grimberg, S.J.; Aitken, M.D.

    1995-12-31

    The biodegradation of phenanthrene solubilized in surfactant micelles was studied using a simple, well-defined laboratory system. The system was designed to evaluate whether phenanthrene present in micelles of the nonionic surfactant Tergitol NP-10 was available to a phenanthrene-degrading bacterium. Results indicate that micellized phenanthrene is essentially unavailable to the microorganism, so that only the phenanthrene present in the aqueous phase is degraded. A modified Michaelis-Menten equation was developed to quantify the effects of surfactant concentration on phenanthrene uptake rates. Experimental data were described well with this equation.

  20. On the influence of surfactant over friction properties of steel

    NASA Astrophysics Data System (ADS)

    Upadhyay, R. K.; Kumaraswamidhas, L. A.

    2014-07-01

    Surfactant wetting properties are important for any tribological system. In order to explore these properties the influence of four surfactant i.e. sodium hexametaphosphate (SHMP); zinc dithiodiphosphate (ZDDP); sodium dodecyl sulphate (SDS); and cetrimonium bromide (C-TAB); on the friction behaviour of physical vapour deposition (PVD) coated surfaces were studied using pin on disk tribometer. Anionic, cationic and non-ionic surfactants are dispersed in oil/water medium. Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX) and X-ray diffraction (XRD) analysis was performed to obtain the surface morphology, chemical composition and structure of the material.

  1. The Lung Surfactant System in Adult Respiratory Distress Syndrome.

    DTIC Science & Technology

    1980-08-01

    STANDAROS- 193 A AD_ THE LUNG SURFACTANT SYSTEM IN ADULT RESPIRATORY DISTRESS SYNDROME FINAL PROGRESS REPORT John U. Balls August 1980 Sponsored by: US...D-A12l 434 THE LUNG SURFACTANT SYvTKl-OJL E~~rP DISTRESS SYNDROME (U) UNIVERSITY OF SOUTH FLORIDA TAMPA COLL OF MEDICINE J U BALIS RUG 8S DRNDi7-78-C...SURFACTANT SYSTEM IN ADULT Final 1 November 1978 - RESPIRATORY DISTU~SS SYNDROME - 30 April 1980 6. PERFORMING ORG. REPORT NUMBER * 7. AUTHOR(e) G. CONTRACT

  2. Surfactant Two-Dimensional Self-Assembly under Confinement

    SciTech Connect

    Sushko, Maria L.; Liu, Jun

    2011-03-28

    Confinement-induced structural rearrangements in supported self-assembled surfactant layers in aqueous salt solutions are investigated using classical Density Functional Theory. The systematic study of the influence of the nature of electrolyte revealed that 2:1 electrolyte stabilizes the hemicylindrical configuration of ionic surfactant layers, while a confinement-induced transition to a tilted monolayer configuration was found in symmetric 1:1 and 2:2 electrolytes. On the basis of this study we formulate a general model for the energetics of structural rearrangements in supported surfactant layers.

  3. Surfactant doped silica aerogels dried at supercritical pressure

    NASA Astrophysics Data System (ADS)

    Parale, V. G.; Mahadik, D. B.; Kavale, M. S.; Rao, A. Venkateswara; Vhatkar, R. S.; Wagh, P. B.; Gupta, Satish C.

    2013-02-01

    By combining the molecular silica precursor methyltrimethoxysilane (MTMS) with methanol, water and Tween-80 solution, we get surfactant-doped silica alcogels. The wet alcogels can be exchanged with methanol and then supercritically extracted with nitrogen to produce surfactant-doped silica aerogels (SDSAs). SDSAs represent a new class of aerogels that are composed of aggregated submicron porous particles that have tunable interparticle nanoporosity. As we increased the percentage of surfactant, the physical properties of silica aerogels changes. In this study we characterized the SDSAs by SEM for morphological study, FTIR for the material composition, contact angle for hydrophobicity determination and thermal conductivity measurements are carried out for thermal insulation application.

  4. Adsorption Kinetics in Micellar Solutions of Nonionic Surfactants

    NASA Astrophysics Data System (ADS)

    Colegate, Daniel M.; Bain, Colin D.

    2005-11-01

    Standard models of the adsorption kinetics of surfactants at the air-water surface assume that micelles break down into monomers in the bulk solution and that only monomers adsorb. We show here that micelles of the nonionic surfactant C14E8 adsorb to the surface of a liquid jet at a diffusion-controlled rate. Micellar adsorption can be switched off by incorporation of a small amount of ionic surfactant into the micelle and switched on again by addition of salt. More sophisticated models of adsorption processes in micellar solutions are required that permit a kinetic flux of micelles to the air-water interface.

  5. Evaporation of droplets of surfactant solutions.

    PubMed

    Semenov, Sergey; Trybala, Anna; Agogo, Hezekiah; Kovalchuk, Nina; Ortega, Francisco; Rubio, Ramón G; Starov, Víctor M; Velarde, Manuel G

    2013-08-13

    The simultaneous spreading and evaporation of droplets of aqueous trisiloxane (superspreader) solutions onto a hydrophobic substrate has been studied both experimentally, using a video-microscopy technique, and theoretically. The experiments have been carried out over a wide range of surfactant concentration, temperature, and relative humidity. Similar to pure liquids, four different stages have been observed: the initial one corresponds to spreading until the contact angle, θ, reaches the value of the static advancing contact angle, θad. Duration of this stage is rather short, and the evaporation during this stage can be neglected. The evaporation is essential during the next three stages. The next stage after the spreading, which is referred to herein as the first stage, takes place at constant perimeter and ends when θ reaches the static receding contact angle, θr. During the next, second stage, the perimeter decreases at constant contact angle θ = θr for surfactant concentration above the critical wetting concentration (CWC). The static receding contact angle decreases during the second stage for concentrations below CWC because the concentration increases due to the evaporation. During the final stage both the perimeter and the contact angle decrease. In what follows, we consider only the longest stages I and II. The developed theory predicts universal curves for the contact angle dependency on time during the first stage, and for the droplet perimeter on time during the second stage. A very good agreement between theory and experimental data has been found for the first stage of evaporation, and for the second stage for concentrations above CWC; however, some deviations were found for concentrations below CWC.

  6. Cold pearl surfactant-based blends.

    PubMed

    Crombie, R L

    1997-10-01

    Pearlizing agents have been used for many years in cosmetic formulations to add a pearlescent effect. Cold pearl surfactant-based blends are mixtures of glycol stearates and surfactants which can be blended in the cold into a wide range of personal-care formulations to create a pearlescent lustre effect. Under controlled manufacturing conditions constant viscosities and crystalline characteristics can be obtained. The development of these blends has been driven by efforts to improve the economics of adding solid pearlizing agents directly into a hot mix formulation. This paper summarizes the history of pearlizers, describes their advantages and physical chemistry of the manufacturing process. Finally some suggestions for applications are given. Les agents nacrants sont utilises depuis de nombreuses annees dans les formulations cosmetiques pour ajouter un effet nacre. Les melanges a froid a base de tensioactif nacre sont des melanges de stearates de glycol et de tensioactifs qui peuvent etre melanges a froid dans une large gamme de formulations d'hygiene personnelle pour creer un effet de lustre nacre. On peut obtenir des viscosites et des proprietes cristallines constantes avec des conditions de fabrication maitrisees. Le developpement de ces melanges a ete porte par les efforts pour ameliorer les couts de l'ajout d'agents nacrants solides directement dans une formulation melangee de l'ajout d'agents nacrants solides directement dans une formulation melangee a chaud. Cet article resume l'histoire des agents nacrants, decrit leurs avantages et al physico-chimie du procede de fabrication. On emet a la fin cetaines suggestions d'applications.

  7. Decontamination by cleaning with fluorocarbon surfactant solutions

    SciTech Connect

    Kaiser, R.; Benson, C.E.; Meyers, E.S.; Vaughen, V.C.A.

    1994-02-01

    In the nuclear industry, facilities and their components inevitably become contaminated with radioactive materials. This report documents the application of a novel particle-removal process developed by Entropic Systems, Inc. (ESI), to decontaminate critical instruments and parts that are contaminated with small radioactive particles that adhere to equipment surfaces. The tests were performed as a cooperative effort between ESI and the Chemical Technology Division of the Oak Ridge National Laboratory (ORNL). ESI developed a new, environmentally compatible process to remove small particles from solid surfaces that is more effective than spraying or sonicating with CFC-113. This process uses inert perfluorinated liquids as working media; the liquids have zero ozone-depleting potential, are nontoxic and nonflammnable, and are generally recognized as nonhazardous materials. In the ESI process, parts to be cleaned are first sprayed or sonicated with a dilute solution of a high-molecular-weight fluorocarbon surfactant in an inert perfluorinated liquid to effect particle removal. The parts are then rinsed with the perfluorinated liquid to remove the fluorocarbon surfactant applied in the first step, and the residual rinse liquid is then evaporated from the parts into an air or nitrogen stream from which it is recovered. Nuclear contamination is inherently a surface phenomenon. The presence of radioactive particles is responsible for all ``smearable`` contamination and, if the radioactive particles are small enough, for some of the fixed contamination. Because radioactivity does not influence the physical chemistry of particle adhesion, the ESI process should be just as effective in removing radioactive particles as it is in removing nonradioactive particles.

  8. Stabilizing and destabilizing protein surfactant-based foams in the presence of a chemical surfactant: Effect of adsorption kinetics.

    PubMed

    Li, Huazhen; Le Brun, Anton P; Agyei, Dominic; Shen, Wei; Middelberg, Anton P J; He, Lizhong

    2016-01-15

    Stimuli-responsive protein surfactants promise alternative foaming materials that can be made from renewable sources. However, the cost of protein surfactants is still higher than their chemical counterparts. In order to reduce the required amount of protein surfactant for foaming, we investigated the foaming and adsorption properties of the protein surfactant, DAMP4, with addition of low concentrations of the chemical surfactant sodium dodecylsulfate (SDS). The results show that the small addition of SDS can enhance foaming functions of DAMP4 at a lowered protein concentration. Dynamic surface tension measurements suggest that there is a synergy between DAMP4 and SDS which enhances adsorption kinetics of DAMP4 at the initial stage of adsorption (first 60s), which in turn stabilizes protein foams. Further interfacial properties were revealed by X-ray reflectometry measurements, showing that there is a re-arrangement of adsorbed protein-surfactant layer over a long period of 1h. Importantly, the foaming switchability of DAMP4 by metal ions is not affected by the presence of SDS, and foams can be switched off by the addition of zinc ions at permissive pH. This work provides fundamental knowledge to guide formulation using a mixture of protein and chemical surfactants towards a high performance of foaming at a low cost.

  9. Computer simulation-molecular-thermodynamic framework to predict the micellization behavior of mixtures of surfactants: application to binary surfactant mixtures.

    PubMed

    Iyer, Jaisree; Mendenhall, Jonathan D; Blankschtein, Daniel

    2013-05-30

    We present a computer simulation-molecular-thermodynamic (CSMT) framework to model the micellization behavior of mixtures of surfactants in which hydration information from all-atomistic simulations of surfactant mixed micelles and monomers in aqueous solution is incorporated into a well-established molecular-thermodynamic framework for mixed surfactant micellization. In addition, we address the challenges associated with the practical implementation of the CSMT framework by formulating a simpler mixture CSMT model based on a composition-weighted average approach involving single-component micelle simulations of the mixture constituents. We show that the simpler mixture CSMT model works well for all of the binary surfactant mixtures considered, except for those containing alkyl ethoxylate surfactants, and rationalize this finding molecularly. The mixture CSMT model is then utilized to predict mixture CMCs, and we find that the predicted CMCs compare very well with the experimental CMCs for various binary mixtures of linear surfactants. This paper lays the foundation for the mixture CSMT framework, which can be used to predict the micellization properties of mixtures of surfactants that possess a complex chemical architecture, and are therefore not amenable to traditional molecular-thermodynamic modeling.

  10. Influences and mechanisms of surfactants on pyrene biodegradation based on interactions of surfactant with a Klebsiella oxytoca strain.

    PubMed

    Zhang, Dong; Zhu, Lizhong; Li, Feng

    2013-08-01

    Surfactant-enhanced bioremediation has been proposed as a promising technology for the treatment of organic polluted soils; however its application has been hindered by the controversial influences and mechanisms of surfactants on the biodegradation of hydrophobic organic compounds. To address this problem, effects of five surfactants on the sorption and biodegradation of pyrene by Klebsiella oxytoca PYR-1, as well as their interactions with bacterial cell surface and membrane lipids were investigated. We found that surfactants enhanced or inhibited pyrene biodegradation depending on their effects on the sorption of pyrene onto bacterial cell, which occurred mainly through modifying cell surface hydrophobicity (such as Tween series surfactants) or disrupting bacterial membrane (such as Triton X-100), respectively. A relatively high positive correlation (P<0.0001) was observed between biodegradation promotion (Bs/B0) and enhancement of sorption coefficients (Kd,s(∗)/Kd,0(∗)) for pyrene in the presence of surfactant, indicating that surfactant-induced sorption played the dominant role during pyrene biodegradation.

  11. Surface-Active and Performance Properties of Cationic Imidazolinium Surfactants Based on Different Fatty Acids

    NASA Astrophysics Data System (ADS)

    Bajpai, Divya; Tyagi, V. K.

    Imidazoline surfactants belong to the category of cationic surfactants. Cationic surfactants are often quaternary nitrogen salts and are widely used both in nonaqueous systems and in applications such as textile softeners, dispersants, and emulsifiers. This study describes the surface-active properties of cationic imidazolinium surfactants synthesized from different fatty acids. Their laundry performance in combination with nonionic surfactants like detergency, foaming property, softening property, rewettability etc., is also emphasized.

  12. The importance of surfactant proteins-New aspects on macrophage phagocytosis.

    PubMed

    Tschernig, Thomas; Veith, Nils T; Diler, Ebru; Bischoff, Markus; Meier, Carola; Schicht, Martin

    2016-11-01

    Surfactant and its components have multiple functions. The so called collectins are surfactant proteins which opsonize bacteria and improve pulmonary host defense via the phagocytosis and clearance of microorganisms and particles. In this special issue of the Annals of Anatomy a new surfactant protein, Surfactant Associated 3, is highlighted. As outlined in this mini review Surfactant Associated 3 is regarded as an enhancer of phagocytosis. In addition, the role played by SP-A is updated and open research questions raised.

  13. Surfactant-induced flow compromises determination of air-water interfacial areas by surfactant miscible-displacement.

    PubMed

    Costanza-Robinson, Molly S; Henry, Eric J

    2017-03-01

    Surfactant miscible-displacement (SMD) column experiments are used to measure air-water interfacial area (AI) in unsaturated porous media, a property that influences solute transport and phase-partitioning. The conventional SMD experiment results in surface tension gradients that can cause water redistribution and/or net drainage of water from the system ("surfactant-induced flow"), violating theoretical foundations of the method. Nevertheless, the SMD technique is still used, and some suggest that experimental observations of surfactant-induced flow represent an artifact of improper control of boundary conditions. In this work, we used numerical modeling, for which boundary conditions can be perfectly controlled, to evaluate this suggestion. We also examined the magnitude of surfactant-induced flow and its impact on AI measurement during multiple SMD flow scenarios. Simulations of the conventional SMD experiment showed substantial surfactant-induced flow and consequent drainage of water from the column (e.g., from 75% to 55% SW) and increases in actual AI of up to 43%. Neither horizontal column orientation nor alternative boundary conditions resolved surfactant-induced flow issues. Even for simulated flow scenarios that avoided surfactant-induced drainage of the column, substantial surfactant-induced internal water redistribution occurred and was sufficient to alter surfactant transport, resulting in up to 23% overestimation of AI. Depending on the specific simulated flow scenario and data analysis assumptions used, estimated AI varied by nearly 40% and deviated up to 36% from the system's initial AI. We recommend methods for AI determination that avoid generation of surface-tension gradients and urge caution when relying on absolute AI values measured via SMD.

  14. Dynamic surface tension of polyelectrolyte/surfactant systems with opposite charges: two states for the surfactant at the interface.

    PubMed

    Ritacco, Hernán A; Busch, Jorge

    2004-04-27

    The molecular reorientation model of Fainerman et al. is conceptually adapted to explain the dynamic surface tension behavior in polyelectrolyte/surfactant systems with opposite charges. The equilibrium surface tension curves and the adsorption dynamics may be explained by assuming that there are two different states for surfactant molecules at the interface. One of these states corresponds to the adsorption of the surfactant as monomers, and the other to the formation of a mixed complex at the surface. The model also explains the plateaus that appear in the dynamic surface tension curves and gives a picture of the adsorption process.

  15. Partitioning of ethoxylated nonionic surfactants into nonaqueous-phase organic liquids: Influence on solubilization behavior

    SciTech Connect

    Zimmerman, J.B.; Kibbey, T.C.G.; Cowell, M.A.; Hayes, K.F.

    1999-01-01

    The ability of surfactants to enhance the apparent aqueous solubilities of nonaqueous-phase liquid (NAPL) contaminants has increased interest in surfactant-enhanced aquifer remediation (SEAR) applications. This study examines the effect of surfactant partitioning on surfactant solubilization efficiency by analyzing the solubilization of several chlorinated NAPLs by a homologous series of linear alcohol ethoxylate nonionic surfactants. In general, it is found that the partitioning of surfactants can, especially in the cases of polar NAPLs, lead to substantial losses of surfactant, leaving little surfactant remaining in aqueous solution for solubilization. More importantly, it is found that neglecting surfactant partitioning can produce artifacts in the measured solubilization capacities of surfactants for NAPLs. For example, when surfactant partitioning is neglected, measurements of the solubilization capacity for homologous series of surfactants are often observed to produce a maximum solubilization capacity as a function of the surfactant hydrophile--lipophile balance number (HLB). The work described here demonstrates that the observed maximum solubilization capacity can result from neglecting partitioning of the surfactant into the NAPL. When solubilization capacity is calculated based on the amount of aqueous surfactant present after partitioning losses, no maximum is observed. The implications of this work for aquifer remediation are discussed.

  16. Tunable Oleo-Furan Surfactants by Acylation of Renewable Furans

    PubMed Central

    2016-01-01

    An important advance in fluid surface control was the amphiphilic surfactant composed of coupled molecular structures (i.e., hydrophilic and hydrophobic) to reduce surface tension between two distinct fluid phases. However, implementation of simple surfactants has been hindered by the broad range of applications in water containing alkaline earth metals (i.e., hard water), which disrupt surfactant function and require extensive use of undesirable and expensive chelating additives. Here we show that sugar-derived furans can be linked with triglyceride-derived fatty acid chains via Friedel–Crafts acylation within single layer (SPP) zeolite catalysts. These alkylfuran surfactants independently suppress the effects of hard water while simultaneously permitting broad tunability of size, structure, and function, which can be optimized for superior capability for forming micelles and solubilizing in water. PMID:27924310

  17. INFLUENCE OF SURFACTANTS ON MICROBIAL DEGRADATION OF ORGANIC COMPOUNDS

    EPA Science Inventory

    Surfactants have the ability to increase aqueous concentrations of poorly soluble compounds and interfacial areas between immiscible fluids, thus potentially improving the accessibility of these substrates to microorganisms. However, both enhancements and inhibitions of biodegrad...

  18. Tunable Oleo-Furan Surfactants by Acylation of Renewable Furans

    DOE PAGES

    Park, Dae Sung; Joseph, Kristeen E.; Koehle, Maura; ...

    2016-10-19

    One important advance in fluid surface control was the amphiphilic surfactant composed of coupled molecular structures (i.e., hydrophilic and hydrophobic) to reduce surface tension between two distinct fluid phases. However, implementation of simple surfactants has been hindered by the broad range of applications in water containing alkaline earth metals (i.e., hard water). This disrupts surfactant function and requires extensive use of undesirable and expensive chelating additives. We show that sugar-derived furans can be linked with triglyceride-derived fatty acid chains via Friedel–Crafts acylation within single layer (SPP) zeolite catalysts. Finally, these alkylfuran surfactants independently suppress the effects of hard water whilemore » simultaneously permitting broad tunability of size, structure, and function, which can be optimized for superior capability for forming micelles and solubilizing in water.« less

  19. Tunable Oleo-Furan Surfactants by Acylation of Renewable Furans

    SciTech Connect

    Park, Dae Sung; Joseph, Kristeen E.; Koehle, Maura; Krumm, Christoph; Ren, Limin; Damen, Jonathan N.; Shete, Meera H.; Lee, Han Seung; Zuo, Xiaobing; Lee, Byeongdu; Fan, Wei; Vlachos, Dionisios G.; Lobo, Raul F.; Tsapatsis, Michael; Dauenhauer, Paul J.

    2016-11-23

    An important advance in fluid surface control was the amphiphilic surfactant comprised of coupled molecular structures (i.e. hydrophilic and hydrophobic) to reduce surface tension between two distinct fluid phases. However, implementation of simple surfactants has been hindered by the broad range of applications in water containing alkaline earth metals (i.e. hard water), which disrupt surfactant function and require extensive use of undesirable and expensive chelating additives. Here we show that sugar-derived furans can be linked with triglyceride-derived fatty acid chains via Friedel-Crafts acylation within single layer (SPP) zeolite catalysts. These alkylfuran surfactants independently suppress the effects of hard water while simultaneously permitting broad tunability of size, structure, and function, which can be optimized for superior capability for forming micelles and solubilizing in water.

  20. Experimental study on thermophoresis of colloids in aqueous surfactant solutions

    NASA Astrophysics Data System (ADS)

    Dong, Ruo-Yu; Zhou, Yi; Yang, Chun; Cao, Bing-Yang

    2015-12-01

    Thermophoresis refers to the motion of particles under a temperature gradient and it is one of the particle manipulation techniques. Regarding the thermophoresis of particles in liquid media, however, many open questions still remain, especially the role of the interfacial effect. This work reports on a systematic experimental investigation of surfactant effects, especially the induced interfacial effect, on the thermophoresis of colloids in aqueous solutions via a microfluidic approach. Two kinds of commonly used surfactants, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB), are selected and the results show that from relatively large concentrations, the two surfactants can greatly enhance the thermophilic mobilities. Specifically, it is found that the colloid-water interfaces modified with more polar end groups can potentially lead to a stronger thermophilic tendency. Due to the complex effects of surfactants, further theoretical model development is needed to quantitatively describe the dependence of thermophoresis on the interface characteristics.

  1. Experimental study on thermophoresis of colloids in aqueous surfactant solutions.

    PubMed

    Dong, Ruo-Yu; Zhou, Yi; Yang, Chun; Cao, Bing-Yang

    2015-12-16

    Thermophoresis refers to the motion of particles under a temperature gradient and it is one of the particle manipulation techniques. Regarding the thermophoresis of particles in liquid media, however, many open questions still remain, especially the role of the interfacial effect. This work reports on a systematic experimental investigation of surfactant effects, especially the induced interfacial effect, on the thermophoresis of colloids in aqueous solutions via a microfluidic approach. Two kinds of commonly used surfactants, sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB), are selected and the results show that from relatively large concentrations, the two surfactants can greatly enhance the thermophilic mobilities. Specifically, it is found that the colloid-water interfaces modified with more polar end groups can potentially lead to a stronger thermophilic tendency. Due to the complex effects of surfactants, further theoretical model development is needed to quantitatively describe the dependence of thermophoresis on the interface characteristics.

  2. INFLUENCE OF SURFACTANTS ON MICROBIAL DEGRADATION OF ORGANIC COMPOUNDS

    EPA Science Inventory

    Surfactants have the ability to increase aqueous concentrations of poorly soluble compounds and interfacial areas between immiscible fluids, thus potentially improving the accessibility of these substrates to microorganisms. However, both enhancements and inhibitions of biodegrad...

  3. The role of surfactants in drop formation and thread breakup

    NASA Astrophysics Data System (ADS)

    Kamat, Pritish; Wagoner, Brayden; Thete, Sumeet; Basaran, Osman

    2016-11-01

    The ability of surfactants to adsorb onto and lower the surface tension of water-air and water-oil interfaces is exploited in industrial applications, nature, and everyday life. An important example is provided by drop formation where a thinning liquid thread connects an about-to-form globular, primary drop to the rest of the liquid that remains on the nozzle when the primary drop falls from it. Surfactants can affect pinch-off in two ways: first, by lowering surface tension they lower capillary pressure (which equals, to highest order, surface tension divided by thread radius), and second, as surfactant concentration along the interface can be non-uniform, they cause the interface to be subjected to a gradient of surface tension, or Marangoni stress. By means of high-accuracy simulations and supporting experiments, we clarify the role played by surfactants on drop formation and thread breakup.

  4. Endotoxin suppresses surfactant synthesis in cultured rat lung cells

    SciTech Connect

    Li, J.J.; Sanders, R.L.; McAdam, K.P.; Gelfand, J.A.; Burke, J.F.

    1989-02-01

    Pulmonary complications secondary to postburn sepsis are a major cause of death in burned patients. Using an in vitro organotypic culture system, we examined the effect of E. coli endotoxin (LPS) on lung cell surfactant synthesis. Our results showed that E. coli endotoxin (1.0, 2.5, 10 micrograms LPS/ml) was capable of suppressing the incorporation of /sup 3/H-choline into de novo synthesized surfactant, lamellar bodies (LB), and common myelin figures (CMF) at 50%, 68%, and 64%, respectively. In a similar study, we were able to show that LPS also inhibited /sup 3/H-palmitate incorporation by cultured lung cells. LPS-induced suppression of surfactant synthesis was reversed by hydrocortisone. Our results suggest that LPS may play a significant role in reducing surfactant synthesis by rat lung cells, and thus contribute to the pathogenesis of sepsis-related respiratory distress syndrome (RDS) in burn injury.

  5. Surfactant and adhesive formulations from alkaline biomass extracts

    NASA Astrophysics Data System (ADS)

    Baxter, Matthew

    This work studies the ability to produce effective surfactant and adhesive formulations using surface active biological material extracted from different biomass sources using alkaline extraction methods. Two urban waste biomass sources were used to produce surfactants, Return Activated Sludge (RAS), and solid Urban Refuse (UR). The third biomass source investigated was isolated mustard protein (MP). RAS and MP extracts were investigated for adhesive production. The results indicate that extracts from the waste biomass sources, RAS and UR, can be combined with a commercial surfactant, sodium dioctyl sulfosuccinate (AOT), to produce surfactants with low interfacial tensions against various oils. These highly surface-active formulations were shown to be useful in the removal of bitumen from contaminated sand. RAS and MP showed potential as protein-based wood adhesives. These sources were used in adhesive formulations to produce a strong bond strength under low-pressure, ambient pressing conditions.

  6. Nonlinear vibrational spectroscopy of surfactants at liquid interfaces

    SciTech Connect

    Miranda, Paulo B.

    1998-12-14

    Surfactants are widely used to modify physical and chemical properties of interfaces. They play an important role in many technological problems. Surfactant monolayer are also of great scientific interest because they are two-dimensional systems that may exhibit a very rich phase transition behavior and can also be considered as a model system for biological interfaces. In this Thesis, we use a second-order nonlinear optical technique (Sum-Frequency Generation - SFG) to obtain vibrational spectra of surfactant monolayer at Iiquidhapor and solid/liquid interfaces. The technique has several advantages: it is intrinsically surface-specific, can be applied to buried interfaces, has submonolayer sensitivity and is remarkably sensitive to the confirmational order of surfactant monolayers.

  7. Graphene-philic surfactants for nanocomposites in latex technology.

    PubMed

    Mohamed, Azmi; Ardyani, Tretya; Bakar, Suriani Abu; Brown, Paul; Hollamby, Martin; Sagisaka, Masanobu; Eastoe, Julian

    2016-04-01

    Graphene is the newest member of the carbon family, and has revolutionized materials science especially in the field of polymer nanocomposites. However, agglomeration and uniform dispersion remains an Achilles' heel (even an elephant in the room), hampering the optimization of this material for practical applications. Chemical functionalization of graphene can overcome these hurdles but is often rather disruptive to the extended pi-conjugation, altering the desired physical and electronic properties. Employing surfactants as stabilizing agents in latex technology circumvents the need for chemical modification allowing for the formation of nanocomposites with retained graphene properties. This article reviews the recent progress in the use of surfactants and polymers to prepare graphene/polymer nanocomposites via latex technology. Of special interest here are surfactant structure-performance relationships, as well as background on the roles surfactant-graphene interactions for promoting stabilization.

  8. MICROEMULSION OF MIXED CHLORINATED SOLVENTS USING FOOD GRADE (EDIBLE) SURFACTANTS

    EPA Science Inventory

    Ground water contamination frequently consists of mixed chlorinated solvents [e.g., tetrachloroethylene (PCE), trichloroethylene (TCE), and trans-1,2- dichloroethylene (DCE)]. In this research, mixtures of the food grade (edible) surfactants bis(2-ethylhexyl) sodium sulfosuccinat...

  9. MICROEMULSION OF MIXED CHLORINATED SOLVENTS USING FOOD GRADE (EDIBLE) SURFACTANTS

    EPA Science Inventory

    Ground water contamination frequently consists of mixed chlorinated solvents [e.g., tetrachloroethylene (PCE), trichloroethylene (TCE), and trans-1,2- dichloroethylene (DCE)]. In this research, mixtures of the food grade (edible) surfactants bis(2-ethylhexyl) sodium sulfosuccinat...

  10. FLUORINATED SURFACTANTS IN THE GREAT LAKES - YESTERDAY, TODAY, AND TOMORROW

    EPA Science Inventory

    Perfluorooctane surfactants have been reported in biota, water, and air samples worldwide. Despite these reports, the main environmental sources of these compounds remain undefined. As a presentation to the emerging chemicals workshop of the International Joint Commission on Grea...

  11. [Study of novel artificial lung surfactants incorporating partially fluorinated amphiphiles].

    PubMed

    Nakahara, Hiromichi

    2012-01-01

    Lung surfactants (LS), a complex of ∼90 wt% lipids (mainly dipalmitoylphosphatidylcholine or DPPC) and ∼10 wt% surfactant proteins (SP-A, -B, -C, and -D), adsorb to an air-alveolar fluid interface and then lower its surface tension down to near zero during expiration. Intratracheal instillation of exogenous LS preparations can effectively compensate for surfactant deficiency in premature infants with respiratory distress syndrome (RDS). Surfacten® (Mitsubishi Tanabe Pharma Corporation, Osaka, Japan), a modified bovine lung extract and an effective surfactant replacement in treatment for RDS patients, is supplemented with DPPC, palmitic acid, and tripalmitin. For the premature infants suffering from RDS, instillation of Surfacten® leads to a dramatic improvement in lung function and compliance. Herein, the author reviews potential use of newly designed preparations containing a mimicking peptide of SP-B and also introduces the current research on the preparations incorporated with partially fluorinated amphiphiles to improve their efficacy.

  12. Water Sorption Isotherms of Surfactants: A Tool To Evaluate Humectancy.

    PubMed

    Asmus, Elisabeth; Popp, Christian; Friedmann, Adrian A; Arand, Katja; Riederer, Markus

    2016-07-06

    Fundamental experimental data for moisture absorption of non-ionic polydisperse surfactants with differing ethylene oxide (EO) content and variable aliphatic portions were measured at relative humidities between 0 and 95% at 25 °C. Remarkable differences in moisture absorption were observed between surfactant classes but also within one series of surfactants differing in either EO content or the long-chain aliphatic fraction. Both the EO units as well as the entire molecular structure, including also the lipophilic domain, were discussed to account for the humectant activity of surfactants. Water sorption isotherms showed an exponential shape, which was argued to be associated with the formation of a "free" water domain. These humectant properties might be relevant to the behavior of a foliar-applied spray droplet of agrochemical formulation products because the uptake of active ingredients will be enhanced as a result of deferred crystal precipitation.

  13. Surfactant dissolution and mobilization of LNAPL contaminants in aquifers.

    PubMed

    Chevalier, Lizette R

    2003-05-01

    Improper disposal, accidental spills and leaks of non-aqueous phase liquids (NAPL) such as gasoline, fuel oil and creosote result in long-term persistent sources of groundwater pollution. Column and 2-D tanks experiments were conducted to evaluate the use of surfactant-enhanced recovery of light non-aqueous phase liquids (LNAPL) in groundwater aquifers. These experiments focused on the use of surfactants to promote dissolution and mobilization in addition to evaluating the increase of aqueous phase permeability as residual NAPL is recovered. Further experiments are presented that show the innovative use of surfactants during primary pumping to recover free product can potentially increase the amount of free product recovered, can potentially reduce the amount of residual NAPL remaining after primary pumping and performs better than the use of surfactants to mobilize trapped residual NAPL.

  14. EFFECT OF INORGANIC CATIONS ON BACTERICIDAL ACTIVITY OF ANIONIC SURFACTANTS

    PubMed Central

    Voss, J. G.

    1963-01-01

    Voss, J. G. (Procter & Gamble Co., Cincinnati, Ohio). Effect of inorganic cations on bactericidal activity of anionic surfactants. J. Bacteriol. 86:207–211. 1963.—The bactericidal effectiveness of two alkyl benzene sulfonates and of three other types of anionic surfactants against Staphylococcus aureus is increased in the presence of low concentrations of divalent cations, especially alkaline earths and metals of group IIB of the periodic table. The cations may act by decreasing the negative charge at the cell surface and increasing adsorption of the surfactant anions, leading to damage to the cytoplasmic membrane and death of the cell. Increased adsorption of surfactant is also found with Escherichia coli, but does not lead to death of the cell. PMID:14058942

  15. Biocompatible surfactants for water-in-fluorocarbon emulsions.

    PubMed

    Holtze, C; Rowat, A C; Agresti, J J; Hutchison, J B; Angilè, F E; Schmitz, C H J; Köster, S; Duan, H; Humphry, K J; Scanga, R A; Johnson, J S; Pisignano, D; Weitz, D A

    2008-10-01

    Drops of water-in-fluorocarbon emulsions have great potential for compartmentalizing both in vitro and in vivo biological systems; however, surfactants to stabilize such emulsions are scarce. Here we present a novel class of fluorosurfactants that we synthesize by coupling oligomeric perfluorinated polyethers (PFPE) with polyethyleneglycol (PEG). We demonstrate that these block copolymer surfactants stabilize water-in-fluorocarbon oil emulsions during all necessary steps of a drop-based experiment including drop formation, incubation, and reinjection into a second microfluidic device. Furthermore, we show that aqueous drops stabilized with these surfactants can be used for in vitro translation (IVT), as well as encapsulation and incubation of single cells. The compatability of this emulsion system with both biological systems and polydimethylsiloxane (PDMS) microfluidic devices makes these surfactants ideal for a broad range of high-throughput, drop-based applications.

  16. Deformation and stability of surfactant - or particle - laden drop

    NASA Astrophysics Data System (ADS)

    Brosseau, Quentin; Pradillo, Gerardo; Oberlander, Andrew; Vlahovska, Petia; SoftMech@Brown Team

    2015-11-01

    We present an experimental study of the behavior of a drop covered with insoluble surfactant or colloidal particles in a uniform DC electric field. Steady drop shapes, drop evolution upon application of the field, and drop relaxation after the field is turned off are observed for leaky dielectric fluids: Polybutadiene (PB), Silicon oil (PDMS), and Castor oil (CO). The surfactant is generated at the drop interface by reaction between end-functionalized PB and PDMS. The experimental data is compared with existing theoretical models for the steady shape of surfactant covered droplet, and adjusted models taking into account the presence of colloidal spheres with range of electrical properties. We will discuss the complex interplay of shape deformation, surfactant elasticity, particle redistribution, and interfacial charging in droplet electrohydrodynamics. Our results are important for understanding electrorheology of emulsions commonly found in the petroleum industry. We acknowledge grant NSF CBET 1437545 for funding.

  17. Follow up of premature babies treated with artificial surfactant (ALEC).

    PubMed Central

    Morley, C J; Morley, R

    1990-01-01

    Of 235 survivors who had taken part in a randomised trial of artificial surfactant and who were born in Cambridge, follow up information was available for 231 (98%) infants. In 12 cases information came from local doctors; all others were assessed at 9 and 18 months (n = 212) or 9 months only (n = 7). There was no difference between those who had been treated with surfactant and control babies in the incidence of neurological impairment, mental impairment, respiratory infections, allergies, or hospital admissions up to 18 months after full term. In those born before 30 weeks' gestation (where surfactant most improves survival) the number of surviving randomised children who were normal was 35 of 61 in the treated group (57%) compared with 25 of 61 in the control group (41%). Improved neonatal survival after prophylactic surfactant treatment is not associated with an increased incidence of neurodevelopmental impairment. PMID:2201266

  18. Dictionary of surfactants English/German and German/English

    SciTech Connect

    Siekmann, K.

    1987-01-01

    This dictionary is supplement to the monograph ''Surfactants in Consumer Products'' edited by Professor Dr. J. Falbe. It comprises approximately 3.200 keywords of the chemistry, technology and applications of surfactants in English/German and German/English. In the monograph the physical-chemical principles of action of the surfactants, their production and their application in laundry detergents, dishwashing detergents and cleaning agents as well as in cosmetics and toiletries are discussed. The technological aspects of application and formulation along with those of production and manufacturing processes are illustrated. Ecological and toxicological questions are probed in depth. Finally, important economic data concerning this branch of industry as well as an attempt to provide a perspective with regard to the future of the surfactant market round out the picture.

  19. Nanoparticle decoration with surfactants: Molecular interactions, assembly, and applications

    NASA Astrophysics Data System (ADS)

    Heinz, Hendrik; Pramanik, Chandrani; Heinz, Ozge; Ding, Yifu; Mishra, Ratan K.; Marchon, Delphine; Flatt, Robert J.; Estrela-Lopis, Irina; Llop, Jordi; Moya, Sergio; Ziolo, Ronald F.

    2017-02-01

    Nanostructures of diverse chemical nature are used as biomarkers, therapeutics, catalysts, and structural reinforcements. The decoration with surfactants has a long history and is essential to introduce specific functions. The definition of surfactants in this review is very broad, following its lexical meaning ;surface active agents;, and therefore includes traditional alkyl modifiers, biological ligands, polymers, and other surface active molecules. The review systematically covers covalent and non-covalent interactions of such surfactants with various types of nanomaterials, including metals, oxides, layered materials, and polymers as well as their applications. The major themes are (i) molecular recognition and noncovalent assembly mechanisms of surfactants on the nanoparticle and nanocrystal surfaces, (ii) covalent grafting techniques and multi-step surface modification, (iii) dispersion properties and surface reactions, (iv) the use of surfactants to influence crystal growth, as well as (v) the incorporation of biorecognition and other material-targeting functionality. For the diverse materials classes, similarities and differences in surfactant assembly, function, as well as materials performance in specific applications are described in a comparative way. Major factors that lead to differentiation are the surface energy, surface chemistry and pH sensitivity, as well as the degree of surface regularity and defects in the nanoparticle cores and in the surfactant shell. The review covers a broad range of surface modifications and applications in biological recognition and therapeutics, sensors, nanomaterials for catalysis, energy conversion and storage, the dispersion properties of nanoparticles in structural composites and cement, as well as purification systems and classical detergents. Design principles for surfactants to optimize the performance of specific nanostructures are discussed. The review concludes with challenges and opportunities.

  20. Mechanics of networks of aliphatic fibers in aqueous surfactant media

    NASA Astrophysics Data System (ADS)

    Zanchetta, Giuliano; Caggioni, Marco; Guida, Vincenzo; Trappe, Veronique

    2012-02-01

    We investigate the structural and rheological properties of aliphatic fibers dispersed in aqueous solutions of anionic surfactants, typically used in liquid detergents to provide yield stress. This system displays an onset to solid-like properties that depends on fiber concentration. In this contribution we will discuss how tuning the state of the surfactant background influences the fiber-fiber interactions and the mechanical properties of the gel.

  1. Use of surfactants to control island size and density

    DOEpatents

    Merrell, Jason; Liu, Feng; Stringfellow, Gerald B.

    2017-08-15

    Methods of controlling island size and density on an OMVPE growth film may comprise adding a surfactant at a critical concentration level, allowing a growth phase for a first period of time, and ending the growth phase when desired island size and density are achieved. For example, the island size and density of an OMVPE grown InGaN thin film may be controlled by adding an antimony surfactant at a critical concentration level.

  2. Group methods of determining surfactants in water (review)

    SciTech Connect

    Subbotina, E.I.; Dedkov, Yu.M.

    1988-01-01

    In recent years new and promising methods for the determination of industrial surfactant waste migration and concentration in the hydrosphere have been developed. These methods include different forms of chromatography, ion selective electrode analysis, titration, and solvent extraction. This article reviews the application and usefulness of each of these methods in the analysis of various surfactants. The methods of chromatography reviewed include liquid column, thin layer, and ion exchange.

  3. Dysfunction of pulmonary surfactant in chronically ventilated premature infants.

    PubMed

    Merrill, Jeffrey D; Ballard, Roberta A; Cnaan, Avital; Hibbs, Anna Maria; Godinez, Rodolfo I; Godinez, Marye H; Truog, William E; Ballard, Philip L

    2004-12-01

    Infants of <30 wk gestation often require respiratory support for several weeks and may develop bronchopulmonary dysplasia (BPD), which is associated with long-term pulmonary disability or death in severe cases. To examine the status of surfactant in infants at high risk for BPD, this prospective study analyzed 247 tracheal aspirate samples from 68 infants of 23-30 wk gestation who remained intubated for 7-84 d. Seventy-five percent of the infants had one or more surfactant samples with abnormal function (minimum surface tension 5.1-21.7 mN/m by pulsating bubble surfactometer), which were temporally associated with episodes of infection (p = 0.01) and respiratory deterioration (p = 0.005). Comparing normal and abnormal surfactant samples, there were no differences in amount of surfactant phospholipid, normalized to total protein that was recovered from tracheal aspirate, or in relative content of phosphatidylcholine and phosphatidylglycerol. Contents of surfactant proteins (SP) A, B, and C, measured in the surfactant pellet by immunoassay, were reduced by 50%, 80%, and 72%, respectively, in samples with abnormal surface tension (p < or = 0.001). On multivariable analysis of all samples, SP-B content (r = -0.58, p < 0.0001) and SP-C content (r = -0.32, p < 0.001) were correlated with surfactant function. We conclude that most premature infants requiring continued respiratory support after 7 d of age experience transient episodes of dysfunctional surfactant that are associated with a deficiency of SP-B and SP-C.

  4. Liquefaction Of Coal With Surfactant And Disposable Catalyst

    NASA Technical Reports Server (NTRS)

    Hickey, Gregory S.; Sharma, Pramod K.

    1996-01-01

    Fuels derived from coal more competitive with petroleum products. Improved coal-liquefaction process exploits synergistic effects of disposable iron oxide catalyst and cheap anionic surfactant. Efficiency of conversion achieved in significantly higher than efficiencies obtained with addition of either surfactant or catalyst alone. No costly pretreatment necessary, and increase in conversion achieved under processing conditions milder than those used heretofore in liquefaction of coal. Quality of distillates obtained after liquefaction in process expected superior to distillates obtained after liquefaction by older techniques.

  5. Interactions of cationic trimeric, gemini and monomeric surfactants with trianionic curcumin in aqueous solution.

    PubMed

    Wang, Meina; Wu, Chunxian; Tang, Yongqiang; Fan, Yaxun; Han, Yuchun; Wang, Yilin

    2014-05-21

    Interactions of trianionic curcumin (Cur(3-)) with a series of cationic surfactants, monomeric surfactant dodecyl trimethylammonium bromide (DTAB), dimeric surfactant hexamethylene-1,6-bis(dodecyldimethylammonium bromide) (12-6-12) and trimeric surfactant tri(dodecyldimethylammonioacetoxy)diethyltriamine trichloride (DTAD), have been investigated in aqueous solution of pH 13.0. Surface tension and spectral measurements indicate that the cationic surfactants display a similar surfactant concentration dependent interaction process with Cur(3-), involving three interaction stages. At first the three cationic surfactants electrostatically bind on Cur(3-) to form the surfactant-Cur(3-) complex. Then the bound and unbound cationic surfactants with Cur(3-) aggregate into surfactant-Cur(3-) mixed micelles through hydrophobic interactions above the critical micelle concentration of the surfactants (CMCC) in the presence of Cur(3-). Finally excess unbound surfactants self-assemble into micelles like those without Cur(3-). For all the three surfactants, the addition of Cur(3-) only decreases the critical micelle concentration of 12-6-12 but does not affect the critical micelle concentration of DTAB and DTAD. As the oligomeric degree of surfactants increases, the intermolecular interaction of the cationic surfactants with Cur(3-) increases and the surfactant amount needed for Cur(3-) encapsulation decreases. Compared with 12-6-12, either the weaker interaction of DTAB with Cur(3-) or stronger interaction of DTAD with Cur(3-) limits the stability or solubility of Cur(3-) in surfactant micelles. Therefore, gemini surfactant 12-6-12 is the best choice to effectively suppress Cur(3-) degradation at very low concentrations. Isothermal titration microcalorimetry, surface tension and (1)H NMR results reveal that 12-6-12 and Cur(3-) form a (12-6-12)2-Cur(3-) complex and start to form micelles at extremely decreased concentrations, where either 12-6-12 or Cur(3-) works as a bridge

  6. Physicochemical treatments of anionic surfactants wastewater: Effect on aerobic biodegradability.

    PubMed

    Aloui, Fathi; Kchaou, Sonia; Sayadi, Sami

    2009-05-15

    The effect of different physicochemical treatments on the aerobic biodegradability of an industrial wastewater resulting from a cosmetic industry has been investigated. This industrial wastewater contains 11423 and 3148mgL(-1) of chemical oxygen demand (COD) and anionic surfactants, respectively. The concentration of COD and anionic surfactants were followed throughout the diverse physicochemical treatments and biodegradation experiments. Different pretreatments of this industrial wastewater using chemical flocculation process with lime and aluminium sulphate (alum), and also advanced oxidation process (electro-coagulation (Fe and Al) and electro-Fenton) led to important COD and anionic surfactants removals. The best results were obtained using electro-Fenton process, exceeding 98 and 80% of anionic surfactants and COD removals, respectively. The biological treatment by an isolated strain Citrobacter braakii of the surfactant wastewater, as well as the pretreated wastewater by the various physicochemical processes used in this study showed that the best results were obtained with electro-Fenton pretreated wastewater. The characterization of the treated surfactant wastewater by the integrated process (electro-coagulation or electro-Fenton)-biological showed that it respects Tunisian discharge standards.

  7. Large scale molecular dynamics study of polymer-surfactant complex

    NASA Astrophysics Data System (ADS)

    Goswami, Monojoy; Sumpter, Bobby

    2012-02-01

    In this work, we study the self-assembly of cationic polyelectrolytes mediated by anionic surfactants in dilute or semi-dilute and gel states. The understanding of the dilute system is a requirement for the understanding of gel states. The importance of polyelectrolyte with oppositely charged colloidal particles can be found in biological systems, such as immobilization of enzymes in polyelectrolyte complexes or nonspecific association of DNA with protein. With the same understanding, interaction of surfactants with polyelectrolytes shows intriguing phenomena that are important for both in academic research as well as industrial applications. Many useful properties of PE surfactant complexes come from the highly ordered structures of surfactant self-assembly inside the PE aggregate. We do large scale molecular dynamics simulation using LAMMPS to understand the structure and dynamics of PE-surfactant systems. Our investigation shows highly ordered ring-string structures that have been observed experimentally in biological systems. We will investigate many different properties of PE-surfactant complexation which will be helpful for pharmaceutical, engineering and biological applications.

  8. Interfacial mechanisms for stability of surfactant-laden films

    PubMed Central

    Chai, Chew; Àlvarez-Valenzuela, Marco A.; Tajuelo, Javier; Fuller, Gerald G.

    2017-01-01

    Thin liquid films are central to everyday life. They are ubiquitous in modern technology (pharmaceuticals, coatings), consumer products (foams, emulsions) and also serve vital biological functions (tear film of the eye, pulmonary surfactants in the lung). A common feature in all these examples is the presence of surface-active molecules at the air-liquid interface. Though they form only molecular-thin layers, these surfactants produce complex surface stresses on the free surface, which have important consequences for the dynamics and stability of the underlying thin liquid film. Here we conduct simple thinning experiments to explore the fundamental mechanisms that allow the surfactant molecules to slow the gravity-driven drainage of the underlying film. We present a simple model that works for both soluble and insoluble surfactant systems in the limit of negligible adsorption-desorption dynamics. We show that surfactants with finite surface rheology influence bulk flow through viscoelastic interfacial stresses, while surfactants with inviscid surfaces achieve stability through opposing surface-tension induced Marangoni flows. PMID:28520734

  9. [Sorption and mechanism of surfactants on bentonite in combined pollution].

    PubMed

    Sun, Xiao-Hui; Lu, Ying-Ying; Chen, Shu-Guang; Li, Ling-Jian; Shen, Xue-You

    2007-04-01

    Sorption of cationic surfactant cetyl pyridinium chloride (CPC), anionic surfactant sodium dodecylbenzene sulfonate (SDBS) and nonionic surfactant Triton X-100 (TX-100) on bentonite was studied. The influences of cation-exchange capacity (CEC), temperature and salinity on the sorption of CPC were also discussed. The results indicate that the sorption of CPC on Na-bentonite is greater than that of TX-100 and SDBS, and SDBS hardly shows any sorption. CPC is adsorbed to Na-bentonite through a combination of hydrophobic bonding and cation-exchange. While TX-100 is adsorbed to Na-bentonite via the formation of an adsorption layer of twain surfactant molecule and hydrogenolysis of silicon-oxygen surface of bentonite and TX-100. The amount of SDBS adsorbed on Ca-bentonite increases with increasing surfactant concentration, reaching a maximum at 1.5 critical micelle concentration (CMC), and then decreases with increasing surfactant loading. The mechanism of the retention appears to be formation of a sparingly soluble Ca-SDBS species, and dissolution in the micelle. The amount of CPC adsorbed on bentonite decreases with increasing temperature, and increases with increasing CEC. NaCl can enhance the sorption of CPC on bentonite.

  10. A Function of Lung Surfactant Protein SP-B

    NASA Astrophysics Data System (ADS)

    Longo, M. L.; Bisagno, A. M.; Zasadzinski, J. A. N.; Bruni, R.; Waring, A. J.

    1993-07-01

    The primary function of lung surfactant is to form monolayers at the alveolar interface capable of lowering the normal surface tension to near zero. To accomplish this process, the surfactant must be capable of maintaining a coherent, tightly packed monolayer that avoids collapse during expiration. The positively charged amino-terminal peptide SP-B1-25 of lung surfactant-specific protein SP-B increases the collapse pressure of an important component of lung surfactant, palmitic acid (PA), to nearly 70 millinewtons per meter. This alteration of the PA isotherms removes the driving force for "squeeze-out" of the fatty acids from the primarily dipalmitoylphosphatidylcholine monolayers of lung surfactant. An uncharged mutant of SP-B1-25 induced little change in the isotherms, suggesting that a specific charge interaction between the cationic peptide and the anionic lipid is responsible for the stabilization. The effect of SP-B1-25 on fatty acid isotherms is remarkably similar to that of simple poly-cations, suggesting that such polymers might be useful as components of replacement surfactants for the treatment of respiratory distress syndrome.

  11. Simulation of Vertical Surfactant Distributions in Drying Latex Films.

    PubMed

    Gromer, A; Thalmann, F; Hébraud, P; Holl, Y

    2017-01-17

    Following our previous contribution ( Gromer, A. et al. Langmuir 2015 , 31 , 10983 - 10994 ) presenting a new simulation tool devoted to particle distributions in drying latex films, this Article describes the prediction of surfactant concentration profiles in the vertical direction during the complete film formation process. The simulation is inspired by cellular automata and equations by Routh and co-workers. It includes effects that were not considered before: surfactant convection by water and surfactant desorption upon particle deformation. It is based on five parameters describing the nature of the polymer/surfactant system and on film formation conditions. In particular, the viscoelastic properties of the polymer were taken into account through the λ̅ parameter introduced by Routh and Russel. Results show the importance of convection by water and the influence of the particular deformation mechanism on the final surfactant distribution. Excesses or depletions can be predicted either on the surface or on the substrate sides, in qualitative agreement with the numerous existing experimental studies. The complex interplay between parameters governing surfactant distributions makes the results unpredictable without the help of such a simulation tool. Therefore, it should be of interest to both industrial and academic scientists.

  12. [Acute toxicity of different type pesticide surfactants to Daphnia magna].

    PubMed

    Li, Xiu-huan; Li, Hua; Chen, Cheng-yu; Li, Jian-tao; Liu, Feng

    2013-08-01

    By using the standard test methods in Experimental Guideline for Environmental Safety Evaluation of Chemical Pesticide to aquatic organisms, a comparative study was conducted on the acute toxicity of 39 nonionic, 6 anionic, and 3 cationic surfactants to Daphnia magna. The acute toxicity of three cationic surfactants 1427, 1227 and C8-10 to D. magna belonged to virulent level, and the toxicity of 1427 was the highest, with the EC50 value being 0.97 x 10(-2) mg x L(-1). The acute toxicity of nonionic surfactants polyoxyethylene ether castor oil EL, Tween, and Span emulsifiers belonged to low level, but the toxicity of alkylphenol polyoxyethylene ether and fatty alcohol polyoxyethylene ether surfactants was relatively high, of which, AEO-7 and AEO-5 displayed high toxicity, with the EC50 value being 0.82 and 0.97 mg x L(-1), respectively. In these surfactants, the more liposolubility, the higher the toxicity was. Most of the anionic surfactants were medium in toxicity, but the acute toxicity of NNO belonged to high toxicity, with the EC50 value being 0.17 mg x L(-1).

  13. Highly stable surfactant assisted polyaniline nanostructures with enhanced electroactivity

    NASA Astrophysics Data System (ADS)

    Jamdegni, Monika; Kaur, Amarjeet

    2016-05-01

    Different nanostructures of Polyaniline(PANI) i.e. nanospheres, nanorods, nanofibers and layered structures have been successfully synthesized using varied concentration of anionic sodium dodecyl sulphate(SDS) and cationic Hexamethyltriammonium bromide (HTAB) by electrochemical method. Surfactant assisted morphology has been studied using FESEM. Incorporation of surfactants to the polymer matrix has been confirmed using FTIR spectroscopy. Electro activity and stability towards reversible redox activity was studied using cyclic voltammatry and chronoamperometry.The anionic surfactant severely enhances electroactivity and areal capacitance (3 Fcm-2) which was found to be two order higher than PANI film prepared without surfactant (0.039 Fcm-2), attributable to its additional doping effect. Immobilization of large surfactant molecule to polymer matrix inhibits its degradation due to nuleophilic attack ascribed to hydrophobic effect of surfactant. For PANI-SDS redox behavior remained almost same after 1000 reverse redox cycles while for PANI-HTAB we got only marginal changes.Our PANI-SDS samples are promising candidates for electro chromic applications.

  14. Sporicidal Activities of Various Surfactant Components against Bacillus subtilis Spores.

    PubMed

    Cho, Won-Il; Cheigh, Chan-Ick; Hwang, Hee-Jeong; Chung, Myong-Soo

    2015-06-01

    The sporicidal activities against Bacillus subtilis spores of surfactant components with hydrophilic and hydrophobic properties that can lead to the denaturation of various proteins comprising the spore structure were investigated. The reduction in spore numbers by each of the surfactant components bornyl acetate, geranyl acetate, pinene, p-cymene, camphene, citral, 2,3-dihydrobenzofuran, polylysine, and thiamine dilaurylsulfate at 1% was estimated at 1 to 2 log CFU/ml. The average hydrophilelipophile balance value of surfactants with sporicidal activity causing a reduction of 1 to 2 log CFU/ml was 9.3, with a range from 6.7 to 15.8, which is similar to the values of various chemical surfactants of 9.6 to 16.7. The results also showed that the surfactants that were hydrophobic were more effective than those that were hydrophilic in killing B. subtilis spores. Furthermore, the sporicidal effect of surfactants like geranyl acetate and γ-terpinene was significantly enhanced in the presence of a germinant, because L-alanine and synergistic cofactors (e.g., K(+) ions) trigger cortex hydrolysis in spores.

  15. Effect of surfactants on single-bubble sonoluminescence

    NASA Astrophysics Data System (ADS)

    Yasui, Kyuichi

    1998-10-01

    The effect of surfactants on single-bubble sonoluminescence (SBSL) is studied theoretically based on the hot-spot model that a SBSL bubble collapses quasiadiabatically and that the quasi-thermal radiation is the origin of the light emission. Stottlemyer and Apfel [J. Acoust. Soc. Am. 102, 1418 (1997)] reported that the surfactant called Triton X-100, which provides free interfacial motion, reduced the magnitude of the light pulse from the bubble. It is clarified by the present study that the effect of the surfactant is caused by the inhibition of condensation of water vapor at the bubble wall at the collapse, which results in lowering the achieved temperature inside a bubble due to the enhancement of the amount of vapor that undergoes endothermal chemical reactions. It is predicted, based on the hot-spot model, that the radiation is not thermalized inside a bubble in the case of SBSL in a solution of the surfactant in water and that the spectrum of SBSL may deviate from the blackbody spectrum and may have some characteristic lines such as the OH line (310 nm). It is suggested that surfactants can be used to enhance the chemical reactions of vapor in sonochemistry. It is also suggested that some of the surfactants are dissociated by the extremely high temperature at the bubble wall at the collapse.

  16. Barrier or carrier? Pulmonary surfactant and drug delivery.

    PubMed

    Hidalgo, Alberto; Cruz, Antonio; Pérez-Gil, Jesús

    2015-09-01

    To consider the lung as a target for drug delivery and to optimise strategies directed at the pulmonary route, it is essential to consider the role of pulmonary surfactant, a thin lipid-protein film lining the respiratory surface of mammalian lungs. Membrane-based surfactant multilayers are essential for reducing the surface tension at the respiratory air-liquid interface to minimise the work of breathing. Different components of surfactant are also responsible for facilitating the removal of potentially pathological entities such as microorganisms, allergens or environmental pollutants and particles. Upon inhalation, drugs or nanoparticles first contact the surfactant layer, and these interactions critically affect their lifetime and fate in the airways. This review summarises the current knowledge on the possible role and effects of the pulmonary surfactant system in drug delivery strategies. It also summarises the evidence that suggests that pulmonary surfactant is far from being an insuperable barrier and could be used as an efficient shuttle for delivering hydrophobic and hydrophilic compounds deep into the lung and the organism. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Solubilization of herbicides by single and mixed commercial surfactants.

    PubMed

    Galán-Jiménez, M C; Gómez-Pantoja, E; Morillo, E; Undabeytia, T

    2015-12-15

    The solubilization capabilities of micellar solutions of three single surfactants, two alcohol alkoxylates B048 and B266, and the tallow alkyl ethoxylated amine ET15, and their equimolar mixed solutions toward the herbicides flurtamone (FL), metribuzin (MTZ) and mesotrione (MST) were investigated. The solubilization capacity was quantified in terms of the molar solubilization ratio (MSR), critical micellar concentration (CMC), micelle-water partition coefficient (Kmc), binding constant (K1), number of aggregation (Nagg) and Stern-Volmer constant (Ksv). The herbicides were greatly solubilized into different loci of the micelles: FL within the inner hydrophobic core, MST at the micelle/water interface and MTZ in the palisade region. Equimolar binary surfactant mixtures did not improve the solubilization of herbicides over those of single components, with the exception of MTZ by the B266/ET15 system which enhanced solubilization by 10-20%. This enhanced solubilization of MTZ was due to an increased number of micelles that arise from both the intermediate Nagg relative to that of the single surfactants and the lower CMC. The use of Ksv values was a better predictor of the solubilization of polar molecules within binary mixtures of these surfactants than the interaction parameter β(M) from regular solution theory (RST). The results herein suggest that the use of mixed surfactant systems for the solubilization of polar molecules in environmental remediation technologies may be very limited in scope, without clear advantages over the use of single surfactant systems.

  18. Calorimetric determination of surfactant/polyelectrolyte binding isotherms.

    PubMed

    Lapitsky, Yakov; Parikh, Maider; Kaler, Eric W

    2007-07-26

    Mixing of oppositely charged surfactants and polyelectrolytes in aqueous solutions leads to cooperative surfactant adsorption onto the polyelectrolyte chains. Experimental determination of surfactant/polyelectrolyte binding isotherms is usually done using custom-built surfactant-ion-specific electrodes. As an alternative, we present an indirect isotherm approximation method that uses conventional isothermal titration calorimetry (ITC). The calorimetric data is fitted to the two-binding-state Satake-Yang adsorption model, which quantifies the extent of binding in terms of the binding constant (Ku) and the cooperativity parameter (u). This approach is investigated using two surfactant/polyelectrolyte mixtures: sodium perfluorooctanoate (FC7) and N,N,N-trimethylammonium derivatized hydroxyethyl cellulose (UCARE Polymer JR-400), whose binding behavior follows the Satake-Yang model, and dodecyltrimethylammonium bromide (DTAB) and poly(styrenesulfonate) (NaPSS), whose behavior deviates dramatically from the Satake-Yang model. These studies demonstrate that, in order to apply the indirect ITC method of binding isotherm determination, the surfactant/polyelectrolyte adsorption process must have no more than two dominant binding states. Thus, the technique works well for the FC7/JR-400 mixture. It fails in the case of the DTAB/NaPSS adsorption, but its mode of failure offers insight into the multiple-binding-state adsorption mechanism.

  19. Effect of Surfactants on the Growth of Individual Cloud Droplets

    NASA Astrophysics Data System (ADS)

    Frossard, A. A.; Li, W.; Gerard, V.; Noziere, B.; Cohen, R. C.

    2016-12-01

    Accurately predicting cloud droplet growth and lifetime remains a large uncertainty in estimates of Earth's changing energy budget. Current findings suggest that surface-active organic compounds and other surfactants in cloud droplets can affect the rate and magnitude of water condensation onto and evaporation from droplets affecting a myriad of cloud properties. This idea represents a significant change from prior thinking that focused solely on solubility as the chemical influence on water uptake to droplets. Recent observations show that surfactants extracted from atmospheric aerosol particles can considerably reduce the surface tension of water, making them important factors in cloud droplet growth that were until recently considered to be negligible. Using the surfactant Igepal CA-630, which has properties similar to that of surfactants extracted from atmospheric aerosol samples, model cloud droplets were created in the laboratory. The evaporation and condensation of the individual droplets were investigated using an aerosol optical trap with Raman spectroscopy. With a change in relative humidity (RH) from 70% to 80%, droplets containing both Igepal and NaCl had much larger changes in droplet radii than droplets containing NaCl only, demonstrating a significant effect of surface tension depression on evaporation and condensation. Given an increase in RH in the atmosphere, this could lead to droplets containing surfactants growing larger than those without surfactants and a substantial change in CCN activity.

  20. Dynamic surface tension of surfactant TA: experiments and theory.

    PubMed

    Otis, D R; Ingenito, E P; Kamm, R D; Johnson, M

    1994-12-01

    A bubble surfactometer was used to measure the surface tension of an aqueous suspension of surfactant TA as a function of bubble area over a range of cycling rates and surfactant bulk concentrations. Results of the surface tension-interfacial area loops exhibited a rich variety of phenomena, the character of which varied systematically with frequency and bulk concentration. A model was developed to interpret and explain these data and for use in describing the dynamics of surface layers under more general circumstances. Surfactant was modeled as a single component with surface tension taken to depend on only the interfacial surfactant concentration. Two distinct mechanisms were considered for the exchange of surfactant between the bulk phase and interface. The first is described by a simple kinetic relationship for adsorption and desorption that pertains only when the interfacial concentration is below its maximum equilibrium value. The second mechanism is "squeeze-out" by which surfactant molecules are expelled from an interface compressed past a maximum packing state. The model provided good agreement with experimental measurements for cycling rates from 1 to 100 cycles/min and for bulk concentrations between 0.0073 and 7.3 mg/ml.

  1. Interfacial mechanisms for stability of surfactant-laden films.

    PubMed

    Bhamla, M Saad; Chai, Chew; Àlvarez-Valenzuela, Marco A; Tajuelo, Javier; Fuller, Gerald G

    2017-01-01

    Thin liquid films are central to everyday life. They are ubiquitous in modern technology (pharmaceuticals, coatings), consumer products (foams, emulsions) and also serve vital biological functions (tear film of the eye, pulmonary surfactants in the lung). A common feature in all these examples is the presence of surface-active molecules at the air-liquid interface. Though they form only molecular-thin layers, these surfactants produce complex surface stresses on the free surface, which have important consequences for the dynamics and stability of the underlying thin liquid film. Here we conduct simple thinning experiments to explore the fundamental mechanisms that allow the surfactant molecules to slow the gravity-driven drainage of the underlying film. We present a simple model that works for both soluble and insoluble surfactant systems in the limit of negligible adsorption-desorption dynamics. We show that surfactants with finite surface rheology influence bulk flow through viscoelastic interfacial stresses, while surfactants with inviscid surfaces achieve stability through opposing surface-tension induced Marangoni flows.

  2. Natural and surfactant modified zeolites: A review of their applications for water remediation with a focus on surfactant desorption and toxicity towards microorganisms.

    PubMed

    Reeve, Peter J; Fallowfield, Howard J

    2017-10-06

    The objective of this review is to highlight the need for further investigation of microbial toxicity caused by desorption of surfactant from Surfactant Modified Zeolite (SMZ). SMZ is a low cost, versatile permeable reactive media which has the potential to treat multiple classes of contaminants. With this combination of characteristics, SMZ has significant potential to enhance water and wastewater treatment processes. Surfactant desorption has been identified as a potential issue for the ongoing usability of SMZ. Few studies have investigated the toxicity of surfactants used in zeolite modification towards microorganisms and fewer have drawn linkages between surfactant desorption and surfactant toxicity. This review provides an overview of natural zeolite chemistry, characteristics and practical applications. The chemistry of commonly used surfactants is outlined, along with the kinetics that drive their adsorption to the zeolite surface. Methodologies to characterise this surfactant loading are also described. Applications of SMZ in water remediation are highlighted, giving focus to applications which deal with biological pollutants and where microorganisms play a role in the remediation process. Studies that have identified surfactant desorption from SMZ are outlined. Finally, the toxicity of a commonly used cationic surfactant towards microorganisms is discussed. This review highlights the potential for surfactant to desorb from the zeolite surface and the need for further research into the toxicity of this desorbed surfactant towards microorganisms, including pathogens and environmental microbes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Influence of water concentrations on the phase transformation of a model surfactant/co-surfactant/water system

    NASA Astrophysics Data System (ADS)

    Lunkad, Raju; Srivastava, Arpita; Debnath, Ananya

    2017-02-01

    The influence of water concentrations on phase transformations of a surfactant/co-surfactant/water system is investigated by using all atom molecular dynamics simulations. At higher water concentrations, where surfactant (behenyl trimethyl ammonium chloride, BTMAC) to co-surfactant (stearyl alcohol, SA) ratio is fixed, BTMAC and SA self-assemble into spherical micelles, which transform into strongly interdigitated one dimensional rippled lamellar phases upon decreasing water concentrations. Fragmentation or fusions of spherical micelles of different sizes are evident from the radial distribution functions at different temperatures. However, at lower water concentrations rippled lamellar phase transforms into an LβI phase upon heating. Our simulations reveal that the concentrations of water can influence available space around the head groups which couple with critical thickness to accommodate the packing fraction required for respective phases. This directs towards obtaining a controlling factor to design desired phases important for industrial and medical applications in the future.

  4. Viscosity of the oil-in-water Pickering emulsion stabilized by surfactant-polymer and nanoparticle-surfactant-polymer system

    NASA Astrophysics Data System (ADS)

    Sharma, Tushar; Kumar, G. Suresh; Chon, Bo Hyun; Sangwai, Jitendra S.

    2014-11-01

    Information on the viscosity of Pickering emulsion is required for their successful application in upstream oil and gas industry to understand their stability at extreme environment. In this work, a novel formulation of oil-in-water (o/w) Pickering emulsion stabilized using nanoparticle-surfactant-polymer (polyacrylamide) system as formulated in our earlier work (Sharma et al., Journal of Industrial and Engineering Chemistry, 2014) is investigated for rheological stability at high pressure and high temperature (HPHT) conditions using a controlled-strain rheometer. The nanoparticle (SiO2 and clay) concentration is varied from 1.0 to 5.0 wt%. The results are compared with the rheological behavior of simple o/w emulsion stabilized by surfactant-polymer system. Both the emulsions exhibit non-Newtonian shear thinning behavior. A positive shift in this behavior is observed for surfactant-polymer stabilized emulsion at high pressure conditions. Yield stress is observed to increase with pressure for surfactant-polymer emulsion. In addition, increase in temperature has an adverse effect on the viscosity of emulsion stabilized by surfactant-polymer system. In case of nanoparticle-surfactant-polymer stabilized o/w emulsion system, the viscosity and yield stress are predominantly constant for varying pressure and temperature conditions. The viscosity data for both o/w emulsion systems are fitted by the Herschel-Bulkley model and found to be satisfactory. In general, the study indicates that the Pickering emulsion stabilized by nanoparticle-surfactant-polymer system shows improved and stable rheological properties as compared to conventional emulsion stabilized by surfactant-polymer system indicating their successful application for HPHT environment in upstream oil and gas industry.

  5. Solubilization and biodegradation of hydrophobic organic compounds in soil/aqueous systems with nonionic surfactants

    SciTech Connect

    Edwards, D.A.; Laha, S.; Liu, Zhongbao; Luthy, R.G.

    1992-01-01

    Nonionic surfactants may strongly interact with hydrophobic organic compounds (HOCs), soil, and microorganisms in soil/aqueous systems. These interactions affect the potential for surfactant-facilitated HOC transport in soil and groundwater systems, and the feasibility of engineered surfactant cleanup of contaminated sites (McCarthy and Wober, 1991). At sufficiently high bulk liquid concentrations at 25 C, most nonionic surfactants form regular micelles in single-phase solutions, whereas certain surfactants, such as C{sub 12}E{sub 4}, may form bilayer lamellae or other types of aggregates in more complex two-phase solutions. The critical concentrations for the onset of micelle and aggregate formation are termed the critical micelle concentration (CMC) and the critical aggregation concentration (CAC), respectively. Important changes occur in surfactant sorption, surfactant solubilization of HOCs, and microbial mineralization of HOCs in the presence of nonionic surfactants at or near these critical surfactant concentrations.

  6. Solubilization and biodegradation of hydrophobic organic compounds in soil/aqueous systems with nonionic surfactants

    SciTech Connect

    Edwards, D.A.; Laha, S.; Liu, Zhongbao; Luthy, R.G.

    1992-05-01

    Nonionic surfactants may strongly interact with hydrophobic organic compounds (HOCs), soil, and microorganisms in soil/aqueous systems. These interactions affect the potential for surfactant-facilitated HOC transport in soil and groundwater systems, and the feasibility of engineered surfactant cleanup of contaminated sites (McCarthy and Wober, 1991). At sufficiently high bulk liquid concentrations at 25 C, most nonionic surfactants form regular micelles in single-phase solutions, whereas certain surfactants, such as C{sub 12}E{sub 4}, may form bilayer lamellae or other types of aggregates in more complex two-phase solutions. The critical concentrations for the onset of micelle and aggregate formation are termed the critical micelle concentration (CMC) and the critical aggregation concentration (CAC), respectively. Important changes occur in surfactant sorption, surfactant solubilization of HOCs, and microbial mineralization of HOCs in the presence of nonionic surfactants at or near these critical surfactant concentrations.

  7. Self-motion of a camphanic acid disk on water with different types of surfactants.

    PubMed

    Nakata, Satoshi; Kirisaka, Junko; Arima, Yoshie; Ishii, Toshio

    2006-10-26

    Control of the self-motion of a camphanic acid disk on water was investigated upon the addition of different kinds of surfactants (Triton X-100 and Brij58 as neutral surfactants, cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, and sodium dodecyl sulfate (SDS) as an anionic surfactant) to the water phase. With an increase in the concentration of surfactant, continuous motion changed to no motion via intermittent motion (repetition between motion and rest), and the concentration regions of these motions were different among these surfactants. Although the concentration regions of these motions were determined by the surface tension for neutral surfactants, they were different than those for CTAB and SDS. These characteristics of self-motion are discussed in relation to the surface tension, depending on the concentration of individual surfactants, and the hydrophilic effect of the surfactants.

  8. Use of surfactants for the remediation of contaminated soils: a review.

    PubMed

    Mao, Xuhui; Jiang, Rui; Xiao, Wei; Yu, Jiaguo

    2015-03-21

    Due to the great harm caused by soil contamination, there is an increasing interest to apply surfactants to the remediation of a variety of contaminated soils worldwide. This review article summarizes the findings of recent literatures regarding remediation of contaminated soils/sites using surfactants as an enhancing agent. For the surfactant-based remedial technologies, the adsorption behaviors of surfactants onto soil, the solubilizing capability of surfactants, and the toxicity and biocompatibility of surfactants are important considerations. Surfactants can enhance desorption of pollutants from soil, and promote bioremediation of organics by increasing bioavailability of pollutants. The removal of heavy metals and radionuclides from soils involves the mechanisms of dissolution, surfactant-associated complexation, and ionic exchange. In addition to the conventional ionic and nonionic surfactants, gemini surfactants and biosurfactants are also applied to soil remediation due to their benign features like lower critical micelle concentration (CMC) values and better biocompatibility. Mixed surfactant systems and combined use of surfactants with other additives are often adopted to improve the overall performance of soil washing solution for decontamination. Worldwide the field studies and full-scale remediation using surfactant-based technologies are yet limited, however, the already known cases reveal the good prospect of applying surfactant-based technologies to soil remediation.

  9. Inactivation of Pulmonary Surfactant Due to Serum-Inhibited Adsorption and Reversal by Hydrophilic Polymers: Experimental

    PubMed Central

    Taeusch, H. William; de la Serna, Jorge Bernardino; Perez-Gil, Jesus; Alonso, Coralie; Zasadzinski, Joseph A.

    2005-01-01

    The rate of change of surface pressure, π, in a Langmuir trough following the deposition of surfactant suspensions on subphases containing serum, with or without polymers, is used to model a likely cause of surfactant inactivation in vivo: inhibition of surfactant adsorption due to competitive adsorption of surface active serum proteins. Aqueous suspensions of native porcine surfactant, organic extracts of native surfactant, and the clinical surfactants Curosurf, Infasurf, and Survanta spread on buffered subphases increase the surface pressure, π, to ∼40 mN/m within 2 min. The variation with concentration, temperature, and mode of spreading confirmed Brewster angle microscopy observations that subphase to surface adsorption of surfactant is the dominant form of surfactant transport to the interface. However (with the exception of native porcine surfactant), similar rapid increases in π did not occur when surfactants were applied to subphases containing serum. Components of serum are surface active and adsorb reversibly to the interface increasing π up to a concentration-dependent saturation value, πmax. When surfactants were applied to subphases containing serum, the increase in π was significantly slowed or eliminated. Therefore, serum at the interface presents a barrier to surfactant adsorption. Addition of either hyaluronan (normally found in alveolar fluid) or polyethylene glycol to subphases containing serum reversed inhibition by restoring the rate of surfactant adsorption to that of the clean interface, thereby allowing surfactant to overcome the serum-induced barrier to adsorption. PMID:15923228

  10. Inactivation of pulmonary surfactant due to serum-inhibited adsorption and reversal by hydrophilic polymers: experimental.

    PubMed

    Taeusch, H William; Bernardino de la Serna, Jorge; Perez-Gil, Jesus; Alonso, Coralie; Zasadzinski, Joseph A

    2005-09-01

    The rate of change of surface pressure, pi, in a Langmuir trough following the deposition of surfactant suspensions on subphases containing serum, with or without polymers, is used to model a likely cause of surfactant inactivation in vivo: inhibition of surfactant adsorption due to competitive adsorption of surface active serum proteins. Aqueous suspensions of native porcine surfactant, organic extracts of native surfactant, and the clinical surfactants Curosurf, Infasurf, and Survanta spread on buffered subphases increase the surface pressure, pi, to approximately 40 mN/m within 2 min. The variation with concentration, temperature, and mode of spreading confirmed Brewster angle microscopy observations that subphase to surface adsorption of surfactant is the dominant form of surfactant transport to the interface. However (with the exception of native porcine surfactant), similar rapid increases in pi did not occur when surfactants were applied to subphases containing serum. Components of serum are surface active and adsorb reversibly to the interface increasing pi up to a concentration-dependent saturation value, pi(max). When surfactants were applied to subphases containing serum, the increase in pi was significantly slowed or eliminated. Therefore, serum at the interface presents a barrier to surfactant adsorption. Addition of either hyaluronan (normally found in alveolar fluid) or polyethylene glycol to subphases containing serum reversed inhibition by restoring the rate of surfactant adsorption to that of the clean interface, thereby allowing surfactant to overcome the serum-induced barrier to adsorption.

  11. Effect of surfactant solubilization on biodegradation of polychlorinated biphenyl congeners by Pseudomonas LB400.

    PubMed

    Billingsley, K A; Backus, S M; Ward, O P

    1999-08-01

    A variety of commercial surfactants were tested to determine their effect on polychlorinated biphenyl (PCB) transformation by Pseudomonas LB400. Initial tests determined that most surfactants were fully or partially able to solubilize the PCB congeners 2,5,2'-chlorobiphenyl (CBP), 2,4,2',4'-CBP, 2,3,5,2',5'-CBP and 2,4,5,2',4',5'-CBP, at concentrations above the surfactants' critical micelle concentration (CMC). Surfactants were also found to have no negative effect on bacterial survival, as cell numbers were the same or higher after incubation in the presence of surfactants than after incubation without surfactants. A comparison of the extent of biotransformation of single PCB congeners by the bacterium revealed that, at surfactant concentrations above the CMC, the presence of an anionic surfactant promoted while nonionic surfactants inhibited PCB transformation, compared to a control with no surfactant. The rates of transformation of PCB congeners were also higher in the presence of the anionic surfactant compared to the control. The inhibitory effects of a nonionic surfactant, Igepal CO-630 at a concentration above its CMC, on transformation of 2,4,5,2',5'-CBP could be eliminated by diluting the surfactant/PCB solution to a concentration close to the surfactant CMC.

  12. Lung Surfactant Protein A (SP-A) Interactions with Model Lung Surfactant Lipids and an SP-B Fragment

    PubMed Central

    2011-01-01

    Surfactant protein A (SP-A) is the most abundant protein component of lung surfactant, a complex mixture of proteins and lipids. SP-A performs host defense activities and modulates the biophysical properties of surfactant in concerted action with surfactant protein B (SP-B). Current models of lung surfactant mechanism generally assume SP-A functions in its octadecameric form. However, one of the findings of this study is that when SP-A is bound to detergent and lipid micelles that mimic lung surfactant phospholipids, it exists predominantly as smaller oligomers, in sharp contrast to the much larger forms observed when alone in water. These investigations were carried out in sodium dodecyl sulfate (SDS), dodecylphosphocholine (DPC), lysomyristoylphosphatidylcholine (LMPC), lysomyristoylphosphatidylglycerol (LMPG), and mixed LMPC + LMPG micelles, using solution and diffusion nuclear magnetic resonance (NMR) spectroscopy. We have also probed SP-A’s interaction with Mini-B, a biologically active synthetic fragment of SP-B, in the presence of micelles. Despite variations in Mini-B’s own interactions with micelles of different compositions, SP-A is found to interact with Mini-B in all micelle systems and perhaps to undergo a further structural rearrangement upon interacting with Mini-B. The degree of SP-A–Mini-B interaction appears to be dependent on the type of lipid headgroup and is likely mediated through the micelles, rather than direct binding. PMID:21553841

  13. Lung surfactant protein A (SP-A) interactions with model lung surfactant lipids and an SP-B fragment.

    PubMed

    Sarker, Muzaddid; Jackman, Donna; Booth, Valerie

    2011-06-07

    Surfactant protein A (SP-A) is the most abundant protein component of lung surfactant, a complex mixture of proteins and lipids. SP-A performs host defense activities and modulates the biophysical properties of surfactant in concerted action with surfactant protein B (SP-B). Current models of lung surfactant mechanism generally assume SP-A functions in its octadecameric form. However, one of the findings of this study is that when SP-A is bound to detergent and lipid micelles that mimic lung surfactant phospholipids, it exists predominantly as smaller oligomers, in sharp contrast to the much larger forms observed when alone in water. These investigations were carried out in sodium dodecyl sulfate (SDS), dodecylphosphocholine (DPC), lysomyristoylphosphatidylcholine (LMPC), lysomyristoylphosphatidylglycerol (LMPG), and mixed LMPC + LMPG micelles, using solution and diffusion nuclear magnetic resonance (NMR) spectroscopy. We have also probed SP-A's interaction with Mini-B, a biologically active synthetic fragment of SP-B, in the presence of micelles. Despite variations in Mini-B's own interactions with micelles of different compositions, SP-A is found to interact with Mini-B in all micelle systems and perhaps to undergo a further structural rearrangement upon interacting with Mini-B. The degree of SP-A-Mini-B interaction appears to be dependent on the type of lipid headgroup and is likely mediated through the micelles, rather than direct binding.

  14. Mature Surfactant Protein-B Expression by Immunohistochemistry as a Marker for Surfactant System Development in the Fetal Sheep Lung

    PubMed Central

    Lock, Mitchell C.; McGillick, Erin V.; Orgeig, Sandra; Zhang, Song; McMillen, I. Caroline; Morrison, Janna L.

    2015-01-01

    Evaluation of the number of type II alveolar epithelial cells (AECs) is an important measure of the lung’s ability to produce surfactant. Immunohistochemical staining of these cells in lung tissue commonly uses antibodies directed against mature surfactant protein (SP)-C, which is regarded as a reliable SP marker of type II AECs in rodents. There has been no study demonstrating reliable markers for surfactant system maturation by immunohistochemistry in the fetal sheep lung despite being widely used as a model to study lung development. Here we examine staining of a panel of surfactant pro-proteins (pro–SP-B and pro–SP-C) and mature proteins (SP-B and SP-C) in the fetal sheep lung during late gestation in the saccular/alveolar phase of development (120, 130, and 140 days), with term being 150 ± 3 days, to identify the most reliable marker of surfactant producing cells in this species. Results from this study indicate that during late gestation, use of anti-SP-B antibodies in the sheep lung yields significantly higher cell counts in the alveolar epithelium than SP-C antibodies. Furthermore, this study highlights that mature SP-B antibodies are more reliable markers than SP-C antibodies to evaluate surfactant maturation in the fetal sheep lung by immunohistochemistry. PMID:26297137

  15. Mature Surfactant Protein-B Expression by Immunohistochemistry as a Marker for Surfactant System Development in the Fetal Sheep Lung.

    PubMed

    Lock, Mitchell C; McGillick, Erin V; Orgeig, Sandra; Zhang, Song; McMillen, I Caroline; Morrison, Janna L

    2015-11-01

    Evaluation of the number of type II alveolar epithelial cells (AECs) is an important measure of the lung's ability to produce surfactant. Immunohistochemical staining of these cells in lung tissue commonly uses antibodies directed against mature surfactant protein (SP)-C, which is regarded as a reliable SP marker of type II AECs in rodents. There has been no study demonstrating reliable markers for surfactant system maturation by immunohistochemistry in the fetal sheep lung despite being widely used as a model to study lung development. Here we examine staining of a panel of surfactant pro-proteins (pro-SP-B and pro-SP-C) and mature proteins (SP-B and SP-C) in the fetal sheep lung during late gestation in the saccular/alveolar phase of development (120, 130, and 140 days), with term being 150 ± 3 days, to identify the most reliable marker of surfactant producing cells in this species. Results from this study indicate that during late gestation, use of anti-SP-B antibodies in the sheep lung yields significantly higher cell counts in the alveolar epithelium than SP-C antibodies. Furthermore, this study highlights that mature SP-B antibodies are more reliable markers than SP-C antibodies to evaluate surfactant maturation in the fetal sheep lung by immunohistochemistry.

  16. Capillary electrophoresis investigation on equilibrium between polymer-related and surfactant-related species in aqueous polymer-surfactant solutions.

    PubMed

    Wu, Yefan; Chen, Miaomiao; Fang, Yun; Zhu, Meng

    2017-03-17

    It was inferred from aqueous solution behavior of nonionic polymers and anionic surfactants that the formation of charged polymer-bound surfactant micelle above critical aggregation concentration (cac) and the formation of free surfactant micelle beyond polymer saturation point (psp), but there was still a lack of direct experimental evidence for the considered equilibrium chemical species. Three modes of capillary electrophoresis are applied in this paper to study the complexation between nonionic polymers, polyvinylpyrrolidone (PVP) or polyethylene glycol (PEG), and sodium dodecylbenzenesulfonate (SDBS) by successfully distinguishing the imaginary charged polymer-bound SDBS micelle from nonionic polymer and SDBS molecule. Perhaps even more important, it is the action of SDBS as both a main surfactant and a UV probe that makes the free surfactant micelle emerged in electropherogram beyond psp, and thus makes it possible for the first time to provide the equilibrium relationship of the polymer-related and the surfactant-related species in the concentration regions divided into by cac and psp. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Surfactants at Single-Walled Carbon Nanotube-Water Interface: Physics of Surfactants, Counter-Ions, and Hydration Shell

    NASA Astrophysics Data System (ADS)

    Khare, Ketan S.; Phelan, Frederick R., Jr.

    Specialized applications of single-walled carbon nanotubes (SWCNTs) require an efficient and reliable method to sort these materials into monodisperse fractions with respect to their defining metrics (chirality, length, etc.) while retaining their physical and chemical integrity. A popular method to achieve this goal is to use surfactants that individually disperse SWCNTs in water and then to separate the resulting colloidal mixture into fractions that are enriched in monodisperse SWCNTs. Recently, experiments at NIST have shown that subtle point mutations of chemical groups in bile salt surfactants have a large impact on the hydrodynamic properties of SWCNT-surfactant complexes during ultracentrifugation. These results provide strong motivation for understanding the rich physics underlying the assembly of surfactants around SWCNTs, the structure and dynamics of counter ions around the resulting complex, and propagation of these effects into the first hydration shell. Here, all-atom molecular dynamics simulations are used to investigate the thermodynamics of SWCNT-bile salt surfactant complexes in water with an emphasis on the buoyant characteristics of the SWCNT-surfactant complexes. Simulation results will be presented along with a comparison with experimental data. Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States.

  18. Dielectrophoresis of a surfactant-laden viscous drop

    NASA Astrophysics Data System (ADS)

    Mandal, Shubhadeep; Bandopadhyay, Aditya; Chakraborty, Suman

    2016-06-01

    The dielectrophoresis of a surfactant-laden viscous drop in the presence of non-uniform DC electric field is investigated analytically and numerically. Considering the presence of bulk-insoluble surfactants at the drop interface, we first perform asymptotic solution for both low and high surface Péclet numbers, where the surface Péclet number signifies the strength of surface convection of surfactants as compared to the diffusion at the drop interface. Neglecting fluid inertia and interfacial charge convection effects, we obtain explicit expression for dielectrophoretic drop velocity for low and high Péclet numbers by assuming small deviation of drop shape from sphericity and small deviation of surfactant concentration from the equilibrium uniform distribution. We then depict a numerical solution, assuming spherical drop, for arbitrary values of Péclet number. Our analyses demonstrate that the asymptotic solution shows excellent agreement with the numerical solution in the limiting conditions of low and high Péclet numbers. The present analysis shows that the flow-induced redistribution of the surfactants at the drop interface generates Marangoni stress, owing to the influence of the surfactant distribution on the local interfacial tension, at the drop interface and significantly alters the drop velocity at steady state. For a perfectly conducting/dielectric drop suspended in perfectly dielectric medium, Marangoni stress always retards the dielectrophoretic velocity of the drop as compared with a surfactant-free drop. For a leaky dielectric drop suspended in another leaky dielectric medium, in the low Péclet number limit, depending on the electrical conductivity and permittivity of both the liquids, the Marangoni stress may aid or retard the dielectrophoretic velocity of the drop. The Marangoni stress also has the ability to move the drop in the opposite direction as compared with a surfactant-free drop. This non-intuitive reverse motion of the drop is

  19. Groundwater pollution by perfluorinated surfactants in Tokyo.

    PubMed

    Murakami, Michio; Kuroda, Keisuke; Sato, Nobuyuki; Fukushi, Tetsuo; Takizawa, Satoshi; Takada, Hideshige

    2009-05-15

    Perfluorinated surfactants (PFSs) in groundwater were analyzed to reveal their distribution and sources. Sixteen groundwater and spring samples were collected from the Tokyo metropolitan area, and nine PFSs, including perfluorooctane-sulfonate (PFOS) and perfluorooctanoate (PFOA), were analyzed by liquid chromatography-tandem mass spectrometry. A column test using artificial street runoff was also performed to study their behavior. PFSs were detected in all groundwater samples, some at concentrations comparable to those in wastewater and street runoff, suggesting widespread contamination of groundwater by PFSs. In particular, PFOS -was more abundant in groundwater than in rivers, wastewater, and street runoff. This was attributed to its production from the degradation of its precursors, as supported by the column test. The occurrence of short-chain perfluorocarboxylates (PFCAs) in groundwater was also consistent with the results of the column test, showing that limited amounts of short-chain PFCAs were removed by soil, as the efficiency of removal increased with the chain length. We evaluated the contributions of PFCAs from wastewater and surface runoff to groundwater by using two indicators, the long/(short + long) ratio and the even(even + odd) ratio. Both ratios showed good agreement in their calculated contributions in heavily contaminated groundwater where breakthroughs likely occurred. Wastewater and surface runoff contributed to 54-86% and 16-46% of PFCAs, respectively, in groundwater.

  20. Model Lung Surfactant Films: Why Composition Matters

    SciTech Connect

    Selladurai, Sahana L.; Miclette Lamarche, Renaud; Schmidt, Rolf; DeWolf, Christine E.

    2016-10-18

    Lung surfactant replacement therapies, Survanta and Infasurf, and two lipid-only systems both containing saturated and unsaturated phospholipids and one containing additional palmitic acid were used to study the impact of buffered saline on the surface activity, morphology, rheology, and structure of Langmuir monolayer model membranes. Isotherms and Brewster angle microscopy show that buffered saline subphases induce a film expansion, except when the cationic protein, SP-B, is present in sufficient quantities to already screen electrostatic repulsion, thus limiting the effect of changing pH and adding counterions. Grazing incidence X-ray diffraction results indicate an expansion not only of the liquid expanded phase but also an expansion of the lattice of the condensed phase. The film expansion corresponded in all cases with a significant reduction in the viscosity and elasticity of the films. The viscoelastic parameters are dominated by liquid expanded phase properties and do not appear to be dependent on the structure of the condensed phase domains in a phase separated film. The results highlight that the choice of subphase and film composition is important for meaningful interpretations of measurements using model systems.

  1. Dispersing carbon nanotubes by chiral network surfactants.

    PubMed

    Lin, Pengcheng; Cong, Yuehua; Zhang, Baoyan

    2015-04-01

    Chiral network surfactants (CNSs) possessing miscibility with carbon nanotubes (CNTs) and chiral materials are applied to disperse CNTs. Ultraviolet-visible absorption spectroscopy is used to quantitatively determine the CNT concentration in homogeneous CNT-CNS dispersions, results indicate that CNSs with more mole fraction of polycyclic conjugated structure have better ability to load and disperse CNTs and the maximal concentration reaches 0.79 mg mL(-1). Fourier transform infrared imaging system is utilized to analyze the dispersibility of CNTs in CNT-CNS composites, and CNS with 6 mol % nonmesogens (S6) induces the best dispersibility. The CNT doped CNSs exhibit lower glass transition temperature, strengthened thermal stability, decreased the thermochromic temperature and enriched reflected colors of CNSs. Furthermore, S6 are used as a promoter to disperse CNTs in chiral host, here, a left-handed chiral liquid crystal (CLC) is selected, the miscibility between CNTs and CLCs is studied by polarized optical microscope, and CNTs can be effectively dispersed in CLCs by S6. The CNT dispersed CLCs can exhibit a faster electro-optical response process than neat CLCs.

  2. Surfactant proteins of the human larynx.

    PubMed

    Sheats, M; Schröder, H; Rausch, F; Bohr, C; Kißlinger, F; de Tristan, J; Iro, H; Garreis, F; Paulsen, F; Schicht, M; Bräuer, L

    2016-11-01

    Surfactant proteins (SPs) originally identified in lung tissue are important players in the innate immune system. Beyond this, they contribute to stability and rheology of gaseous or aqueous interphases. In the present study, we determined the expression and presence of SPs (A, B, C and D) in different areas of the human larynx. mRNA expression of SP-A, -B, -C and -D was analyzed by means of RT-PCR in healthy samples of epiglottis, vocal and vestibular folds, subglottis and trachea. Distribution and localization of all four SPs were analyzed by Western blot and immunohistochemistry in healthy human tissue samples. All four SPs were detected at the mRNA- and protein level in the human larynx as well as by means of immunohistochemistry in the different tissue samples of the human larynx. The results reveal that all four SPs are produced with different expression patterns within the human larynx. Based on the known functions, our results suggest that SPs might be involved in maintaining mucus rheology and subsequently they could be essential components for proper phonation. Moreover, the proteins seem to play a role in immune defense of the larynx. Copyright © 2016 Elsevier GmbH. All rights reserved.

  3. Alkyl-imidazolium glycosides: non-ionic-cationic hybrid surfactants from renewable resources.

    PubMed

    Salman, Abbas Abdulameer; Tabandeh, Mojtaba; Heidelberg, Thorsten; Hussen, Rusnah Syahila Duali; Ali, Hapipah Mohd

    2015-08-14

    A series of surfactants combining carbohydrate and imidazolium head groups were prepared and investigated on their assembly behavior. The presence of the imidazolium group dominated the interactions of the surfactants, leading to high CMCs and large molecular surface areas, reflected in curved rather than lamellar surfactant assemblies. The carbohydrate, on the other hand, stabilized molecular assemblies slightly and reduced the surface tension of surfactant solutions considerably. A comparative emulsion study discourages the use of pure alkyl imidazolium glycosides owing to reduced assembly stabilities compared with APGs. However, the surfactants are believed to have potential as component in carbohydrate based surfactant mixtures. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. An Investigation of CNT Cytotoxicity by Using Surfactants in Different Ratio

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Kumar, Neeraj; Thakur, Rajesh; Bhanjana, Gaurav; Dilbaghi, Neeraj

    2011-12-01

    This account reports a comparative analysis on dispersion of multiwalled and single walled carbon nanotubes with different surfactants like—Triton X-100, Tween 20, Tween 80, and sodium dodecyl sulfate (SDS). Dispersion of CNTs has been characterized by UV-Vis spectroscopy, electron microscopy and probe microscopy. An optimum CNT-to-surfactant ratio has been determined for each surfactant. Surfactant concentration in different ratio is found to deteriorate the quality of nanotube dispersion. Electron microscopy analysis of a high-surfactant sample concentration enables us to construct a plausible mechanism for increase or decrease in CNT dispersion at high surfactant concentration.

  5. Surfactant enhanced remediation of an alluvial aquifer contaminated with DNAPL

    SciTech Connect

    Londergan, J.T.; Meinardus, H.W.; Pope, G.A.; Brown, C.L.

    1997-12-31

    During 1996, a successful demonstration of surfactant-enhanced-aquifer-remediation (SEAR) and the use of partitioning interwell tracer tests (PITTs) was conducted beneath the former waste disposal trenches at Operable Unit 2 at Hill AFB, Utah. The trenches had received large volumes of chlorinated solvents from degreasing operations. The solvents drained downward, pooling in an alluvial sand aquifer confined in a buried paleochannel eroded into thick clay deposits. The hydraulic conductivity of the alluvium is in the range of 10{sup -3} to 10{sup -2} cm/sec. The well array installed for the demonstration consisted of a line of three injection wells, a line of three extraction wells, a central observation well, and a single hydraulic control well. The distance between injectors and extractors was 20 feet; the distance between individual injectors and extractors in line was 10 feet. The water table was 25 feet below ground surface with a saturated zone approximately 19 feet thick. There was a 4 foot thick zone of DNAPL 42-46 feet below ground surface. The injectors and extractors were completed in this DNAPL zone. The demonstration was conducted in two phases. The first of these consisted of an initial partitioning interwell tracer test (PITT) followed by a pilot scale surfactant flood. The PITT indicated that a total of approximately 346 gallons of DNAPL was present in, the demonstration area. The pilot scale surfactant flood demonstrated the efficacy of the surfactant, showed there was no degradation of hydraulic conductivity due to the introduction of a surfactant solution, and demonstrated that the effluent could be efficiently treated by the on-site steam stripper. Approximately 185 gallons of DNAPL were removed from the aquifer by the pilot scale surfactant flood. The second phase consisted of a pre-flood PITT, a line drive surfactant flood, and a post-flood PITT.

  6. Cell-specific modulation of surfactant proteins by ambroxol treatment

    SciTech Connect

    Seifart, Carola . E-mail: zwiebel@mailer.uni-marburg.de; Clostermann, Ursula; Seifart, Ulf

    2005-02-15

    Ambroxol [trans-4-(2-amino-3,5-dibromobenzylamino)-cyclohexanole hydrochloride], a mucolytic agent, was postulated to provide surfactant stimulatory properties and was previously used to prevent surfactant deficiency. Currently, the underlying mechanisms are not exactly clear. Because surfactant homeostasis is regulated by surfactant-specific proteins (SP), we analyzed protein amount and mRNA expression in whole lung tissue, isolated type II pneumocytes and bronchoalveolar lavage of Sprague-Dawley rats treated with ambroxol i.p. (75 mg/kg body weight, twice a day [every 12 h]). The methods used included competitive polymerase chain reaction (RT-PCR), Northern blotting, Western immunoblotting, and immunohistochemistry. In isolated type II pneumocytes of ambroxol-treated animals, SP-C protein and mRNA content were increased, whereas SP-A, -B and -D protein, mRNA, and immunoreactivity remained unaffected. However, ambroxol treatment resulted in a significant increase of SP-B and in a decrease of SP-D in whole lung tissue with enhanced immunostaining for SP-B in Clara Cells. SP-A and SP-D were significantly decreased in BAL fluid of ambroxol-treated animals. The data suggest that surfactant protein expression is modulated in a cell-specific manner by ambroxol, as type II pneumocytes exhibited an increase in SP-C, whereas Clara cells exhibited an increase in the immunoreactivity for SP-B accounting for the increased SP-B content of whole lung tissue. The results indicate that ambroxol may exert its positive effects, observed in the treatment of diseases related to surfactant deficiency, via modulation of surfactant protein expression.

  7. Cell-specific modulation of surfactant proteins by ambroxol treatment.

    PubMed

    Seifart, Carola; Clostermann, Ursula; Seifart, Ulf; Müller, Bernd; Vogelmeier, Claus; von Wichert, Peter; Fehrenbach, Heinz

    2005-02-15

    Ambroxol [trans-4-(2-amino-3,5-dibromobenzylamino)-cyclohexanole hydrochloride], a mucolytic agent, was postulated to provide surfactant stimulatory properties and was previously used to prevent surfactant deficiency. Currently, the underlying mechanisms are not exactly clear. Because surfactant homeostasis is regulated by surfactant-specific proteins (SP), we analyzed protein amount and mRNA expression in whole lung tissue, isolated type II pneumocytes and bronchoalveolar lavage of Sprague-Dawley rats treated with ambroxol i.p. (75 mg/kg body weight, twice a day [every 12 h]). The methods used included competitive polymerase chain reaction (RT-PCR), Northern blotting, Western immunoblotting, and immunohistochemistry. In isolated type II pneumocytes of ambroxol-treated animals, SP-C protein and mRNA content were increased, whereas SP-A, -B and -D protein, mRNA, and immunoreactivity remained unaffected. However, ambroxol treatment resulted in a significant increase of SP-B and in a decrease of SP-D in whole lung tissue with enhanced immunostaining for SP-B in Clara Cells. SP-A and SP-D were significantly decreased in BAL fluid of ambroxol-treated animals. The data suggest that surfactant protein expression is modulated in a cell-specific manner by ambroxol, as type II pneumocytes exhibited an increase in SP-C, whereas Clara cells exhibited an increase in the immunoreactivity for SP-B accounting for the increased SP-B content of whole lung tissue. The results indicate that ambroxol may exert its positive effects, observed in the treatment of diseases related to surfactant deficiency, via modulation of surfactant protein expression.

  8. [Washing copper (II)-contaminated soil using surfactant solutions].

    PubMed

    Zhao, Bao-wei; Wu, Yong-qi; Ma, Chan-Yuan; Zhu, Rui-jia

    2009-10-15

    The batch equilibrium washing of copper (II) in the soil matrix by anionic surfactant, sodium dodecylbenzyl sulfonate (SDBS), nonionic surfactant, octylphenoxypolyethoxyethanol (TX100), and their mixture (SDBS-TX100), was studied and compared. The influences of surfactant concentrations, washing time, pH values of solutions, ratios of soil to water and inorganic salts on washing efficiency were investigated. It was shown that the washing efficiency differed with the kinds of surfactants. Given the initial surfactant concentrations, the washing of copper (II) by single SDBS was greater than those by single TX100 and the mixed SDBS-TX100. The washing efficiency by 6 000 mg x L(-1) of SDBS was up to 46.3%, which was 5.8, 10.8, 10.8 and 19.3 times as those by SDBS-TX100 (3:1), SDBS-TX100 (1:1), SDBS-TX100 (1:3) and single TX100 respectively. When the ratio of soil to water was 1 to 10 and washing time reached 24 h, the washing efficiency achieved the maximum. pH values of solutions had obvious effect on the washing of copper (II). The washing efficiency of copper decreased sharply with the increase of pH. At the high acidity (pH = 1.50), the washing efficiency of copper (II) was up to 95%. The smaller the ratios of soil to water were, the higher the washing efficiencies would be. The existence of inorganic salts with the certain concentrations, such as Na+, Ca2+ and Mg2+, could not influence the washing capacity of surfactants, but the excessive Mg2+ (more than 500 mg x L(-1)) could resulted in the precipitation of SDBS. The results will make an implication for surfactant-enhanced remediation of soils contaminated with heavy metals.

  9. Surfactant for bacterial pneumonia in late preterm and term infants.

    PubMed

    Tan, Kenneth; Lai, Nai Ming; Sharma, Ajay

    2012-02-15

    Pulmonary surfactant is an important part of the host defence against respiratory infections. Bacterial pneumonia in late preterm or term newborn infants often leads to surfactant deficiency or dysfunction, as surfactant is either inactivated or peroxidated. Studies of animal models of pneumonia and clinical case reports suggest that exogenous surfactant might be beneficial to infants with bacterial pneumonia. To assess the effect of exogenous surfactant treatment on mortality and pulmonary complications in infants with bacterial pneumonia. We used standard Cochrane Collaboration methodology to conduct our search of databases. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 6); MEDLINE (accessed via Ovid SP June 2011); EMBASE (via Ovid SP 1980 to June 2011); and CINAHL Plus (accessed via EBSCOHost June 2011). We limited our search to randomised and quasi-randomised trials of surfactant replacement therapy in infants > 35 weeks gestation with bacterial pneumonia in the first 28 days of life. The primary outcome measures were death, time to resolution of pneumonia, incidence of chronic lung disease, pneumothoraces and pulmonary haemorrhage. We assessed all studies with predefined criteria as to whether they were eligible for inclusion. We extracted data using RevMan 5 (RevMan 2011). We used the standard Cochrane Collaboration methodology for data collection and analysis to assess risk of bias, heterogeneity, treatment effect, missing data and reporting bias where appropriate. We did not identify any studies that met our inclusion criteria. There is no evidence from randomised controlled trials (RCTs) to support or refute the efficacy of surfactant in near-term and term infants with proven or suspected bacterial pneumonia. RCTs are still required to answer this question.

  10. Surfactant and temperature effects on paraben transport through silicone membranes.

    PubMed

    Waters, Laura J; Dennis, Laura; Bibi, Aisha; Mitchell, John C

    2013-08-01

    This study investigates the effects of two surfactants (one anionic and one non-ionic) and controlled modifications in temperature (298-323K) on the permeation of two structurally similar compounds through a silicone membrane using a Franz diffusion cell system. In all cases the presence of an anionic surfactant, namely sodium dodecyl sulphate (SDS), reduced the permeation of both compounds (methylparaben and ethylparaben) over a period of 24h. The degree of permeation reduction was proportional to the concentration of surfactant with a maximum effect observed, with an average reduction of approximately 50%, at the highest surfactant concentration of 20mM. Differences were seen around the critical micelle concentration (CMC) of SDS implying the effect was partially connected with the favoured formation of micelles. In contrast, the presence of non-ionic surfactant (Brij 35) had no effect on the permeation of methylparaben or ethylparaben at any of the concentrations investigated, both above and below the CMC of the surfactant. From these findings the authors conclude that the specific effects of SDS are a consequence of ionic surfactant-silicone interactions retarding the movement of paraben through the membrane through indirect modifications to the surface of the membrane. As expected, an increase in experimental temperature appeared to enhance the permeation of both model compounds, a finding that is in agreement with previously reported data. Interestingly, in the majority of cases this effect was optimum at the second highest temperature studied (45°C) which suggests that permeation is a temperature-dependent phenomenon.

  11. Pulmonary Inflammation Disrupts Surfactant Function during Pneumocystis carinii Pneumonia

    PubMed Central

    Wright, Terry W.; Notter, Robert H.; Wang, Zhengdong; Harmsen, Allen G.; Gigliotti, Francis

    2001-01-01

    During Pneumocystis carinii pneumonia (PCP) in mice, the degree of pulmonary inflammation correlates directly with the severity of lung function deficits. Therefore, studies were undertaken to determine whether the host inflammatory response contributes to PCP-related respiratory impairment, at least in part, by disrupting the pulmonary surfactant system. Protein and phospholipid content and surfactant activity were measured in the lavage fluid of infected mice in either the absence or presence of an inflammatory response. At 9 weeks postinfection with P. carinii, nonreconstituted SCID mice exhibited no signs of pulmonary inflammation, respiratory impairment, or surfactant dysfunction. Lavage fluid obtained from these mice had protein/phospholipid (Pr/PL) ratios (64% ± 4.7%) and minimum surface tension values (4.0 ± 0.9 mN/m) similar to those of P. carinii-free control mice. However, when infected SCID mice were immunologically reconstituted, an intense inflammatory response ensued. Pr/PL ratios (218% ± 42%) and minimum surface tension values (27.2 ± 2.7 mN/m) of the lavage fluid were significantly elevated compared to those of the lavage fluid from infected, nonreconstituted mice (P < 0.05). To examine the specific role of CD8+ T-cell-mediated inflammation in surfactant dysfunction during PCP, mice with defined T-cell populations were studied. P. carinii-infected, CD4+-depleted mice had elevated lavage fluid Pr/PL ratios (126% ± 20%) and elevated minimum surface tension values (16.3 ± 1.0 mN/m) compared to normal mice (P < 0.05). However, when infected mice were additionally depleted of CD8+ cells, Pr/PL ratios were normal and surfactant activity was improved. These findings demonstrate that the surfactant pathology associated with PCP is related to the inflammatory process rather than being a direct effect of P. carinii. Moreover, CD8+ lymphocytes are involved in the mechanism leading to surfactant dysfunction. PMID:11159965

  12. Drag reduction efficiency for polymer-surfactant mixtures

    SciTech Connect

    Kim, C.A.; Kim, J.T.; Choi, H.J.

    1996-12-31

    In a high Reynolds number fluid flow, significant energy loss occurs due to friction. However, by the addition of a minute amount of additives into this turbulent flow, frictional drag can be drastically reduced. This drag reduction phenomenon provides considerable motivation for diverse research to investigate its origin and application. Drag reduction has been reported for several solvent/additive systems, including dilute solution of high molecular weight polymers, surfactants, and micellar systems. Polymer systems as drag reducers have been extensively investigated. Recently, Choi and Jhon investigated the concentration dependence of drag reduction for PEO in water and PIB in kerosene systems using the rotating disk apparatus (RDA). However, due to the thermal instability and molecular degradation of drag reducing polymers, it is necessary to select alternative drag reducers. The possible formation of a polymer-surfactant complex takes on the character of a polyelectrolyte and it is shown that such polymer-surfactant complexes may have enhanced drag reduction properties based on the investigation of the turbulent pipe flow properties of high molecular weight PEO in SDS solution. In this study, we discuss details of conformation transitions of PEO molecules depending on external conditions such as pH, SDS and shear rate by adding the surfactant (Sodium dodecyl sulfate SDS, C{sub 12}H{sub 25}O{sub 4}SNa, (Fw:288.4) from Sigma Co. was used as a surfactant) and the PAA molecules. We also investigate modes of intermolecular interactions of both non-ionic and ionic polymers with surfactant and, finally, the polymer-surfactant complex under turbulent flow in an RDA.

  13. Stabilization of lamellar oil-water liquid crystals by surfactant/ co-surfactant monolayers

    NASA Astrophysics Data System (ADS)

    Braganza, L. F.; Dubois, M.; Tabony, J.

    1989-03-01

    LIQUID crystals are divided into two main classes, thermotropic and lyotropic. Thermotropic liquid crystals are formed by melting, whereas lyotropic liquid crystals arise from the association of molecules, such as soap and water, that in general are not in themselves liquid crystalline. Thermotropic liquid crystals are used for liquid-crystal displays; lyotropic liquid crystals occur in living cells. Here we report a novel sequence of lyotropic liquid crystals comprising alternate layers of oil and water whose thickness varies linearly with the relative proportions of oil and water, and we have determined their structure using neutron diffraction methods. The oil and water layers are separated and stabilized by a monolayer film of surfactant and co-surfactant. The individual layers are typically a hundred ångströms or more in thickness, and total lamellar spacings of up to 1,000 Å were observed. This behaviour is difficult to describe in terms of the theories of colloid stability currently used to describe lyotropic liquid crystals. An understanding of the self-organization of such systems over such large distances would elucidate how long-range liquid-crystalline ordering arises in living cells. Moreover, thermotropic liquid crystals are expensive and chemically relatively unstable, and lamellar mesophases of the lyotopic type described here could lead to inexpensive, chemically stable liquid-crystalline materials suitable for industrial application.

  14. Surfactant-assisted dispersion of carbon nanotubes: mechanism of stabilization and biocompatibility of the surfactant

    NASA Astrophysics Data System (ADS)

    Singh, Raman Preet; Jain, Sanyog; Ramarao, Poduri

    2013-10-01

    Nanoparticles (NPs) are thermodynamically unstable system and tend to aggregate to reduce free energy. The aggregation property of NPs results in inhomogeneous exposure of cells to NPs resulting in variable cellular responses. Several types of surfactants are used to stabilize NP dispersions and obtain homogenous dispersions. However, the effects of these surfactants, per se, on cellular responses are not completely known. The present study investigated the application of Pluronic F68 (PF68) for obtaining stable dispersion of NPs using carbon nanotubes as model NPs. PF68-stabilized NP suspensions are stable for long durations and do not show signs of aggregation or settling during storage or after autoclaving. The polyethylene oxide blocks in PF68 provide steric hindrance between adjacent NPs leading to stable NP dispersions. Further, PF68 is biocompatible in nature and does not affect integrity of mitochondria, lysosomes, DNA, and nuclei. Also, PF68 neither induce free radical or cytokine production nor does it interfere with cellular uptake mechanisms. The results of the present study suggest that PF68-assisted dispersion of NPs produced suspensions, which are stable after autoclaving. Further, PF68 does not interfere with normal physiological functions suggesting its application in nanomedicine and nanotoxicity evaluation.

  15. Solution rheology of polyelectrolytes and polyelectrolyte-surfactant systems

    NASA Astrophysics Data System (ADS)

    Plucktaveesak, Nopparat

    The fundamental understanding of polyelectrolytes in aqueous solutions is an important branch of polymer research. In this work, the rheological properties of polyelectrolytes and polyelectrolyte/surfactant systems are studied. Various synthetic poly electrolytes are chosen with varied hydrophobicity. We discuss the effects of adding various surfactants to aqueous solutions of poly(ethylene oxide)-b-poly(propylene oxide)- b-polyethylene oxide)-g-poly(acrylic acid) (PEO-PPO-PAA) in the first chapter. Thermogelation in aqueous solutions of PEO-PPO-PAA is due to micellization caused by aggregation of poly(propylene oxide) (PPO) blocks resulting from temperature-induced dehydration of PPO. When nonionic surfactants with hydrophilic-lipophilic balance (HLB) parameter exceeding 11 or Cn alkylsulfates; n-octyl (C8), n-decyl (C 10) and n-dodecyl (C12) sulfates are added, the gelation threshold temperature (Tgel) of 1.0wt% PEO-PPO-PAA in aqueous solutions increases. In contrast, when nonionic surfactants with HLB below 11 are added, the gelation temperature decreases. On the other hand, alkylsulfates with n = 16 or 18 and poly(ethylene oxide) (PEO) do not affect the Tgel. The results imply that both hydrophobicity and tail length of the added surfactant play important roles in the interaction of PEO-PPO-PAA micelles and the surfactant. In the second chapter, the solution behavior of alternating copolymers of maleic acid and hydrophobic monomer is studied. The alternating structure of monomers with two-carboxylic groups and hydrophobic monomers make these copolymers unique. Under appropriate conditions, these carboxylic groups dissociate leaving charges on the chain. The potentiometric titrations of copolymer solutions with added CaCl2 reveal two distinct dissociation processes corresponding to the dissociation of the two adjacent carboxylic acids. The viscosity data as a function of polymer concentration of poly(isobutylene-alt-sodium maleate), poly

  16. Surfactant Saturation of Drops in Microgravity by Terrestrial Simulation

    NASA Astrophysics Data System (ADS)

    Viviani, Antonio

    It is well known that diffusion plays an appreciable role in mass transfer only in the case of weak gravitational convection. However, even under such conditions the use of a surfactant as a dif-fusing substance essentially complicates the mass transfer processes. The appearance of gas or liquid inclusions in the surfactant solution causes the development of solutocapillary motion on their surface, which may become a generator of the large-scale flows in the surrounding liquid, especially in microgravity conditions. The paper presents the results of terrestrial simulation of such flows during saturation of the drop of weakly soluble fluid by a surfactant from its water solution forming a thin ( 1 ) horizontal layer. In our experiments, we used chlorobenzene and water as the basic fluids of the drop and the surrounding medium, respectively, and isopropyl alcohol -as a surfactant. The initial concentration 0 of the alcohol in the solution ranged from 5 to 50%. This lent specific feature to the saturation process, manifesting itself in the fact that at concentration higher than 25% a mutual dissolution of water and chlorobenzene began to increase. Visualization of flow structures and concentration fields showed that in laboratory conditions even at maximum suppression of the gravitational convection the saturation of the surfactant is a rather complicated process specified by the initial surfactant concentration in the solution and by the degree of the solution homogeneity. In the case of initially homoge-neous solution, a complicated character of mass transfer between the drop and the surrounding medium is evidently due to the small values of surfactant diffusion coefficients in basic flu-ids. Penetration of the surfactant into the drop leads to the formation of local inhomigeneities of the solution density at both sides of the interface and to the development of a slow three-dimensional flow of gravitational nature. An increase in the concentration gives rise to a

  17. Surfactant uptake dynamics in mammalian cells elucidated with quantitative coherent anti-stokes Raman scattering microspectroscopy.

    PubMed

    Okuno, Masanari; Kano, Hideaki; Fujii, Kenkichi; Bito, Kotatsu; Naito, Satoru; Leproux, Philippe; Couderc, Vincent; Hamaguchi, Hiro-o

    2014-01-01

    The mechanism of surfactant-induced cell lysis has been studied with quantitative coherent anti-Stokes Raman scattering (CARS) microspectroscopy. The dynamics of surfactant molecules as well as intracellular biomolecules in living Chinese Hamster Lung (CHL) cells has been examined for a low surfactant concentration (0.01 w%). By using an isotope labeled surfactant having CD bonds, surfactant uptake dynamics in living cells has been traced in detail. The simultaneous CARS imaging of the cell itself and the internalized surfactant has shown that the surfactant molecules is first accumulated inside a CHL cell followed by a sudden leak of cytosolic components such as proteins to the outside of the cell. This finding indicates that surfactant uptake occurs prior to the cell lysis, contrary to what has been believed: surface adsorption of surfactant molecules has been thought to occur first with subsequent disruption of cell membranes. Quantitative CARS microspectroscopy enables us to determine the molecular concentration of the surfactant molecules accumulated in a cell. We have also investigated the effect of a drug, nocodazole, on the surfactant uptake dynamics. As a result of the inhibition of tubulin polymerization by nocodazole, the surfactant uptake rate is significantly lowered. This fact suggests that intracellular membrane trafficking contributes to the surfactant uptake mechanism.

  18. Surfactant treatment before first breath for respiratory distress syndrome in preterm lambs: comparison of a peptide-containing synthetic lung surfactant with porcine-derived surfactant

    PubMed Central

    van Zyl, Johann M; Smith, Johan

    2013-01-01

    Background In a recent study utilizing a saline-lavaged adult rabbit model, we described a significant improvement in systemic oxygenation and pulmonary shunt after the instillation of a novel synthetic peptide-containing surfactant, Synsurf. Respiratory distress syndrome in the preterm lamb more closely resembles that of the human infant, as their blood gas, pH values, and lung mechanics deteriorate dramatically from birth despite ventilator support. Moreover, premature lambs have lungs which are mechanically unstable, with the advantage of being able to measure multiple variables over extended periods. Our objective in this study was to investigate if Synsurf leads to improved systemic oxygenation, lung mechanics, and histology in comparison to the commercially available porcine-derived lung surfactant Curosurf® when administered before first breath in a preterm lamb model. Materials and methods A Cesarean section was performed under general anesthesia on 18 time-dated pregnant Dohne Merino ewes at 129–130 days gestation. The premature lambs were delivered and ventilated with an expiratory tidal volume of 6–8 mL/kg for the first 30 minutes and thereafter at 8–10 mL/kg. In a randomized controlled trial, the two surfactants tested were Synsurf and Curosurf®, both at a dose of 100 mg/kg phospholipids (1,2-dipalmitoyl-L-α-phosphatidylcholine; 90% in Synsurf, 40% in Curosurf®). A control group of animals was treated with normal saline. Measurements of physiological variables, blood gases, and lung mechanics were made before and after surfactant and saline replacement and at 15, 30, 45, 60, 90, 120, 180, 240 and 300 minutes after treatment. The study continued for 5 hours. Results Surfactant treatment led to a significant improvement in oxygenation within 30 minutes, with the Synsurf group and the Curosurf® group having significantly higher ratios between arterial partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2; P = 0.021) compared to that

  19. Effect of surfactant and surfactant blends on pseudoternary phase diagram behavior of newly synthesized palm kernel oil esters.

    PubMed

    Mahdi, Elrashid Saleh; Sakeena, Mohamed H F; Abdulkarim, Muthanna F; Abdullah, Ghassan Z; Sattar, Munavvar Abdul; Noor, Azmin Mohd

    2011-01-01

    The purpose of this study was to select appropriate surfactants or blends of surfactants to study the ternary phase diagram behavior of newly introduced palm kernel oil esters. Nonionic surfactant blends of Tween(®) and Tween(®)/Span(®) series were screened based on their solubilization capacity with water for palm kernel oil esters. Tween(®) 80 and five blends of Tween(®) 80/Span(®) 80 and Tween(®) 80/Span(®) 85 in the hydrophilic-lipophilic balance (HLB) value range of 10.7-14.0 were selected to study the phase diagram behavior of palm kernel oil esters using the water titration method at room temperature. High solubilization capacity was obtained by Tween(®) 80 compared with other surfactants of Tween(®) series. High HLB blends of Tween(®) 80/Span(®) 85 and Tween(®) 80/Span(®) 80 at HLB 13.7 and 13.9, respectively, have better solubilization capacity compared with the lower HLB values of Tween(®) 80/Span(®) 80. All the selected blends of surfactants were formed as water-in-oil microemulsions, and other dispersion systems varied in size and geometrical layout in the triangles. The high solubilization capacity and larger areas of the water-in-oil microemulsion systems were due to the structural similarity between the lipophilic tail of Tween(®) 80 and the oleyl group of the palm kernel oil esters. This study suggests that the phase diagram behavior of palm kernel oil esters, water, and nonionic surfactants is not only affected by the HLB value, but also by the structural similarity between palm kernel oil esters and the surfactant used. The information gathered in this study is useful for researchers and manufacturers interested in using palm kernel oil esters in pharmaceutical and cosmetic preparation. The use of palm kernel oil esters can improve drug delivery and reduce the cost of cosmetics.

  20. Ecotoxicological characterization of polyoxyethylene glycerol ester non-ionic surfactants and their mixtures with anionic and non-ionic surfactants.

    PubMed

    Ríos, Francisco; Fernández-Arteaga, Alejandro; Lechuga, Manuela; Fernández-Serrano, Mercedes

    2017-03-03

    This paper reports on a study that investigated the aquatic toxicity of new non-ionic surfactants derived from renewable raw materials, polyoxyethylene glycerol ester (PGE), and their binary mixtures with anionic and non-ionic surfactants. Toxicity of pure PGEs was determined using representative organisms from different trophic levels: luminescent bacteria (Vibrio fischeri), microalgae (Pseudokirchneriella subcapitata), and freshwater crustaceans (Daphnia magna). Relationships between toxicity and the structural parameters such