Electrochemical preparation of poly(methylene blue)/graphene nanocomposite thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erçarıkcı, Elif; Dağcı, Kader; Topçu, Ezgi

2014-07-01

Highlights: • Poly(MB)/graphene thin films are prepared by a simple electrochemical approach. • Graphene layers in the film show a broad band in visible region of absorbance spectra. • Morphology of composite films indicates both disordered and ordered regions. • XRD reveals that nanocomposite films include rGO layers after electropolymerization process. • Chemically prepared graphene is better than electrochemically prepared graphene for electrooxidation of nitrite. - Abstract: Poly(methylene blue)/graphene nanocomposite thin films were prepared by electropolymerization of methylene blue in the presence of graphene which have been synthesized by two different methods of a chemical oxidation process and an electrochemicalmore » approach. Synthesized nanocomposite thin films were characterized by using cyclic voltammetry, UV–vis. absorption spectroscopy, powder X-ray diffraction, and scanning tunneling microscopy techniques. Electrocatalytical properties of prepared poly(methylene blue)/graphene nanocomposite films were compared toward electrochemical oxidation of nitrite. Under optimized conditions, electrocatalytical effect of nanocomposite films of chemically prepared graphene through electrochemical oxidation of nitrite was better than that of electrochemically prepared graphene.« less

Carbon nanotubes/fluorinated polymers nanocomposite thin films for electrical contacts lubrication

NASA Astrophysics Data System (ADS)

Benedetto, A.; Viel, P.; Noël, S.; Izard, N.; Chenevier, P.; Palacin, S.

2007-09-01

The need to operate in extreme environmental conditions (ultra high vacuum, high temperatures, aerospatial environment, …) and the miniaturization toward micro electromechanical systems is demanding new materials in the field of low-level electrical contacts lubrication. Dry and chemically immobilized lubrication is expected to be an alternative to the traditional wet lubricants oils. With the goal to conciliate electrical conductivity and lubricant properties we designed nanocomposite thin films composed of a 2D carbon nanotubes network embedded in an organic matrix. The nanotubes networks were deposited on gold surfaces modified by electrochemical cathodic grafting of poly(acrylonitrile). The same substrate served for covalently bonding the low-friction organic matrix. Three different matrixes were tested: a perfluorinated oligomer chemically grafted and two different polyfluorinated acrylates electrochemically grafted. The nanocomposite thin films have been characterized by ATR FT-IR, XPS and Raman spectroscopy. We measured the effects of the different matrixes and the nanotubes addition on the tribological properties and on the contact resistances of the films.

Enhanced physicochemical properties of chitosan/whey protein isolate composite film by sodium laurate-modified TiO2 nanoparticles.

PubMed

Zhang, Wei; Chen, Jiwang; Chen, Yue; Xia, Wenshui; Xiong, Youling L; Wang, Hongxun

2016-03-15

Chitosan/whey protein isolate film incorporated with sodium laurate-modified TiO2 nanoparticles was developed. The nanocomposite film was characterized by scanning electron microscopy, X-ray diffraction and differential scanning calorimetry, and investigated in physicochemical properties as color, tensile strength, elongation at break, water vapor permeability and water adsorption isotherm. Our results showed that the nanoparticles improved the compatibility of whey protein isolate and chitosan. Addition of nanoparticles increased the whiteness of chitosan/whey protein isolate film, but decreased its transparency. Compared with binary film, the tensile strength and elongation at break of nanocomposite film were increased by 11.51% and 12.01%, respectively, and water vapor permeability was decreased by 7.60%. The equilibrium moisture of nanocomposite film was lower than binary film, and its water sorption isotherm of the nanocomposite film fitted well to Guggenheim-Anderson-deBoer model. The findings contributed to the development of novel food packaging materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characteristics of Thermoplastic Potato Starch/Bentonite Nanocomposite Film

NASA Astrophysics Data System (ADS)

Zakaria, N. H.; Muhammad, N.; Abdullah, M. M. A. B.; Sandu, I. G.; Wan, C. L. Mei

2018-06-01

The aim of this study is to investigate the effect of bentonite towards thermoplastic potato starch nanocomposite films on the mechanical, microstructure and physical properties. The nanocomposite films were prepared using bentonite nano filler (0, 1, 5, 10, 15 and 20%) through solution casting technique. Obtained result indicate that, tensile strength increased significantly with increasing bentonite content and the highest tensile strength was recorded for nanocomposite film with 20% bentonite content. Meanwhile, elongation at break increased as the bentonite content increased from 0 to 15%, however significantly decreased at 20% bentonite content due to ductile structure and anti-plasticizing effect. Besides, good dispersion between bentonite nano filler and starch matrix with slightly remaining anglomerates was evident in scanning electron microscopy (SEM) image. Overall result shows that the addition of bentonite nano filler in potato starch film significantly influenced the properties of the films.

Investigation on sodium benzoate release from poly(butylene adipate-co-terephthalate)/organoclay/sodium benzoate based nanocomposite film and their antimicrobial activity.

PubMed

Mondal, Dibyendu; Bhowmick, Biplab; Maity, Dipanwita; Mollick, Md Masud R; Rana, Dipak; Rangarajan, Vivek; Sen, Ramkrishna; Chattopadhyay, Dipankar

2015-03-01

Polymeric nanocomposites embedded with nontoxic antimicrobial agents have recently gained potential industrial significance, mainly for their applicability to preserve food quality and ensure safety. In this study, a poly(butylene adipate-co-terephthalate) (PBAT)/organoclay (CMMT) based nanocomposite film doped with sodium benzoate (SB) as antimicrobial agent was prepared by a solution mixing process. A homogenous dispersion of organoclay (cetyltrimethylammonium-modified montmorillonite [CMMT]) in PBAT matrix was observed by X-ray diffraction and transmission electron microscopy. PBAT/CMMT nanocomposite film showed higher barrier properties against water and methanol vapor compared to the PBAT film. The release of SB from PBAT and its nanocomposite film was measured and the relevant data were fitted to the Weibull model. The higher values of Weibull's shape factor and scale parameter as corroborated by experimental findings indicated faster rate of SB release from PBAT/CMMT/SB nanocomposite film, when compared to the pristine PBAT film. Bacterial inhibition studies were accomplished against 2 food pathogenic bacteria, Bacillus subtilis and Staphylococcus aureus, by determining the zone of inhibition and corresponding growth profiles. Both bacterial inhibition studies and growth profiles established that PBAT/CMMT/SB demonstrated better antimicrobial activity than PBAT/SB film. Therefore, PBAT/CMMT/SB nanocomposite film can be used for food packaging application as it showed good barrier properties and antimicrobial activity against food pathogenic bacteria. © 2015 Institute of Food Technologists®

Fabrication of antibacterial PVA nanocomposite films containing dendritic polymer functionalized multi-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Sapalidis, Andreas; Sideratou, Zili; Panagiotaki, Katerina N.; Sakellis, Elias; Kouvelos, Evangelos P.; Papageorgiou, Sergios; Katsaros, Fotios

2018-03-01

A series of Poly(vinyl alcohol) (PVA) nanocomposite films containing quaternized hyperbranched polyethyleneimine (PEI) functionalized multi-walled carbon nanotubes (ox-CNTs@QPEI) are prepared by solvent casting technique. The modified carbon based material exhibits high aqueous solubility, due to the hydrophilic character of the functionalized hyperbranched dendritic polymer. The quaternized PEI successfully wraps around nanotube walls, as polycations provide electrostatic repulsion. Various contents of ox-CNTs@QPEI ranging from 0.05 to 1.0 % w/w were employed to prepare functionalized PVA nanocomposites. The developed films exhibit adequate optical transparency, improved mechanical properties and extremely high antibacterial behavior due to the excellent dispersion of the functionalized carbon nanotubes into the PVA matrix.

Development of photo-modified starch/kefiran/TiO2 bio-nanocomposite as an environmentally-friendly food packaging material.

PubMed

Goudarzi, Vahid; Shahabi-Ghahfarrokhi, Iman

2018-05-21

This paper reports on an experiment in which starch/kefiran/TiO 2 (SKT)-based bio-nanocomposite films were developed and modified by photo-chemical reaction. In so doing, film-forming solutions were exposed to ultraviolet A (UV-A) for different times (1, 6, and 12 h). The obtained results indicated that increasing UV-A exposure time brought about an increase (≈14.9%) in the tensile strength of bio-nanocomposites. However, elongation at break and Young's modulus of irradiated film specimen decreased (≈32%, ≈12%, respectively) by increasing UV-A exposure time, and the moisture-sensitive parameters of specimen decreased using UV-A irradiation. According to the results, the functional properties of irradiated bio-nanocomposite are depended on the ratio of cross-linkages between polymer chains and the potentially produced mono and disaccharide by UV-A. Copyright © 2018. Published by Elsevier B.V.

Nanocrystalline cellulose (NCC) reinforced alginate based biodegradable nanocomposite film.

PubMed

Huq, Tanzina; Salmieri, Stephane; Khan, Avik; Khan, Ruhul A; Le Tien, Canh; Riedl, Bernard; Fraschini, Carole; Bouchard, Jean; Uribe-Calderon, Jorge; Kamal, Musa R; Lacroix, Monique

2012-11-06

Nanocrystalline cellulose (NCC) reinforced alginate-based nanocomposite film was prepared by solution casting. The NCC content in the matrix was varied from 1 to 8% ((w/w) % dry matrix). It was found that the nanocomposite reinforced with 5 wt% NCC content exhibits the highest tensile strength which was increased by 37% compared to the control. Incorporation of NCC also significantly improved water vapor permeability (WVP) of the nanocomposite showing a 31% decrease due to 5 wt% NCC loading. Molecular interactions between alginate and NCC were supported by Fourier Transform Infrared Spectroscopy. The X-ray diffraction studies also confirmed the appearance of crystalline peaks due to the presence of NCC inside the films. Thermal stability of alginate-based nanocomposite films was improved after incorporation of NCC. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fracture Analysis of MWCNT/Epoxy Nanocomposite Film Deposited on Aluminum Substrate.

PubMed

Her, Shiuh-Chuan; Chien, Pao-Chu

2017-04-13

Multi-walled carbon nanotube (MWCNT) reinforced epoxy films were deposited on an aluminum substrate by a hot-pressing process. Three-point bending tests were performed to determine the Young's modulus of MWCNT reinforced nanocomposite films. Compared to the neat epoxy film, nanocomposite film with 1 wt % of MWCNT exhibits an increase of 21% in the Young's modulus. Four-point-bending tests were conducted to investigate the fracture toughness of the MWCNT/epoxy nanocomposite film deposited on an aluminum substrate with interfacial cracks. Based on the Euler-Bernoulli beam theory, the strain energy in a film/substrate composite beam is derived. The difference of strain energy before and after the propagation of the interfacial crack are calculated, leading to the determination of the strain energy release rate. Experimental test results show that the fracture toughness of the nanocomposite film deposited on the aluminum substrate increases with the increase in the MWCNT content.

Multicolored Emission and Lasing in DCM-Adamantane Plasma Nanocomposite Optical Films.

PubMed

Alcaire, María; Cerdán, Luis; Zamarro, Fernando Lahoz; Aparicio, Francisco J; González, Juan Carlos; Ferrer, Francisco J; Borras, Ana; Espinós, Juan Pedro; Barranco, Angel

2017-03-15

We present a low-temperature versatile protocol for the fabrication of plasma nanocomposite thin films to act as tunable emitters and optical gain media. The films are obtained by the remote plasma-assisted deposition of a 4-(dicyano-methylene)-2-methyl-6-(4-dimethylamino-styryl)-4H-pyran (DCM) laser dye alongside adamantane. The experimental parameters that determine the concentration of the dye in the films and their optical properties, including light absorption, the refractive index, and luminescence, are evaluated. Amplified spontaneous emission experiments in the DCM/adamantane nanocomposite waveguides show the improvement of the copolymerized nanocomposites' properties compared to films that were deposited with DCM as the sole precursor. Moreover, one-dimensional distributed feed-back laser emission is demonstrated and characterized in some of the nanocomposite films that are studied. These results open new paths for the optimization of the optical and lasing properties of plasma nanocomposite polymers, which can be straightforwardly integrated as active components in optoelectronic devices.

Assessment of morphology and property of graphene oxide-hydroxypropylmethylcellulose nanocomposite films.

PubMed

Ghosh, Tapas Kumar; Gope, Shirshendu; Mondal, Dibyendu; Bhowmik, Biplab; Mollick, Md Masud Rahaman; Maity, Dipanwita; Roy, Indranil; Sarkar, Gunjan; Sadhukhan, Sourav; Rana, Dipak; Chakraborty, Mukut; Chattopadhyay, Dipankar

2014-05-01

Graphene oxide (GO) was synthesized by Hummer's method and characterized by using Fourier transform infrared spectroscopy and Raman spectroscopy. The as synthesized GO was used to make GO/hydroxypropylmethylcellulose (HPMC) nanocomposite films by the solution mixing method using different concentrations of GO. The nanocomposite films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and thermo-gravimetric analysis. Mechanical properties, water absorption property and water vapor transmission rate were also measured. XRD analysis showed the formation of exfoliated HPMC/GO nanocomposites films. The FESEM results revealed high interfacial adhesion between the GO and HPMC matrix. The tensile strength and Young's modulus of the nanocomposite films containing the highest weight percentage of GO increased sharply. The thermal stability of HPMC/GO nanocomposites was slightly better than pure HPMC. The water absorption and water vapor transmission rate of HPMC film was reduced with the addition of up to 1 wt% GO. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of nanoclay type on the physical and antimicrobial properties of PVOH-based nanocomposite films

USDA-ARS?s Scientific Manuscript database

Polyvinyl alcohols-based nanocomposite films were fabricated with four types of montmorillonite (MMT) nanoclay, including 18-amino stearic acid (I.24TL), methyl, bis hydroxyethyl, octadecyl ammonium (I.34TCN), di-methyl, di-hydrogenated tallow ammonium/siloxane (I.44PSS) organically modified MMT, an...

Dielectric spectroscopy of Ag-starch nanocomposite films

NASA Astrophysics Data System (ADS)

Meena; Sharma, Annu

2018-04-01

In the present work Ag-starch nanocomposite films were fabricated via chemical reduction route. The formation of Ag nanoparticles was confirmed using transmission electron microscopy (TEM). Further the effect of varying concentration of Ag nanoparticles on the dielectric properties of starch has been studied. The frequency response of dielectric constant (ε‧), dielectric loss (ε″) and dissipation factor tan(δ) has been studied in the frequency range of 100 Hz to 1 MHz. Dielectric data was further analysed using Cole-Cole plots. The dielectric constant of starch was found to be 4.4 which decreased to 2.35 in Ag-starch nanocomposite film containing 0.50 wt% of Ag nanoparticles. Such nanocomposites with low dielectric constant have potential applications in microelectronic technologies.

The wettability, mechanical and antimicrobial properties of polylactide/montmorillonite nanocomposite films.

PubMed

Rapacz-Kmita, Alicja Rapacz-Kmita; Pierchała, Małgorzata Karolina; Tomas-Trybuś, Anna; Szaraniec, Barbara; Karwot, Janusz

2017-01-01

The aim of this study was to evaluate the effect of the not activated (unmodified) montmorillonite (MMT) filler on the antibacterial properties of polymer nanocomposites with a biodegradable polylactide (PLA) matrix. The subject of research was selected to verify the reports on the lack of antibacterial properties of unmodified montmorillonite in nanocomposites and to investigate the potential conditions of their manufacturing which are decisive for the resulting properties. Evaluation of antibacterial and mechanical properties of both the starting materials and the obtained nanocomposites filled with layered silicates as well as the wettability of the materials, measured by a sitting drop method was made on samples in the form of a film. The results show that the surface wettability of the polymer nanocomposites did not exhibit significant change compared to the film of neat PLA. However, a significant improvement in the mechanical and antimicrobial properties of the nanocomposite films obtained in a specific solvent casting process of the nanocomposite preceded by exfoliation of the film in an ultrasonic homogenizer was demonstrated. The antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Enterococcus faecalis was also observed, and, moreover, the montmorillonite-containing films revealed a zone of inhibition of bacterial growth when tested against the lactosepositive bacteria of the Enterobacteriaceae family, which are present in the waste water. The advantageous properties of the obtained PLA/MMT nanocomposites suggest that the unmodified montmorillonite may be potentially used as filler for polymer films in the packaging industry.

Migration of nanosized layered double hydroxide platelets from polylactide nanocomposite films.

PubMed

Schmidt, B; Katiyar, V; Plackett, D; Larsen, E H; Gerds, N; Koch, C Bender; Petersen, J H

2011-01-01

Melt-extruded L-polylactide (PLA) nanocomposite films were prepared from commercially available PLA and laurate-modified Mg-Al layered double hydroxide (LDH-C12). Three films were tested for total migration as well as specific migration of LDH, tin, laurate and low molecular weight PLA oligomers (OLLA). This is the first reported investigation on the migration properties of PLA-LDH nanocomposite films. The tests were carried out as part of an overall assessment of the suitability of such films for use as food contact materials (FCM). Total migration was determined according to a European standard method. All three films showed migration of nanosized LDH, which was quantified using acid digestion followed by inductively coupled plasma mass spectrometric (ICP-MS) detection of (26)Mg. Migration of LDH from the films was also confirmed by examining migrates using transmission electron microscopy (TEM) and was attributed indirectly to the significant PLA molecular weight reduction observed in extruded PLA-LDH-C12 films. Migration of tin was detected in two of the film samples prepared by dispersion of LDH-C12 using a masterbatch technique and migration of the laurate organomodifier took place from all three film types. The results indicate that the material properties are in compliance with the migration limits for total migration and specific lauric acid migration as set down by the EU legislation for FCM, at least if a reduction factor for fresh meat is taken into consideration. The tin detected arises from the use of organotin catalysts in the manufacture of PLA.

Electrochemical detection of nitrite on poly(pyronin Y)/graphene nanocomposites modified ITO substrate

NASA Astrophysics Data System (ADS)

Şinoforoğlu, Mehmet; Dağcı, Kader; Alanyalıoğlu, Murat; Meral, Kadem

2016-06-01

The present study reports on an easy preparation of poly(pyronin Y)/graphene (poly(PyY)/graphene) nanocomposites thin films on indium tin oxide coated glass substrates (ITO). The thin films of poly(PyY)/graphene nanocomposites are prepared by a novel method consisting of three steps; (i) preparation of graphene oxide (GO) thin films on ITO by spin-coating method, (ii) self-assembly of PyY molecules from aqueous solution onto the GO thin film, (iii) surface-confined electropolymerization (SCEP) of the adsorbed PyY molecules on the GO thin film. The as-prepared poly(PyY)/graphene nanocomposites thin films are characterized by using electroanalytical and spectroscopic techniques. Afterwards, the graphene-based polymeric dye thin film on ITO is used as an electrode in an electrochemical cell. Its performance is tested for electrochemical detection of nitrite. Under optimized conditions, the electrocatalytical effect of the nanocomposites thin film through electrochemical oxidation of nitrite is better than that of GO coated ITO.

Biodegradable Nanocomposite Films Based on Sodium Alginate and Cellulose Nanofibrils

PubMed Central

Deepa, B.; Abraham, Eldho; Pothan, Laly A.; Cordeiro, Nereida; Faria, Marisa; Thomas, Sabu

2016-01-01

Biodegradable nanocomposite films were prepared by incorporation of cellulose nanofibrils (CNF) into alginate biopolymer using the solution casting method. The effects of CNF content (2.5, 5, 7.5, 10 and 15 wt %) on mechanical, biodegradability and swelling behavior of the nanocomposite films were determined. The results showed that the tensile modulus value of the nanocomposite films increased from 308 to 1403 MPa with increasing CNF content from 0% to 10%; however, it decreased with further increase of the filler content. Incorporation of CNF also significantly reduced the swelling percentage and water solubility of alginate-based films, with the lower values found for 10 wt % in CNF. Biodegradation studies of the films in soil confirmed that the biodegradation time of alginate/CNF films greatly depends on the CNF content. The results evidence that the stronger intermolecular interaction and molecular compatibility between alginate and CNF components was at 10 wt % in CNF alginate films. PMID:28787850

Processing-structure-properties relationships in PLA nanocomposite films

NASA Astrophysics Data System (ADS)

Di Maio, L.; Scarfato, P.; Garofalo, E.; Galdi, M. R.; D'Arienzo, L.; Incarnato, L.

2014-05-01

This work deals on the possibility to improve performances of PLA-based nanocomposite films, for packaging applications, through conveniently tuning materials and processing conditions in melt compounding technology. In particular, two types of polylactic acid and different types of filler selected from montmorillonites and bentonites families were used to prepare the hybrid systems by using a twin-screw extruder. The effect of biaxial drawing on morphology and properties of the nanocomposites, produced by film blowing, was investigated.

High oxygen nanocomposite barrier films based on xylan and nanocrystalline cellulose

Treesearch

Amit Saxena; Thomas J. Elder; Jeffrey Kenvin; Arthur J. Ragauskas

2010-01-01

The goal of this work is to produce nanocomposite film with low oxygen permeability by casting an aqueous solution containing xylan, sorbitol and nanocrystalline cellulose. The morphology of the resulting nanocomposite films was examined by scanning electron microscopy and atomic force microscopy which showed that control films containing xylan and sorbitol had a more...

Organically Modified Nanoclay-Reinforced Rigid Polyurethane Films

NASA Astrophysics Data System (ADS)

Park, Yong Tae; Qian, Yuqiang; Lindsay, Chris; Stein, Andreas; Macosko, Christopher

2012-02-01

The nanodispersion of vermiculite in polyurethanes was investigated to produce organoclay-reinforced rigid gas barrier films. Reducing gas transport can improve the insulation performance of closed cell polyurethane foam. In a previous study, the dispersion of vermiculite in polyurethanes without organic modification was not sufficient due to the non-uniform dispersion morphology. When vermiculite was modified by cation exchange with long-chain quaternary ammonium cations, the dispersion in methylene diphenyl diisocyanate (MDI) was significantly improved. Dispersion was improved by combining high intensity dispersive mixing with efficient distributive mixing. Polymerization conditions were also optimized in order to provide a high state of nanodispersion in the polyurethane nanocomposite. The dispersions were characterized using rheological, microscopic and scattering/diffraction techniques. The final nanocomposites showed enhancement of mechanical properties and reduction in permeability to carbon dioxide at low clay concentration (around 2 wt percent).

Large-Strain Transparent Magnetoactive Polymer Nanocomposites

NASA Technical Reports Server (NTRS)

Meador, Michael A.

2012-01-01

A document discusses polymer nano - composite superparamagnetic actuators that were prepared by the addition of organically modified superparamagnetic nanoparticles to the polymer matrix. The nanocomposite films exhibited large deformations under a magnetostatic field with a low loading level of 0.1 wt% in a thermoplastic polyurethane elastomer (TPU) matrix. The maximum actuation deformation of the nanocomposite films increased exponentially with increasing nanoparticle concentration. The cyclic deformation actuation of a high-loading magnetic nanocomposite film was examined in a low magnetic field, and it exhibited excellent reproducibility and controllability. Low-loading TPU nanocomposite films (0.1-2 wt%) were transparent to semitransparent in the visible wavelength range, owing to good dispersion of the magnetic nanoparticles. Magnetoactuation phenomena were also demonstrated in a high-modulus, high-temperature polyimide resin with less mechanical deformation.

Physicochemical and antifungal properties of bio-nanocomposite film based on gelatin-chitin nanoparticles.

PubMed

Sahraee, Samar; Milani, Jafar M; Ghanbarzadeh, Babak; Hamishehkar, Hamed

2017-04-01

The gelatin-based nanocomposite films containing chitin nanoparticles (N-chitin) with concentrations of 0, 3, 5 and 10% were prepared and their physical, thermal and anti-microbial properties were investigated. Scanning electron microscopy (SEM) micrographs showed that N-chitin size distribution was around 60-70nm which dispersed appropriately at low concentration in gelatin matrix. The results showed that incorporation of N-chitin significantly influenced apparent color and transparency of the gelatin films. The reduced water vapor permeability (WVP) and solubility and higher surface hydrophobicity of the nanocomposite films were obtained by enhancing N-chitin concentration in film formulation. The use of N-chitin up to 5% concentration in the gelatin based nanocomposite film led to improved mechanical properties. Also, the results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) confirmed improved stability of nanocomposite films against melting and degradation at high temperatures in comparison to neat gelatin film. The well compatibility of chitin nanoparticles with gelatin polymer was concluded from Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) plots. Finally, the gelatin based nanocomposite films had anti-fungal properties against Aspergillus niger in the contact surface zone. Increasing the concentration of N-chitin up to 5% enlarged inhibition zone diameter, but the nanocomposite film containing 10% N-chitin showed smaller inhibition zone. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid fabrication of hierarchically structured supramolecular nanocomposite thin films in one minute

DOEpatents

Xu, Ting; Kao, Joseph

2016-11-08

Functional nanocomposites containing nanoparticles of different chemical compositions may exhibit new properties to meet demands for advanced technology. It is imperative to simultaneously achieve hierarchical structural control and to develop rapid, scalable fabrication to minimize degradation of nanoparticle properties and for compatibility with nanomanufacturing. The assembly kinetics of supramolecular nanocomposite in thin films is governed by the energetic cost arising from defects, the chain mobility, and the activation energy for inter-domain diffusion. By optimizing only one parameter, the solvent fraction in the film, the assembly kinetics can be precisely tailored to produce hierarchically structured thin films of supramolecular nanocomposites in approximately one minute. Moreover, the strong wavelength dependent optical anisotropy in the nanocomposite highlights their potential applications for light manipulation and information transmission. The present invention opens a new avenue in designing manufacture-friendly continuous processing for the fabrication of functional nanocomposite thin films.

Microstructures, mechanical behavior and strengthening mechanism of TiSiCN nanocomposite films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wei; Liu, Ping; Xue, Zenghui

Recently, the arguments have existed in the strengthening mechanism and microstructural model of the nanocomposite film due to lack of the convincible experimental evidences. In this investigation, the quarternary TiSiCN nanocomposite films with the different C and Si contents are synthesized by the reactive-magnetron-sputtering technique. The TiSiCN film is characterized as the nanocomposite structure with the TiN nanocrystallites surrounded by the (Si 3N 4 + C + CN x) interface phase. When the C/Si content ratio is 2:2, the TiSiCN nanocomposite film is remarkably strengthened with the maximal hardness and elastic modulus of 46.1 GPa and 425 GPa, respectively. Meanwhile,more » the (Si 3N 4 + C + CN x) interfaces exhibit as a crystallized form, which can coordinate the growth misorientations and maintain the coherently epitaxial growth between the TiN nanocrystallites and interfaces. Through the high-resolution transmission electron microscopy (HRTEM) observations, this investigation firstly provides the direct experimental evidence for the crystallized feature of the interfaces when the TiSiCN nanocomposite film is strengthened, suggesting that the strengthening effect of the TiSiCN nanocomposite film can be attributed to the coherent-interface strengthening mechanism, which is expressed as the “nc-TiN/c-Si 3N 4/c-C/c-CN x” model.« less

Microstructures, mechanical behavior and strengthening mechanism of TiSiCN nanocomposite films

DOE PAGES

Li, Wei; Liu, Ping; Xue, Zenghui; ...

2017-05-18

Recently, the arguments have existed in the strengthening mechanism and microstructural model of the nanocomposite film due to lack of the convincible experimental evidences. In this investigation, the quarternary TiSiCN nanocomposite films with the different C and Si contents are synthesized by the reactive-magnetron-sputtering technique. The TiSiCN film is characterized as the nanocomposite structure with the TiN nanocrystallites surrounded by the (Si 3N 4 + C + CN x) interface phase. When the C/Si content ratio is 2:2, the TiSiCN nanocomposite film is remarkably strengthened with the maximal hardness and elastic modulus of 46.1 GPa and 425 GPa, respectively. Meanwhile,more » the (Si 3N 4 + C + CN x) interfaces exhibit as a crystallized form, which can coordinate the growth misorientations and maintain the coherently epitaxial growth between the TiN nanocrystallites and interfaces. Through the high-resolution transmission electron microscopy (HRTEM) observations, this investigation firstly provides the direct experimental evidence for the crystallized feature of the interfaces when the TiSiCN nanocomposite film is strengthened, suggesting that the strengthening effect of the TiSiCN nanocomposite film can be attributed to the coherent-interface strengthening mechanism, which is expressed as the “nc-TiN/c-Si 3N 4/c-C/c-CN x” model.« less

Nanocomposite thin films for triggerable drug delivery.

PubMed

Vannozzi, Lorenzo; Iacovacci, Veronica; Menciassi, Arianna; Ricotti, Leonardo

2018-05-01

Traditional drug release systems normally rely on a passive delivery of therapeutic compounds, which can be partially programmed, prior to injection or implantation, through variations in the material composition. With this strategy, the drug release kinetics cannot be remotely modified and thus adapted to changing therapeutic needs. To overcome this issue, drug delivery systems able to respond to external stimuli are highly desirable, as they allow a high level of temporal and spatial control over drug release kinetics, in an operator-dependent fashion. Areas covered: On-demand drug delivery systems actually represent a frontier in this field and are attracting an increasing interest at both research and industrial level. Stimuli-responsive thin films, enabled by nanofillers, hold a tremendous potential in the field of triggerable drug delivery systems. The inclusion of responsive elements in homogeneous or heterogeneous thin film-shaped polymeric matrices strengthens and/or adds intriguing properties to conventional (bare) materials in film shape. Expert opinion: This Expert Opinion review aims to discuss the approaches currently pursued to achieve an effective on-demand drug delivery, through nanocomposite thin films. Different triggering mechanisms allowing a fine control on drug delivery are described, together with current challenges and possible future applications in therapy and surgery.

Influence of PA6 nanocomposite films on the stability of vacuum-aged beef loins during storage in modified atmospheres.

PubMed

Picouet, P A; Fernandez, A; Realini, C E; Lloret, E

2014-01-01

A masterbatch of polyamide 6 (PA6) containing dispersed nanoclays, was used to fabricate a novel multilayer film for vacuum packed meat. Performance of the nanocomposite was compared to a control PA6 multilayer and a high barrier commercial film. Addition of nanoclays improved oxygen barrier properties, UV-blocking capability and stiffness. Beef loins were vacuum-aged using the three films for 0 7, 14 and 21 days at 2°C. After each ageing time, beef steaks were packaged in commercial trays and high oxygen atmosphere and stored at 4°C for 9 days. Beef quality parameters and gas content were studied during display time in MAP (1, 3, 6 and 9 d). Beef quality parameters were not influenced by the packaging materials used during ageing and the performance of nanocomposites was comparable to high barrier films. Ageing had a positive impact on the stabilization of redness up to day 6 in MAP. Thereafter, oxymyoglobin content and oxidation levels were negatively influenced by ageing. © 2013.

Structural mechanical and antibacterial properties of HPMC/SF-AgNPs nanocomposite films

NASA Astrophysics Data System (ADS)

Harish, K. V.; Rao, B. Lakshmeesha; Asha, S.; Vipin, C.; Sangappa, Y.

2018-04-01

In the present study, Hydroxypropyl Methylcellulose (HPMC) pure and HPMC/SF-AgNPs biopolymer nanocomposite films were prepared by simple solution casting method. The prepared nanocomposite films were characterized using UV-Visible spectroscopy(UV-Vis), X-ray diffraction (XRD) measurements. The mechanical properties of HPMC/SF-AgNPs nanocomposites were found to be decrease with increase in the AgNP's concentrations. The HPMC/SF-AgNPs nanocomposites showed very good antibacterial activity against human pathogens P. aeruginosa, E.coli, and S.aureus.

Poly(vinyl acetate)/clay nanocomposite materials for organic thin film transistor application.

PubMed

Park, B J; Sung, J H; Park, J H; Choi, J S; Choi, H J

2008-05-01

Nanocomposite materials of poly(vinyl acetate) (PVAc) and organoclay were fabricated, in order to be utilized as dielectric materials of the organic thin film transistor (OTFT). Spin coating condition of the nanocomposite solution was examined considering shear viscosity of the composite materials dissolved in chloroform. Intercalated structure of the PVAc/clay nanocomposites was characterized using both wide-angle X-ray diffraction and TEM. Fracture morphology of the composite film on silicon wafer was also observed by SEM. Dielectric constant (4.15) of the nanocomposite materials shows that the PVAc/clay nanocomposites are applicable for the gate dielectric materials.

Effect of halloysite content on carboxymethyl cellulose/halloysite nanotube bio-nanocomposite films

NASA Astrophysics Data System (ADS)

Suppiah, Kathiravan; Leng, Teh Pei; Husseinsyah, Salmah; Rahman, Rozyanty; Keat, Yeoh Cheow

2017-04-01

Carboxymethyl cellulose/halloysite nanotube (CMC/HNT) bio-nanocomposite films were prepared by solution casting method. The effect of HNT content on tensile properties and morphology were studied. The results showed that the tensile strength of the CMC/HNT bio-nanocomposite films achieved optimum at 10 wt% of HNT content. The elongation at break and modulus of elasticity increased with increasing HNT content. The morphology of CMC/HNT bio-nanocomposite films showed that the poor distribution of HNT filler was observed at 20 wt% of HNT content.

Organic-Inorganic Hydrophobic Nanocomposite Film with a Core-Shell Structure

PubMed Central

Liu, Peng; Chen, Ying; Yu, Zhiwu

2016-01-01

A method to prepare novel organic-inorganic hydrophobic nanocomposite films was proposed by a site-specific polymerization process. The inorganic part, the core of the nanocomposite, is a ternary SiO2–Al2O3–TiO2 nanoparticles, which is grafted with methacryloxy propyl trimethoxyl silane (KH570), and wrapped by fluoride and siloxane polymers. The synthesized samples are characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrscopy, X-ray diffractometry (XRD), contact angle meter (CA), and scanning electron microscope (SEM). The results indicate that the novel organic-inorganic hydrophobic nanocomposite with a core-shell structure was synthesized successfully. XRD analysis reveals the nanocomposite film has an amorphous structure, and FTIR analysis indicates the nanoparticles react with a silane coupling agent (methacryloxy propyl trimethoxyl silane KH570). Interestingly, the morphology of the nanoparticle film is influenced by the composition of the core. Further, comparing with the film synthesized by silica nanoparticles, the film formed from SiO2–Al2O3–TiO2 nanoparticles has higher hydrophobic performance, i.e., the contact angle is greater than 101.7°. In addition, the TEM analysis reveals that the crystal structure of the particles can be changed at high temperatures. PMID:28774141

Nano CaCO₃ imprinted starch hybrid polyethylhexylacrylate\\polyvinylalcohol nanocomposite thin films.

PubMed

Prusty, Kalyani; Swain, Sarat K

2016-03-30

Starch hybrid polyethylhexylacrylate (PEHA)/polyvinylalcohol (PVA) nanocomposite thin films are prepared by different composition of nano CaCO3 in aqueous medium. The chemical interaction of nano CaCO3 with PEHA in presence of starch and PVA is investigated by Fourier transforms infrared spectroscopy (FTIR). X-ray diffraction (XRD) is used in order to study the change in crystallite size and d-spacing during the formation of nanocomposite thin film. The surface morphology of nanofilms is studied by scanning electron microscope (SEM). The topology and surface roughness of the films is noticed by atomic force microscope (AFM). The tensile strength, thermal stability and thermal conductivity of films are increased with increase in concentrations of CaCO3 nanopowder. The chemical resistance and biodegradable properties of the nanocomposite thin films are also investigated. The growth of bacteria and fungi in starch hybrid PEHA film is reduced substantially with imprint of nano CaCO3. Copyright © 2015 Elsevier Ltd. All rights reserved.

Methods of making non-covalently bonded carbon-titania nanocomposite thin films and applications of the same

DOEpatents

Liang, Yu Teng; Vijayan, Baiju K.; Gray, Kimberly A.; Hersam, Mark C.

2016-07-19

In one aspect, a method of making non-covalently bonded carbon-titania nanocomposite thin films includes: forming a carbon-based ink; forming a titania (TiO.sub.2) solution; blade-coating a mechanical mixture of the carbon-based ink and the titania solution onto a substrate; and annealing the blade-coated substrate at a first temperature for a first period of time to obtain the carbon-based titania nanocomposite thin films. In certain embodiments, the carbon-based titania nanocomposite thin films may include solvent-exfoliated graphene titania (SEG-TiO.sub.2) nanocomposite thin films, or single walled carbon nanotube titania (SWCNT-TiO.sub.2) nanocomposite thin films.

Mineralized agar-based nanocomposite films: Potential food packaging materials with antimicrobial properties.

PubMed

Malagurski, Ivana; Levic, Steva; Nesic, Aleksandra; Mitric, Miodrag; Pavlovic, Vladimir; Dimitrijevic-Brankovic, Suzana

2017-11-01

New mineralized, agar-based nanocomposite films (Zn-carbonate and Zn-phosphate/agar) were produced by a combination of in situ precipitation and a casting method. The presence of minerals significantly influenced the morphology, properties and functionality of the obtained nanocomposites. Reinforcement with the Zn-mineral phase improved the mechanical properties of the carbonate-mineralized films, but had a negligible effect on the phosphate-mineralized samples. Both nanocomposites showed improved optical and thermal properties, better Zn(II) release potential in a slightly acidic environment and exhibited antimicrobial activity against S. aureus. These results suggest that Zn-mineralized agar nanocomposite films could be potentially used as affordable, eco-friendly and active food packaging materials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physical-mechanical properties of agar/κ-carrageenan blend film and derived clay nanocomposite film.

PubMed

Rhim, Jong-Whan

2012-12-01

Binary blend films with different mixing ratio of agar and κ-carrageenan were prepared using a solution casting method with and without nanoclay and the effect of their composition on the mechanical, water vapor barrier, and water resistance properties was tested. The tensile strength (TS) of the κ-carrageenan film was greater than that of agar film. The water vapor permeability (WVP) of the agar film was lower than that of κ-carrageenan film, the swelling ratio (SR) and water solubility (WS) of κ-carrageenan film were higher than those of agar film. Each property of the binary blend films varied proportionately depending on the mixing ratio of each component. The XRD result indicated that the nanocomposite with agar/κ-carrageenan/clay (Cloisite(®) Na(+)) was intercalated. Consequently, the mechanical strength, water vapor barrier properties, and water contact angle (CA) were significantly (P < 0.05) improved through nanocomposite formation. © 2012 Institute of Food Technologists®

Study on swift heavy ions induced modifications of Ag-ZnO nanocomposite thin film

NASA Astrophysics Data System (ADS)

Singh, S. K.; Singhal, R.; Siva Kumar, V. V.

2017-03-01

In the present work, swift heavy ion (SHI) irradiation induced modifications in structural and optical properties of Ag-ZnO nanocomposite thin films have been investigated. Ag-ZnO nanocomposite (NCs) thin films were synthesized by RF magnetron sputtering technique and irradiated with 100 MeV Ag7+ ions at three different fluences 3 × 1012, 1 × 1013 and 3 × 1013 ions/cm2. Rutherford Backscattering Spectrometry revealed Ag concentration to be ∼8.0 at.%, and measured thickness of the films was ∼55 nm. Structural properties of pristine and irradiated films have been analyzed by X-ray diffraction analysis and found that variation in crystallite size of the film with ion irradiation. X-ray photoelectron spectroscopy (XPS) indicates the formation of Ag-ZnO nanocomposite thin film with presence of Ag, Zn and O elements. Oxidation state of Ag and Zn also estimated by XPS analysis. Surface plasmon resonance (SPR) of Ag nanoparticle has appeared at ∼475 nm in the pristine thin film, which is blue shifted by ∼30 nm in film irradiated at fluence of 3 × 1012 ions/cm2 and completely disappeared in film irradiated at higher fluences, 1 × 1013 and 3 × 1013 ions/cm2. A marginal change in the optical band gap of Ag-ZnO nanocomposite thin film is also found with increasing ion fluence. Surface morphology of pristine and irradiated films have been studied using Atomic Force Microscopy (AFM). Raman and Photo-luminance (PL) spectra of nanocomposite thin films have been investigated to understand the ion induced modifications such as lattice defects and disordering in the nanocomposite thin film.

Role of silver nanotube on conductivity, dielectric permittivity and current voltage characteristics of polyvinyl alcohol-silver nanocomposite film

NASA Astrophysics Data System (ADS)

Mukherjee, P. S.; Das, A. K.; Dutta, B.; Meikap, A. K.

2017-12-01

A comprehensive study on the prevailing conduction mechanism, dielectric relaxation and current voltage behaviour of Polyvinyl alcohol (PVA) - Silver (Ag) nanotube composite film has been reported. Introduction of Ag nanotubes enhances the conductivity and dielectric permittivity of film. Film shows semiconducting behaviour with two activation energies. The dc conductivity of the nanocomposite film obeys the adiabatic small polaron model. The dielectric permittivity can be analysed by modified Cole-Cole model. A non-Debye type asymmetric behaviour has been observed in the sample. The back to back Schottky diode concept has been used to describe the current-voltage characteristic of the composite film.

Optical properties of diamond like carbon nanocomposite thin films

NASA Astrophysics Data System (ADS)

Alam, Md Shahbaz; Mukherjee, Nillohit; Ahmed, Sk. Faruque

2018-05-01

The optical properties of silicon incorporated diamond like carbon (Si-DLC) nanocomposite thin films have been reported. The Si-DLC nanocomposite thin film deposited on glass and silicon substrate by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) process. Fourier transformed infrared spectroscopic analysis revealed the presence of different bonding within the deposited films and deconvolution of FTIR spectra gives the chemical composition i.e., sp3/sp2 ratio in the films. Optical band gap calculated from transmittance spectra increased from 0.98 to 2.21 eV with a variation of silicon concentration from 0 to 15.4 at. %. Due to change in electronic structure by Si incorporation, the Si-DLC film showed a broad photoluminescence (PL) peak centered at 467 nm, i.e., in the visible range and its intensity was found to increase monotonically with at. % of Si.

Impressive nonlinear optical response exhibited by Poly(vinylidene fluoride) (PVDF)/reduced graphene oxide (RGO) nanocomposite films

NASA Astrophysics Data System (ADS)

Sabira, K.; Saheeda, P.; Divyasree, M. C.; Jayalekshmi, S.

2017-12-01

In the present work, the nonlinear optical properties of free-standing films of Poly(vinylidene fluoride) (PVDF)/reduced graphene oxide (RGO) nanocomposite are investigated to assess their suitability as efficient optical limiters. The PVDF/RGO nanocomposite films are generated by mixing different concentrations of RGO as the filler, with PVDF, using solution casting method. The XRD and FTIR data of these nanocomposite films confirm the enhancement in the β phase of PVDF when RGO is added to PVDF, which is one of the prime factors, enhancing the nonlinear response of the nanocomposite. The open aperture and closed aperture Z-scan technique under nanosecond excitation (532 nm, 7 ns) is used to investigate the nonlinear optical characteristics of the PVDF/RGO nanocomposite films. These films are found to exhibit two photon absorption assisted optical non linearity in the nanosecond regime. The highlight of the present work is the observation of quite low values of the normalized transmittance and low optical limiting threshold power in free standing films of PVDF/RGO nanocomposite. These flexible, free-standing and stable nanocomposite films offer high application prospects in the design of efficient optical limiting devices of any desired size or shape.

Effect of annealing temperatures on the morphology and structural properties of PVDF/MgO nanocomposites thin films

NASA Astrophysics Data System (ADS)

Rozana, M. D.; Arshad, A. N.; Wahid, M. H. M.; Habibah, Z.; Sarip, M. N.; Rusop, M.

2018-05-01

This study investigates the effect of annealing on the topography, morphology and crystal phases of poly(vinylideneflouride)/Magnesium Oxide (MgO) nanocomposites thin films via AFM, FESEM and ATR-FTIR. The nanocomposites thin films were annealed at temperatures ranging from 70°C to 170°C. The annealed PVDF/MgO nanocomposites thin films were then cooled at room temperature before removal from the oven. This is to restructure the crystal lattice and to reduce imperfection for the PVDF/MgO nanocomposites thin films. PVDF/MgO nanocomposites thin films with annealing temperatures of 70°C, 90°C and 110°C showed uniform distribution of MgO nanoparticles, relatively low average surface roughness and no visible of defects. High application of annealing temperature on PVDF/MgO nanocomposites thin films caused tear-like defects on the thin films surface as observed by FESEM. The PVDF/MgO nanocomposites thin films annealed at 70°C was found to be a favourable film to be utilized in this study due to its enhanced β-crystalites of PVDF as evident in ATR-FTIR spectra.

High energy density and efficiency achieved in nanocomposite film capacitors via structure modulation

NASA Astrophysics Data System (ADS)

Zeng, Yi; Shen, Zhong-Hui; Shen, Yang; Lin, Yuanhua; Nan, Ce-Wen

2018-03-01

Flexible dielectric polymer films with high energy storage density and high charge-discharge efficiency have been considered as promising materials for electrical power applications. Here, we design hierarchical structured nanocomposite films using nonlinear polymer poly(vinylidene fluoride-HFP) [P(VDF-HFP)] with inorganic h-boron nitride (h-BN) nanosheets by electrospinning and hot-pressing methods. Our results show that the addition of h-BN nanosheets and the design of the hierarchical multilayer structure in the nanocomposites can remarkably enhance the charge-discharge efficiency and energy density. A high charge-discharge efficiency of 78% and an energy density of 21 J/cm3 can be realized in the 12-layered PVDF/h-BN nanocomposite films. Phase-field simulation results reveal that the spatial distribution of the electric field in these hierarchical structured films affects the charge-discharge efficiency and energy density. This work provides a feasible route, i.e., structure modulation, to improve the energy storage performances for nanocomposite films.

Flexible Transparent Supercapacitors Based on Hierarchical Nanocomposite Films.

PubMed

Chen, Fanhong; Wan, Pengbo; Xu, Haijun; Sun, Xiaoming

2017-05-31

Flexible transparent electronic devices have recently gained immense popularity in smart wearable electronics and touch screen devices, which accelerates the development of the portable power sources with reliable flexibility, robust transparency and integration to couple these electronic devices. For potentially coupled as energy storage modules in various flexible, transparent and portable electronics, the flexible transparent supercapacitors are developed and assembled from hierarchical nanocomposite films of reduced graphene oxide (rGO) and aligned polyaniline (PANI) nanoarrays upon their synergistic advantages. The nanocomposite films are fabricated from in situ PANI nanoarrays preparation in a blended solution of aniline monomers and rGO onto the flexible, transparent, and stably conducting film (FTCF) substrate, which is obtained by coating silver nanowires (Ag NWs) layer with Meyer rod and then coating of rGO layer on polyethylene terephthalate (PET) substrate. Optimization of the transparency, the specific capacitance, and the flexibility resulted in the obtained all-solid state nanocomposite supercapacitors exhibiting enhanced capacitance performance, good cycling stability, excellent flexibility, and superior transparency. It provides promising application prospects for exploiting flexible, low-cost, transparent, and high-performance energy storage devices to be coupled into various flexible, transparent, and wearable electronic devices.

Development of biodegradable metaloxide/polymer nanocomposite films based on poly-ε-caprolactone and terephthalic acid.

PubMed

Varaprasad, Kokkarachedu; Pariguana, Manuel; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Sadiku, Emmanuel Rotimi

2017-01-01

The present investigation describes the development of metal-oxide polymer nanocomposite films from biodegradable poly-ε-caprolactone, disposed poly(ethylene terephthalate) oil bottles monomer and zinc oxide-copper oxide nanoparticles. The terephthalic acid and zinc oxide-copper oxide nanoparticles were synthesized by using a temperature-dependent precipitation technique and double precipitation method, respectively. The terephthalic acid synthesized was confirmed by FTIR analysis and furthermore, it was characterized by thermal analysis. The as-prepared CuO-ZnO nanoparticles structure was confirmed by XRD analysis and its morphology was analyzed by SEM/EDS and TEM. Furthermore, the metal-oxide polymer nanocomposite films have excellent mechanical properties, with tensile strength and modulus better than pure films. The metal-oxide polymer nanocomposite films that were successfully developed show a relatively brighter colour when compared to CuO film. These new metal-oxide polymer nanocomposite films can replace many non-degradable plastics. The new metal-oxide polymer nanocomposite films developed are envisaged to be suitable for use in industrial and domestic packaging applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Transport, mechanical and global migration data of multilayer copolyamide nanocomposite films with different layouts.

PubMed

Scarfato, P; Garofalo, E; Di Maio, L; Incarnato, L

2017-06-01

Transport, mechanical and global migration data concern multilayer food packaging films with different layouts, all incorporating a layered silicate/polyamide nanocomposite as oxygen barrier layer, and a low-density polyethylene (LDPE) as moisture resistant layer in direct contact with food. The data are related to "Tuning of co-extrusion processing conditions and film layout to optimize the performances of PA/PE multilayer nanocomposite films for food packaging" by Garofalo et al. (2017) [1]. Nanocomposite multilayer films, with different relative layer thicknesses and clay types, were produced using a laboratory scale co-extrusion blown-film equipment and were analyzed in terms of transport to oxygen and water vapor, mechanical properties and overall migration. The results have shown that all the multilayer hybrid films, based on the copolyamide layer filled with Cloisite 30B, displayed the most significant oxygen barrier improvements and the best mechanical properties compared to the unfilled films. No significant alteration of the overall migration values was observed, as expectable [2], [3], [4]. The performance improvement was more relevant in the case of the film with the thinner nanocomposite layer.

Solution-processable alumina: PVP nanocomposite dielectric layer for high-performance organic thin-film transistors

NASA Astrophysics Data System (ADS)

Lin, Hui; Kong, Xiao; Li, Yiran; Kuang, Peng; Tao, Silu

2018-03-01

In this article, we have investigated the effect of nanocomposite gate dielectric layer built by alumina (Al2O3) and poly(4-vinyphenol) (PVP) with solution method which could enhance the dielectric capability and decrease the surface polarity. Then, we used modify layer to optimize the surface morphology of dielectric layer to further improve the insulation capability, and finally we fabricated the high-performance and low-voltage organic thin-film transistors by using this nanocomposite dielectric layer. The result shows that the devices with Al2O3:10%PVP dielectric layer with a modified layer exhibited a mobility of 0.49 cm2/Vs, I on/Ioff ratio of 7.8 × 104, threshold voltage of - 1.2 V, sub-threshold swing of 0.3 V/dec, and operating voltage as low as - 4 V. The improvement of devices performance was owing to the good insulation capability, appropriate capacitance of dielectric layer, and preferable interface contact, smaller crystalline size of active layer.

Chemical Synthesis and Optical Properties of CdS Poly(Lactic Acid) Nanocomposites and Their Transparent Fluorescent Films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Cai-Feng; Cheng, Yu-Peng; Xie, He-Yi

2011-01-01

This paper describes the chemical synthesis of cadmium sulfide (CdS) polymer nanocomposites by covalently grafting poly(lactic acid) (PLA) onto the surfaces of CdS nanocrystals (NCs). Synthesis of the nanocomposites involved two steps. Lactic acid (LA) capped CdS NCs were first prepared by reacting cadmium chloride (CdCl2) with sodium sulfide (Na2S) using LA as the organic ligand in H2O/N,N-dimethylformamide (DMF) solution. Next CdS PLA nanocomposites were formed by in situ ring-opening polymerization of lactide on the surface of modified CdS NCs. Transparent fluorescent films were then successfully prepared by blending as-prepared CdS PLA nanocomposites with high-molecular-weight PLA. The as-prepared CdS NCsmore » and their nanocomposites were studied by transmission electron microscopic imaging, thermogravimetric analyses, and spectroscopic measurements (ultraviolet-visible absorption and photoluminescence). The spectroscopic studies revealed that the CdS polymer nanocomposites exhibited good optical properties in terms of their photoluminescence and transparency.« less

Microstructural parameters and high third order nonlinear absorption characteristics of Mn-doped PbS/PVA nanocomposite films

NASA Astrophysics Data System (ADS)

Ramezanpour, B.; Mahmoudi Chenari, Hossein; Sadigh, M. Khadem

2017-11-01

In this work, undoped and Mn-doped PbS/PVA nanocomposite films have been successfully fabricated using the simple solution-casting method. Their crystalline structure was examined by X-ray powder diffraction (XRD). XRD pattern show the formation of cubic structure of PbS for Mn-doped PbS in PVA matrix. Microstructure parameters of Mn-doped PbS/PVA nanocomposite films were obtained through the size-strain plot (SSP) method. The thermal stability of the nanocomposite film was determined using Thermogravimetric analysis (TGA). Furthermore, Z-scan technique was used to investigate the optical nonlinearity of nanocomposite films by a continuous-wave laser irradiation at the wavelength of 655 nm. This experimental results show that undoped PbS/PVA nanocomposite films indicate high nonlinear absorption characteristics. Moreover, the nanocomposite films with easy preparation characteristics, high thermal stability and nonlinear absorption properties can be used as an active element in optics and photonic devices.

Bio-active nanocomposite films based on nanocrystalline cellulose reinforced styrylquinoxalin-grafted-chitosan: Antibacterial and mechanical properties.

PubMed

Fardioui, Meriem; Meftah Kadmiri, Issam; Qaiss, Abou El Kacem; Bouhfid, Rachid

2018-07-15

In this study, active nanocomposite films based on cellulose nanocrystalline (NCC) reinforced styrylquinoxalin-grafted-chitosan are prepared by solvent-casting process. The structures of the two styrylquinoxaline derivatives were confirmed by FT-IR, 1 H, 13 C NMR spectral data and the study of the antibacterial activity against Escherichia coli (EC), Staphylococcus aureus (SA), Bacillus subtilis (BS) and Pseudomonas Aeruginosa (PA) exhibits that they have a good antibacterial activity against (PA). On their side, the styrylquinoxalin-g-chitosan films are able to inhibit the growth of (PA) through their contact area without being damaged by the antibacterial test conditions. The addition of 5wt% of NCCs as nano-reinforcements revealed no change at the level of antibacterial activity but led to an important improvement of the mechanical properties (more than 60% and 90% improvement in Young's modulus and tensile strength, respectively) of the modified-chitosan films. Thereby, the present nanocomposite films are prepared by a simple way and featured by good mechanical and antibacterial properties which enhance the possibility to use them as bio-based products for biomedical and food packaging. Copyright © 2018 Elsevier B.V. All rights reserved.

Enhanced mechanical properties of hydrothermal carbamated cellulose nanocomposite film reinforced with graphene oxide.

PubMed

Gan, Sinyee; Zakaria, Sarani; Syed Jaafar, Sharifah Nabihah

2017-09-15

Cellulose carbamate (CC) was synthesized via hydrothermal process and mixed with graphene oxide (GO) to form a homogeneous cellulose matrix nanocomposite films. The properties of CC/GO nanocomposite films fabricated using simple solution-mixing method with different GO loadings were studied. Transmission electron microscope analysis showed the exfoliation of self-synthesized GO nanosheets within the CC matrix. X-ray diffraction results confirmed the crystalline structure of CC/GO films as the CC/GO mass ratio increased from 100/0 to 100/4. The mechanical properties of CC/GO film were significantly improved as compared to neat CC film. From thermogravimetric analysis result, the introduction of GO enhanced the thermal stability and carbon yields. The 3D homogeneous porous structures of the CC/GO films were observed under Field emission scanning electron microscope. These improvements in nanocomposite film properties could be confirmed by Fourier transform infrared spectroscopy due to the strong and good interactions between CC and GO. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dielectric properties and effect of electrical aging on space charge accumulation in polyimide/TiO2 nanocomposite films

NASA Astrophysics Data System (ADS)

Zha, Jun-Wei; Dang, Zhi-Min; Song, Hong-Tao; Yin, Yi; Chen, George

2010-11-01

In situ polymerized polyimide/TiO2 (PI/TiO2) nanocomposite films with good electrical aging resistance are studied. Space charge distribution in the PI/TiO2 nanocomposite films are measured using the pulsed electroacoustic method. Dielectric properties of the films are measured in the frequency range of 102 Hz-106 Hz by an impedance analyzer (Agilent 4294A) at room temperature. These nanocomposite films are also characterized by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). It is demonstrated that the nano-TiO2 particles strongly affect dielectric breakdown, lifetime and space charge distribution, and increase the voltage endurance of the nanocomposite films significantly. SEM analyses show that the nanocomposite films are destroyed after corona aging. The relation of space charge distribution with the concentration of the nano-TiO2 particles and the aging time is explored. Results show that an increase in dielectric permittivity of the nanocomposite films is observed with increasing filler concentration. However, the accumulation of space charge decreases with increasing nano-TiO2 particles concentration for the same corona aging time, and depends on the dielectric permittivity of the nanocomposite films.

High Performances of Artificial Nacre-Like Graphene Oxide-Carrageenan Bio-Nanocomposite Films.

PubMed

Zhu, Wenkun; Chen, Tao; Li, Yi; Lei, Jia; Chen, Xin; Yao, Weitang; Duan, Tao

2017-05-16

This study was inspired by the unique multi-scale and multi-level 'brick-and-mortar' (B&M) structure of nacre layers. We prepared the B&M, environmentally-friendly graphene oxide-carrageenan (GO-Car) nanocomposite films using the following steps. A natural polyhydroxy polymer, carrageenan, was absorbed on the surface of monolayer GO nanosheets through hydrogen-bond interactions. Following this, a GO-Car hybridized film was produced through a natural drying process. We conducted structural characterization in addition to analyzing mechanical properties and cytotoxicity of the films. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses showed that the nanocomposite films had a similar morphology and structure to nacre. Furthermore, the results from Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Thermogravimetric (TG/DTG) were used to explain the GO-Car interaction. Analysis from static mechanical testers showed that GO-Car had enhanced Young's modulus, maximum tensile strength and breaking elongation compared to pure GO. The GO-Car nanocomposite films, containing 5% wt. of Car, was able to reach a tensile strength of 117 MPa. The biocompatibility was demonstrated using a RAW264.7 cell test, with no significant alteration found in cellular morphology and cytotoxicity. The preparation process for GO-Car films is simple and requires little time, with GO-Car films also having favorable biocompatibility and mechanical properties. These advantages make GO-Car nanocomposite films promising materials in replacing traditional petroleum-based plastics and tissue engineering-oriented support materials.

High Performances of Artificial Nacre-Like Graphene Oxide-Carrageenan Bio-Nanocomposite Films

PubMed Central

Zhu, Wenkun; Chen, Tao; Li, Yi; Lei, Jia; Chen, Xin; Yao, Weitang; Duan, Tao

2017-01-01

This study was inspired by the unique multi-scale and multi-level ‘brick-and-mortar’ (B&M) structure of nacre layers. We prepared the B&M, environmentally-friendly graphene oxide-carrageenan (GO-Car) nanocomposite films using the following steps. A natural polyhydroxy polymer, carrageenan, was absorbed on the surface of monolayer GO nanosheets through hydrogen-bond interactions. Following this, a GO-Car hybridized film was produced through a natural drying process. We conducted structural characterization in addition to analyzing mechanical properties and cytotoxicity of the films. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses showed that the nanocomposite films had a similar morphology and structure to nacre. Furthermore, the results from Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Thermogravimetric (TG/DTG) were used to explain the GO-Car interaction. Analysis from static mechanical testers showed that GO-Car had enhanced Young’s modulus, maximum tensile strength and breaking elongation compared to pure GO. The GO-Car nanocomposite films, containing 5% wt. of Car, was able to reach a tensile strength of 117 MPa. The biocompatibility was demonstrated using a RAW264.7 cell test, with no significant alteration found in cellular morphology and cytotoxicity. The preparation process for GO-Car films is simple and requires little time, with GO-Car films also having favorable biocompatibility and mechanical properties. These advantages make GO-Car nanocomposite films promising materials in replacing traditional petroleum-based plastics and tissue engineering-oriented support materials. PMID:28772897

Nanocomposites prepared from acrylonitrile butadiene rubber and organically modified montmorillonite with vinyl groups

NASA Astrophysics Data System (ADS)

Han, Mijeong; Kim, Hoonjung; Kim, Eunkyoung

2006-01-01

Nanocomposites were prepared from acrylonitrile-butadiene rubber (NBR), vinyl groups containing organically modified montmorillonite and additives, such as zinc oxide, stearic acid, and sulfur. The organically modified montmorillonites used in these nanocomposites were prepared by ion exchange reactions of N,N'-dimethylalkyl-(p-vinylbenzyl)-ammonium chlorides (DAVBAs, alkyl = octyl, dodecyl, and octadecyl) with sodium montmorillonite (Na+-MMT). NBR nanocomposites were obtained by controlling both the mixing and vulcanization conditions, by using a Brabender mixer and hot-press process. X-ray diffraction (XRD) analysis shows that, depending on the amount of montmorillonite that is added, both exfoliated and intercalated nanocomposite structures are formed. The NBR/DAVBA-MMT nanocomposites exhibit much higher mechanical properties (e.g., tensile strength, Young's modulus, 300% modulus, and hardness) as well as gas barrier properties as compared to NBR Na+-MMT or NBR composites generated from modified montmorillonites without vinyl groups. Consistent with the results of XRD, transmission electron microscopy (TEM) reveals that the intercalation and exfoliation structures of the nanocomposites coexist and that the DAVBA-MMT layers are well dispersed in NBR.

Barrier and Mechanical Properties of Starch-Clay Nanocomposite Films

USDA-ARS?s Scientific Manuscript database

The poor barrier and mechanical properties of biopolymer-based food packaging can potentially be enhanced by the use of layered silicates (nanoclay) to produce nanocomposites. In this study, starch-clay nano-composites were synthesized by a melt extrusion method. Natural (MMT) and organically modifi...

An Amperometric Immunosensor Based on Multi-Walled Carbon Nanotubes-Thionine-Chitosan Nanocomposite Film for Chlorpyrifos Detection

PubMed Central

Sun, Xia; Cao, Yaoyao; Gong, Zhili; Wang, Xiangyou; Zhang, Yan; Gao, Jinmei

2012-01-01

In this work, a novel amperometric immunosensor based on multi-walled carbon nanotubes-thionine-chitosan (MWCNTs-THI-CHIT) nanocomposite film as electrode modified material was developed for the detection of chlorpyrifos residues. The nanocomposite film was dropped onto a glassy carbon electrode (GCE), and then the anti-chlorpyrifos monoclonal antibody was covalently immobilized onto the surface of MWCNTs-THI-CHIT/GCE using the crosslinking agent glutaraldehyde (GA). The modification procedure was characterized by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimized conditions, a linear relationship between the relative change in peak current of different pulse voltammetry (DPV) and the logarithm of chlorpyrifos solution concentration was obtained in the range from 0.1 to 1.0 × 105 ng/mL with a detection limit of 0.046 ng/mL. The proposed chlorpyrifos immunosensor exhibited high reproducibility, stability, and good selectivity and regeneration, making it a potential alternative tool for ultrasensitive detection of chlorpyrifos residues in vegetables and fruits. PMID:23443396

Negative capacitance in (FeCoZr)-(PZT) nanocomposite films

NASA Astrophysics Data System (ADS)

Kołtunowicz, T. N.; Fedotova, J. A.; Zhukowski, P.; Saad, A.; Fedotov, A.; Kasiuk, J. V.; Larkin, A. V.

2013-03-01

In this work, attention was focused on the inductive contribution to the real part of admittance G(T, f) in (Fe0.45Co0.45Zr0.10)x(PZT)(1-x) nanocomposite films deposited in a mixed argon-oxygen atmosphere. The observed G(x, f, T) dependences for the films on the dielectric side of the insulator-metal transition demonstrated the negative capacitance (NC) effect that was maximal for the nanocomposites with 0.40 < x < 0.60, where the metallic FeCoZr nanoparticles were totally oxidized. The NC effect was explained by a specially developed model for the ac hopping conductance of the electrons between the fully oxidized nanoparticles embedded in the PZT matrix. In accordance with the model, under the determined conditions the observed structure of nanocomposites led to an increase in the hopping electron mean lifetime on nanoparticles and hence to the possibility of positive angles of the phase shifts θ and a proper NC (inductive-like contribution) effect.

Doxorubicin loaded carboxymethyl cellulose/graphene quantum dot nanocomposite hydrogel films as a potential anticancer drug delivery system.

PubMed

Javanbakht, Siamak; Namazi, Hassan

2018-06-01

Creating anticancer properties in the hydrogel film could make it as a candidate for treating cancer tissues. In this work, a novel hydrogel nanocomposite films with anticancer properties were designed via incorporation of graphene quantum dot (GQD) as a nanoparticle into carboxymethyl cellulose (CMC) hydrogel and using doxorubicin (DOX) as drug model with broad-spectrum anticancer properties. Drug release studies carried out at two different pHs and the MTT assay was evaluated for DOX-loaded CMC/GQD nanocomposite hydrogel films against blood cancer cells (K562). The prepared nanocomposite hydrogel films were characterized using Fourier transform infrared (FT-IR), UV-Vis spectroscopy, scanning electron microscopy (SEM), permeability and mechanical properties. The prepared CMC/GQD nanocomposite hydrogel films showed an improvement in vitro swelling, degradation, water vapor permeability and pH-sensitive drug delivery properties along with not significant toxicity against blood cancer cells (K562). According to the obtained results, this nanocomposite hydrogel films can be proposed to use as an anticancer film and drug delivery system. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of potassium sorbate on antimicrobial and physical properties of starch-clay nanocomposite films.

PubMed

Barzegar, Hassan; Azizi, Mohammad Hossein; Barzegar, Mohsen; Hamidi-Esfahani, Zohreh

2014-09-22

Using fresh foods which undergo the least processing operations developed widely in recent years. Active packaging is a novel method for preserving these products. Active starch-clay nanocomposite films which contained potassium sorbate (PS) at a level of 0, 5, 7.5 and 10 g PS/100 g starch were produced and their physical, mechanical and antimicrobial properties were evaluated. In order to evaluate antimicrobial properties of films Aspergillus niger was used. The results showed that 5% of the PS did not produce antimicrobial property in the film, but by increasing the content of the additive in film formulation, antimicrobial effect increased. PS increased water permeability and elongation at break of the films, but decreased tensile strength. The rate of PS migration into the semi-solid medium in starch-nanocomposites was lower than starch films. This shows that nanocomposite films could retain their antimicrobial property for longer time. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development of polylactic acid nanocomposite films reinforced with cellulose nanocrystals derived from coffee silverskin.

PubMed

Sung, Soo Hyun; Chang, Yoonjee; Han, Jaejoon

2017-08-01

Bio-nanocomposite films based on polylactic acid (PLA) matrix reinforced with cellulose nanocrystals (CNCs) were developed using a twin-screw extruder. The CNCs were extracted from coffee silverskin (CS), which is a by-product of the coffee roasting process. They were extracted by alkali treatment followed by sulfuric acid hydrolysis. They were used as reinforcing agents to obtain PLA/CNC nanocomposites by addition at different concentrations (1%, 3%, and 5% CNCs). Morphological, tensile, and barrier properties of the bio-nanocomposites were analyzed. The tensile strength and Young's modulus increased with both 1% and 3% CNCs. The water vapor permeability decreased gradually with increasing addition of CNCs up to 3% and good oxygen barrier properties were found for all nanocomposites. These results suggest that CNCs from CS can improve the physical properties of PLA-based biopolymer film. The developed PLA/CNC bio-nanocomposite films can potentially be used for biopolymer materials with enhanced barrier and mechanical properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Work function measurements of copper nanoparticle intercalated polyaniline nanocomposite thin films

NASA Astrophysics Data System (ADS)

Patil, U. V.; Ramgir, Niranjan S.; Bhogale, A.; Debnath, A. K.; Muthe, K. P.; Gadkari, S. C.; Kothari, D. C.

2017-05-01

The nature of contact between the electrode and the sensing material plays a crucial role in governing the sensing mechanism. Thin films of polyaniline (PANI) and copper-polyaniline nanocomposite (NC) have been deposited at room temperatures by in-situ oxidative polymerization of aniline in the presence of Cu nanoparticles. For sensing applications a thin film Au (gold) ˜100 nm is deposited and used as a conducting electrode. To understand the nature of contact (i.e., ohmic or Schottky) the work function of the conducting polyaniline and nanocomposite films were measured using Kelvin Probe method. I-V characteristics of PANI and NC films investigated at room temperatures further corroborates and confirms the formation of Ohmic contact as evident from work function measurements.

The Antifungal Activity of Functionalized Chitin Nanocrystals in Poly (Lactid Acid) Films

PubMed Central

Salaberria, Asier M.; H. Diaz, Rene; Andrés, María A.; Fernandes, Susana C.M.; Labidi, Jalel

2017-01-01

As, in the market, poly (lactic acid) (PLA) is the most used polymer as an alternative to conventional plastics, and as functionalized chitin nanocrystals (CHNC) can provide structural and bioactive properties, their combination sounds promising in the preparation of functional nanocomposite films for sustainable packaging. Chitin nanocrystals were successfully modified via acylation using anhydride acetic and dodecanoyl chloride acid to improve their compatibility with the matrix, PLA. The nanocomposite films were prepared by extrusion/compression approach using different concentrations of both sets of functionalized CHNC. This investigation brings forward that both sets of modified CHNC act as functional agents, i.e., they slightly improved the hydrophobic character of the PLA nanocomposite films, and, very importantly, they also enhanced their antifungal activity. Nonetheless, the nanocomposite films prepared with the CHNC modified with dodecanoyl chloride acid presented the best properties. PMID:28772902

PET based nanocomposite films for microwave packaging applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galdi, M. R., E-mail: mrgaldi@unisa.it; Olivieri, R.; Liguori, L.

In recent years, changes in life standards have promoted the diffusion of Ready to Cook (RTC) and Ready to Eat (RTE) products for microwave ovens. However, the main limits in microwave (MW) ovens usage are often related to the proper choice of packaging materials suitable for such technology. In fact, packages for microwaveable RTC and RTE foods should ensure adequate preservation of the product before cooking/heating such as high barriers to gases and aromas and adequate control of water vapor transmission. In addition, microwaveable packaging material must be transparent to MW, thermally stable and resistant to the mechanical stress inducedmore » by the accumulation in the head space of volatile substances produced during the cooking. Polymeric materials are good candidates for microwaveable packaging thanks to their transparency to MW. In the last years a great interest is devoted to developing innovative solution based on the use of additives or systems that act as susceptors or heating enhancers for improving the characteristics of polymers in cooking/heating in MW ovens. The present work was focused on the production and characterization of nanocomposite copolyester based films suitable for microwaveable food packaging applications. The matrices selected consist in two PET copolymers modified with carbon black (ULTRA STD) and with titanium oxide (ULTRA NA). Nanocomposite co-extruded multilayer films were produced using different percentages (0%, 2% and 4%wt/wt) of Cloisite 20A (C20A). Films were analyzed for evaluating the effect of nanofiller on the morphology and barrier properties. Moreover, to verify the effectiveness of the designed systems in reducing the cooking times of meat products, MW heating tests were carried out on pork meat hamburgers in MW oven at varying supplied powers. The cooking tests have pointed out that the selected matrices are efficient in reducing cooking times and that even low concentration of C20A acts as heating enhancers of

PET based nanocomposite films for microwave packaging applications

NASA Astrophysics Data System (ADS)

Galdi, M. R.; Olivieri, R.; Liguori, L.; Albanese, D.; Di Matteo, M.; Di Maio, L.

2015-12-01

In recent years, changes in life standards have promoted the diffusion of Ready to Cook (RTC) and Ready to Eat (RTE) products for microwave ovens. However, the main limits in microwave (MW) ovens usage are often related to the proper choice of packaging materials suitable for such technology. In fact, packages for microwaveable RTC and RTE foods should ensure adequate preservation of the product before cooking/heating such as high barriers to gases and aromas and adequate control of water vapor transmission. In addition, microwaveable packaging material must be transparent to MW, thermally stable and resistant to the mechanical stress induced by the accumulation in the head space of volatile substances produced during the cooking. Polymeric materials are good candidates for microwaveable packaging thanks to their transparency to MW. In the last years a great interest is devoted to developing innovative solution based on the use of additives or systems that act as susceptors or heating enhancers for improving the characteristics of polymers in cooking/heating in MW ovens. The present work was focused on the production and characterization of nanocomposite copolyester based films suitable for microwaveable food packaging applications. The matrices selected consist in two PET copolymers modified with carbon black (ULTRA STD) and with titanium oxide (ULTRA NA). Nanocomposite co-extruded multilayer films were produced using different percentages (0%, 2% and 4%wt/wt) of Cloisite 20A (C20A). Films were analyzed for evaluating the effect of nanofiller on the morphology and barrier properties. Moreover, to verify the effectiveness of the designed systems in reducing the cooking times of meat products, MW heating tests were carried out on pork meat hamburgers in MW oven at varying supplied powers. The cooking tests have pointed out that the selected matrices are efficient in reducing cooking times and that even low concentration of C20A acts as heating enhancers of PET.

Preparation of Electrically Conductive Polystyrene/Carbon Nanofiber Nanocomposite Films

ERIC Educational Resources Information Center

Sun, Luyi; O'Reilly, Jonathan Y.; Tien, Chi-Wei; Sue, Hung-Jue

2008-01-01

A simple and effective approach to prepare conductive polystyrene/carbon nanofiber (PS/CNF) nanocomposite films via a solution dispersion method is presented. Inexpensive CNF, which has a structure similar to multi-walled carbon nanotubes, is chosen as a nanofiller in this experiment to achieve conductivity in PS films. A good dispersion is…

Understanding physicochemical properties changes from multi-scale structures of starch/CNT nanocomposite films.

PubMed

Liu, Siyuan; Li, Xiaoxi; Chen, Ling; Li, Lin; Li, Bing; Zhu, Jie

2017-11-01

From the view of multi-scale structures of hydroxypropyl starch (HPS)/carbon nanotube (CNT) nanocomposite films, the film physicochemical properties were affected by comprehensive factors including molecular interaction, short range molecular conformation, crystalline structure and aggregated structure. The less original HPS hydrogen bonding that was broken, less decreased order of HPS short range molecular conformation, lower film crystallinity and larger size of micro-ordered regions contributed to higher tensile strength and Young's modulus of the film with CNT content of 0.5% (g/g, CNT in HPS). The higher film overall crystallinity and larger size of micro-ordered regions of the film with CNT content of 0.05%-0.3% compared with those of control contributed to better film barrier property. The addition of CNT with the content of 0.05%-0.5% broke the original HPS hydrogen bonding and decreased the order of starch short range molecular conformation, which counteracted the positive effect of CNT on the thermal stability of the material, thus thermal degradation temperature of these nanocomposite films did not increase. But the sharp increase of film crystallinity increased film thermal degradation temperature. This study provided a better understanding of film physicochemical properties changes which guides to rational design of starch-based nanocomposite films for packaging and coating application. Copyright © 2017. Published by Elsevier B.V.

Natural biopolymer-based nanocomposite films for packaging applications.

PubMed

Rhim, Jong-Whan; Ng, Perry K W

2007-01-01

Concerns on environmental waste problems caused by non-biodegradable petrochemical-based plastic packaging materials as well as the consumer's demand for high quality food products has caused an increasing interest in developing biodegradable packaging materials using annually renewable natural biopolymers such as polysaccharides and proteins. Inherent shortcomings of natural polymer-based packaging materials such as low mechanical properties and low water resistance can be recovered by applying a nanocomposite technology. Polymer nanocomposites, especially natural biopolymer-layered silicate nanocomposites, exhibit markedly improved packaging properties due to their nanometer size dispersion. These improvements include increased modulus and strength, decreased gas permeability, and increased water resistance. Additionally, biologically active ingredients can be added to impart the desired functional properties to the resulting packaging materials. Consequently, natural biopolymer-based nanocomposite packaging materials with bio-functional properties have a huge potential for application in the active food packaging industry. In this review, recent advances in the preparation of natural biopolymer-based films and their nanocomposites, and their potential use in packaging applications are addressed.

ZnO-PVA nanocomposite films for low threshold optical limiting applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viswanath, Varsha; Beenakumari, C.; Muneera, C. I.

Zinc oxide-PVA nanocomposite films were fabricated adopting a simple method based on solution-casting, incorporating small weight percentages (<1.2 wt%) of ZnO in PVA (∼0.625×10{sup −3}M to 7×10{sup −3}M), and their structure, morphology, linear and low threshold nonlinear optical properties were investigated. The films were characterized as nanostructured ZnO encapsulated between the molecules/chains of the semicrystalline host polymer PVA. The samples exhibited low threshold nonlinear absorption and negative nonlinear refraction, as studied using the Z-scan technique. A switchover from SA to RSA was observed as the concentration of ZnO was increased. The optical limiting of 632.8 nm CW laser light displayedmore » by these nanocomposite films is also demonstrated. The estimated values of the effective coefficients of nonlinear absorption, nonlinear refraction and third-order nonlinear susceptibility, |χ{sup (3)}|, compared to those reported for continuous wave laser light excitation, measure up to the highest among them. The results show that the ZnO-PVA nanocomposite films have great potential applications in future optical and photonic devices.« less

Thermally stimulated nonlinear refraction in gelatin stabilized Cu-PVP nanocomposite thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamgadge, Y. S., E-mail: ystamgadge@gmail.com; Atkare, D. V.; Pahurkar, V. G.

2016-05-06

This article illustrates investigations on thermally stimulated third order nonlinear refraction of Cu-PVP nanocomposite thin films. Cu nanoparticles have been synthesized using chemical reduction method and thin films in PVP matrix have been obtained using spin coating technique. Thin films have been characterized by X-ray diffraction (XRD) and Ultraviolet-visible (UV-vis) spectroscopyfor structural and linear optical studies. Third order nonlinear refraction studies have been performed using closed aperture z-scan technique under continuous wave (CW) He-Ne laser. Cu-PVP nanocomposites are found to exhibit strong nonlinear refractive index stimulated by thermal lensing effect.

Silver-embedded modified hyperbranched epoxy/clay nanocomposites as antibacterial materials.

PubMed

Roy, Buddhadeb; Bharali, Pranjal; Konwar, B K; Karak, Niranjan

2013-01-01

Silver-embedded modified hyperbranched epoxy/clay nanocomposites were prepared at different wt.% of octadecyl amine-modified montmorillonite at a constant silver concentration (1 wt.%). UV-visible, XRD and TEM studies confirmed the formation of silver nanoparticles. Compared to the system without silver and clay, the gloss from 70° to 94°, scratch hardness from 4 to 5.8 kg, impact strength from 60 to 90 cm, tensile strength from 8.5 to 15.5 MPa, adhesive strength from 5 to 7.1 × 10(9)N/m, flexibility from >6 to <4mm, and thermostability from 230 to 260 °C increased for the modified system. Resistance to aqueous 10% HCl, 0.5% NaOH, 10% NaCl also increased. The nanocomposites showed antibacterial activity in well diffusion assays against Staphylococcus aureus (ATCC11632), Bacillus subtilis (ATCC11774), Escherichia coli (MTCC40), Pseudomonas aeruginosa (MTCC7814) and Klebsiella pneumoniae (ATCC10031). The results showed that these nanocomposites have potential to be used as antimicrobial materials. Copyright © 2012 Elsevier Ltd. All rights reserved.

Non-conductive ferromagnetic carbon-coated (Co, Ni) metal/polystyrene nanocomposites films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takacs, H., E-mail: helene.takacs@gmail.com; LTM-CNRS-UJF, CEA, LETI, Minatec Campus, Grenoble 38054; Viala, B.

2016-03-07

This article reports non-conductive ferromagnetic properties of metal/polymer nanocomposite films intended to be used for RF applications. The nanocomposite arrangement is unique showing a core double-shell structure of metal-carbon-polystyrene: M/C//P{sub 1}/P{sub 2}, where M = Co, Ni is the core material, C = graphene or carbon is the first shell acting as a protective layer against oxidation, P{sub 1} = pyrene-terminated polystyrene is the second shell for electrical insulation, and P{sub 2} = polystyrene is a supporting matrix (// indicates actual grafting). The nanocomposite formulation is briefly described, and the film deposition by spin-coating is detailed. Original spin-curves are reported and analyzed. One key outcome is the achievementmore » of uniform and cohesive films at the wafer scale. Structural properties of films are thoroughly detailed, and weight and volume fractions of M/C are considered. Then, a comprehensive overview of DC magnetic and electrical properties is reported. A discussion follows on the magnetic softness of the nanocomposites vs. that of a single particle (theoretical) and the raw powder (experimental). Finally, unprecedented achievement of high magnetization (∼0.6 T) and ultra-high resistivity (∼10{sup 10 }μΩ cm) is shown. High magnetization comes from the preservation of the existing protective shell C, with no significant degradation on the particle net-moment, and high electrical insulation is ensured by adequate grafting of the secondary shell P{sub 1}. To conclude, the metal/polymer nanocomposites are situated in the landscape of soft ferromagnetic materials for RF applications (i.e., inductors and antennas), by means of two phase-diagrams, where they play a crucial role.« less

Switchable 3-0 magnetoelectric nanocomposite thin film with high coupling.

PubMed

McDannald, Austin; Ye, Linghan; Cantoni, Claudia; Gollapudi, Sreenivasulu; Srinivasan, Gopalan; Huey, Bryan D; Jain, Menka

2017-03-02

A mixed precursor solution method was used to deposit 3-0 nanocomposite thin films of PbZr 0.52 Ti 0.48 O 3 (PZT) and CoFe 2 O 4 (CFO). The piezoelectric behavior of PZT and magnetostrictive behavior of CFO allow for magnetoelectric (ME) coupling through strain transfer between the respective phases. High ME coupling is desired for many applications including memory devices, magnetic field sensors, and energy harvesters. The spontaneous phase separation in the 3-0 nanocomposite film was observed, with 25 nm CFO particle or nanophases distributed in discrete layers through the thickness of the PZT matrix. Magnetic-force microscopy images of the nanocomposite thin film under opposite magnetic poling conditions revealed in-plane pancake-like regions of higher concentration of the CFO nanoparticles. The constraints on the size and distribution of the CFO nanoparticles created a unique distribution in a PZT matrix and achieved values of ME coupling of 3.07 V cm -1 Oe -1 at a DC bias of 250 Oe and 1 kHz, increasing up to 25.0 V cm -1 Oe -1 at 90 kHz. Piezo-force microscopy was used to investigate the ferroelectric domain structure before and after opposite magnetic poling directions. It was found that in this nanocomposite, the polarization of the ferroelectric domains switched direction as a result of switching the direction of the magnetization by magnetic fields.

NIR-Vis-UV Light-Responsive Actuator Films of Polymer-Dispersed Liquid Crystal/Graphene Oxide Nanocomposites.

PubMed

Cheng, Zhangxiang; Wang, Tianjie; Li, Xiao; Zhang, Yihe; Yu, Haifeng

2015-12-16

To take full advantage of sunlight for photomechanical materials, NIR-vis-UV light-responsive actuator films of polymer-dispersed liquid crystal (PDLC)/graphene oxide (GO) nanocomposites were fabricated. The strategy is based on phase transition of LCs from nematic to isotropic phase induced by combination of photochemical and photothermal processes in the PDLC/GO nanocomposites. Upon mechanical stretching of the film, both topological shape change and mesogenic alignment occurred in the separated LC domains, enabling the film to respond to NIR-vis-UV light. The homodispersed GO flakes act as photoabsorbent and nanoscale heat source to transfer NIR or VIS light into thermal energy, heating the film and photothermally inducing phase transition of LC microdomains. By utilizing photochemical phase transition of LCs upon UV-light irradiation, one azobenzene dye was incorporated into the LC domains, endowing the nanocomposite films with UV-responsive property. Moreover, the light-responsive behaviors can be well-controlled by adjusting the elongation ratio upon mechanical treatment. The NIR-vis-UV light-responsive PDLC/GO nanocomposite films exhibit excellent properties of easy fabrication, low-cost, and good film-forming and mechanical features, promising their numerous applications in the field of soft actuators and optomechanical systems driven directly by sunlight.

Synthesis and characterization of CdS/PVA nanocomposite films

NASA Astrophysics Data System (ADS)

Wang, Hongmei; Fang, Pengfei; Chen, Zhe; Wang, Shaojie

2007-08-01

A series CdS/PVA nanocomposite films with different amount of Cd salt have been prepared by means of the in situ synthesis method via the reaction of Cd 2+-dispersed poly vinyl-alcohol (PVA) with H 2S. The as-prepared films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption, photoluminescence (PL) spectra, Fourier transform infrared spectroscope (FTIR) and thermogravimetric analysis (TGA). The XRD results indicated the formation of CdS nanoparticles with hexagonal phase in the PVA matrix. The primary FTIR spectra of CdS/PVA nanocomposite in different processing stages have been discussed. The vibrational absorption peak of Cd sbnd S bond at 405 cm -1 was observed, which further testified the generation of CdS nanoparticles. The TGA results showed incorporation of CdS nanoparticles significantly altered the thermal properties of PVA matrix. The photoluminescence and UV-vis spectroscopy revealed that the CdS/PVA films showed quantum confinement effect.

Electrochemical detection of Hg (II) ions using EDTA-PANI/SWNTs nanocomposite modified SS electrode

NASA Astrophysics Data System (ADS)

Deshmukh, M. A.; Patil, H. K.; Shirsat, M. D.; Ramanavicius, A.

2017-05-01

Detection of Hg (II) ions using EDTA modified polyaniline (PANI) and single walled carbon nanotubes (SWNTs) nanocomposite (PANI/SWNTs) was performed electrochemically via cyclic voltammetry (CV) technique. Dodecyl benzene sulphonic next step, PANI/SWNTs nanocomposite was modified acid sodium salt (DBSA) was used as a surfactant during this synthesis to get uniform suspension SWNTs. In the by EDTA solution containing crosslinking agent 1-ethyl-3(3-(dimethylamino) propyl) - carbodiimide (EDC) utilizing dip coating technique. The sensitivity of EDTA modified PANI/SWNTs nanocomposite towards Hg (II) ions was investigated. Differential pulse voltammetry (DPV) technique was applied for the electrochemical detection of Hg (II) ions.

Poly(vinylidene fluoride) Flexible Nanocomposite Films with Dopamine-Coated Giant Dielectric Ceramic Nanopowders, Ba(Fe0.5Ta0.5)O3, for High Energy-Storage Density at Low Electric Field.

PubMed

Wang, Zhuo; Wang, Tian; Wang, Chun; Xiao, Yujia; Jing, Panpan; Cui, Yongfei; Pu, Yongping

2017-08-30

Ba(Fe 0.5 Ta 0.5 )O 3 /poly(vinylidene fluoride) (BFT/PVDF) flexible nanocomposite films are fabricated by tape casting using dopamine (DA)-modified BFT nanopowders and PVDF as a matrix polymer. After a surface modification of installing a DA layer with a thickness of 5 nm, the interfacial couple interaction between BFT and PVDF is enhanced, resulting in less hole defects at the interface. Then the dielectric constant (ε'), loss tangent (tan δ), and AC conductivity of nanocomposite films are reduced. Meanwhile, the value of the reduced dielectric constant (Δε') and the strength of interfacial polarization (k) are introduced to illustrate the effect of DA on the dielectric behavior of nanocomposite films. Δε' can be used to calculate the magnitude of interfacial polarization, and the strength of the dielectric constant contributed by the interface can be expressed as k. Most importantly, the energy-storage density and energy-storage efficiency of nanocomposite films with a small BFT@DA filler content of 1 vol % at a low electric field of 150 MV/m are enhanced by about 15% and 120%, respectively, after DA modification. The high energy-storage density of 1.81 J/cm 3 is obtained in the sample. This value is much larger than the reported polymer-based nanocomposite films. In addition, the outstanding cycle and bending stability of the nanocomposite films make it a promising candidate for future flexible portable energy devices.

Polyimide Nanocomposites Prepared from High-Temperature, Reduced Charge Organoclays

NASA Technical Reports Server (NTRS)

Delozier, D. M.; Orwoll, R. A.; Cahoon, J. F.; Ladislaw, J. S.; Smith, J. G., Jr.; Connell, J. W.

2003-01-01

Montmorillonite clays modified with the dihydrochloride salt of 1,3-bis(3-aminophenoxy)benzene (APB) were used in the preparation of polyimide/organoclay hybrid films. Organoclays with varying surface charge based upon APB were prepared and examined for their dispersion behavior in the polymer matrix. High molecular weight poly(amide acid) solutions were prepared in the presence of the organoclays. Films were cast and subsequently heated to 300C to cause imidization. The resulting nanocomposite films, containing 3 wt% of organoclay, were characterized by transmission electron microscopy and X-ray diffraction. The clay's cation exchange capacity (CEC) played a key role in determining the extent of dispersion in the polyimide matrix. Considerable dispersion was observed in some of the nanocomposite films. The most effective organoclay was found to have a CEC of 0.70 meq/g. Nanocomposite films prepared with 3-8 wt% of this organoclay were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and thin-film tensile testing. High levels of clay dispersion could be achieved even at the higher clay loadings. Results from mechanical testing revealed that while the moduli of the nanocomposites increased with increasing clay loadings, both strength and elongation decreased.

Achieving 3-D Nanoparticle Assembly in Nanocomposite Thin Films via Kinetic Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Jingyu; Xiao, Yihan; Xu, Ting

Nanocomposite thin films containing well-ordered nanoparticle (NP) assemblies are ideal candidates for the fabrication of metamaterials. Achieving 3-D assembly of NPs in nanocomposite thin films is thermodynamically challenging as the particle size gets similar to that of a single polymer chain. The entropic penalties of polymeric matrix upon NP incorporation leads to NP aggregation on the film surface or within the defects in the film. Controlling the kinetic pathways of assembly process provides an alternative path forward by arresting the system in nonequilibrium states. Here, we report the thin film 3-D hierarchical assembly of 20 nm NPs in supramolecules withmore » a 30 nm periodicity. By mediating the NP diffusion kinetics in the supramolecular matrix, surface aggregation of NPs was suppressed and NPs coassemble with supramolecules to form new 3-D morphologies in thin films. Lastly, the present studies opened a viable route to achieve designer functional composite thin films via kinetic control.« less

Achieving 3-D Nanoparticle Assembly in Nanocomposite Thin Films via Kinetic Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Jingyu; Xiao, Yihan; Xu, Ting

Nanocomposite thin films containing well-ordered nanoparticle (NP) assemblies are ideal candidates for the fabrication of metamaterials. Achieving 3-D assembly of NPs in nanocomposite thin films is thermodynamically challenging as the particle size gets similar to that of a single polymer chain. The entropic penalties of polymeric matrix upon NP incorporation leads to NP aggregation on the film surface or within the defects in the film. Controlling the kinetic pathways of assembly process provides an alternative path forward by arresting the system in nonequilibrium states. Here, we report the thin film 3-D hierarchical assembly of 20 nm NPs in supramolecules withmore » a 30 nm periodicity. By mediating the NP diffusion kinetics in the supramolecular matrix, surface aggregation of NPs was suppressed and NPs coassemble with supramolecules to form new 3-D morphologies in thin films. The present studies opened a viable route to achieve designer functional composite thin films via kinetic control.« less

Achieving 3-D Nanoparticle Assembly in Nanocomposite Thin Films via Kinetic Control

DOE PAGES

Huang, Jingyu; Xiao, Yihan; Xu, Ting

2017-02-20

Nanocomposite thin films containing well-ordered nanoparticle (NP) assemblies are ideal candidates for the fabrication of metamaterials. Achieving 3-D assembly of NPs in nanocomposite thin films is thermodynamically challenging as the particle size gets similar to that of a single polymer chain. The entropic penalties of polymeric matrix upon NP incorporation leads to NP aggregation on the film surface or within the defects in the film. Controlling the kinetic pathways of assembly process provides an alternative path forward by arresting the system in nonequilibrium states. Here, we report the thin film 3-D hierarchical assembly of 20 nm NPs in supramolecules withmore » a 30 nm periodicity. By mediating the NP diffusion kinetics in the supramolecular matrix, surface aggregation of NPs was suppressed and NPs coassemble with supramolecules to form new 3-D morphologies in thin films. Lastly, the present studies opened a viable route to achieve designer functional composite thin films via kinetic control.« less

Preparation and characterization of nanocrystalline cellulose/Eucommia ulmoides gum nanocomposite film.

PubMed

Sun, Qianqian; Zhao, Xinkun; Wang, Dongmei; Dong, Juane; She, Diao; Peng, Pai

2018-02-01

The nanocomposite films were prepared using Eucommia ulmoides gum (EUG) matrix reinforced with nanocrystalline cellulose (NCC) at different concentrations. Subsequently, the obtained films were characterized by Raman spectra, AFM, XRD, TGA, and DSC. Meanwhile, the wettability, mechanical, and water vapor barrier properties of these films were analyzed. AFM noticed that the average sizes of NCC were 81.95×50.17×13.06nm, while the size of molecular chain for EUG was 2530×57.33×1.28nm. In comparison with control film, a certain amount of NCC obviously improved elongation at break and enhanced their crystallinity and ΔH m . More importantly, NCC/EUG nanocomposite films presented lower thermal stability, glass transition temperature (T g ), melting temperature (T m ), and water vapor permeability (WVP) values, especially the WVP values of 4% NCC film were the lowest as 0.28×10 -9 , 0.30×10 -9 , and 0.58×10 -9 g/m/h/Pa at RH 34%, 55%, and 76%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Silver/poly(vinyl alcohol) nanocomposite film prepared using water in oil microemulsion for antibacterial applications.

PubMed

Fatema, Ummul K; Rahman, M Muhibur; Islam, M Rakibul; Mollah, M Yousuf A; Susan, Md Abu Bin Hasan

2018-03-15

Water in oil microemulsion (w/o) is a simple preparative route for nanoparticles where water droplets (dispersed in continuous oil medium and stabilized by surfactants and cosurfactants) act as nanoreactors to carry out chemical reactions. If polymeric matrix is incorporated inside the core of the microemulsions, it should prevent the agglomeration of nanoparticles after separation from microemulsions. Thus polymer nanocomposite films prepared from w/o microemulsions are expected to give narrow and homogeneous size distribution of nanoparticles throughout the polymer host. Silver/poly(vinyl alcohol) (Ag/PVA) nanocomposite film was successfully prepared, for the first time, using Triton X-100 (TX-100)/1-butanol/cyclohexane/water microemulsion. Reduction of the metal salt was carried out in the core of w/o microemulsion droplets containing PVA polymeric matrix. After separation from the microemulsion, Ag/PVA nanocomposite film was then prepared by solution casting method. The antibacterial activity of the nanocomposites was tested against Gram-negative, Escherichia coli and Gram-positive, Staphylococcus aureus by agar diffusion method. Ag nanoparticles with an average diameter of 105 nm could be synthesized using PVA, whereas in the absence of PVA the nanoparticles agglomerated. The distribution of Ag nanoparticles on PVA surface of the nanocomposite film prepared using microemulsion was uniform, whereas the film prepared through in situ generation of Ag nanoparticles by chemical reduction process on PVA host showed non-uniform, coagulated, bunches of Ag nanoparticles. The film synthesized using microemulsion exhibited enhanced antibacterial efficacy compared to that prepared through in situ synthesis under the same test condition. Copyright © 2017 Elsevier Inc. All rights reserved.

Preparation and characteristics of TFMB functionalized graphene oxide/polyimide nanocomposite films

NASA Astrophysics Data System (ADS)

Liu, Lin; Wang, Yiyao; Gao, Yixin

2018-04-01

Polyimide(PI), with its great thermal and mechanical properties, has been widely used in various fields, such as aerospace and microelectronics. However, with the development of high technology, common PI materials can not satisfy the demands, due to its high resistance. In this work, we used 2,2'- Bis(trifluoromethyl) benzidine(TFMB) to functionalize GO and further form GO-TFMB/PI nanocomposite film. In the end, we got GO-TFMB/PI nanocomposite films with excellent thermal stability, better toughness and better electrical conductivity. As shown in results, the incorporation of GO-TFMB maintained excellent thermal stability. With the addition of GO-TFMB, the resistivity of the composite film decreased continuously. And when the content of GO-TFMB was 0.8 wt%, the resistivity could achieve the excellent antistatic material standard.

Nanoscale deformation mechanism of TiC/a-C nanocomposite thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, C. Q.; Pei, Y. T.; Shaha, K. P.

2009-06-01

This paper concentrates on the deformation behavior of amorphous diamondlike carbon composite materials. Combined nanoindentation and ex situ cross-sectional transmission electron microscopy investigations are carried out on TiC/a-C nanocomposite films, with and without multilayered structures deposited by pulse dc magnetron sputtering. It is shown that by controlling the distribution of nanocrystallites forming nanoscale multilayers, the system can be used as a 'microstructural ruler' that is able to distinguish various deformation patterns, which can be hardly detected otherwise in a homogeneous structure. It is shown that rearrangement of nanocrystallites and displacement of a-C matrix occur at length scales from tens ofmore » nanometer down to 1 nm. At submicrometer scale homogeneous nucleation of multiple shear bands has been observed within the nanocomposites. The multilayered structure in the TiC/a-C nanocomposite film contributes to an enhanced toughness.« less

Investigation of Zinc Oxide-Loaded Poly(Vinyl Alcohol) Nanocomposite Films in Tailoring Their Structural, Optical and Mechanical Properties

NASA Astrophysics Data System (ADS)

Aslam, Muhammad; Kalyar, Mazhar Ali; Raza, Zulfiqar Ali

2018-04-01

Wurtzite ZnO nanoparticles, as a nanofiller, were incorporated in a poly(vinyl alcohol) (PVA) matrix to prepare multipurpose nanocomposite films using a solution casting approach. Some advanced analytical techniques were used to investigate the properties of prepared nanocomposite films. The mediation of ZnO nanofillers resulted in modification of structural, optical and mechanical properties of nanocomposite films. A comprehensive band structure investigation might be useful for designing technological applications like in optoelectronic devices. The experimental results were found to be closely dependent on the nanofiller contents. Some theoretical models like Tauc's and Wemple-DiDomenico, were employed to investigate the band structure parameters. The imaginary part of the dielectric constant was used to investigate the band gap. Then, the Helpin-Tsai model was employed to predict Young's moduli of the prepared nanocomposite films. On 3 wt.% ZnO nanofiller loading, the optical band gap of the PVA-based nanocomposite film was decreased from 5.26 eV to 3 eV, the tensile strength increased from 25.3 MPa to 48 MPa and Young's modulus increased from 144 MPa to 544 MPa.

Investigation of Zinc Oxide-Loaded Poly(Vinyl Alcohol) Nanocomposite Films in Tailoring Their Structural, Optical and Mechanical Properties

NASA Astrophysics Data System (ADS)

Aslam, Muhammad; Kalyar, Mazhar Ali; Raza, Zulfiqar Ali

2018-07-01

Wurtzite ZnO nanoparticles, as a nanofiller, were incorporated in a poly(vinyl alcohol) (PVA) matrix to prepare multipurpose nanocomposite films using a solution casting approach. Some advanced analytical techniques were used to investigate the properties of prepared nanocomposite films. The mediation of ZnO nanofillers resulted in modification of structural, optical and mechanical properties of nanocomposite films. A comprehensive band structure investigation might be useful for designing technological applications like in optoelectronic devices. The experimental results were found to be closely dependent on the nanofiller contents. Some theoretical models like Tauc's and Wemple-DiDomenico, were employed to investigate the band structure parameters. The imaginary part of the dielectric constant was used to investigate the band gap. Then, the Helpin-Tsai model was employed to predict Young's moduli of the prepared nanocomposite films. On 3 wt.% ZnO nanofiller loading, the optical band gap of the PVA-based nanocomposite film was decreased from 5.26 eV to 3 eV, the tensile strength increased from 25.3 MPa to 48 MPa and Young's modulus increased from 144 MPa to 544 MPa.

Fabrication of γ-MPS-Modified HNT-PMMA Nanocomposites by Ultrasound-Assisted Miniemulsion Polymerization

NASA Astrophysics Data System (ADS)

Buruga, Kezia; Kalathi, Jagannathan T.

2018-04-01

Halloysite nanotubes (HNTs) were modified with γ-methacryloxypropyltrimethoxysilane (γ-MPS) to improve their interaction with the polymer, and the modified HNTs (MHNTs) were subsequently used for the synthesis of MHNT-polymethylmethacrylate (PMMA) nanocomposites by miniemulsion polymerization assisted by ultrasound. Reduced agglomeration of HNTs due to modification with γ-MPS was evident from scanning electron microscopy analysis. Modification of HNTs and exfoliation of MHNTs in the polymer nanocomposite were confirmed by the presence of their respective characteristic peaks in Fourier-transform infrared spectra and x-ray diffraction patterns. Transmission electron microscopic analysis showed that the surface of the MHNTs differed significantly from that of unmodified HNTs. MHNT-PMMA nanocomposite exhibited significantly higher glass-transition temperature (T g) compared with neat PMMA or unmodified HNT-PMMA nanocomposite. Hence, such modification of HNTs along with miniemulsion polymerization assisted by ultrasound is a promising approach to achieve better dispersion of HNTs in the polymer and to obtain nanocomposites with enhanced properties.

Optical, mechanical and structural properties of PMMA/SiO2 nanocomposite thin films

NASA Astrophysics Data System (ADS)

Soni, Gyanesh; Srivastava, Subodh; Soni, Purushottam; Kalotra, Pankaj; Vijay, Y. K.

2018-01-01

We have fabricated PMMA/SiO2 nanocomposite flexible thin films of 60 μm thicknesses by using solution casting method in the presence of transverse electric field. In this paper, we have investigated the effect of SiO2 nanoparticle (NP) loading on optical and mechanical properties of the composite thin film. The SEM images show that nanocomposite thin films have a smoother and uniform morphology. The transmittance peak near 1103 cm-1 in FT-IR spectrum confirms the presence of SiO2 NPs in the composite thin film. It is observed that optical bandgap decreases with an increase in the SiO2 NP concentration. Dynamic mechanical analysis shows that presence of SiO2 NP enhances the mechanical strength of the composite thin film.

Development of novel nano-composite membranes as introduction systems for mass spectrometers: Contrasting nano-composite membranes and conventional inlet systems

NASA Astrophysics Data System (ADS)

Miranda, Luis Diego

This dissertation presents the development of novel nano-composite membranes as introduction systems for mass spectrometers. These nano-composite membranes incorporate anodic aluminum oxide (AAO) membranes as templates that can be used by themselves or modified by a variety of chemical deposition processes. Two types of nano-composite membranes are presented. The first nano-composite membrane has carbon deposited within the pores of an AAO membrane. The second nano-composite membrane is made by coating an AAO membrane with a thin polymer film. The following chapters describe the transmission properties these nano-composite membranes and compare them to conventional mass spectrometry introduction systems. The nano- composite membranes were finally coupled to the inlet system of an underwater mass spectrometer revealing their utility in field deployments.

Evaporation-induced self-assembly of quantum dots-based concentric rings on polymer-based nanocomposite films.

PubMed

Zhang, Shaofu; Luan, Weiling; Zhong, Qixin; Yin, Shaofeng; Yang, Fuqian

2016-10-12

The "ball-on-film" template is used to construct concentric rings on the surface of PMMA-QDs (polymethyl methacrylate - quantum dots) nanocomposite films via the evaporation of pure chloroform droplets, which are confined by a steel ball. The concentric rings consist of QDs, as revealed by the fluorescence images of the concentric rings. The photoluminescence intensity of the concentric rings increases with the increase of the distance to the ball center, suggesting that the amount of QDs accumulated around the contact line at individual stick state increases with the increase of the distance to the ball center. Both the wavelength and cross-sectional area (width) of the concentric rings increase approximately linearly with increasing distance to the ball center, independent of the ball size, the film thickness and the QDs concentration. For the PMMA-QDs nanocomposite films prepared from the same QDs concentration in chloroform, the thicker the PMMA-QDs nanocomposite film, the larger the wavelength for the same distance to the ball center. The effect of confinement of two steel balls on the surface patterns over the PMMA-QDs nanocomposite films is studied via a template of "two spheres on film". Symmetric surface patterns are formed. There exist two types of featureless zone between the two balls, depending on the distance between the two balls: one is the inner featureless zone and the other is the outer featureless zone. The size of both featureless zones increases with the increase of the ball distance.

Graphene-metallic nanocomposites as modifiers in electrochemical glucose biosensor transducers

NASA Astrophysics Data System (ADS)

Altuntas, Derya Bal; Tepeli, Yudum; Anik, Ulku

2016-09-01

Graphene sheets and three different graphene-metallic nanocomposites including graphene-copper (graphene-Cu), graphene-nickel (graphene-Ni) and graphene-platinum (graphene-Pt) were prepared and characterized in the first place. Then the electrochemical performances of these nanocomposites were tested in glucose biosensor transducers, which were formed by combining these metallic nanocomposites with glucose oxidase enzyme and glassy carbon paste electrode (GCPE). This is the first work that includes the usage of these graphene-Me nanocomposites as a part of glucose biosensor transducer. Fabricated amperometric biosensors linear ranges were obtained as follow: For the plain graphene, the linear range was found in the concentration range between 50 μM and 800 μM with the RSD (n = 3 for 50 μM glucose) value of 12.86% and LOD value of 7.2 μM. For graphene-Pt modified glucose biosensor, the linear range was between 10 μM and 600 μM with the RSD (n = 3 for 50 μM glucose) value of 3.45% and LOD value of 3.06 μM. In the case of graphene-Ni modified glucose biosensor, the values were 25 μM to 600 μM with the RSD (n = 3 for 50 μM glucose) value of 8.76% and LOD value of 24.71 μM and for graphene-Cu modified glucose biosensor linear range was 25 μM to 400 μM with the RSD (n = 3 for 50 μM glucose) value of 3.93% and LOD value of 2.87 μM.

Stretchable Electronic Sensors of Nanocomposite Network Films for Ultrasensitive Chemical Vapor Sensing.

PubMed

Yan, Hong; Zhong, Mengjuan; Lv, Ze; Wan, Pengbo

2017-11-01

A stretchable, transparent, and body-attachable chemical sensor is assembled from the stretchable nanocomposite network film for ultrasensitive chemical vapor sensing. The stretchable nanocomposite network film is fabricated by in situ preparation of polyaniline/MoS 2 (PANI/MoS 2 ) nanocomposite in MoS 2 suspension and simultaneously nanocomposite deposition onto prestrain elastomeric polydimethylsiloxane substrate. The assembled stretchable electronic sensor demonstrates ultrasensitive sensing performance as low as 50 ppb, robust sensing stability, and reliable stretchability for high-performance chemical vapor sensing. The ultrasensitive sensing performance of the stretchable electronic sensors could be ascribed to the synergistic sensing advantages of MoS 2 and PANI, higher specific surface area, the reliable sensing channels of interconnected network, and the effectively exposed sensing materials. It is expected to hold great promise for assembling various flexible stretchable chemical vapor sensors with ultrasensitive sensing performance, superior sensing stability, reliable stretchability, and robust portability to be potentially integrated into wearable electronics for real-time monitoring of environment safety and human healthcare. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biopolymer-based nanocomposites: effect of lignin acetylation in cellulose triacetate films

PubMed Central

Nevárez, Laura Alicia Manjarrez; Casarrubias, Lourdes Ballinas; Celzard, Alain; Fierro, Vanessa; Muñoz, Vinicio Torres; Davila, Alejandro Camacho; Lubian, José Román Torres; Sánchez, Guillermo González

2011-01-01

We have prepared all-biopolymer nanocomposite films using lignin as a filler and cellulose triacetate (CTA) as a polymer matrix, and characterized them by several analytical methods. Three types of lignin were tested: organosolv, hydrolytic and kraft, with or without acetylation. They were used in the form of nanoparticles incorporated at 1 wt% in CTA. Self-supported films were prepared by vapor-induced phase separation at controlled temperature (35–55 °C) and relative humidity (10–70%). The efficiency of acetylation of each type of lignin was studied and discussed, as well as its effects on film structure, homogeneity and mechanical properties. The obtained results are explained in terms of intermolecular filler-matrix interaction at the nanometer scale, for which the highest mechanical resistance was reached using hydrolytic lignin in the nanocomposite. PMID:27877425

Mechanical and solubility properties of bio-nanocomposite film of semi refined kappa carrageenan/ZnO nanoparticles

NASA Astrophysics Data System (ADS)

Saputri, Apriliana Eka; Praseptiangga, Danar; Rochima, Emma; Panatarani, Camellia; Joni, I. Made

2018-02-01

The aim of this present work is to develop semi refined kappa carrageenan based bio-nanocomposite film as an alternative to synthetic petroleum based food packaging materials. Among natural polymers, carrageenan is one of the most promising material, since it is a renewable bioresource. The ZnO nanoparticles (0.5%; 1.0%; 1.5% w/w carrageenan) was incorporated into carrageenan polymer to prepare bio-nanocomposite films, where ZnO acts as reinforcement for carrageenan matrix. The mechanical and solubility properties of the prepared films were investigated as a function of ZnO concentration. The results indicated that the addition of ZnO exhibits greater solubility compared to the neat film. The elongation at break is insignificantly different on the films with and without addition ZnO. The tensile strength of the film was highest for the sample with 0.5% ZnO. These mechanical and solubility properties suggest that bio-nanocomposite film of semi refined kappa carrageenan and nanoparticle ZnO can be effectively used as food packaging material.

Optical studies of CdSe/PVA nanocomposite films

NASA Astrophysics Data System (ADS)

Kushwaha, Kamal Kumar; Ramrakhaini, Meera

2018-05-01

The nanocomposite films of CdSe nanocrystals in polyvinyl alcohol (PVA) matrix were synthesized by environmental friendly chemical method. These composites were characterized by X-ray diffraction which indicates the hexagonal crystalline structure of CdSe with crystal size up to a few nm. The crystal size is found to decrease by increasing PVA Concentration. The photoluminescence (PL) characteristics of these composite films with varying concentration of PVA as well as Cd2+ content have been investigated. The PL peak of CdSe was observed at 510 nm and higher intensity is observed by increasing PVA concentration without any change in position of PL peak. Due to proper passivation of surface states non-radiative transition are reduced which enhance the PL intensity. By increasing concentration of Cd2+ content in the CdSe/PVA nanocomposite films, smaller CdSe nanocrystals were obtained giving higher intensity and blue shift in the PL peak due to enhanced oscillator strength and quantum confinement effect. The PL peak in green and blue region makes these composite films promising materials for optical display devices. The Refractive index of these composites was also measured at sodium line with the help of Abee's refractometer and was found in the range of 2.20-2.45. It is seen that refractive index varies with polymer concentration. This may be useful for their potential application in anti-reflection coating, display devices and optical sensors.

Rheological and thermal properties of polylactide/silicate nanocomposites films.

PubMed

Ahmed, Jasim; Varshney, Sunil K; Auras, Rafeal

2010-03-01

Polylactide (DL)/polyethylene glycol/silicate nanocomposite blended biodegradable films have been prepared by solvent casting method. Rheological and thermal properties were investigated for both neat amorphous polylactide (PLA-DL form) and blend of montmorillonite (clay) and poly (ethylene glycol) (PEG). Melt rheology of the PLA individually and blends (PLA/clay; PLA/PEG; PLA/PEG/clay) were performed by small amplitude oscillation shear (SAOS) measurement. Individually, PLA showed an improvement in the viscoelastic properties in the temperature range from 180 to 190 degrees C. Incorporation of nanoclay (3% to 9% wt) was attributed by significant improvements in the elastic modulus (G') of PLA/clay blend due to intercalation at higher temperature. Both dynamic modulii of PLA/PEG blend were significantly reduced with addition of 10% PEG. Rheometric measurement could not be conducted while PLA/PEG blends containing 25% PEG. A blend of PLA/PEG/clay (68/23/9) showed liquid-like properties with excellent flexibility. Thermal analysis of different clay loading films indicated that the glass transition temperatures (T(g)) remained unaffected irrespective of clay concentration due to immobilization of polymer chain in the clay nanocomposite. PEG incorporation reduced the T(g) of the blend (PLA/PEG and PLA/PEG/clay) significantly. Both rheological and thermal analysis data supported plasticization and flexibility of the blended films. It is also interesting to study competition between PLA and PEG for the intercalation into the interlayer spacing of the clay. This study indicates that PLA/montmorillonite blend could serve as effective nano-composite for packaging and other applications.

Development of an antimicrobial material based on a nanocomposite cellulose acetate film for active food packaging.

PubMed

Rodríguez, Francisco J; Torres, Alejandra; Peñaloza, Ángela; Sepúlveda, Hugo; Galotto, María J; Guarda, Abel; Bruna, Julio

2014-01-01

Nanocomposites based on biopolymers have been recognised as potential materials for the development of new ecofriendly food packaging. In addition, if these materials incorporate active substances in their structure, the potential applications are much higher. Therefore, this work was oriented to develop nanocomposites with antimicrobial activity based on cellulose acetate (CA), a commercial organoclay Cloisite30B (C30B), thymol (T) as natural antimicrobial component and tri-ethyl citrate (TEC) as plasticiser. Nanocomposites were prepared by a solvent casting method and consisted of 5% (w/w) of C30B, 5% (w/w) of TEC and variable content of T (0%, 0.5% and 2% w/w). To evaluate the effect of C30B into the CA matrix, CA films without this organoclay but with T were also prepared. All nanocomposites showed the intercalation of CA into the organoclay structure; furthermore this intercalation was favoured when 2% (w/w) of T was added to the nanocomposite. In spite of the observed intercalation, the presence of C30B inside the CA matrices increased the opacity of the films significantly. On the other hand, T showed a plasticiser effect on the thermal properties of CA nanocomposites decreasing glass transition, melting temperature and melting enthalpy. The presence of T in CA nanocomposites also allowed the control de Listeria innocua growth when these materials were placed in contact with this Gram-positive bacterium. Interestingly, antimicrobial activity was increased with the presence of C30B. Finally, studies on T release showed that the clay structure inside the CA matrix did not affect its release rate; however, this nanofiller affected the partition coefficient KP/FS which was higher to CA nanocomposites films than in CA films without organoclay. The results obtained in the present study are really promising to be applied in the manufacture of food packaging materials.

Storage stability of banana chips in polypropylene based nanocomposite packaging films.

PubMed

Manikantan, M R; Sharma, Rajiv; Kasturi, R; Varadharaju, N

2014-11-01

In this study, polypropylene (PP) based nanocomposite films of 15 different compositions of nanoclay, compatibilizer and thickness were developed and used for packaging and storage of banana chips. The effect of nanocomposite films on the quality characteristics viz. moisture content (MC), water activity (WA), total color difference(TCD), breaking force (BF), free fatty acid (FFA), peroxide value(PV), total plate count (TPC) and overall acceptability score of banana chips under ambient condition at every 15 days interval were studied for 120 days. All quality parameters of stored banana chips increased whereas overall acceptability scores decreased during storage. The elevation in FFA, BF and TCD of stored banana chips increased with elapse of storage period as well as with increased proportion of both nanoclay and compatibilizer but decreased by reducing the thickness of film. Among all the packaging materials, the WA of banana chips remained lower than 0.60 i.e. critical limit for microbial growth up to 90 days of storage. The PV of banana chips packaged also remained within the safe limit of 25 meq oxygen kg(-1) throughout the storage period. Among all the nanocomposite films, packaging material having 5 % compatibilizer, 2 % nanoclay & 100 μm thickness (treatment E) and 10 % compatibilizer, 4 % nanoclay & 120 μm thickness (treatment N) showed better stability of measured quality characteristics of banana chips than any other treatment.

Probing localized strain in solution-derived YB a2C u3O7 -δ nanocomposite thin films

NASA Astrophysics Data System (ADS)

Guzman, Roger; Gazquez, Jaume; Mundet, Bernat; Coll, Mariona; Obradors, Xavier; Puig, Teresa

2017-07-01

Enhanced pinning due to nanoscale strain is unique to the high-Tc cuprates, where pairing may be modified with lattice distortion. Therefore a comprehensive understanding of the defect landscape is required for a broad range of applications. However, determining the type and distribution of defects and their associated strain constitutes a critical task, and for this aim, real-space techniques for atomic resolution characterization are necessary. Here, we use scanning transmission electron microscopy (STEM) to study the atomic structure of individual defects of solution-derived YB a2C u3O7 (YBCO) nanocomposites, where the inclusion of incoherent secondary phase nanoparticles within the YBCO matrix dramatically increases the density of Y1B a2C u4O8 (Y124) intergrowths, the commonest defect in YBCO thin films. The formation of the Y124 is found to trigger a concatenation of strain-derived interactions with other defects and the concomitant nucleation of intrinsic defects, which weave a web of randomly distributed nanostrained regions that profoundly transform the vortex-pinning landscape of the YBCO nanocomposite thin films.

Nanocomposites of rice and banana flours blend with montmorillonite: partial characterization.

PubMed

Rodríguez-Marín, María L; Bello-Pérez, Luis A; Yee-Madeira, Hernani; Zhong, Qixin; González-Soto, Rosalía A

2013-10-01

Rice and banana flours are inexpensive starchy materials that can form films with more improved properties than those made with their starch because flour and starch present different hydrophobicity. Montmorillonite (MMT) can be used to further improve the properties of starch-based films, which has not received much research attention for starchy flours. The aim of this work was to evaluate the mechanical and barrier properties of nanocomposite films of banana and rice flours as matrix material with addition of MMT as a nanofiller. MMT was modified using citric acid to produce intercalated structures, as verified by the X-ray diffraction pattern. The intercalated MMT was blended with flour slurries, and films were prepared by casting. Nanocomposite films of banana and rice flours presented an increase in the tensile at break and elongation percentage, respectively, more than their respective control films without MMT. This study showed that banana and rice flours could be alternative raw materials to use in making nanocomposite films. Copyright © 2013 Elsevier B.V. All rights reserved.

Biodegradation and cytotoxicity of ciprofloxacin-loaded hydroxyapatite-polycaprolactone nanocomposite film for sustainable bone implants.

PubMed

Nithya, Rajendran; Meenakshi Sundaram, Nachiappan

2015-01-01

In recent years there has been a steep increase in the number of orthopedic patients for many reasons. One major reason is osteomyelitis, caused by pyrogenic bacteria, with progressive infection of the bone or bone marrow and surrounding tissues. So antibiotics must be introduced during bone implantation to avoid prolonged infection. The objective of the study reported here was to prepare a composite film of nanocrystalline hydroxyapatite (HAp) and polycaprolactone (PCL) polymer loaded with ciprofloxacin, a frequently used antibiotic agent for bone infections. Nanocrystalline HAp was synthesized by precipitation method using the precursor obtained from eggshell. The nanocomposite film (HAp-PCL-ciprofloxacin) was prepared by solvent evaporation. Drug-release and biodegradation studies were undertaken by immersing the composite film in phosphate-buffered saline solution, while a cytotoxicity test was performed using the fibroblast cell line NIH-3T3 and osteoblast cell line MG-63. The pure PCL film had quite a low dissolution rate after an initial sharp weight loss, whereas the ciprofloxacin-loaded HAp-PCL nanocomposite film had a large weight loss due to its fast drug release. The composite film had higher water absorption than the pure PCL, and increasing the concentration of the HAp increased the water absorption. The in vitro cell-line study showed a good biocompatibility and bioactivity of the developed nanocomposite film. The prepared film will act as a sustainable bone implant in addition to controlled drug delivery.

Moisture Absorption Behaviour of Biopolymer Polycapralactone (PCL) / Organo Modified Montmorillonite Clay (OMMT) biocomposite films

NASA Astrophysics Data System (ADS)

Malik, Neetu; Shrivastava, Sharad; Bandhu Ghosh, Subrata

2018-04-01

Bio composite materials were fabricated using mixing biodegradable polymer polycaptalactone (PCL) and Organo Modified Montmorillonite Clay (OMMT) through solution casting. Various samples of bio composite films were prepared by varying the OMMT wt% composition by 0.1%, 0.5%, 1% and 1.5%. Thereafter, the density and water absorption of the composites were investigated with respect to immersion time in water. The moisture absorption results show that with an increase in weight percentage (from 0.1 to wt 1.5%) of OMMT within the bio polymer films, the absorption value of bio-nanocomposite films reduced rapidly from 34.4% to 22.3%. The density of hybrid composites also increased with increase in weight percentage of OMMT. The swelling characteristic of PCL increased with increasing % of OMMT clay. These results indicate that the optimized composition of constituents in composite membrane could effectively reduce the anhydrous conditions of bio-composite film.

Ductile all-cellulose nanocomposite films fabricated from core-shell structured cellulose nanofibrils.

PubMed

Larsson, Per A; Berglund, Lars A; Wågberg, Lars

2014-06-09

Cellulosic materials have many desirable properties such as high mechanical strength and low oxygen permeability and will be an important component in a sustainable biomaterial-based society, but unfortunately they often lack the ductility and formability offered by petroleum-based materials. This paper describes the fabrication and characterization of nanocomposite films made of core-shell modified cellulose nanofibrils (CNFs) surrounded by a shell of ductile dialcohol cellulose, created by heterogeneous periodate oxidation followed by borohydride reduction of the native cellulose in the external parts of the individual fibrils. The oxidation with periodate selectively produces dialdehyde cellulose, and the process does not increase the charge density of the material. Yet the modified cellulose fibers could easily be homogenized to CNFs. Prior to film fabrication, the CNF was shown by atomic force microscopy to be 0.5-2 μm long and 4-10 nm wide. The films were fabricated by filtration, and besides uniaxial tensile testing at different relative humidities, they were characterized by scanning electron microscopy and oxygen permeability. The strength-at-break at 23 °C and 50% RH was 175 MPa, and the films could, before rupture, be strained, mainly by plastic deformation, to about 15% and 37% at 50% RH and 90% RH, respectively. This moisture plasticization was further utilized to form a demonstrator consisting of a double-curved structure with a nominal strain of 24% over the curvature. At a relative humidity of 80%, the films still acted as a good oxygen barrier, having an oxygen permeability of 5.5 mL·μL/(m(2)·24 h·kPa). These properties indicate that this new material has a potential for use as a barrier in complex-shaped structures and hence ultimately reduce the need for petroleum-based plastics.

Hydrothermal Synthesis Au-Bi2Te3 Nanocomposite Thermoelectric Film with a Hierarchical Sub-Micron Antireflection Quasi-Periodic Structure.

PubMed

Tian, Junlong; Zhang, Wang; Zhang, Yuan; Xue, Ruiyang; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

2015-06-03

In this work, Au-Bi(2)Te(3) nanocomposite thermoelectric film with a hierarchical sub-micron antireflection quasi-periodic structure was synthesized via a low-temperature chemical route using Troides helena (Linnaeus) forewing (T_FW) as the biomimetic template. This method combines chemosynthesis with biomimetic techniques, without the requirement of expensive equipment and energy intensive processes. The microstructure and the morphology of the Au-Bi(2)Te(3) nanocomposite thermoelectric film was analyzed by X-ray diffraction (XRD), field-emission scanning-electron microscopy (FESEM), and transmission electron microscopy (TEM). Coupled the plasmon resonances of the Au nanoparticles with the hierarchical sub-micron antireflection quasi-periodic structure, the Au-Bi(2)Te(3) nanocomposite thermoelectric film possesses an effective infrared absorption and infrared photothermal conversion performance. Based on the finite difference time domain method and the Joule effect, the heat generation and the heat source density distribution of the Au-Bi(2)Te(3) nanocomposite thermoelectric film were studied. The heterogeneity of heat source density distribution of the Au-Bi(2)Te(3) nanocomposite thermoelectric film opens up a novel promising technique for generating thermoelectric power under illumination.

Effect of Surfactant Type and Sonication Energy on the Electrical Conductivity Properties of Nanocellulose-CNT Nanocomposite Films.

PubMed

Siljander, Sanna; Keinänen, Pasi; Räty, Anna; Ramakrishnan, Karthik Ram; Tuukkanen, Sampo; Kunnari, Vesa; Harlin, Ali; Vuorinen, Jyrki; Kanerva, Mikko

2018-06-20

We present a detailed study on the influence of sonication energy and surfactant type on the electrical conductivity of nanocellulose-carbon nanotube (NFC-CNT) nanocomposite films. The study was made using a minimum amount of processing steps, chemicals and materials, to optimize the conductivity properties of free-standing flexible nanocomposite films. In general, the NFC-CNT film preparation process is sensitive concerning the dispersing phase of CNTs into a solution with NFC. In our study, we used sonication to carry out the dispersing phase of processing in the presence of surfactant. In the final phase, the films were prepared from the dispersion using centrifugal cast molding. The solid films were analyzed regarding their electrical conductivity using a four-probe measuring technique. We also characterized how conductivity properties were enhanced when surfactant was removed from nanocomposite films; to our knowledge this has not been reported previously. The results of our study indicated that the optimization of the surfactant type clearly affected the formation of freestanding films. The effect of sonication energy was significant in terms of conductivity. Using a relatively low 16 wt. % concentration of multiwall carbon nanotubes we achieved the highest conductivity value of 8.4 S/cm for nanocellulose-CNT films ever published in the current literature. This was achieved by optimizing the surfactant type and sonication energy per dry mass. Additionally, to further increase the conductivity, we defined a preparation step to remove the used surfactant from the final nanocomposite structure.

Fabrication and characterization of polyvinyl alcohol/metal (Ca, Mg, Ti) doped zirconium phosphate nanocomposite films for scaffold-guided tissue engineering application.

PubMed

Kalita, Himani; Pal, Pallabi; Dhara, Santanu; Pathak, Amita

2017-02-01

Nanocomposite films of polyvinyl alcohol (PVA) and zirconium phosphate (ZrP)/doped ZrP (doped with Ca, Mg, Ti) nanoparticles have been developed by solvent casting method to assess their potential as matrix material in scaffold-guided tissue engineering application. The prepared ZrP and doped ZrP nanoparticles as well as the nanocomposite films were characterized by various spectroscopic and microscopic techniques. Nanoindentation studies revealed improved nanomechanical properties in the PVA/doped ZrP nanocomposite films (highest for PVA/Ti doped ZrP: hardness=262.4MPa; elastic modulus=5800MPa) as compared to the PVA/ZrP and neat PVA films. In-vitro cell culture experiments carried out to access the cellular viability, attachment, proliferation, and migration on the substrates, using mouse fibroblast (3T3) cell lines, inferred enhanced bioactivity in the PVA/doped ZrP nanocomposite films (highest for PVA/Ca doped ZrP) in contrast to PVA/ZrP and neat PVA films. Controlled biodegradability as well as swelling behavior, superior bioactivity and improved mechanical properties of the PVA/doped ZrP nanocomposite films make them promising matrix materials for scaffold-guided tissue engineering application. Copyright © 2016 Elsevier B.V. All rights reserved.

Self-assembled Co-BaZrO 3 nanocomposite thin films with ultra-fine vertically aligned Co nanopillars

DOE PAGES

Huang, Jijie; Li, Leigang; Lu, Ping; ...

2017-05-11

A simple one-step pulsed laser deposition (PLD) method has been applied to grow self-assembled metal-oxide nanocomposite thin films. The as-deposited Co-BaZrO 3 films show high epitaxial quality with ultra-fine vertically aligned Co nanopillars (diameter <5 nm) embeded in BZO matrix. The diameter of the nanopillars can be further tuned by varying the deposition frequency. The metal and oxide phases grow separately without inter-diffusion or mixing. Taking advantage of this unique structure, a high saturation magnetization of ~1375 emu/cm 3 in the Co- BaZrO 3 nanocomposites has been achieved and further confirmed by Lorentz microscopy imaging in TEM. Furthermore, the coercivitymore » values of this nanocomposite thin films range from 600 Oe (20 Hz) to 1020 Oe (2 Hz), which makes the nanocomposite an ideal candidate for high-density perpendicular recording media.« less

Dielectric property study of poly(4-vinylphenol)-graphene oxide nanocomposite thin film

NASA Astrophysics Data System (ADS)

Roy, Dhrubojyoti

2018-05-01

Thin film capacitor device having a sandwich structure of indium tin oxide (ITO)-coated glass/polymer or polymer nanocomposite /silver has been fabricated and their dielectric and leakage current properties has been studied. The dielectric properties of the capacitors were characterized for frequencies ranging from 1 KHz to 1 MHz. 5 wt% Poly(4-vinylphenol)(PVPh)-Graphene (GO) nanocomposite exhibited an increase in dielectric constant to 5.6 and small rise in dielectric loss to around˜0.05 at 10 KHz w.r.t polymer. The DC conductivity measurements reveal rise of leakage current in nanocomposite.

Photodynamic action of curcumin derived polymer modified ZnO nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hariharan, R.; Senthilkumar, S.; Suganthi, A., E-mail: suganthiphd09@gmail.com

2012-11-15

Highlights: ► ZnO/PVA nano sensitized with curcumin and its metal complex were synthesized by vacuum evaporation method. ► M/cur sensitized on ZnO/PVA nanocomposites were characterized. ► Generation of {sup 1}O{sub 2} and ROS were detected by optical and EPR-spin trapping method. ► It was found that photoinduced cleavage of DNA using Zn/cur–ZnO/PVA was superior. ► Photodegradation of MB in water catalyzed by ZnO/PVA–Zn/cur was also superior under visible light. -- Abstract: The photodynamic action of ZnO nano can be improved by modifying the surface by PVA and encapsulating the natural product, curcumin. The synthesized ZnO/PVA nanocomposites have been characterized usingmore » XRD, SEM, TEM, FTIR, TG–DTA, etc. Here we are reporting the photodynamic effect of ZnO nanocomposites on pUC18 DNA. Based on optical and EPR measurements, singlet oxygen and other ROS were responsible for photocleavage of DNA. Most importantly, derived curcumin modified ZnO/PVA nanocomposites were comparatively more effective than derived curcumin complex against HeLa cell lines under in vitro condition. In addition, photodegradation of methylene blue (MB) in water catalyzed by nano ZnO/PVA–curcumin derivative was investigated at room temperature. Under visible irradiation photocatalytic activity of ZnO nanomaterial sensitized curcumin was higher than those of curcumin and nano ZnO.« less

Analysis of ultraviolet exposure effects on the surface properties of epoxy/graphene nanocomposite films on Mylar substrate

NASA Astrophysics Data System (ADS)

Clausi, Marialaura; Santonicola, M. Gabriella; Schirone, Luigi; Laurenzi, Susanna

2017-05-01

In this paper, we present a study of the effects generated by exposure to UV-C radiation on nanocomposite films made of graphene nanoplatelets dispersed in an epoxy matrix. The nanocomposite films, at different nanoparticle size and concentration, were fabricated on Mylar substrate using the spin coating process. The effects of UV-C irradiation on the surface hydrophobicity and on the electrical properties of the epoxy/graphene films were investigated using contact angle measurements and electrical impedance spectroscopy, respectively. According to our results, the UV-C irradiation selectively degrades the polymer matrix of the nanocomposite films, giving rise to more conductive and hydrophobic layers due to exposure of the graphene component of the composite material. The results presented here have important implications in the design of spacecraft components and structures destined for long-term space missions.

Pd-Ni-MWCNT nanocomposite thin films: preparation and structure

NASA Astrophysics Data System (ADS)

Kozłowski, Mirosław; Czerwosz, ElŻbieta; Sobczak, Kamil

2017-08-01

The properties of nanocomposite palladium-nickel-multi-walled (Pd-Ni-MWCNT) films deposited on aluminum oxide (Al2O3) substrate have been prepared and investigated. These films were obtained by 3 step process consisted of PVD/CVD/PVD methods. The morphology and structure of the obtained films were characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques at various stages of the film formation. EDX spectrometer was used to measurements of elements segregation in the obtained film. TEM and STEM (Scanning Transmission Electron Microscopy) observations showed MWCNTs decorated with palladium nanoparticles in the film obtained in the last step of film formation (final PVD process). The average size of the palladium nanoparticles observed both on MWCNTs and carbonaceous matrix does not exceed 5 nm. The research was conducted on the use of the obtained films as potential sensors of gases (e.g. H2, NH3, CO2) and bio-sensors or optical sensors.

Characterization of an Olive Flounder Bone Gelatin-Zinc Oxide Nanocomposite Film and Evaluation of Its Potential Application in Spinach Packaging.

PubMed

Beak, Songee; Kim, Hyeri; Song, Kyung Bin

2017-11-01

Olive flounder bone gelatin (OBG) was used for a film base material in this study. In addition, zinc oxide nanoparticles (ZnO) were incorporated into the OBG film to prepare a nanocomposite film and to impart antimicrobial activity to it. The tensile strength of the OBG film increased by 6.62 MPa, and water vapor permeability and water solubility decreased by 0.93 × 10 -9 g/m s Pa and 13.79%, respectively, by the addition of ZnO to the OBG film. In particular, the OBG-ZnO film exhibited antimicrobial activity against Listeria monocytogenes. To investigate the applicability of the OBG-ZnO packaging film, fresh spinach was wrapped in this film and stored for a week. The results indicated that the OBG-ZnO film showed antimicrobial activity against L. monocytogenes inoculated on spinach without affecting the quality of spinach, such as vitamin C content and color. Thus, the OBG-ZnO nanocomposite film can be applied as an efficient antimicrobial food packaging material. As a base material of edible films, gelatin was extracted from olive flounder bone, which is fish processing by-product. Olive flounder bone gelatin (OBG) nanocomposite films were prepared with zinc oxide nanoparticles (ZnO). For an application to antimicrobial packaging, spinach was wrapped with the OBG-ZnO nanocomposite film. © 2017 Institute of Food Technologists®.

Effect of heterocyclic based organoclays on the properties of polyimide-clay nanocomposites.

PubMed

Krishnan, P Santhana Gopala; Joshi, Mangala; Bhargava, Prachur; Valiyaveettil, Suresh; He, Chaobin

2005-07-01

Polyimide-clay nanocomposites were prepared from their precursor, namely, polyamic acid, by the solution-casting method. Organomodified montmorillonite (MMT) clay was prepared by treating Na+MMT (Kunipia F) with three different intercalating agents, namely, piperazine dihydrochloride, 1,3-bis(4-piperidinylpropane) dihydrochloride and 4,4'-bipiperidine dihydrochloride at 80 degrees C. Polyamic acid solutions containing various weight percentages of organomodified MMT were prepared by reacting 4,4'-(1,1'-biphenyl-4,4'-diyldioxy)dianiline with bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride in N-methyl-2-pyrrolidinone containing dispersed particles of organomodified MMT at 20 degrees C. Nanocomposite films were prepared from these solutions by solution casting and heated subsequently at a programmed heating rate. These films were transparent and brown in color. The extent of layer separation in nanocomposite films depends upon the chemical structure of the organoclay. These films were characterized by inherent viscosity, FT-IR, DSC, TMA, WAXD, TEM, UV, and TGA. The tensile behavior and surface energy studies were also investigated. The nanocomposite films had superior tensile properties, thermal behavior, and solvent resistance. Among the three organoclays, piperazine dihydrochloride was the best modifier.

Thermomechanical properties of polymer nanocomposites: Exploring a unified relationship with planar polymer films

NASA Astrophysics Data System (ADS)

Bansal, Amitabh

The thermal and mechanical response of polymers, which provide limitations to their practical use, are greatly improved by the addition of a small fraction of an inorganic nanofiller. However, the resulting changes in polymer properties are poorly understood, primarily due to the non-uniform spatial distribution of nanoparticles. This research explores the properties of polystyrene filed with silica nanoparticles and illustrates for the first time that the thermodynamic properties of "polymer nanocomposites" are quantitatively equivalent to the well-understood case of planar polymer films with a uniform thickness. These ideas are quantified by drawing a direct analogy between thin film thickness and an appropriate average ligament thickness measured using electron microscopy. The change in polymer glass transition temperatures with decreasing ligament thickness were found to be quantitatively equivalent to the corresponding thin film data. In combination with viscoelastic properties of the nanocomposites that are in quantitative agreement with data from thin films, these conclusions provide a facile means of understanding and predicting the thermomechanical properties and, potentially, the engineering properties of practically relevant polymer nanocomposites. Grafting of high molecular weight polystyrene onto the silica nanoparticles greatly improves the dispersion quality of nanofillers and also provides a means to tailor the thermo-mechanical properties in nanocomposites. It is concluded that the grafted polystyrene is akin to polymer brushes on flat surfaces. The mobility and stiffness of these grafted chains are expected to be low as compared to the free polymer. In this context a mechanism for the increase in glass transition is proposed: (1) the stiff grafted chains will tend to decrease mobility and thus increase glass transition, (2) the extent of interdigitation of the grafted polystyrene into the matrix will determine the extent to which the nanocomposite

Development of LLDPE based active nanocomposite films with nanoclays impregnated with volatile compounds.

PubMed

Tornuk, Fatih; Sagdic, Osman; Hancer, Mehmet; Yetim, Hasan

2018-05-01

In this study, a novel procedure was performed for grafting of nanoclays (montmorillonite (MMT) and halloysite (HNT)) with essential oil constituents (thymol (THY), eugenol (EUG) and carvacrol (CRV)) using Tween 80 as surfactant and then the nanoclay particles were incorporated into LLDPE pellets (5 wt%) to produce active nanocomposite films using a twin screw extruder. The resulting nanocomposite films were analyzed for antimicrobial and antioxidant capacity as well as thickness, mechanical, color, barrier, thermal properties and surface morphology and molecular composition. Release of the active compounds from the films at the refrigerated and room temperature conditions were also tested. The results showed that the films had strong in vitro antibacterial activity against pathogenic bacteria (Salmonella Typhimurium, Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus) while their effect against lactic acid bacteria (Lactobacillus rhamnosus and Lb. casei) was limited. The lowest and highest DPPH scavenging ability levels were 65.59% and % 87.92, belonged to THY-MMT and EUG-MMT, respectively. Release of active compounds at 24 °C was much more rapid than at 4 °C. CRV-HNT and THY-HNT provided slower release than the other films. SEM results showed that nanoclays were uniformly dispersed in the polymer matrix with exceptional agglomerates. Incorporation of the active nanoclays significantly (P > 0.05) improved tensile strength and elongation of the films. The results confirmed that LLDPE based active nanocomposite films could be successfully produced due to its good interaction with MMT and HNT, activated with THY, EUG and CRV. Copyright © 2018 Elsevier Ltd. All rights reserved.

Interpreting Neutron Reflectivity Profiles of Diblock Copolymer Nanocomposite Thin Films Using Hybrid Particle-Field Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahalik, Jyoti P.; Dugger, Jason W.; Sides, Scott W.

Mixtures of block copolymers and nanoparticles (block copolymer nanocomposites) are known to microphase separate into a plethora of microstructures, depending on the composition, length scale and nature of interactions among its different constituents. Theoretical and experimental works on this class of nanocomposites have already high-lighted intricate relations among chemical details of the polymers, nanoparticles, and various microstructures. Confining these nanocomposites in thin films yields an even larger array of structures, which are not normally observed in the bulk. In contrast to the bulk, exploring various microstructures in thin films by the experimental route remains a challenging task. Here in thismore » work, we construct a model for the thin films of lamellar forming diblock copolymers containing spherical nanoparticles based on a hybrid particle-field approach. The model is benchmarked by comparison with the depth profiles obtained from the neutron reflectivity experiments for symmetric poly(deuterated styrene-b-n butyl methacrylate) copolymers blended with spherical magnetite nanoparticles covered with hydrogenated poly(styrene) corona. We show that the model based on a hybrid particle-field approach provides details of the underlying microphase separation in the presence of the nanoparticles through a direct comparison to the neutron reflectivity data. This work benchmarks the application of the hybrid particle-field model to extract the interaction parameters for exploring different microstructures in thin films containing block copolymers and nanocomposites.« less

Interpreting Neutron Reflectivity Profiles of Diblock Copolymer Nanocomposite Thin Films Using Hybrid Particle-Field Simulations

DOE PAGES

Mahalik, Jyoti P.; Dugger, Jason W.; Sides, Scott W.; ...

2018-04-10

Mixtures of block copolymers and nanoparticles (block copolymer nanocomposites) are known to microphase separate into a plethora of microstructures, depending on the composition, length scale and nature of interactions among its different constituents. Theoretical and experimental works on this class of nanocomposites have already high-lighted intricate relations among chemical details of the polymers, nanoparticles, and various microstructures. Confining these nanocomposites in thin films yields an even larger array of structures, which are not normally observed in the bulk. In contrast to the bulk, exploring various microstructures in thin films by the experimental route remains a challenging task. Here in thismore » work, we construct a model for the thin films of lamellar forming diblock copolymers containing spherical nanoparticles based on a hybrid particle-field approach. The model is benchmarked by comparison with the depth profiles obtained from the neutron reflectivity experiments for symmetric poly(deuterated styrene-b-n butyl methacrylate) copolymers blended with spherical magnetite nanoparticles covered with hydrogenated poly(styrene) corona. We show that the model based on a hybrid particle-field approach provides details of the underlying microphase separation in the presence of the nanoparticles through a direct comparison to the neutron reflectivity data. This work benchmarks the application of the hybrid particle-field model to extract the interaction parameters for exploring different microstructures in thin films containing block copolymers and nanocomposites.« less

Effects of preparation methods on the structure and mechanical properties of wet conditioned starch/montmorillonite nanocomposite films.

PubMed

Müller, Péter; Kapin, Éva; Fekete, Erika

2014-11-26

TPS/Na-montmorillonite nanocomposite films were prepared by solution and melt blending. Clay content changed between 0 and 25 wt% based on the amount of dry starch. Structure, tensile properties, and water content of wet conditioned films were determined as a function of clay content. Intercalated structure and VH-type crystallinity of starch were found for all the nanocomposites independently of clay and plasticizer content or preparation method, but at larger than 10 wt% clay content nanocomposites prepared by melt intercalation contained aggregated particles as well. In spite of the incomplete exfoliation clay reinforces TPS considerably. Preparation method has a strong influence on mechanical properties of wet conditioned films. Mechanical properties of the conditioned samples prepared by solution homogenization are much better than those of nanocomposites prepared by melt blending. Water, which was either adsorbed or bonded in the composites in conditioning or solution mixing process, respectively, has different effect on mechanical properties. Copyright © 2014 Elsevier Ltd. All rights reserved.

PLGA/Ag nanocomposites: in vitro degradation study and silver ion release.

PubMed

Fortunati, E; Latterini, L; Rinaldi, S; Kenny, J M; Armentano, I

2011-12-01

New nanocomposite films based on a biodegradable poly (DL-Lactide-co-Glycolide) copolymer (PLGA) and different concentration of silver nanoparticles (Ag) were developed by solvent casting. In vitro degradation studies of PLGA/Ag nanocomposites were conducted under physiological conditions, over a 5 week period, and compared to the behaviour of the neat polymer. Furthermore the silver ions (Ag(+)) release upon degradation was monitored to obtain information on the properties of the nanocomposites during the incubation. The obtained results suggest that the PLGA film morphology can be modified introducing a small percentage of silver nanoparticles that do not affect the degradation mechanism of PLGA polymer in the nanocomposite. However results clearly evinced the stabilizing effect of the Ag nanoparticles in the PLGA polymer and the mineralization process induced by the combined effect of silver and nanocomposite surface topography. The Ag(+) release can be controlled by the polymer degradation processes, evidencing a prolonged antibacterial effect.

Modifying Silicates for Better Dispersion in Nanocomposites

NASA Technical Reports Server (NTRS)

Campbell, Sandi

2005-01-01

An improved chemical modification has been developed to enhance the dispersion of layered silicate particles in the formulation of a polymer/silicate nanocomposite material. The modification involves, among other things, the co-exchange of an alkyl ammonium ion and a monoprotonated diamine with interlayer cations of the silicate. The net overall effects of the improved chemical modification are to improve processability of the nanocomposite and maximize the benefits of dispersing the silicate particles into the polymer. Some background discussion is necessary to give meaning to a description of this development. Polymer/silicate nanocomposites are also denoted polymer/clay composites because the silicate particles in them are typically derived from clay particles. Particles of clay comprise layers of silicate platelets separated by gaps called "galleries." The platelet thickness is 1 nm. The length varies from 30 nm to 1 m, depending on the silicate. In order to fully realize the benefits of polymer/silicate nanocomposites, it is necessary to ensure that the platelets become dispersed in the polymer matrices. Proper dispersion can impart physical and chemical properties that make nanocomposites attractive for a variety of applications. In order to achieve nanometer-level dispersion of a layered silicate into a polymer matrix, it is typically necessary to modify the interlayer silicate surfaces by attaching organic functional groups. This modification can be achieved easily by ion exchange between the interlayer metal cations found naturally in the silicate and protonated organic cations - typically protonated amines. Long-chain alkyl ammonium ions are commonly chosen as the ion-exchange materials because they effectively lower the surface energies of the silicates and ease the incorporation of organic monomers or polymers into the silicate galleries. This completes the background discussion. In the present improved modification of the interlayer silicate surfaces

Cu/Cu2O nanocomposite films as a p-type modified layer for efficient perovskite solar cells.

PubMed

Chen, You-Jyun; Li, Ming-Hsien; Huang, Jung-Chun-Andrew; Chen, Peter

2018-05-16

Cu/Cu 2 O films grown by ion beam sputtering were used as p-type modified layers to improve the efficiency and stability of perovskite solar cells (PSCs) with an n-i-p heterojunction structure. The ratio of Cu to Cu 2 O in the films can be tuned by the oxygen flow ratio (O 2 /(O 2  + Ar)) during the sputtering of copper. Auger electron spectroscopy was performed to determine the elemental composition and chemical state of Cu in the films. Ultraviolet photoelectron spectroscopy and photoluminescence spectroscopy revealed that the valence band maximum of the p-type Cu/Cu 2 O matches well with the perovskite. The Cu/Cu 2 O film not only acts as a p-type modified layer but also plays the role of an electron blocking buffer layer. By introducing the p-type Cu/Cu 2 O films between the low-mobility hole transport material, spiro-OMeTAD, and the Ag electrode in the PSCs, the device durability and power conversion efficiency (PCE) were effectively improved as compared to the reference devices without the Cu/Cu 2 O interlayer. The enhanced PCE is mainly attributed to the high hole mobility of the p-type Cu/Cu 2 O film. Additionally, the Cu/Cu 2 O film serves as a protective layer against the penetration of humidity and Ag into the perovskite active layer.

Production and characterization of a new biodegradable fenugreek seed gum based active nanocomposite film reinforced with nanoclays.

PubMed

Memiş, Saliha; Tornuk, Fatih; Bozkurt, Fatih; Durak, M Zeki

2017-10-01

In the present work, fenugreek seed gum (FSG)/clay nanocomposite films were prepared with nanoclays (Na + montmorillonite [MMT], halloysite [HNT] and Nanomer ® I.44 P [NM]) at different amounts (0, 2.5, 5.0 and 7.5g clay/100g FSG) by solution casting method and characterized. Increasing amount of nanoclay significantly (P<0.05) improved oxygen barrier and thermal properties of the biodegradable films. Agar diffusion tests revealed that FSG based nanocomposite films exhibited strong antimicrobial properties against foodborne pathogens namely Listeria monocytogenes, Escherichia coli O157:H7, Staphylococcus aureus and Bacillus cereus independently of clay type and concentration. In the case of mechanical properties, nanoclay incorporation up to 5% provided higher (P<0.05) tensile strength (TS) properties while elongation at break (EB) values of the films significantly (P<0.05) decreased in the presence of clay in the film matrix. SEM micrographs showed that especially lower levels (up to 5%) of nanoclay reinforcements provided a homogeneous and smooth film structure. In conclusion, FSG based nanocomposite films reinforced with nanoclays up to 5% showed a precious potential to be used in antimicrobial food packaging applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Thickness dependent optical properties of PEMA and (PEMA){sub 0.85}/(ZnO){sub 0.15} nanocomposite films deposited by spray pyrolysis technique on ITO substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thakur, Anjna, E-mail: anjna56@gmail.com; Thakur, Priya; Yadav, Kamlesh, E-mail: kamlesh.yadav001@gmail.com

2016-05-06

In this paper, poly (ethyl methacrylate) (PEMA) and (PEMA){sub 0.85}/(ZnO){sub 0.15} nanocomposite films for 2, 3, 4 and 5 minutes have been deposited by spray pyrolysis technique on indium tin oxide (ITO) coated substrate. The effect of thickness of the film on the morphological and optical properties of PEMA and (PEMA){sub 0.85}/(ZnO){sub 0.15} nanocomposite films are studied. The morphological and optical properties of pure PEMA and (PEMA){sub 0.85}/(ZnO){sub 0.15} nanocomposite films are compared. The field emission scanning electron microscopy (FESEM) shows that as the thickness of film increases, uniformity of films increases. It is found from UV-Visible spectra that themore » energy band gap decreases with increasing the deposition time and refractive index increases with increasing the thickness of the film. The band gap of the nanocomposites is found less than the pure polymer film and opposite trend is observed for refractive index. The optical absorption of PEMA/ZnO nanocomposite films is higher than pure PEMA film. The thickness of the nanocomposite film plays a significant role in the tunability of the optical properties.« less

Characterization of the new biodegradable WPI/clay nanocomposite films based on kefiran exopolysaccharide.

PubMed

Zolfi, Mohsen; Khodaiyan, Faramarz; Mousavi, Mohammad; Hashemi, Maryam

2015-06-01

Physico-mechanical, thermal and structural characteristics of nanocomposite film composed of kefiran-whey protein isolate (WPI)-montmorillonite (MMT; 1, 3 and 5 % w/w) were studied. Incorporation of MMT significantly affected the mechanical attributes of the kefiran-WPI films. The tensile strength and Young's modulus increased and the percentage of elongation at break decreased as the MMT content increased. Moisture content, moisture absorption and water solubility decreased as the MMT concentration increased. Differential scanning calorimetry indicated that the glass transition temperature for kefiran-WPI film was -12.5 °C and was noticeably affected by an increase in MMT. X-ray diffraction analysis showed formation of an exfoliated structure with the addition of small amounts of MMT to the kefiran-WPI matrix. Intercalation and some exfoliation occurred up to 5 % (wt) increase in MMT. Scanning electron microscopy demonstrated ideal dispersion for MMT nanoparticles into the structure of the bio-nanocomposite films.

Carbon Nanotube/Conductive Additive/Space Durable Polymer Nanocomposite Films for Electrostatic Charge Dissipation

NASA Technical Reports Server (NTRS)

Smith, Joseph G., Jr.; Watson, Kent A.; Delozier, Donavon M.; Connell, John W.

2003-01-01

Thin film membranes of space environmentally stable polymeric materials possessing low color/solar absorptivity (alpha) are of interest for potential applications on Gossamer spacecraft. In addition to these properties, sufficient electrical conductivity is required in order to dissipate electrostatic charge (ESC) build-up brought about by the charged orbital environment. One approach to achieve sufficient electrical conductivity for ESC mitigation is the incorporation of single wall carbon nanotubes (SWNTs). However, when the SWNTs are dispersed throughout the polymer matrix, the nanocomposite films tend to be significantly darker than the pristine material resulting in a higher alpha. The incorporation of conductive additives in combination with a decreased loading level of SWNTs is one approach for improving alpha while retaining conductivity. Taken individually, the low loading level of conductive additives and SWNTs is insufficient in achieving the percolation level necessary for electrical conductivity. When added simultaneously to the film, conductivity is achieved through a synergistic effect. The chemistry, physical, and mechanical properties of the nanocomposite films will be presented.

Preparation of mesoporous carbon nitride structure by the dealloying of Ni/a-CN nanocomposite films

NASA Astrophysics Data System (ADS)

Zhou, Han; Shen, Yongqing; Huang, Jie; Liao, Bin; Wu, Xianying; Zhang, Xu

2018-05-01

The preparation of mesoporous carbon nitride (p-CN) structure by the selective dealloying process of Ni/a-CN nanocomposite films is investigated. The composition and structure of the Ni/a-CN nanocomposite films and porous carbon nitride (p-CN) films are determined by scan electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Phase separated structure including nickel carbide phase and the surrounding amorphous carbon nitride (a-CN) matrix are detected for the as-deposited films. Though the bulk diffusion is introduced in the film during the annealing process, the grain sizes for the post-annealed films are around 10 nm and change little comparing with the ones of the as-deposited films, which is associated with the thermostability of the CN surrounding in the film. The p-CN skeleton with its pore size around 12.5 nm is formed by etching the post-annealed films, indicative of the stability of the phase separated structure during the annealing process.

Antibacterial effect of visible light reactive TiO2/Ag nanocomposite thin film on the orthodontic appliances.

PubMed

Yun, Kwidug; Oh, Gyejeong; Vang, Mongsook; Yang, Hongso; Lim, Hyunpil; Koh, Jeongtae; Jeong, Woonjo; Yoon, Dongjoo; Lee, Kyungku; Lee, Kwangmin; Park, Sangwon

2011-08-01

This study evaluated the antibacterial effect of a visible light reactive TiO2/Ag nanocomposite thin film on dental orthodontic wire (STS 304 wire). The growth of S. mutans and A. actinomycetemcomitans was suppressed on the specimens coated with TiO2/Ag compared to the uncoated specimens. The antibacterial effect of the TiO2/Ag nanocomposite thin film was improved under visible light irradiation.

Exchange-coupled hard magnetic Fe-Co/CoPt nanocomposite films fabricated by electro-infiltration

NASA Astrophysics Data System (ADS)

Wen, Xiao; Andrew, Jennifer S.; Arnold, David P.

2017-05-01

This paper introduces a potentially scalable electro-infiltration process to produce exchange-coupled hard magnetic nanocomposite thin films. Fe-Co/CoPt nanocomposite films are fabricated by deposition of CoFe2O4 nanoparticles onto Si substrate, followed by electroplating of CoPt. Samples are subsequently annealed under H2 to reduce the CoFe2O4 to magnetically soft Fe-Co and also induce L10 ordering in the CoPt. Resultant films exhibit 0.97 T saturation magnetization, 0.70 T remanent magnetization, 127 kA/m coercivity and 21.8 kJ/m3 maximum energy density. First order reversal curve (FORC) analysis and δM plot are used to prove the exchange coupling between soft and hard magnetic phases.

Fabrication of gelatin-TiO2 nanocomposite film and its structural, antibacterial and physical properties.

PubMed

He, Qingyan; Zhang, Yuchen; Cai, Xixi; Wang, Shaoyun

2016-03-01

Biodegradable fish skin gelatin-titanium dioxide (TiO2) nanocomposite films were fabricated and characterized as a function of incorporating amount of TiO2 nanoparticles (gelatin/TiO2 ratio of 30:1, 20:1 and 10:1). A uniform distribution of TiO2 nanoparticles into gelatin matrix was observed using atomic force microscopy (AFM) micrographs. The data of intrinsic fluorescence spectra, Fourier transform infrared spectra (FTIR) and X-ray diffraction confirmed the interaction between protein and nanoparticles through hydrogen bonding. The TiO2-incorporated gelatin nanocomposite films exhibited more effective antibacterial activity for Escherichia coli after irradiating 120 min by UV light (365 nm), which were 54.38% for E. coli and 44.89% for Staphylococcus aureus, respectively. The analysis of physical properties revealed that addition of TiO2 nanoparticles to gelatin films significantly increased the tensile strength and elongation at break, while decreased its water vapor permeability. The light barrier measurements indicated that these films were highly transparent, and they had excellent barrier properties against UVC light at the same time. The results demonstrated the feasibility of incorporating nanoparticles to improve the properties of gelatin films, and it is of significance in utilizing the gelatin and titanium dioxide to produce biodegradable nanocomposite film as packaging material in food industry. Copyright © 2015 Elsevier B.V. All rights reserved.

Highly Modified Cellulose Nanocrystals and Formation of Epoxy-CNC Nanocomposites.

PubMed

Abraham, Eldho; Kam, Doron; Nevo, Yuval; Slattegard, Rikard; Rivkin, Amit; Lapidot, Shaul; Shoseyov, Oded

2016-10-05

This work presents an environmentally friendly, iodine-catalysed chemical modification method to generate highly hydrophobic, optically active cellulose nanocrystals (CNC). The high degree of ester substitution (DS=2.18), hydrophobicity, crystalline behaviour and optical activity of the generated acetylated CNC (Ac-CNC) were quantified by TEM, FTIR, solid 13C NMR, contact angle, XRD and POM analyses. Ac-CNC possessing substantial enhancement in thermal stability (16.8%) and forms thin films with interlayer distance of 50-150 nm, presenting cavities suitable for entrapping nano and micro particles. Generated Ac-CNC proved as an effective reinforcing agent in hydrophobic polymer matrices for fabricating high performance nanocomposites. When integrated at a very low weight percentage (0.5%) in an epoxy matrix, Ac-CNC provided for a 73% increase in tensile strength and a 98% increase in modulus, demonstrating its remarkable reinforcing potential and effective stress transfer behaviour. The method of modification and the unique properties of the modified CNC (hydrophobicity, crystallinity, reinforcing ability and optical activity) render them a novel bionanomaterial for a range of multipurpose applications.

Adjustable magnetoelectric effect of self-assembled vertical multiferroic nanocomposite films by the in-plane misfit strain and ferromagnetic volume fraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Huaping, E-mail: wuhuaping@gmail.com; Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540; Chai, Guozhong

The strain-mediated magnetoelectric (ME) property of self-assembled vertical multiferroic nanocomposite films epitaxially grown on cubic substrates was calculated by a nonlinear thermodynamic theory combined with the elastic theory. The dependent relations of phase state of ferroelectric films with the in-plane misfit strain, out-of-plane misfit strain, temperature, and volume fraction of ferromagnetic phase were confirmed. The effects of in-plane misfit strain and ferromagnetic volume fraction on the polarization and dielectric constant of ferroelectric films at room temperature were elaborately analyzed for the vertical BaTiO{sub 3}-CoFe{sub 2}O{sub 4} and PbTiO{sub 3}-CoFe{sub 2}O{sub 4} nanocomposite films. Our calculated results confirmed the relationship amongmore » ME effect and in-plane misfit strain and ferromagnetic volume fraction in the nanocomposite films. The ME voltage coefficients of vertical BaTiO{sub 3}-CoFe{sub 2}O{sub 4} and PbTiO{sub 3}-CoFe{sub 2}O{sub 4} nanocomposite films displayed various maximums and abrupt points at special phases and phase transition boundaries. The ME voltage coefficients of lead-free BaTiO{sub 3}-CoFe{sub 2}O{sub 4} nanocomposite films epitaxially grown on different substrates could reach a comparative value of ∼2 V·cm{sup −1}·Oe{sup −1} under the controllable in-plane misfit strain induced by substrate clamping. Our results provided an available method for the optimal design of vertical multiferroic nanocomposites with adjustable ME effect by optimizing the ferromagnetic volume fraction and substrate type.« less

Room temperature magneto-transport properties of nanocomposite Fe-In2O3 thin films

NASA Astrophysics Data System (ADS)

Tambasov, Igor A.; Gornakov, Kirill O.; Myagkov, Victor G.; Bykova, Liudmila E.; Zhigalov, Victor S.; Matsynin, Alexey A.; Yozhikova, Ekaterina V.

2015-12-01

A ferromagnetic Fe-In2O3 nanocomposite thin film has been synthesized by the thermite reaction Fe2O3+In→Fe-In2O3. Measurements of the Hall carrier concentration, Hall mobility and magnetoresistance have been conducted at room temperature. The nanocomposite Fe-In2O3 thin film had n=1.94·1020 cm-3, μ=6.45 cm2/Vs and negative magnetoresistance. The magnetoresistance for 8.8 kOe was ~-0.22%.The negative magnetoresistance was well described by the weak localization and model proposed by Khosla and Fischer.

W:Al 2O 3 nanocomposite thin films with tunable optical properties prepared by atomic layer deposition

DOE PAGES

Babar, Shaista; Mane, Anil U.; Yanguas-Gil, Angel; ...

2016-06-17

Here, a systematic alteration in the optical properties of W:Al 2O 3 nanocomposite films is demonstrated by precisely varying the W cycle percentage (W%) from 0 to 100% in Al 2O 3 during atomic layer deposition. The direct and indirect band energies of the nanocomposite materials decrease from 5.2 to 4.2 eV and from 3.3 to 1.8 eV, respectively, by increasing the W% from 10 to 40. X-ray absorption spectroscopy reveals that, for W% < 50, W is present in both metallic and suboxide states, whereas, for W% ≥ 50, only metallic W is seen. This transition from dielectric tomore » metallic character at W% ~ 50 is accompanied by an increase in the electrical and thermal conductivity and the disappearance of a clear band gap in the absorption spectrum. The density of the films increases monotonically from 3.1 g/cm 3 for pure Al 2O 3 to 17.1 g/cm 3 for pure W, whereas the surface roughness is greatest for the W% = 50 films. The W:Al 2O 3 nanocomposite films are thermally stable and show little change in optical properties upon annealing in air at 500 °C. These W:Al 2O 3 nanocomposite films show promise as selective solar absorption coatings for concentrated solar power applications.« less

Size dependent nonlinear optical properties of spin coated zinc oxide-polystyrene nanocomposite films

NASA Astrophysics Data System (ADS)

Jeeju, Pullarkat P.; Jayalekshmi, S.; Chandrasekharan, K.; Sudheesh, P.

2012-11-01

Using simple wet chemical method at room temperature, zinc oxide (ZnO) nanoparticles embedded in polystyrene (PS) matrix were synthesized. The size of the ZnO nanoparticles could be varied by varying the precursor concentration, reaction time and stirring speed. Transparent films of ZnO/PS nanocomposites of thickness around 1 μm were coated on ultrasonically cleaned glass substrates by spin coating. The optical absorptive nonlinearity in ZnO/PS nanocomposite films was investigated using open aperture Z-scan technique with nanosecond laser pulses at 532 nm. The results indicate optical limiting type nonlinearity in the films due to two-photon absorption in ZnO. These films also show a self-defocusing type negative nonlinear refraction in closed aperture Z-scan experiment. The observed nonlinear absorption is strongly dependent on particle size and the normalized transmittance could be reduced to as low as 0.43 by the suitable choice of the ZnO nanoparticle size. These composite films can hence be used as efficient optical limiters for sensor protection. The much-pronounced nonlinear response of these composite films, compared to pure ZnO, combined with the improved stability of ZnO nanoparticles in the PS matrix offer prospects of application of these composite films in the fabrication of stable non-linear optical devices.

Ti 3 C 2 T x (MXene)–polyacrylamide nanocomposite films

DOE PAGES

Naguib, Michael; Saito, Tomonori; Lai, Sophia; ...

2016-07-20

Polymer nanocomposite films are of great interest due to their enhanced properties over base polymers. By incorporating 2D titanium carbide a representative of a new family of 2D materials, MXenes, as nanofillers into a water soluble polyacrylamide (PAM) matrix, the resulting films benefit from the flexibility, robustness, and processability of PAM, as well as the conductivity and mechanical properties of MXene fillers. We report on manufacturing and characterization of MXene-PAM nanocomposite films. Dimethylsulfoxide (DMSO) intercalation in-between the Ti 3C 2-based MXene layers led to full delamination of the MXene layers and hence a uniform dispersion of hydrophilic MXene nanosheets inmore » aqueous PAM solutions was achieved. Moreover, the polymer composite solutions of up to 75 wt.% MXene loading were sonicated and cast onto large Teflon trays and dried at room temperature to produce shiny black films. The observation of reduced 0002 peaks of Ti 3C 2T x phase in X-ray diffraction patterns and TEM images indicate the presence of well dispersed nanoflakes. The as-prepared composite films are flexible and the conductivity was increased significantly to 3 x 10 -3 S cm -1 for 6 wt. % MXene-PAM films. With high MXene loading, some non-uniformity between the top and bottom surfaces was observed. This could be due to the segregation of MXene layers in composite films during drying. Finally, the power law dependence of conductivity above the percolation threshold is presented through detailed conductivity measurements.« less

Processing and properties of eco-friendly bio-nanocomposite films filled with cellulose nanocrystals from sugarcane bagasse.

PubMed

El Achaby, Mounir; El Miri, Nassima; Aboulkas, Adil; Zahouily, Mohamed; Bilal, Essaid; Barakat, Abdellatif; Solhy, Abderrahim

2017-03-01

Novel synthesis strategy of eco-friendly bio-nanocomposite films have been exploited using cellulose nanocrystals (CNC) and polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) blend matrix as a potential in food packaging application. The CNC were extracted from sugarcane bagasse using sulfuric acid hydrolysis, and they were successfully characterized regarding their morphology, size, crystallinity and thermal stability. Thereafter, PVA/CMC-CNC bio-nanocomposite films, at various CNC contents (0.5-10wt%), were fabricated by the solvent casting method, and their properties were investigated. It was found that the addition of 5wt% CNC within a PVA/CMC increased the tensile modulus and strength by 141% and 83% respectively, and the water vapor permeability was reduced by 87%. Additionally, the bio-nanocomposites maintained the same transparency level of the PVA/CMC blend film (transmittance of ∼90% in the visible region), suggesting that the CNC were dispersed at the nanoscale. In these bio-nanocomposites, the adhesion properties and the large number of functional groups that are present in the CNC's surface and the macromolecular chains of the PVA/CMC blend are exploited to improve the interfacial interactions between the CNC and the blend. Consequently, these eco-friendly structured bio-nanocomposites with superior properties are expected to be useful in food packaging applications. Copyright © 2016. Published by Elsevier B.V.

Preparation and characterization of polymeric nanocomposite films for application as protective coatings

NASA Astrophysics Data System (ADS)

Gagliardi, S.; Rondino, F.; D'Erme, C.; Persia, F.; Menchini, F.; Santarelli, M. L.; Paulke, B.-R.; Enayati, A. L.; Falconieri, M.

2017-08-01

Addiction of ceramic nanoparticles to acrylic polymers provides a simple and effective means to produce paints with important properties, such as mechanical resistance and tailored wettability, even though for optimal performances, an engineered nanoparticle distribution would be desirable. In this paper we report on the realization and on the morphological and functional characterization of nanocomposites where the nanophase is distributed on the surface of acrylic polymer films, in order to enhance the expression of surface-related properties. To this aim, commercial titanium oxide and silicon oxide nanopowders were dispersed in water and the suspensions were air-sprayed on polymeric films prepared by paint brushing, thus producing a nanostructured ceramic surface coating. Control of the pH of suspensions and acrylic acid functionalization of the surface of titania were used together with high power ultrasonic treatments in order to control dimension of the aggregates in the sprayed suspensions. Optical microscopy, mechanical profilometry, and atomic force microscopy were used to characterize the nanocomposite surface morphology and correlate it to the coating functional properties, evaluated through mechanical abrasion tests and contact angle measurements; also, colorimetry on coated stones was performed in order to test the impact of the coatings on the aesthetical appearance and their photostability under UV irradiation. Results show that the nanostructured ceramic layer slightly improves the resistance of coatings to mechanical abrasion in case of polymer films prepared from latexes. The nanocomposite surface layer does not affect the wettability of the polymer, which remained slightly hydrophilic; this behavior is likely due to inadequate distribution of the nanophase. On the other hand UV-induced superhydrophilicity was observed when the concentration of surface titania nanoparticles is about 0.6 mg/cm2. Colorimetric analysis on historical and Carrara

Improvement of food packaging related properties in whey protein isolate‑based nanocomposite films and coatings by addition of montmorillonite nanoplatelets

NASA Astrophysics Data System (ADS)

Schmid, Markus; Merzbacher, Sarah; Brzoska, Nicola; Müller, Kerstin; Jesdinszki, Marius

2017-11-01

In the present study the effects of the addition of montmorillonite (MMT) nanoplatelets on whey protein isolate (WPI)-based nanocomposite films and coatings were investigated. The main objective was the development of WPI-based MMT-nanocomposites with enhanced barrier and mechanical properties. WPI-based nanocomposite cast-films and coatings were prepared by dispersing 0 % (reference sample), 3 %, 6 %, 9 % (w/w protein) MMT, or, depending on the protein concentration, also 12 % and 15 % (w/w protein) MMT into native WPI-based dispersions, followed by subsequent denaturation during the drying and curing process. The natural MMT nanofillers could be randomly dispersed into film-forming WPI-based nanodispersions, displaying good compatibility with the hydrophilic biopolymer matrix. As a result, by addition of 15 % (w/w protein) MMT into 10 % (w/w dispersion) WPI-based cast-films or coatings, the oxygen permeability (OP) was reduced by 91 % for glycerol-plasticized and 84 % for sorbitol-plasticized coatings, water vapor transmission rate (WVTR) was reduced by 58 % for sorbitol-plasticized cast-films. Due to the addition of MMT- nanofillers the Young’s modulus and tensile strength improved by 315 % and 129 %, respectively, whereas elongation at break declined by 77 % for glycerol-plasticized cast-films. In addition, comparison of plasticizer type revealed that sorbitol-plasticized cast-films were generally stiffer and stronger, but less flexible compared glycerol-plasticized cast-films. Viscosity measurements demonstrated good processability and suitability for up-scaled industrial processes of native WPI-based nanocomposite dispersions, even at high nanofiller-loadings. These results suggest that the addition of natural MMT- nanofillers into native WPI-based matrices to form nanocomposite films and coatings holds great potential to replace well-established, fossil-based packaging materials for at least certain applications such as oxygen barriers as part of

Thermally tunable VO2-SiO2 nanocomposite thin-film capacitors

NASA Astrophysics Data System (ADS)

Sun, Yifei; Narayanachari, K. V. L. V.; Wan, Chenghao; Sun, Xing; Wang, Haiyan; Cooley, Kayla A.; Mohney, Suzanne E.; White, Doug; Duwel, Amy; Kats, Mikhail A.; Ramanathan, Shriram

2018-03-01

We present a study of co-sputtered VO2-SiO2 nanocomposite dielectric thin-film media possessing continuous temperature tunability of the dielectric constant. The smooth thermal tunability is a result of the insulator-metal transition in the VO2 inclusions dispersed within an insulating matrix. We present a detailed comparison of the dielectric characteristics of this nanocomposite with those of a VO2 control layer and of VO2/SiO2 laminate multilayers of comparable overall thickness. We demonstrated a nanocomposite capacitor that has a thermal capacitance tunability of ˜60% between 25 °C and 100 °C at 1 MHz, with low leakage current. Such thermally tunable capacitors could find potential use in applications such as sensing, thermal cloaks, and phase-change energy storage devices.

Thin-film transistors with a graphene oxide nanocomposite channel.

PubMed

Jilani, S Mahaboob; Gamot, Tanesh D; Banerji, P

2012-12-04

Graphene oxide (GO) and graphene oxide-zinc oxide nanocomposites (GO-ZnO) were used as channel materials on SiO(2)/Si to fabricate thin-film transistors (TFT) with an aluminum source and drain. Pure GO-based TFT showed poor field-effect characteristics. However, GO-ZnO-nanocomposite-based TFT showed better field-effect performance because of the anchoring of ZnO nanostructures in the GO matrix, which causes a partial reduction in GO as is found from X-ray photoelectron spectroscopic data. The field-effect mobility of charge carriers at a drain voltage of 1 V was found to be 1.94 cm(2)/(V s). The transport of charge carriers in GO-ZnO was explained by a fluctuation-induced tunneling mechanism.

Optical properties of PbS/PVP nanocomposites films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patel, Mitesh H., E-mail: miteshpatel7204@gmail.com; Chaudhuri, Tapas K.; Patel, Vaibhav K.

2016-05-06

PbS/Polyvinylpyrrolidone (PVP) nanocomposites films with different volume fraction of PbS have been deposited from single molecular precursors. X-ray diffraction patterns conforms the formation of PbS nanocrystals in PVP matrix. The transmission spectra of the films in the wavelength range of 300 to 2400 nm show the absorption edges are blue shifted due to formation of PbS Nanoparticles. The band gap determined are 2.4, 1.5 and 1.25 eV for PbS volume fraction of 8.5, 16, 27%, respectively. The corresponding refractive indices, n determined from Fresnel relation are 1.8, 2, and 2.35 which are in between that of PbS (4.2) and PVP (1.48).

Ag+12 ion induced modifications of structural and optical properties of ZnO-PMMA nanocomposite films

NASA Astrophysics Data System (ADS)

Sharma, Sarla; Vyas, Rishi; Vijay, Y. K.

2013-02-01

The influence of swift heavy ion (SHI) irradiation on structural and photoluminescence (PL) properties of ZnO-PMMA nanocomposite films, prepared by solution casting method, was studied. The ZnO-PMMA nanocomposite films were irradiated using 120 MeV Ag+12 ions at different fluences varying from 1×1011 to 1×1013 ions/cm2. The intensity of the X-ray diffraction peaks is increased at the high fluence, without evolution of any new peak. A shift in absorption edge (i.e. shift in optical band gap) towards higher wavelength was observed after irradiation and PL from ZnO-PMMA nanocomposite films is found to increase up to a critical fluence and then found to be suppressed for higher fluence (1×1012 ion/cm2). The change in photoluminescence after irradiation can be attributed to the change in microstructure of PMMA matrix as well as the agglomeration of ZnO nanoparticles.

Inorganic nanocomposite films with polymer nanofillers made by the concurrent multi-beam multi-target pulsed laser deposition

NASA Astrophysics Data System (ADS)

Darwish, Abdalla M.; Sarkisov, Sergey S.; Mele, Paolo; Saini, Shrikant; Moore, Shaelynn; Bastian, Tyler; Dorlus, Wydglif; Zhang, Xiaodong; Koplitz, Brent

2017-08-01

We report on the new class of inorganic nanocomposite films with the inorganic phase hosting the polymer nanofillers made by the concurrent multi-beam multi-target pulsed laser deposition of the inorganic target material and matrix assisted pulsed laser evaporation of the polymer (MBMT-PLD/MAPLE). We used the exemplary nanocomposite thermoelectric films of aluminum-doped ZnO known as AZO with the nanofillers made of poly(methyl methacrylate) known as PMMA on various substrates such as SrTiO3, sapphire, fused silica, and polyimide. The AZO target was ablated with the second harmonic (532 nm) of the Nd:YAG Q-switched laser while PMMA was evaporated from its solution in chlorobenzene frozen in liquid nitrogen with the fundamental harmonic (1064 nm) of the same laser (50 Hz pulse repetition rate). The introduction of the polymer nanofillers increased the electrical conductivity of the nanocomposite films (possibly due to the carbonization of PMMA and the creation of additional channels of electric current) three times and reduced the thermal conductivity by 1.25 times as compared to the pure AZO films. Accordingly, the increase of the thermoelectric figure-of merit ZT would be 4 times. The best performance was observed for the sapphire substrates where the films were the most uniform. The results point to a huge potential of the optimization of a broad variety of optical, opto-electronic, and solar-power nanocomposite inorganic films by the controllable introduction of the polymer nanofillers using the MBMT-PLD/MAPLE method.

A sulphonated carbon dot-chitosan hybrid hydrogel nanocomposite as an efficient ion-exchange film for Ca2+ and Mg2+ removal

NASA Astrophysics Data System (ADS)

Baruah, Upama; Konwar, Achyut; Chowdhury, Devasish

2016-04-01

We have developed a hybrid hydrogel nanocomposite film via conjugation of oxidised carbon dots synthesized from 11-mercaptoundecanoic acid with chitosan. The potential applicability of the film was then successfully tested for the removal of Ca2+ and Mg2+ ions from solution.We have developed a hybrid hydrogel nanocomposite film via conjugation of oxidised carbon dots synthesized from 11-mercaptoundecanoic acid with chitosan. The potential applicability of the film was then successfully tested for the removal of Ca2+ and Mg2+ ions from solution. Electronic supplementary information (ESI) available: The ESI includes the detailed synthesis and characterization of carbon dots both before and after oxidation and of the carbon dot-chitosan nanocomposite films viz. DLS, SEM, UV-visible, FTIR, PL spectroscopy and TGA. See DOI: 10.1039/c6nr01129b

Organo-modified bentonites as new flame retardant fillers in epoxy resin nanocomposites

NASA Astrophysics Data System (ADS)

Benelli, Tiziana; D'Angelo, Emanuele; Mazzocchetti, Laura; Saraga, Federico; Sambri, Letizia; Franchini, Mauro Comes; Giorgini, Loris

2016-05-01

The present work deals with two organophilic bentonites, based on nitrogen-containing compounds: these organoclays were synthesized via an ion exchange process starting from pristine bentonite with 6-(4-butylphenyl)-1,3,5-triazine-2,4-diamine (BFTDA) and 11-amino-N-(pyridine-2yl)undecanamide (APUA) and then used for the production of epoxy-based flame retardant nanocomposites. The amount of organic modifier in the organoclays Bento-BFTDA and Bento-APUA was determined with a TGA analysis and is around 0.4mmol/g for both samples. The effect of the organoclays on a commercial epoxy resin nanocomposite's thermo-mechanical and flammability properties was investigated. Composites containing 3wt% and 5wt% of the nanofillers were prepared by solventless addition of each organoclay to the epoxy resin, followed by further addition of the hardener component. For the sake of comparison a similar nanocomposite with the plain unmodified bentonite was produced in similar condition. The nanocomposites's thermo-mechanical properties of all the produced samples were measured and they resulted slightly improved or practically unaffected. On the contrary, when the flame behaviour was assessed in the cone-calorimeter, an encouraging decrease of 17% in the peak heat released rate (pHRR) was obtained at 3wt% loading level with Bento-APUA. This is a promising result, assessing that the APUA modified organoclay might act as flame retardant.

Photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite films in an aerated 0.5 M NaCl solution

NASA Astrophysics Data System (ADS)

Boonserm, Aleena; Kruehong, Chaiyaput; Seithtanabutara, Varinrumpai; Artnaseaw, Apichart; Kwakhong, Panomkorn

2017-10-01

This research aimed to investigate the photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite films using electrochemical measurements in an aerated 0.5 M NaCl solution under white light illumination. The CdS/TiO2 nanocomposite films were prepared by chemical bath deposition technique in a solution of cadmium and sulfide ions. The high resolution images of CdS/TiO2 nanocomposite films were provided by field emission scanning electron microscope. Theirs chemical identification and quantitative compositional information, crystallinity and actual chemical compounds formed were determined by energy dispersive spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The results indicated that the photoelectrochemical activity of the films depended strongly on CdS content. From the preparation of CdS/TiO2 nanocomposite films by 5, 10 and 15 dipping cycles in the chemical solutions, the best photoelectrochemical response was revealed by the 10 dipping cycles-prepared film. Galvanic couple testing demonstrated that the photoelectrochemical response of the film decreased continuously compared to that of anodized nanoporous TiO2 substrate which described by photocorrosion of CdS nanoparticles. In addition, chloride-ion attack also induced pitting corrosion leading to fluctuation and deterioration of photoelectrochemical response. CdO2 and Cd(OH)2 depositions were found as the main photocorrosion products on collapsed nanostructured-surface. The relevance between photoelectrochemical response and corrosion behavior of CdS/TiO2 nanocomposite film was discussed in detail.

Graphene Oxide/Poly(3-hexylthiophene) Nanocomposite Thin-Film Phototransistor for Logic Circuit Applications

NASA Astrophysics Data System (ADS)

Mansouri, S.; Coskun, B.; El Mir, L.; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed; Yakuphanoglu, F.

2018-04-01

Graphene is a sheet-structured material that lacks a forbidden band, being a good candidate for use in radiofrequency applications. We have elaborated graphene-oxide-doped poly(3-hexylthiophene) nanocomposite to increase the interlayer distance and thereby open a large bandgap for use in the field of logic circuits. Graphene oxide/poly(3-hexylthiophene) (GO/P3HT) nanocomposite thin-film transistors (TFTs) were fabricated on silicon oxide substrate by spin coating method. The current-voltage ( I- V) characteristics of TFTs with various P3HT compositions were studied in the dark and under light illumination. The photocurrent, charge carrier mobility, subthreshold voltage, density of interface states, density of occupied states, and I ON/ I OFF ratio of the devices strongly depended on the P3HT weight ratio in the composite. The effects of white-light illumination on the electrical parameters of the transistors were investigated. The results indicated that GO/P3HT nanocomposite thin-film transistors have high potential for use in radiofrequency applications, and their feasibility for use in digital applications has been demonstrated.

Mechanical comparison of a polymer nanocomposite to a ceramic thin-film anti-reflective filter.

PubMed

Druffel, Thad; Geng, Kebin; Grulke, Eric

2006-07-28

Thin-film filters on optical components have been in use for decades and, for those industries utilizing a polymer substrate, the mismatch in mechanical behaviour has caused problems. Surface damage including scratches and cracks induces haze on the optical filter, reducing the transmission of the optical article. An in-mold anti-reflective (AR) filter incorporating 1/4-wavelength thin films based on a polymer nanocomposite is outlined here and compared with a traditional vacuum deposition AR coating. Nanoindentation and nanoscratch techniques are used to evaluate the mechanical properties of the thin films. Scanning electron microscopy (SEM) images of the resulting indentations and scratches are then compared to the force deflection curves to further explain the phenomena. The traditional coatings fractured by brittle mechanisms during testing, increasing the area of failure, whereas the polymer nanocomposite gave ductile failure with less surface damage.

Preparation and Characterization of Polyimide/Organoclay Nanocomposites

NASA Technical Reports Server (NTRS)

Delozier, D. M.; Orwoll, R. A.; Cahoon, J. F.; Johnston, N. J.; Smith, J. G., Jr.; Connell, J. W.

2002-01-01

Organically modified montmorrrillonite clay, containing a long chain aliphatic quarternary ammonium cation, was used to prepare polyimide/organoclay hybrids. Several approaches were examined in an attempt to achieve fully exfoliated nanocomposites. These included simple mixing of the clay in a pre-made high molecular weight poly(amide acid) solution; simple mixing followed by sonication of the organoclay/poly(amide acid) solutions; and the preparation of high molecular weight poly(amide acid)s in the presence of the organoclay dispersed in N-methyl-2-pyrrolidinone (NMP). The best results were obtained using the in-situ polymerization approach. The resulting nanocomposite films (both amide acid and imide), containing 3-8% by weight of organoclay, were characterized by differential scanning calorimetry (DSC), dynamic thermogravimetric analysis (TGA), transmission electron microscopy (TEM), X-ray diffraction (XRD), and thin film tensile properties. A significant degree of dispersion was observed in the nanocomposite films of the amide acid and the imide. After thermal treatment of amide acid films to effect imidization, in both air and nitrogen, the films were visually darker than control films without clay and the level of clay dispersion appeared to have decreased. In the latter case, the separation between the layers of the clay decreased to a spacing less than that present in the original organoclay. These observations suggest that thermal degradation of the aliphatic quarternary ammonium cation occurred likely during thermal treatment to effect imidization and solvent removal. These thermal degradation effects were less pronounced when thermal treatment was performed under nitrogen. The polyimide/organoclay hybrid films exhibited higher room temperature tensile moduli and lower strength and elongation to break than the control films.

Preparation and characterization of bio-nanocomposite films based on soy protein isolate and montmorillonite using melt extrusion

USDA-ARS?s Scientific Manuscript database

The non-biodegradable and non-renewable nature of plastic packaging has led to a renewed interest in packaging materials based on bio-nanocomposites (biopolymer matrix reinforced with nanoparticles such as layered silicates). Bio-nanocomposite films based on soy protein isolate (SPI) and montmorillo...

Thermal hydrogen reduction for preservation of mesoporous silica film nanocomposites with a hexagonal structure containing amphiphilic triphenylene

NASA Astrophysics Data System (ADS)

Lintang, Hendrik O.; Jalani, Mohamad Azani; Yuliati, Leny

2017-11-01

We highlight that columnar assembly of self-assembled templates was successfully utilized using sol-gel technique of mesostructured silica for the quality improvement of transparent mesoporous film nanocomposites with a hexagonal structure through appropriate heat treatment methods and self-assembled templates in the removal of organic components. In contrast to the reported mesostructured silica film nanocomposites containing columnar assembly of trinuclear gold(I) pyrazolate complex ([Au3Pz3]C10TEG/silicahex) with calcination at 450 °C, mesostructured silica film nanocomposites from self-assembled template of triphenylene bearing amphiphilic decoxy triethylene glycol side chains (TPC10TEG/silicahex) can be completely collapsed upon calcination at 450 °C. This hexagonal structure can be only preserved with calcination at 250 °C although intensity of its main diffraction peak of d100 at 2θ of 3.70° was significantly decreased. On the other hands, thermal hydrogen reduction at the same temperature was found to be the best heat treatment to preserve the quality of mesoporous silica film nanocomposites with decreasing in intensity of diffraction peak up to 30%. Such phenomenon might be caused by slow decomposition of organic components with the presence of hydrogen gas upon heating to shrinkage the silica wall from interpenetration of ethylene glycol segments of the side chains and to open bonding of benzene ring from the core.

Preparation and characterization of Chitosan/Konjac glucomannan/CdS nanocomposite film with low infrared emissivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Feng-Ying; Zhou, Yu-Ming, E-mail: fchem@seu.edu.cn; Sun, Yan-qing

Novel organic-inorganic nanocomposite films were prepared with Chitosan (CS), Konjac glucomannan (KGM) and CdS by one-step synthesis. As-prepared films were characterized by IR spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and infrared emissometer (IR). The results indicated that grown CdS dendrites were formed with reaction time of 12 h for Cd{sup 2+} and CS/KGM, and were well dispersed in CS/KGM with an average diameter of 40 nm. The CS/KGM/CdS nanocomposite films had significantly low infrared emissivity. When the mole ratio of CdS to summation of CS and KGM construction units was 1.0 with CdS size of 10-20 nm,more » the film got the lowest infrared emissivity value of 0.011, which could be attributed to the strong synergism effect existing between CS/KGM and CdS dendrites.« less

Chemical synthesis and characterization of chitosan/silver nanocomposites films and their potential antibacterial activity.

PubMed

Shah, Aamna; Hussain, Izhar; Murtaza, Ghulam

2018-05-12

This study provides the optimum preparation parameters for functional chitosan silver nanocomposite (CSN) films with promising antibacterial efficacy though prepared with very low silver nitrate (AgNO 3 ) concentration. Chitosan nano‑silver composites were fabricated by In-situ chemical method utilizing the reducing ability of sodium borohydride (NaBH 4 ) and afterward casted into films. Utilization of response surface methodology, NCSS, and SigmaPlot for the optimization of CSN and their predicted antibacterial efficacy assessment of the selected bacterial strains (standard and clinical) was the essential part of the study. The cumulative silver ions released from the CSN films was examined by AAS and was found pH dependent. The developed nanocomposite films exhibited strong antibacterial activity against ATCC strains of Gram-positive Staphylococcus aureus, Gram-negative bacteria (Pseudomonas aeruginosa) and clinically isolated strains of MRSA. The antibacterial activity CSN films were compared with three commercially available dressings (Aquacel Ag®, Bactigras®, and Kaltostat®) and Quench cream. Statistical analysis of the results indicated that the developed CSN films were equally or even more effective than commercial products. Thus the fabricated CSN films may act as a potential candidate to overcome the emerging antibiotic resistance particularly in hospital-acquired skin infections caused by MRSA. Copyright © 2018. Published by Elsevier B.V.

Optical, structural and electrochromic behavior studies on nanocomposite thin film of aniline, o-toluidine and WO3

NASA Astrophysics Data System (ADS)

Najafi-Ashtiani, Hamed; Bahari, Ali

2016-08-01

In the field of materials for electrochromic (EC) applications much attention was paid to the derivatives of aniline. We report on the optical, structural and electrochromic properties of electrochromic thin film based on composite of WO3 nanoparticles and copolymer of aniline and o-toluidine prepared by electrochemical polymerization method on fluorine doped tin oxide (FTO) coated glass. The thin film was studied by X-ray diffraction (XRD) and Fourier transforms infrared (FTIR) spectroscopy. The morphology of prepared thin film was characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and the thermal gravimetric analysis (TGA) as well. The optical spectra of nanocomposite thin film were characterized in the 200-900 nm wavelength range and EC properties of nanocomposite thin film were studied by cyclic voltammetry (CV). The calculation of optical band gaps of thin film exhibited that the thin film has directly allowed transition with the values of 2.63 eV on first region and 3.80 eV on second region. Dispersion parameters were calculated based on the single oscillator model. Finally, important parameters such as dispersion energy, oscillator energy and lattice dielectric constant were determined and compared with the data from other researchers. The nonlinear optical properties such as nonlinear optical susceptibility, nonlinear absorption coefficient and nonlinear refractive index were extracted. The obtained results of nanocomposite thin film can be useful for the optoelectronic applications.

Flexible and conductive MXene films and nanocomposites with high capacitance

DOE PAGES

Ling, Zheng; Ren, Chang E.; Zhao, Meng-Qiang; ...

2014-11-11

MXenes, a new family of 2D materials, combine hydrophilic surfaces with metallic conductivity. Delamination of MXene produces single-layer nanosheets with thickness of about a nanometer and lateral size of the order of micrometers. The high aspect ratio of delaminated MXene renders it promising nanofiller in multifunctional polymer nanocomposites. In this study, Ti 3C 2T x MXene was mixed with either a charged polydiallyldimethylammonium chloride (PDDA) or an electrically neutral polyvinyl alcohol (PVA) to produce Ti 3C 2T x/polymer composites. The as-fabricated composites are flexible and have electrical conductivities as high as 2.2 × 10 4 S/m in the case ofmore » the Ti 3C 2T x/PVA composite film and 2.4 × 10 5 S/m for pure Ti 3C 2T x films. The tensile strength of the Ti 3C 2T x/PVA composites was significantly enhanced compared with pure Ti 3C 2T x or PVA films. The intercalation and confinement of the polymer between the MXene flakes not only increased flexibility but also enhanced cationic intercalation, offering an impressive volumetric capacitance of ~530 F/cm 3 for MXene/PVA-KOH composite film at 2 mV/s. Finally, to our knowledge, this study is a first, but crucial, step in exploring the potential of using MXenes in polymer-based multifunctional nanocomposites for a host of applications, such as structural components, energy storage devices, wearable electronics, electrochemical actuators, and radiofrequency shielding, to name a few.« less

Thin film lithium-based batteries and electrochromic devices fabricated with nanocomposite electrode materials

DOEpatents

Gillaspie, Dane T; Lee, Se-Hee; Tracy, C. Edwin; Pitts, John Roland

2014-02-04

Thin-film lithium-based batteries and electrochromic devices (10) are fabricated with positive electrodes (12) comprising a nanocomposite material composed of lithiated metal oxide nanoparticles (40) dispersed in a matrix composed of lithium tungsten oxide.

Impacts of zeolite nanoparticles on substrate properties of thin film nanocomposite membranes for engineered osmosis

NASA Astrophysics Data System (ADS)

Salehi, Tahereh Mombeini; Peyravi, Majid; Jahanshahi, Mohsen; Lau, Woei-Jye; Rad, Ali Shokuhi

2018-04-01

In this work, microporous substrates modified by zeolite nanoparticles were prepared and used for composite membrane making with the aim of reducing internal concentration polarization (ICP) effect of membranes during engineered osmosis applications. Nanocomposite substrates were fabricated via phase inversion technique by embedding nanostructured zeolite (clinoptilolite) in the range of 0-0.6 wt% into matrix of polyethersulfone (PES) substrate. Of all the substrates prepared, the PES0.4 substrate (with 0.4 wt% zeolite) exhibited unique characteristics, i.e., increased surface porosity, lower structural parameter ( S) (from 0.78 to 0.48 mm), and enhanced water flux. The thin film nanocomposite (TFN) membrane made of this optimized substrate was also reported to exhibit higher water flux compared to the control composite membrane during forward osmosis (FO) and pressure-retarded osmosis (PRO) test, without compromising reverse solute flux. The water flux of such TFN membrane was 43% higher than the control TFC membrane (1.93 L/m2 h bar) with salt rejection recorded at 94.7%. An increment in water flux is ascribed to the reduction in structural parameter, leading to reduced ICP effect.

Synthesis and characterization of HDPE/N-MWNT nanocomposite films.

PubMed

Chouit, Fairouz; Guellati, Ounassa; Boukhezar, Skander; Harat, Aicha; Guerioune, Mohamed; Badi, Nacer

2014-01-01

In this work, a series of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) with several weight percentages (0.1, 0.4, 0.8, and 1.0 wt.%) were synthesized by catalytic chemical vapor deposition (CCVD) technique. The N-MWCNTs were first characterized and then dispersed in high-density polyethylene (HDPE) polymer matrix to form a nanocomposite. The HDPE/N-MWCNT nanocomposite films were prepared by melt mixing and hot pressing; a good dispersion in the matrix and a good N-MWCNT-polymer interfacial adhesion have been verified by scanning electron microscopy (SEM). Raman spectroscopy measurements have been performed on prepared samples to confirm the presence and nature of N-MWNTs in HDPE matrix. The X-ray diffraction (XRD) analysis demonstrated that the crystalline structure of HDPE matrix was not affected by the incorporation of the N-MWNTs.

Synthesis and characterization of HDPE/N-MWNT nanocomposite films

PubMed Central

2014-01-01

In this work, a series of nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) with several weight percentages (0.1, 0.4, 0.8, and 1.0 wt.%) were synthesized by catalytic chemical vapor deposition (CCVD) technique. The N-MWCNTs were first characterized and then dispersed in high-density polyethylene (HDPE) polymer matrix to form a nanocomposite. The HDPE/N-MWCNT nanocomposite films were prepared by melt mixing and hot pressing; a good dispersion in the matrix and a good N-MWCNT-polymer interfacial adhesion have been verified by scanning electron microscopy (SEM). Raman spectroscopy measurements have been performed on prepared samples to confirm the presence and nature of N-MWNTs in HDPE matrix. The X-ray diffraction (XRD) analysis demonstrated that the crystalline structure of HDPE matrix was not affected by the incorporation of the N-MWNTs. PMID:25024676

Thermal and rheological properties of L-polylactide/polyethylene glycol/silicate nanocomposites films.

PubMed

Ahmed, Jasim; Varshney, Sunil K; Auras, Rafael; Hwang, Sung W

2010-10-01

The melt rheology and thermal properties of polylactide (PLA)-based nanocomposite films that were prepared by solvent casting method with L-PLA, polyethylene glycol (PEG), and montmorillonite clay were studied. The neat PLA showed predominantly solid-like behavior (G' > G″) and the complex viscosity (η*) decreased systematically as the temperature increased from 184 to 196 °C. The elastic modulus (G') of PLA/clay blend showed a significant improvement in the magnitude in the melt, while clay concentration was at 6% wt or higher. At similar condition, PEG dramatically reduced dynamic modulii and complex viscosity of PLA/PEG blend as function of concentration. A nanocomposite blend of PLA/PEG/clay (74/20/6) when compared to the neat polymer and PLA/PEG blend exhibited intermediate values of elastic modulus (G') and complex viscosity (η*) with excellent flexibility. Thermal analysis of different clay loading blends indicated that the melting temperature (T(m)) and glass transition temperature (T(g)) remained unaffected irrespective of clay concentration due to immobilization of polymer chain in the clay nanocomposite. PEG incorporation reduced the T(g) and the T(m) of the blends (PLA/PEG and PLA/PEG/clay) significantly, however, crystallinity increased in the similar condition. The transmission electron microscopy (TEM) image of nanocomposite films indicated good compatibility between PLA and PEG, whereas clay was not thoroughly distributed in the PLA matrix and remained as clusters. The percent crystallinity obtained by X-ray was significantly higher than that of differential scanning calorimeter (DSC) data for PLA.

Structure and physical properties of starch/poly vinyl alcohol/sodium montmorillonite nanocomposite films.

PubMed

Ali, Samer S; Tang, Xiaozhi; Alavi, Sajid; Faubion, Jon

2011-12-14

Nanocomposites of starch, poly vinyl alcohol (PVOH), and sodium montmorillonite (Na(+)MMT) were produced by solution mixing and cast into films. Tensile strength (TS) and elongation at the break (E%) of the films ranged from 11.60 to 22.35 MPa and 28.93-211.40%, respectively, while water vapor permeability (WVP) ranged from 0.718 to 1.430 g·mm/kPa·h·m(2). In general, an increase in Na(+)MMT content (0-20%) enhanced TS and decreased E% and WVP. Use of higher molecular weight PVOH increased both TS and E% and also decreased WVP. Mechanical properties were negatively affected, but water vapor barrier properties improved with increasing starch content (0-80%). X-ray diffraction and transmission electron microscopy were used to analyze the nanostructure, and molecular conformations and interactions in the multicomponent nanocomposites were inferred from glass transition behavior. Interactions between starch and PVOH were strongest, followed by polymer/clay interactions. On the basis of this insight, a conceptual model was presented to explain the phenomena of intercalation and exfoliation in the starch/PVOH/Na(+)MMT nanocomposites.

Mechanical, structural and thermal properties of Ag-Cu and ZnO reinforced polylactide nanocomposite films.

PubMed

Ahmed, Jasim; Arfat, Yasir Ali; Castro-Aguirre, Edgar; Auras, Rafael

2016-05-01

Plasticized polylactic acid (PLA) based nanocomposite films were prepared by incorporating polyethylene glycol (PEG) and two selected nanoparticles (NPs) [silver-copper (Ag-Cu) alloy (<100 nm) and zinc oxide (ZnO) (<50 and <100 nm)] through solvent casting method. Incorporation of Ag-Cu alloy into the PLA/PEG matrix increased the glass transition temperature (Tg) significantly. The crystallinity of the nanocomposites (NCs) was significantly influenced by NP incorporation as evidenced from differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. The PLA nanocomposite reinforced with NPs exhibited much higher tensile strength than that of PLA/PEG blend. Melt rheology of NCs exhibited a shear-thinning behavior. The mechanical property drastically reduced with a loading of NPs, which is associated with degradation of PLA. SEM micrographs exhibited that both Ag-Cu alloy and ZnO NPs were dispersed well in the PLA film matrix. Copyright © 2016 Elsevier B.V. All rights reserved.

Direct electrochemistry and electrocatalysis of glucose oxidase immobilized on reduced graphene oxide and silver nanoparticles nanocomposite modified electrode.

PubMed

Palanisamy, Selvakumar; Karuppiah, Chelladurai; Chen, Shen-Ming

2014-02-01

The direct electrochemistry of glucose oxidase (GOx) was successfully realized on electrochemically reduced graphene oxide and silver nanoparticles (RGO/Ag) nanocomposite modified electrode. The fabricated nanocomposite was characterized by field emission scanning electron microscope and energy dispersive spectroscopy. The GOx immobilized nanocomposite modified electrode showed a pair of well-defined redox peaks with a formal potential (E°) of -0.422 V, indicating that the bioactivity of GOx was retained. The heterogeneous electron transfer rate constant (Ks) of GOx at the nanocomposite was calculated to be 5.27 s(-1), revealing a fast direct electron transfer of GOx. The GOx immobilized RGO/Ag nanocomposite electrode exhibited a good electrocatalytic activity toward glucose over a linear concentration range from 0.5 to 12.5 mM with a detection limit of 0.16 mM. Besides, the fabricated biosensor showed an acceptable sensitivity and selectivity for glucose. Copyright © 2013 Elsevier B.V. All rights reserved.

Nanocomposites biodegradable coating on BOPET films to enhance hot seal strength properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barbaro, G., E-mail: giovannibarbaro@email.it; Galdi, M. R., E-mail: mrgaldi@unisa.it; Di Maio, L., E-mail: ldimaio@unisa.it

2015-12-17

The coating technology is a strategic solution to improve the properties of flexible packaging films. Indeed, additional functional layers are often designed and added as coating on the substrate, in order to improve the characteristic of the flexible packaging and to meet the requirements for the desired gas or vapour barrier, for adhesion and sealing, or for improving the film printability, its aesthetics and durability. Moreover, this technology allows to functionalize a polymeric substrate applying materials with different chemistry, rheology, thermal and structural characteristics. BOPET films are widely used for food packaging applications thanks to their good gas barrier andmore » mechanical properties, high transparency and for the excellent printability. In regard to sealing performance, BOPET films show poor sealing properties so they are mostly submitted to lamination processes with polyethylene. Nevertheless, this solution compromises the PET recyclability and influences the gas permeability of the multilayer PET based structures. The aim of this work is to investigate on the effect of nanocomposite biodegradable coatings for BOPET substrates in enhancing the heat sealing strength of eco-compatible PET/PLA films. At this regards, different percentages of Cloisite C30B (0%, 2% and 4%{sub wt/wt}) have been added to PLA by solution intercalation technique and the nanocomposite biodegradable materials produced have been applied on BOPET commercial films by casting. The BOPET coated films have been characterized in order to evaluate the heat sealing strength and the mechanical, gas permeability and surface properties. The results have shown that the addition of nanoclay in PLA coating significantly enhance the hot tack properties of the PET/PLA system produced, while the oxygen and water vapour permeability are slightly increased if compared to pure BOPET films.« less

Nanocomposites biodegradable coating on BOPET films to enhance hot seal strength properties

NASA Astrophysics Data System (ADS)

Barbaro, G.; Galdi, M. R.; Di Maio, L.; Incarnato, L.

2015-12-01

The coating technology is a strategic solution to improve the properties of flexible packaging films. Indeed, additional functional layers are often designed and added as coating on the substrate, in order to improve the characteristic of the flexible packaging and to meet the requirements for the desired gas or vapour barrier, for adhesion and sealing, or for improving the film printability, its aesthetics and durability. Moreover, this technology allows to functionalize a polymeric substrate applying materials with different chemistry, rheology, thermal and structural characteristics. BOPET films are widely used for food packaging applications thanks to their good gas barrier and mechanical properties, high transparency and for the excellent printability. In regard to sealing performance, BOPET films show poor sealing properties so they are mostly submitted to lamination processes with polyethylene. Nevertheless, this solution compromises the PET recyclability and influences the gas permeability of the multilayer PET based structures. The aim of this work is to investigate on the effect of nanocomposite biodegradable coatings for BOPET substrates in enhancing the heat sealing strength of eco-compatible PET/PLA films. At this regards, different percentages of Cloisite C30B (0%, 2% and 4%wt/wt) have been added to PLA by solution intercalation technique and the nanocomposite biodegradable materials produced have been applied on BOPET commercial films by casting. The BOPET coated films have been characterized in order to evaluate the heat sealing strength and the mechanical, gas permeability and surface properties. The results have shown that the addition of nanoclay in PLA coating significantly enhance the hot tack properties of the PET/PLA system produced, while the oxygen and water vapour permeability are slightly increased if compared to pure BOPET films.

Synthesis of Nm-PHB (nanomelanin-polyhydroxy butyrate) nanocomposite film and its protective effect against biofilm-forming multi drug resistant Staphylococcus aureus.

PubMed

Kiran, George Seghal; Jackson, Stephen A; Priyadharsini, Sethu; Dobson, Alan D W; Selvin, Joseph

2017-08-22

Melanin is a dark brown ubiquitous photosynthetic pigment which have many varied and ever expanding applications in fabrication of radio-protective materials, food packaging, cosmetics and in medicine. In this study, melanin production in a Pseudomonas sp. which was isolated from the marine sponge Tetyrina citirna was optimized employing one-factor at a time experiments and characterized for chemical nature and stability. Following sonication nucleated nanomelanin (Nm) particles were formed and evaluated for antibacterial and antioxidant properties. Nanocomposite film was fabricated using combinations (% w/v) of polyhydroxy butyrate-nanomelanin (PHB:Nm) blended with 1% glycerol. The Nm was found to be spherical in shape with a diameter of 100-140 nm and showed strong antimicrobial activity against both Gram positive and Gram negative bacteria. The Nm-PHB nanocomposite film was homogeneous, smooth, without any cracks, and flexible. XRD and DSC data indicated that the film was crystalline in nature, and was thermostable up to 281.87 °C. This study represents the first report on the synthesis of Nm and fabrication of Nm-PHB nanocomposite film which show strong protective effect against multidrug resistant Staphyloccoccus aureus. Thus this Nm-PHB nanocomposite film may find utility as packaging material for food products by protecting the food products from oxidation and bacterial contamination.

Chemical Functionalization, Self-Assembly, and Applications of Nanomaterials and Nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiao, Tifeng; Yan, Xingbin; Balan, Lavinia

2014-01-01

This special issue addresses the research studies on chemical functionalization, self-assembly, and applications of nanomaterials and nanocomposites. It contains twentyfour articles including two reviews and twenty-two research articles. It is used to create new functional nanomaterials and nanocomposites with a variety of sizes and morphologies such as Zn/Al layered double hydroxide, tin oxide nanowires, FeOOH-modified anion resin, Au nanoclusters silica composite nanospheres, Ti-doped ZnO sol-composite films, TiO2/ZnO composite, graphene oxide nanocomposites, LiFePO4/C nanocomposites, and chitosan nanoparticles. These nanomaterials and nanocomposites have widespread applications in tissue engineering, antitumor, sensors, photoluminescence, electrochemical, and catalytic properties. In addition, this themed issue includes somemore » research articles about self-assembly systems covering organogels and Langmuir films. Furthermore, B. Blasiak et al. performed a literature survey on the recent advances in production, functionalization, toxicity reduction, and application of nanoparticles in cancer diagnosis, treatment, and treatment monitoring. P. Colson et al. performed a literature survey on the recent advances in nanosphere lithography due to its compatibility with wafer-scale processes as well as its potential to manufacture a wide variety of homogeneous one-, two-, or three-dimensional nanostructures.« less

Nanocomposite TiN films with embedded MoS2 inorganic fullerenes produced by combining supersonic cluster beam deposition with cathodic arc reactive evaporation

NASA Astrophysics Data System (ADS)

Piazzoni, C.; Blomqvist, M.; Podestà, A.; Bardizza, G.; Bonati, M.; Piseri, P.; Milani, P.; Davies, C.; Hatto, P.; Ducati, C.; Sedláčková, K.; Radnóczi, G.

2008-01-01

We report the production and characterization of nanocomposite thin films consisting of a titanium nitride matrix with embedded molybdenum disulphide fullerene-like nanoparticles. This was achieved by combining a cluster source generating a pulsed supersonic beam of MoS2 clusters with an industrial cathodic arc reactive evaporation apparatus used for TiN deposition. Cluster-assembled films show the presence of MoS2 nanocages and nanostructures and the survival of such structures dispersed in the TiN matrix in the co-deposited samples. Nanotribological characterization by atomic force microscopy shows that the presence of MoS2 nanoparticles even in very low concentration modifies the behaviour of the TiN matrix.

Graphene Oxide-Polymer Composite Langmuir Films Constructed by Interfacial Thiol-Ene Photopolymerization

NASA Astrophysics Data System (ADS)

Luo, Xiaona; Ma, Kai; Jiao, Tifeng; Xing, Ruirui; Zhang, Lexin; Zhou, Jingxin; Li, Bingbing

2017-02-01

The effective synthesis and self-assembly of graphene oxide (GO) nanocomposites are of key importance for a broad range of nanomaterial applications. In this work, a one-step chemical strategy is presented to synthesize stable GO-polymer Langmuir composite films by interfacial thiol-ene photopolymerization at room temperature, without use of any crosslinking agents and stabilizing agents. It is discovered that photopolymerization reaction between thiol groups modified GO sheets and ene in polymer molecules is critically responsible for the formation of the composite Langmuir films. The film formed by Langmuir assembly of such GO-polymer composite films shows potential to improve the mechanical and chemical properties and promotes the design of various GO-based nanocomposites. Thus, the GO-polymer composite Langmuir films synthesized by interfacial thiol-ene photopolymerization with such a straightforward and clean manner, provide new alternatives for developing chemically modified GO-based hybrid self-assembled films and nanomaterials towards a range of soft matter and graphene applications.

Cellulose whiskers versus microfibrils: influence of the nature of the nanoparticle and its surface functionalization on the thermal and mechanical properties of nanocomposites.

PubMed

Siqueira, Gilberto; Bras, Julien; Dufresne, Alain

2009-02-09

In the present work, nanowhiskers and microfibrillated cellulose (MFC) both extracted from sisal were used to reinforce polycaprolactone (PCL). We report the influence of the nanoparticle's nature on the mechanical and thermal properties of the ensuing nanocomposites. The surface of both the nanoparticles was chemically modified to improve their compatibilization with the polymeric matrix. N-Octadecyl isocyanate (C18H37NCO) was used as the grafting agent. PCL nanocomposite films reinforced with sisal whiskers or MFC (raw or chemically modified) were prepared by film casting. The thermal behavior (Tg, Tm, Tc, and degree of crystallinity) and the mechanical properties of the nanocomposites in both the linear and the nonlinear range were determined using differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA), and tensile tests, respectively. Significant differences were reported according to the nature of the nanoparticle and amount of nanofillers used as reinforcement. It was also proved that the chemical treatment clearly improves the ultimate properties of the nanocomposites.

Fish DNA-modified clays: Towards highly flame retardant polymer nanocomposite with improved interfacial and mechanical performance.

PubMed

Zabihi, Omid; Ahmadi, Mojtaba; Khayyam, Hamid; Naebe, Minoo

2016-12-05

Deoxyribonucleic Acid (DNA) has been recently found to be an efficient renewable and environmentally-friendly flame retardant. In this work, for the first time, we have used waste DNA from fishing industry to modify clay structure in order to increase the clay interactions with epoxy resin and take benefit of its additional thermal property effect on thermo-physical properties of epoxy-clay nanocomposites. Intercalation of DNA within the clay layers was accomplished in a one-step approach confirmed by FT-IR, XPS, TGA, and XRD analyses, indicating that d-space of clay layers was expanded from ~1.2 nm for pristine clay to ~1.9 nm for clay modified with DNA (d-clay). Compared to epoxy nanocomposite containing 2.5%wt of Nanomer I.28E organoclay (m-clay), it was found that at 2.5%wt d-clay loading, significant enhancements of ~14%, ~6% and ~26% in tensile strength, tensile modulus, and fracture toughness of epoxy nanocomposite can be achieved, respectively. Effect of DNA as clay modifier on thermal performance of epoxy nanocomposite containing 2.5%wt d-clay was evaluated using TGA and cone calorimetry analysis, revealing significant decreases of ~4000 kJ/m 2 and ~78 kW/m 2 in total heat release and peak of heat release rate, respectively, in comparison to that containing 2.5%wt of m-clay.

Fish DNA-modified clays: Towards highly flame retardant polymer nanocomposite with improved interfacial and mechanical performance

NASA Astrophysics Data System (ADS)

Zabihi, Omid; Ahmadi, Mojtaba; Khayyam, Hamid; Naebe, Minoo

2016-12-01

Deoxyribonucleic Acid (DNA) has been recently found to be an efficient renewable and environmentally-friendly flame retardant. In this work, for the first time, we have used waste DNA from fishing industry to modify clay structure in order to increase the clay interactions with epoxy resin and take benefit of its additional thermal property effect on thermo-physical properties of epoxy-clay nanocomposites. Intercalation of DNA within the clay layers was accomplished in a one-step approach confirmed by FT-IR, XPS, TGA, and XRD analyses, indicating that d-space of clay layers was expanded from ~1.2 nm for pristine clay to ~1.9 nm for clay modified with DNA (d-clay). Compared to epoxy nanocomposite containing 2.5%wt of Nanomer I.28E organoclay (m-clay), it was found that at 2.5%wt d-clay loading, significant enhancements of ~14%, ~6% and ~26% in tensile strength, tensile modulus, and fracture toughness of epoxy nanocomposite can be achieved, respectively. Effect of DNA as clay modifier on thermal performance of epoxy nanocomposite containing 2.5%wt d-clay was evaluated using TGA and cone calorimetry analysis, revealing significant decreases of ~4000 kJ/m2 and ~78 kW/m2 in total heat release and peak of heat release rate, respectively, in comparison to that containing 2.5%wt of m-clay.

Fish DNA-modified clays: Towards highly flame retardant polymer nanocomposite with improved interfacial and mechanical performance

PubMed Central

Zabihi, Omid; Ahmadi, Mojtaba; Khayyam, Hamid; Naebe, Minoo

2016-01-01

Deoxyribonucleic Acid (DNA) has been recently found to be an efficient renewable and environmentally-friendly flame retardant. In this work, for the first time, we have used waste DNA from fishing industry to modify clay structure in order to increase the clay interactions with epoxy resin and take benefit of its additional thermal property effect on thermo-physical properties of epoxy-clay nanocomposites. Intercalation of DNA within the clay layers was accomplished in a one-step approach confirmed by FT-IR, XPS, TGA, and XRD analyses, indicating that d-space of clay layers was expanded from ~1.2 nm for pristine clay to ~1.9 nm for clay modified with DNA (d-clay). Compared to epoxy nanocomposite containing 2.5%wt of Nanomer I.28E organoclay (m-clay), it was found that at 2.5%wt d-clay loading, significant enhancements of ~14%, ~6% and ~26% in tensile strength, tensile modulus, and fracture toughness of epoxy nanocomposite can be achieved, respectively. Effect of DNA as clay modifier on thermal performance of epoxy nanocomposite containing 2.5%wt d-clay was evaluated using TGA and cone calorimetry analysis, revealing significant decreases of ~4000 kJ/m2 and ~78 kW/m2 in total heat release and peak of heat release rate, respectively, in comparison to that containing 2.5%wt of m-clay. PMID:27917901

Room temperature synthesis and optical studies on Ag and Au mixed nanocomposite polyvinylpyrrolidone polymer films.

PubMed

Udayabhaskar, R; Mangalaraja, R V; Manikandan, D; Arjunan, V; Karthikeyan, B

2012-12-01

Optical properties of silver, gold and bimetallic (Au:Ag) nanocomposite polymer films which are prepared by chemical method have been reported. The experimental data was correlated with the theoretical calculations using Mie theory. We adopt small change in the theoretical calculations of bimetallic/mixed particle nanocomposite and the theory agrees well with the experimental data. Polyvinylpyrrolidone (PVP) was used as reducing and capping agent. Fourier transform infrared spectroscopy (FTIR) study reveals the presence of different functional groups, the possible mechanism that leads to the formation of nanoparticles by using PVP alone as reducing agent. Optical absorption spectra of Ag and Au nanocomposite polymers show a surface plasmon resonance (SPR) band around 430 and 532 nm, respectively. Thermal annealing effect on the prepared samples at 60 °C for different time durations result in shift of SPR band maximum and varies the full width at half maximum (FWHM). Absorption spectra of Au:Ag bimetallic films show bands at 412 and 547 nm confirms the presence of Ag and Au nanoparticles in the composite. Copyright © 2012 Elsevier B.V. All rights reserved.

Phytic acid/graphene oxide nanocomposites modified electrode for electrochemical sensing of dopamine.

PubMed

Wang, Donglei; Xu, Fei; Hu, Jiajie; Lin, Meng

2017-02-01

An electrochemical sensor for determining dopamine was developed by modifying phytic acid/graphene oxide (PA/GO) nanocomposites onto a glassy carbon electrode (GCE). PA functionalized GO was prepared by an ultra-sonication method. Subsequently, the PA/GO nanocomposites were drop-casted on a glassy carbon substrate. The structural feature of the PA/GO modified GCE was confirmed by attenuated total reflection infrared (ATR-IR) spectroscopy. The proposed electrochemical sensor was applied to detect various concentrations of DA by differential pulse voltammetry (DPV). The PA/GO/GCE was considered to be highly sensitive to DA in the range of 0.05-10μM. In addition, the PA/GO/GCE demonstrated high electrochemical selectivity toward DA in the presence of ascorbic acid (AA) and uric acid (UA). The prepared electrochemical DA sensor was applied for detection of DA in dopamine hydrochloride injection and spiked samples of human urine with satisfactory results. Copyright © 2016 Elsevier B.V. All rights reserved.

Carbon Nanotube/Space Durable Polymer Nanocomposite Films for Electrostatic Charge Dissipation

NASA Technical Reports Server (NTRS)

Smith, J. G., Jr.; Watson, K. A.; Thompson, C. M.; Connell, J. W.

2002-01-01

Low solar absorptivity, space environmentally stable polymeric materials possessing sufficient electrical conductivity for electrostatic charge dissipation (ESD) are of interest for potential applications on spacecraft as thin film membranes on antennas, solar sails, large lightweight space optics, and second surface mirrors. One method of imparting electrical conductivity while maintaining low solar absorptivity is through the use of single wall carbon nanotubes (SWNTs). However, SWNTs are difficult to disperse. Several preparative methods were employed to disperse SWNTs into the polymer matrix. Several examples possessed electrical conductivity sufficient for ESD. The chemistry, physical, and mechanical properties of the nanocomposite films will be presented.

Investigation on direct electrochemical and electrocatalytic behavior of hemoglobin on palladium-graphene modified electrode.

PubMed

Chen, Wei; Niu, Xueliang; Li, Xiaoyan; Li, Xiaobao; Li, Guangjiu; He, Bolin; Li, Qiutong; Sun, Wei

2017-11-01

Palladium-graphene (Pd-GR) nanocomposite was acted as modifier for construction of the modified electrode with direct electrochemistry of hemoglobin (Hb) realized. By using Nafion as the immobilization film, Hb was fixed tightly on Pd-GR nanocomposite modified carbon ionic liquid electrode. Electrochemical behaviors of Hb modified electrode were checked by cyclic voltammetry and a pair of redox peaks originated from direct electron transfer of Hb was appeared. The Hb modified electrode had excellent electrocatalytic activity to the reduction of trichloroacetic acid and sodium nitrite in the concentration range from 0.6 to 13.0mmol·L -1 and from 0.04 to 0.5 mmol·L -1 . Therefore Pd-GR nanocomposite was proven to be a good candidate for the fabrication of third-generation electrochemical biosensor. Copyright © 2017 Elsevier B.V. All rights reserved.

Dimensional effects on the tunneling conductivity of gold-implanted nanocomposite films

NASA Astrophysics Data System (ADS)

Grimaldi, C.; Cattani, M.; Salvadori, M. C.

2015-03-01

We study the dependence of the electrical conductivity on the gold concentration of Au-implanted polymethylmethacrylate (PMMA) and alumina nanocomposite thin films. For Au contents larger than a critical concentration, the conductivity of Au-PMMA and Au-alumina is well described by percolation in two dimensions, indicating that the critical correlation length for percolation is larger than the thickness of the films. Below the critical loading, the conductivity is dominated by tunneling processes between isolated Au particles dispersed in PMMA or alumina continuous matrices. Using an effective medium analysis of the tunneling conductivity, we show that Au-PMMA behaves as a tunneling system in two dimensions, as the film thickness is comparable to the mean Au particle size. On the contrary, the conductivity of Au-alumina films is best described by tunneling in three dimensions, although the film thickness is only a few times larger than the particle size. We interpret the enhancement of the effective dimensionality of Au-alumina films in the tunneling regime as due to the larger film thickness as compared to the mean interparticle distances.

Fabrication, characterization and in-vitro cytotoxicity of magnetic nanocomposite polymeric film for multi-functional medical application

NASA Astrophysics Data System (ADS)

Zhao, Lingyun; Xu, Xiaoyu; Wang, Xiaowen; Zhang, Xiaodong; Gao, Fuping; Tang, Jintian

2009-07-01

Cancer comprehensive treatment has been fully acknowledged as it can provide an effective multimodality approach for fighting cancers. In this study, various innovative technologies for cancer treatment including cancer nanotechnology, chemotherapy by sustainable release, as well as magnetic induction hyperthermia (MIH) have been integrated for the purpose of cancer comprehensive treatment. Briefly, such kind of treatment can be realized by applying of the tailored magnetic nanoparticles (MNPs) composite polymeric film. Fe3O4 MNPs acting as the agent for MIH, and anti-cancer drug docetaxel as chemotherapeutic agent were incorporated within the biodegradable polymeric film. Physiochemical characterizations on MNPs and the film have been systematically carried out by various instrumental analyses. Our results demonstrated that the film has been successfully fabricated by the solvent cast method. Hyperthermia could be induced by stimulating the nanocomposite film under an alternative magnetic field (AMF). The incorporation of MNPs, as well as hyperthermia would facilitate the drug release from the polymeric film. The in-vitro cytotoxicity results indicated the bi-modal cancer treatment approach for combined MIH and chemotherapy is more effective than the mono-modal treatment by docetaxel treatment. The magnetic nanocomposite film can realize cancer comprehensive treatment thus has great potential in clinical application.

Methyl parathion detection in vegetables and fruits using silver@graphene nanoribbons nanocomposite modified screen printed electrode

NASA Astrophysics Data System (ADS)

Govindasamy, Mani; Mani, Veerappan; Chen, Shen-Ming; Chen, Tse-Wei; Sundramoorthy, Ashok Kumar

2017-04-01

We have developed a sensitive electrochemical sensor for Organophosphorus pesticide methyl parathion (MP) using silver particles supported graphene nanoribbons (Ag@GNRs). The Ag@GNRs nanocomposite was prepared through facile wet chemical strategy and characterized by TEM, EDX, XRD, Raman, UV-visible, electrochemical and impedance spectroscopies. The Ag@GNRs film modified screen printed carbon electrode (SPCE) delivers excellent electrocatalytic ability to the reduction of MP. The Ag@GNRs/SPCE detects sub-nanomolar concentrations of MP with excellent selectivity. The synergic effects between special electrocatalytic ability of Ag and excellent physicochemical properties of GNRs (large surface area, high conductivity, high area-normalized edge-plane structures and abundant catalytic sites) make the composite highly suitable for MP sensing. Most importantly, the method is successfully demonstrated in vegetables and fruits which revealed its potential real-time applicability in food analysis.

Dynamic Mechanical Characterization of Thin Film Polymer Nanocomposites

NASA Technical Reports Server (NTRS)

Herring, Helen M.; Gates, Thomas S. (Technical Monitor)

2003-01-01

Many new materials are being produced for aerospace applications with the objective of maximizing certain ideal properties without sacrificing others. Polymer composites in various forms and configurations are being developed in an effort to provide lighter weight construction and better thermal and electrical properties and still maintain adequate strength and stability. To this end, thin film polymer nanocomposites, synthesized for the purpose of influencing electrical conductivity using metal oxide particles as filler without incurring losses in mechanical properties, were examined to determine elastic modulus and degree of dispersion of particles. The effects of various metal oxides on these properties will be discussed.

Influence of deposition temperature and amorphous carbon on microstructure and oxidation resistance of magnetron sputtered nanocomposite Crsbnd C films

NASA Astrophysics Data System (ADS)

Nygren, Kristian; Andersson, Matilda; Högström, Jonas; Fredriksson, Wendy; Edström, Kristina; Nyholm, Leif; Jansson, Ulf

2014-06-01

It is known that mechanical and tribological properties of transition metal carbide films can be tailored by adding an amorphous carbon (a-C) phase, thus making them nanocomposites. This paper addresses deposition, microstructure, and for the first time oxidation resistance of magnetron sputtered nanocomposite Crsbnd C/a-C films with emphasis on studies of both phases. By varying the deposition temperature between 20 and 700 °C and alternating the film composition, it was possible to deposit amorphous, nanocomposite, and crystalline Crsbnd C films containing about 70% C and 30% Cr, or 40% C and 60% Cr. The films deposited at temperatures below 300 °C were X-ray amorphous and 500 °C was required to grow crystalline phases. Chronoamperometric polarization at +0.6 V vs. Ag/AgCl (sat. KCl) in hot 1 mM H2SO4 resulted in oxidation of Crsbnd C, yielding Cr2O3 and C, as well as oxidation of C. The oxidation resistance is shown to depend on the deposition temperature and the presence of the a-C phase. Physical characterization of film surfaces show that very thin C/Cr2O3/Crsbnd C layers develop on the present material, which can be used to improve the oxidation resistance of, e.g. stainless steel electrodes.

A comparative study of gelatin and starch-based nano-composite films modified by nano-cellulose and chitosan for food packaging applications.

PubMed

Noorbakhsh-Soltani, S M; Zerafat, M M; Sabbaghi, S

2018-06-01

Environmental concerns have led to extensive research for replacing polymer-based food packaging with bio-nano-composites. In this study, incorporation of nano-cellulose into gelatin and starch matrices is investigated for this purpose. Chitosan is used to improve mechanical, anti-fungal and waterproof properties. Experiments are designed and analyzed using response surface methodology. Nano-Cellulose is synthesized via acid hydrolysis and incorporated in base matrices through wet processing. Also, tensile strength test, food preservation, transparency in visible and UV and water contact angle are performed on the nano-composite films. DSC/TGA and air permeability tests are also performed on the optimal films. The results show that increasing nano-cellulose composition to 10% leads to increase the tensile strength at break to 8121 MN/m 2 and decrease the elongation at break. Also, increasing chitosan composition from 5% to 30% can enhance food preservation up to 15 days. Copyright © 2018 Elsevier Ltd. All rights reserved.

MEMS sensor material based on polypyrrole carbon nanotube nanocomposite: film deposition and characterization

NASA Astrophysics Data System (ADS)

Teh, Kwok-Siong; Lin, Liwei

2005-11-01

Conductive polymer-based nanocomposite has been utilized as a MEMS sensing material via a one-step, selective on-chip deposition process at room temperature. A doped polypyrrole (PPy) variant synthesized by incorporating multi-walled carbon nanotube (MWCNT) into electropolymerized PPy has been shown to improve the sensing performance utilizing a two-terminal, micro-gap chemiresistor architecture. The dodecylbenzenesulfonate (DBS)-doped PPy-MWCNT nanocomposites are found to be responsive to oxidants, such as hydrogen peroxide (H2O2), and this effect can be extended to glucose detection using H2O2 as a proxy material. The oxidant sensing effect is demonstrated by subjecting a glucose oxidase (GOx)-laden PPy-MWCNT nanocomposite film to various concentrations of glucose solution. Such PPy-MWCNT nanocomposite, when applied in a chemiresistor configuration, obviates the need for reference electrode and electron mediators, by measuring the direct and reversible, oxidation-reduction induced conductivity change. Experimentally, GOx-laden, doped PPy-MWCNT is tested to be sensitive to glucose concentration up to 20 mM, which covers the physiologically important range for diabetics of 0-20 mM.

Transparent 'solution' of ultrathin magnesium hydroxide nanocrystals for flexible and transparent nanocomposite films.

PubMed

Wang, Jie-Xin; Sun, Qian; Chen, Bo; Wu, Xi; Zeng, Xiao-Fei; Zhang, Cong; Zou, Hai-Kui; Chen, Jian-Feng

2015-05-15

Transparent solutions of nanocrystals exhibit many unique properties, and are thus attractive materials for numerous applications. However, the synthesis of transparent nanocrystal solutions of magnesium hydroxide (MH) with wide applications is yet to be realized. Here, we report a facile two-step process, which includes a direct reactive precipitation in alcohol phase instead of aqueous phase combined with a successive surface modification, to prepare transparent alcohol solutions containing lamellar MH nanocrystals with an average size of 52 nm and an ultrathin thickness of 1-2 nm, which is the thinnest MH nanoplatelet reported in the literatures. Further, highly flexible and transparent nanocomposite films are fabricated with a solution mixing method by adding the transparent MH nanocrystal solutions into PVB solution. Considering the simplicity of the fabrication process, high transparency and good flexibility, this MH/polymer nanocomposite film is promising for flame-resistant applications in plastic electronics and optical devices with high transparency, such as flexible displays, optical filters, and flexible solar cells.

Rational interface design of epoxy-organoclay nanocomposites: role of structure-property relationship for silane modifiers.

PubMed

Bruce, Alex N; Lieber, Danielle; Hua, Inez; Howarter, John A

2014-04-01

Montmorillonite was modified by three silane surfactants with different functionalities to investigate the role of surfactant structure on the properties of a final epoxy-organoclay nanocomposite. N-aminopropyldimethylethoxysilane (APDMES), an aminated monofunctional silane, was chosen as a promising surfactant for several reasons: (1) it will bond to silica in montmorillonite, (2) it will bond to epoxide groups, and (3) to overcome difficulties found with trifunctional aminosilane bonding clay layers together and preventing exfoliation. A trifunctional and non-aminated version of APDMES, 3-aminopropyltriethoxysilane (APTES) and n-propyldimethylmethoxysilane (PDMMS), respectively, was also studied to provide comparison to this rationally chosen surfactant. APDMES and APTES were grafted onto montmorillonite in the same amount, while PDMMS was barely grafted (<1 wt%). The gallery spacing of APDMES organoclay was greater than APTES or PDMMS, but the final nanocomposite gallery spacing was not dependent on the surfactant used. Different concentrations of APDMES modified montmorillonite yielded different properties, as concentration decreased glass transition temperature increased, thermal stability increased, and the storage modulus decreased. Storage modulus, glass transition temperature, and thermal stability were more similar for epoxy-organoclay composites modified with the same concentration of silane surfactant, neat epoxy, and epoxy-montmorillonite nanocomposite. Copyright © 2013 Elsevier Inc. All rights reserved.

Acetylene Gas-Sensing Properties of Layer-by-Layer Self-Assembled Ag-Decorated Tin Dioxide/Graphene Nanocomposite Film

PubMed Central

Jiang, Chuanxing; Yin, Nailiang; Yao, Yao; Shaymurat, Talgar; Zhou, Xiaoyan

2017-01-01

This paper demonstrates an acetylene gas sensor based on an Ag-decorated tin dioxide/reduced graphene oxide (Ag–SnO2/rGO) nanocomposite film, prepared by layer-by-layer (LbL) self-assembly technology. The as-prepared Ag–SnO2/rGO nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectrum. The acetylene sensing properties were investigated using different working temperatures and gas concentrations. An optimal temperature of 90 °C was determined, and the Ag–SnO2/rGO nanocomposite sensor exhibited excellent sensing behaviors towards acetylene, in terms of response, repeatability, stability and response/recovery characteristics, which were superior to the pure SnO2 and SnO2/rGO film sensors. The sensing mechanism of the Ag–SnO2/rGO sensor was attributed to the synergistic effect of the ternary nanomaterials, and the heterojunctions created at the interfaces between SnO2 and rGO. This work indicates that the Ag–SnO2/rGO nanocomposite is a good candidate for constructing a low-temperature acetylene sensor. PMID:28927021

The Enhancement Of UV Sensor Response By Zinc Oxide Nanorods / Reduced Graphene Oxide Bilayer Nanocomposites Film

NASA Astrophysics Data System (ADS)

Mohammed, Ali A. A.; Suriani, AB; Jabur, Akram R.

2018-05-01

Zinc oxide nanorods (ZnO NRs) / reduced graphene oxide (rGO) nanocomposites assisted by sodium dodecyl sulfate surfactant (ZnO NRs/rGO-SDS) showed a good response for UV sensor application that has sensitivity of around ∼32.54. Whereas, the UV sensor response on pristine ZnO NRs showed almost 15 times lower response than the ZnO NRs/rGO-SDS nanocomposites. The pristine ZnO NRs were prepared by sol-gel immersion method before rGO solution was sprayed on the ZnO films using spraying method. The GO solution was produced via electrochemical exfoliation method at 0.1 M SDS electrolyte then the solution was reduced using hydrazine hydrate under 24 hours magnetic stirring at a temperature of around ∼100 °C. The samples were characterized using energy dispersive X-ray, field emission scanning electron microscope, micro-Raman, ultraviolet visible, X-ray diffraction, UV lamp and four-point probe measurement. The aim of this study was to improve the UV sensor response based on ZnO/rGO-SDS nanocomposites. In conclusion, the fabricated ZnO NRs/rGO-SDS nanocomposites assisted with SDS is a good candidate for the use in UV sensor applications as compared to pristine ZnO NRs films.

AuNPs/CNOs/SWCNTs/chitosan-nanocomposite modified electrochemical sensor for the label-free detection of carcinoembryonic antigen.

PubMed

Rizwan, Mohammad; Elma, Syazwani; Lim, Syazana Abdullah; Ahmed, Minhaz Uddin

2018-06-01

In this work, a nanocomposite of gold nanoparticles (AuNPs), carbon nano-onions (CNOs), single-walled carbon nanotubes (SWCNTs) and chitosan (CS) (AuNPs/CNOs/SWCNTs/CS) was prepared for the development of highly sensitive electrochemical immunosensor for the detection of carcinoembryonic antigen (CEA), clinical tumor marker. Firstly, layer-by-layer fabrication of the CEA-immunosensors was studied using cyclic voltammetry (CV) and square wave voltammetry (SWV). By combining the advantages of large surface area and electronic properties of AuNPs, CNOs, SWCNTs, and film forming properties of CS, AuNPs/CNOs/SWCNTs/CS-nanocomposite-modified glassy carbon electrode showed a 200% increase in effective surface area and electronic conductivity. The calibration plot gave a negative linear relationship between log[concentration] of CEA and electrical current with a correlation coefficient of 0.9875. The CEA-immunosensor demonstrated a wide linear detection range of 100 fg mL -1 to 400 ng mL -1 with a low detection limit of 100 fg mL -1 . In addition to high sensitivity, reproducibility and large stability, CEA-immunosensor provided an excellent selectivity and resistant-to-interference in the presence of other antigens in serum and hence a potential to be used with real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Impact behavior of f-silica and amine terminated polybutadiene co-acrylonitrile rubber modified novolac epoxy/Kevlar nanocomposites

NASA Astrophysics Data System (ADS)

Kavita, Pal, Vijayeta; Tiwari, R. K.

2018-05-01

In the present work, nano-fumed silica treated with 3-Glycidoxypropyl trimethoxy silane (f-silica) was used as a nanoreinforcement in the fabrication of amine terminated polybutadiene co-acrylonitrile rubber (ATBN) modified Kevlar/epoxy based nanocomposites. Nanocomposites with different f-silica loading (0, 0.5, 1.0 and 2.0 wt. %) and having same ATBN (10 wt. %) were made and characterized by Izod impact test for evaluating impact strength values. All the nanocomposites showed better impact strength than neat Kevlar/novolac epoxy based composite.

Enhanced mechanical, thermal and antimicrobial properties of poly(vinyl alcohol)/graphene oxide/starch/silver nanocomposites films.

PubMed

Usman, Adil; Hussain, Zakir; Riaz, Asim; Khan, Ahmad Nawaz

2016-11-20

In the present work, synthesis of poly(vinyl alcohol)/graphene oxide/starch/silver (PVA/GO/Starch/Ag) nanocomposites films is reported. Such films have been characterized and investigated for their mechanical, thermal and antimicrobial properties. The exfoliation of GO in the PVA matrix occurs owing to the non-covalent interactions of the polymer chains of PVA and hydrophilic surface of the GO layers. Presence of GO in PVA and PVA/starch blends were found to enhance the tensile strength of the nanocomposites system. It was found that the thermal stability of PVA as well as PVA/starch blend systems increased by the incorporation of GO where strong physical bonding between GO layers and PVA/starch blends is assumed to cause thermal barrier effects. Antimicrobial properties of the prepared films were investigated against Escherichia coli and Staphylococcus aureus. Our results show enhanced antimicrobial properties of the prepared films where PVA-GO, PVA-Ag, PVA-GO-Ag and PVA-GO-Ag-Starch showed antimicrobial activity in ascending order. Copyright © 2016 Elsevier Ltd. All rights reserved.

High barrier multilayer packaging by the coextrusion method: The effect of nanocomposites and biodegradable polymers on flexible film properties

NASA Astrophysics Data System (ADS)

Thellen, Christopher T.

The objective of this research was to investigate the use of nanocomposite and multilayer co-extrusion technologies for the development of high gas barrier packaging that is more environmentally friendly than many current packaging system. Co-extruded bio-based and biodegradable polymers that could be composted in a municipal landfill were one direction that this research was aimed. Down-gauging of high performance barrier films using nanocomposite technology and co-extrusion was also investigated in order to reduce the amount of solid waste being generated by the packaging. Although the research is focused on military ration packaging, the technologies could easily be introduced into the commercial flexible packaging market. Multilayer packaging consisting of poly(m-xylylene adipamide) nanocomposite layers along with adhesive and tie layers was co-extruded using both laboratory and pilot-scale film extrusion equipment. Co-extrusion of biodegradable polyhydroxyalkanoates (PHA) along with polyvinyl alcohol (PVOH) and tie layers was also accomplished using similar co-extrusion technology. All multilayer films were characterized for gas barrier, mechanical, and thermal properties. The biodegradability of the PVOH and PHA materials in a marine environment was also investigated. The research has shown that co-extrusion of these materials is possible at a research and pilot level. The use of nanocomposite poly(m-xylylene adipamide) was effective in down-gauging the un-filled barrier film to thinner structures. Bio-based PHA/PVOH films required the use of a malefic anhydride grafted PHA tie layer to improve layer to layer adhesion in the structure to avoid delamination. The PHA polymer demonstrated a high rate of biodegradability/mineralization in the marine environment while the rate of biodegradation of the PVOH polymer was slower.

Thermoluminescence of the Films, Nanocomposites, and Solutions of the Silicon Organic Polymer Poly(di- n-hexyl silane)

NASA Astrophysics Data System (ADS)

Ostapenko, N. I.; Kerita, O. A.; Ostapenko, Yu. V.

2018-03-01

A comparative study of low-temperature thermoluminescence (5-120 K) of silicon organic polymer poly(di-n-hexyl silane) films, nanocomposites (when the polymer is introduced into nanopores of silica MCM-41 and SBA-15 with diameter of pores 2.8 and 10 nm) as well as solutions of polymer in tetrahydrofuran with different concentrations from 10-3 to 10-5 mol/L was carried out. It was shown that it is possible to control the number of charge carrier traps, as well as their energy distribution by changing the diameter of silica nanopores. It is established that maxima and FWHMs of the thermoluminescence curves of nanocomposites significantly depend on the pore diameter of the nanoporous silica. This result agrees with the data obtained in the investigation of polymer solutions. In the nanocomposite with a minimum pore diameter (2.8 nm), the number and depth of the traps as well as dispersion of their energy are significantly reduced compared to their values in the polymer film.

Study of the structure of 3D-ordered macroporous GaN-ZnS:Mn nanocomposite films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurdyukov, D. A., E-mail: kurd@gvg.ioffe.ru; Shishkin, I. I.; Grudinkin, S. A.

A film-type 3D-ordered macroporous GaN-ZnS:Mn nanocomposite with the structure of an inverted opal is fabricated. Structural studies of the nanocomposite are performed, and it is shown that GaN and ZnS:Mn introduced into the pores of the silica opal are nanocrystallites misoriented with respect to each other. It is shown that the nanocomposite is a structurally perfect 3D photonic crystal. The efficiency of using a buffer of GaN crystallites to preclude interaction between the surface of the spherical a-SiO{sub 2} particles forming the opal matrix and chemically active substances introduced into the pores is demonstrated.

Laser Deposition of Polymer Nanocomposite Thin Films and Hard Materials and Their Optical Characterization

DTIC Science & Technology

2013-12-05

visible light on instruments such as microscope tips and micro- surgical tools. Hard carbon known as diamond-like carbon films produced by pulsed laser ...visible (610 nm) LED source and a supplemental infra-red 980-nm laser diode (for the studies of the upconversion fluorescence). The basic package...5/2013 Final Performance Report 15 Sep 2012- 14 Sep 2013 LASER DEPOSITION OF POLYMER NANOCOMPOSITE THIN FILMS AND HARD MATERIALS AND THEIR OPTICAL

Dielectric tunability of vertically aligned ferroelectric-metal oxide nanocomposite films controlled by out-of-plane misfit strain

NASA Astrophysics Data System (ADS)

Wu, Huaping; Ma, Xuefu; Zhang, Zheng; Zhu, Jun; Wang, Jie; Chai, Guozhong

2016-04-01

A nonlinear thermodynamic model based on the vertically aligned nanocomposite (VAN) thin films of ferroelectric-metal oxide system has been developed to investigate the physical properties of the epitaxial Ba0.6Sr0.4TiO3 (BST) films containing vertical Sm2O3 (SmO) nanopillar arrays on the SrTiO3 substrate. The phase diagrams of out-of-plane lattice mismatch vs. volume fraction of SmO are calculated by minimizing the total free energy. It is found that the phase transformation and dielectric response of BST-SmO VAN systems are extremely dependent on the in-plane misfit strain, the out-of-plane lattice mismatch, the volume fraction of SmO phase, and the external electric field applied to the nanocomposite films at room temperature. In particular, the BST-SmO VAN systems exhibit higher dielectric properties than pure BST films. Giant dielectric response and maximum tunability are obtained near the lattice mismatch where the phase transition occurs. Under the in-plane misfit strain of umf=0.3 % and the out-of-plane lattice mismatch of u3=0.002 , the dielectric tunability can be dramatically enhanced to 90% with the increase of SmO volume fraction, which is well consistent with previous experimental results. This work represents an approach to further understand the dependence of physical properties on the lattice mismatch (in-plane and out-of-plane) and volume fraction, and to manipulate or optimize functionalities in the nanocomposite oxide thin films.

Preparation and mechanical properties of modified nanocellulose/PLA composites from cassava residue

NASA Astrophysics Data System (ADS)

Huang, Lijie; Zhang, Xiaoxiao; Xu, Mingzi; Chen, Jie; Shi, Yinghan; Huang, Chongxing; Wang, Shuangfei; An, Shuxiang; Li, Chunying

2018-02-01

Nanocellulose was prepared by a mechanochemical method using cassava residue as a raw material and phosphoric acid as the auxiliary agent. The prepared nanocellulose was hydrophobically modified with stearic acid to improve its dispersibility. This modified nanocellulose was added to polylactic acid (PLA) film-forming liquids at concentrations of 0%, 0.5%, 1.0%, 1.5% and 2.0%, and the effect of modified nanocellulose on the mechanical properties of polylactic acid (PLA) films were investigated. When at least 0.5% modified nanocellulose is added, more active groups of modified nanocellulose are adsorbed onto the PLA molecular chain. Although the tensile strength of the film is only improved by 13.59%, the flexibility of the film decreases, and the elastic modulus decreases by 28.91%. When 1% modified nanocellulose is added, the modified nanocellulose and PLA are tangled together through molecular chains and they co-crystallize to form a stable network structure. The tensile strength of the nanocomposite films is enhanced by 40.03%, the elastic modulus is enhanced by 55.65%, and the flexibility of the film decreases.

Pulsed photoinitiated fabrication of inkjet printed titanium dioxide/reduced graphene oxide nanocomposite thin films.

PubMed

Bourgeois, Briley; Luo, Sijun; Riggs, Brian; Ji, Yaping; Adireddy, Shiva; Schroder, Kurt; Farnsworth, Stan; Chrisey, Douglas; Escarra, Matthew

2018-08-03

This work reports a new technique for scalable and low-temperature processing of nanostructured TiO 2 thin films, allowing for practical manufacturing of TiO 2 -based devices such as perovskite solar cells at low-temperature or on flexible substrates. Dual layers of dense and mesoporous TiO 2 /graphitic oxide nanocomposite films are synthesized simultaneously using inkjet printing and pulsed photonic irradiation. Investigation of process parameters including precursor concentration (10-20 wt%) and exposure fluence (4.5-8.5 J cm -2 ) reveals control over crystalline quality, graphitic oxide phase, film thickness, dendrite density, and optical properties. Raman spectroscopy shows the E g peak, characteristic of anatase phase titania, increases in intensity with higher photonic irradiation fluence, suggesting increased crystallinity through higher fluence processing. Film thickness and dendrite density is shown to increase with precursor concentration in the printed ink. The dense base layer thickness was controlled between 20 and 80 nm. The refractive index of the films is determined by ellipsometry to be 1.92 ± 0.08 at 650 nm. Films exhibit an energy weighted optical transparency of 91.1%, in comparison to 91.3% of a thermally processed film, when in situ carbon materials were removed. Transmission and diffuse reflectance are used to determine optical band gaps of the films ranging from 2.98 to 3.38 eV in accordance with the photonic irradiation fluence and suggests tunability of TiO 2 phase composition. The sheet resistance of the synthesized films is measured to be 14.54 ± 1.11 Ω/□ and 28.90 ± 2.24 Ω/□ for films as-processed and after carbon removal, respectively, which is comparable to high temperature processed TiO 2 thin films. The studied electrical and optical properties of the light processed films show comparable results to traditionally processed TiO 2 while offering the distinct advantages of scalable manufacturing, low-temperature processing

Chitosan nanocomposite films: enhanced electrical conductivity, thermal stability, and mechanical properties.

PubMed

Marroquin, Jason B; Rhee, K Y; Park, S J

2013-02-15

A novel, high-performance Fe(3)O(4)/MWNT/Chitosan nanocomposite has been prepared by a simple solution evaporation method. A significant synergistic effect of Fe(3)O(4) and MWNT provided enhanced electrical conductivity, mechanical properties, and thermal stability on the nanocomposites. A 5% (wt) loading of Fe(3)O(4)/MWNT in the nanocomposite increased conductivity from 5.34×10(-5) S/m to 1.49×10(-2) S/m compared to 5% (wt) MWNT loadings. The Fe(3)O(4)/MWNT/Chitosan films also exhibited increases in tensile strength and modulus of 70% and 155%, respectively. The integral procedure decomposition temperature (IPDT) was enhanced from 501 °C to 568 °C. These effects resulted from a number of factors: generation of a greater number of conductive channels through interactions between MWNT and Fe(3)O(4) surfaces, a higher relative crystallinity, the antiplasticizing effects of Fe(3)O(4), a restricted mobility and hindrance of depolymerization of the Chitosan chain segments, as well as uniform distribution, improved dispersion, and strong interfacial adhesion between the MWNT and Chitosan matrix. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fabrication and physical properties of transparent poly (methyl-methacrylate)-layered silicate nanocomposites

NASA Astrophysics Data System (ADS)

Vasiliu, Elena

Transparent polymer nanocomposites have promising potential for protective coating applications with improved surface resistance, higher temperature performance and low gas permeability for containers and films. Extremely thin protective layers are required for improved performance of various electronic devices in aviation, aerospace and medical equipment as well as for lenses and fiber optics in optical communications. This research study developed a method for fabricating optically transparent nanocomposites of poly(methyl-methacrylate)(PMMA) and a commercial organically-modified layered silicate CloisiteRTM 6A (C6A). The nanocomposites were produced by dispersing C6A and PMMA separately in a common solvent xylene followed by mixing the two solutions by mechanical stirring and/or ultrasonic agitation and then removing the solvent by evaporation. Processing conditions such as the mixing methods and times and the rates of solvent removal were investigated in order to achieve a high degree of dispersion and exfoliation of C6A in the polymer matrix and produce a nanocomposite material with high optical transparency. Small-angle x-ray scattering (SAXS) was used to monitor the morphology of the C6A after each processing step. Thin films of PMMA/C6A nanocomposites were produced by casting and spraying. SAXS results suggest that C6A was partially exfoliated in the composite material with an average of 2 to 3 platelets per crystallite. Transmission electron microscopy (TEM) confirmed the existence of both exfoliated and intercalated C6A in PMMA. One mm thick discs were obtained by molding the sprayed films. The optical transmission of the nanocomposite films and discs was measured with an UV/VIS spectrometer. The spectroscopic results served to identify the best process for producing PMMA-C6A films of high optical transparency. Even the nanocomposite films containing up to 20 wt.% C6A prepared by this process exhibited optical transmittance in the range of 80 to 90

One-Step Electrochemical Fabrication of Reduced Graphene Oxide/Gold Nanoparticles Nanocomposite-Modified Electrode for Simultaneous Detection of Dopamine, Ascorbic Acid, and Uric Acid

PubMed Central

Lee, Chang-Seuk; Yu, Su Hwan; Kim, Tae Hyun

2017-01-01

Here, we introduce the preparation of the hybrid nanocomposite-modified electrode consisting of reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) using the one-step electrochemical method, allowing for the simultaneous and individual detection of dopamine (DA), ascorbic acid (AA), and uric acid (UA). RGO/AuNPs nanocomposite was formed on a glassy carbon electrode by the co-reduction of GO and Au3+ using the potentiodynamic method. The RGO/AuNPs nanocomposite-modified electrode was produced by subjecting a mixed solution of GO and Au3+ to cyclic sweeping from −1.5 V to 0.8 V (vs. Ag/AgCl) at a scan rate 10 mV/s for 3 cycles. The modified electrode was characterized by scanning electron microscopy, Raman spectroscopy, contact angle measurement, electrochemical impedance spectroscopy, and cyclic voltammetry. Voltammetry results confirm that the RGO/AuNPs nanocomposite-modified electrode has high catalytic activity and good resolution for the detection of DA, AA, and UA. The RGO/AuNPs nanocomposite-modified electrode exhibits stable amperometric responses for DA, AA, and UA, respectively, and its detection limits were estimated to be 0.14, 9.5, and 25 μM. The modified electrode shows high selectivity towards the determination of DA, AA, or UA in the presence of potentially active bioelements. In addition, the resulting sensor exhibits many advantages such as fast amperometric response, excellent operational stability, and appropriate practicality. PMID:29301209

Innovative Linear Low Density Polyethylene Nanocomposite Films Reinforced with Organophilic Layered Double Hydroxides: Fabrication, Morphology and Enhanced Multifunctional Properties.

PubMed

Xie, Jiazhuo; Wang, Haijun; Wang, Zhou; Zhao, Qinghua; Yang, Yuechao; Waterhouse, Geoffrey I N; Hao, Lei; Xiao, Zihao; Xu, Jing

2018-01-08

Herein, we reported the successful development of novel nanocomposite films based on linear low density polyethylene (LLDPE) with enhanced anti-drop, optical, mechanical, thermal and water vapor barrier properties by introducing organophilic layered double hydroxides (OLDHs) nanosheets. OLDHs loadings were varied from 0-6 wt.%. Structural analyses using the Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) indicated that the OLDHs nanosheets were homogeneously dispersed with an ordered alignment in the LLDPE matrix. The LLDPE film containing 2 wt.% OLDHs (denoted as OLDHs-2) showed the optimal mechanical, thermal and water vapor barrier properties, whilst the anti-drop and optical performance of the films improved with increasing OLDHs content. The enhanced antidrop properties of the composite films relative to pristine LLDPE can be expected to effectively reduce agricultural losses to disease when the films are applied as agricultural films, whilst the superior light transmittance and water-retaining properties of the composite films will boost agricultural production. Results presented suggest that multifunctional LLDPE/OLDHs nanocomposites show great promise as low cost agricultural plastic films.

Nanocrystal-polymer nanocomposite electrochromic device

DOEpatents

Milliron, Delia; Runnerstrom, Evan; Helms, Brett; Llordes, Anna; Buonsanti, Raffaella; Garcia, Guillermo

2015-12-08

Described is an electrochromic nanocomposite film comprising a solid matrix of an oxide based material, the solid matrix comprising a plurality of transparent conducting oxide (TCO) nanostructures dispersed in the solid matrix and a lithium salt dispersed in the solid matrix. Also described is a near infrared nanostructured electrochromic device having a functional layer comprising the electrochromic nanocomposite film.

Development of silane grafted ZnO core shell nanoparticles loaded diglycidyl epoxy nanocomposites film for antimicrobial applications.

PubMed

Suresh, S; Saravanan, P; Jayamoorthy, K; Ananda Kumar, S; Karthikeyan, S

2016-07-01

In this article a series of epoxy nanocomposites film were developed using amine functionalized (ZnO-APTES) core shell nanoparticles as the dispersed phase and a commercially available epoxy resin as the matrix phase. The functional group of the samples was characterized using FT-IR spectra. The most prominent peaks of epoxy resin were found in bare epoxy and in all the functionalized ZnO dispersed epoxy nanocomposites (ZnO-APTES-DGEBA). The XRD analysis of all the samples exhibits considerable shift in 2θ, intensity and d-spacing values but the best and optimum concentration is found to be 3% ZnO-APTES core shell nanoparticles loaded epoxy nanocomposites supported by FT-IR results. From TGA measurements, 100wt% residue is obtained in bare ZnO nanoparticles whereas in ZnO core shell nanoparticles grafted DGEBA residue percentages are 37, 41, 45, 46 and 52% for 0, 1, 3, 5 and 7% ZnO-APTES-DGEBA respectively, which is confirmed with ICP-OES analysis. From antimicrobial activity test, it was notable that antimicrobial activity of 7% ZnO-APTES core shell nanoparticles loaded epoxy nanocomposite film has best inhibition zone effect against all pathogens under study. Copyright © 2016 Elsevier B.V. All rights reserved.

Nanocomposite materials based on poly(vinyl chloride) and bovine serum albumin modified ZnO through ultrasonic irradiation as a green technique: Optical, thermal, mechanical and morphological properties.

PubMed

Mallakpour, Shadpour; Darvishzadeh, Marzieh

2018-03-01

In this project, physicochemical properties of poly(vinyl chloride) (PVC) reinforced by ZnO nanoparticles (NPs) were studied. Firstly, ZnO NPs were modified with bovine serum albumin (BSA) as an organo-modifier and biocompatible substance through ultrasound irradiation as environmental friendly, low cost and rapid means. Nanocomposite (NC) films were prepared by loadings of various ratios of ZnO/BSA NPs (3, 6 and 9wt%) inside the PVC. Structural morphology and physical properties of the ZnO-BSA NPs and NC films were investigated via Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), transmission electron microscopy and field emission scanning electron microscopy. According to the obtained information from the TGA, an increase in the thermal stability can be clearly observed. Also the results of contact angle analysis indicated with increasing percent of ZnO/BSA NPs into PVC the hydrophilic behaviors of NCs were increased. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of nanoscopic free volume and interfacial interaction in an epoxy resin/modified clay nanocomposite using positron annihilation spectroscopy.

PubMed

Patil, Pushkar N; Sudarshan, Kathi; Sharma, Sandeep K; Maheshwari, Priya; Rath, Sangram K; Patri, Manoranjan; Pujari, Pradeep K

2012-12-07

Epoxy/clay nanocomposites are synthesized using clay modified with the organic modifier N,N-dimethyl benzyl hydrogenated tallow quaternary ammonium salt (Cloisite 10A). The purpose is to investigate the influence of the clay concentration on the nanostructure, mainly on the free-volume properties and the interfacial interactions, of the epoxy/clay nanocomposite. Nanocomposites having 1, 3, 5 and 7.5 wt. % clay concentrations are prepared using the solvent-casting method. The dispersion of clay silicate layers and the morphologies of the fractured surfaces in the nanocomposites are studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The observed XRD patterns reveal an exfoliated clay structure in the nanocomposite with the lowest clay concentration (≤1 wt. %). The ortho-positronium lifetime (τ(3)), a measure of the free-volume size, as well as the fractional free volume (f(v)) are seen to decrease in the nanocomposites as compared to pristine epoxy. The intensity of free positron annihilation (I(2)), an index of the epoxy-clay interaction, decreases with the addition of clay (1 wt. %) but increases linearly at higher clay concentrations. Positron age-momentum correlation measurements are also carried out to elucidate the positron/positronium states in pristine epoxy and in the nanocomposites. The results suggest that in the case of the nanocomposite with the studied lowest clay concentration (1 wt. %), free positrons are primarily localized in the epoxy-clay interfaces, whereas at higher clay concentrations, annihilation takes place from the intercalated clay layers. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Plasma - enhanced dispersion of metal and ceramic nanoparticles in polymer nanocomposite films

NASA Astrophysics Data System (ADS)

Maguire, Paul; Liu, Yazi; Askari, Sadegh; Patel, Jenish; Macia-Montero, Manuel; Mitra, Somak; Zhang, Richao; Sun, Dan; Mariotti, Davide

2015-09-01

In this work we demonstrate a facile method to synthesize a nanoparticle/PEDOT:PSS hybrid nanocomposite material in aqueous solution through atmospheric pressure direct current (DC) plasma processing at room temperature. Both metal (Au) and ceramic (TiO2) nanoparticle composite films have been fabricated. Nanoparticle dispersion is enhanced considerable and remains stable. TiO2/polymer hybrid nanoparticles with a distinct core shell structure have been obtained. Increased nanoparticle/PEDOT:PSS nanocomposite electrical conductivity has been observed. The improvement in nanocomposite properties is due to the enhanced dispersion and stability in liquid polymer of microplasma processed Au or TiO2 nanoparticles. Both plasma induced surface charge and nanoparticle surface termination with specific plasma chemical species are thought to provide an enhanced barrier to nanoparticle agglomeration and promote nanoparticle-polymer bonding. This is expected to have a significant benefit in materials processing with inorganic nanoparticles for applications in energy storage, photocatalysis and biomedical sensors. Engineering and Physical Sciences Research Council (EPSRC: EP/K006088/1, EP/K006142, Nos. EP/K022237/1).

BaTiO3/PVDF Nanocomposite Film with High Energy Storage Density

NASA Astrophysics Data System (ADS)

Wang, Xiaohui

2016-03-01

A gradated multilayer BaTiO3/poly(vinylidenefluoride) thin film structure is presented to achieve both a higher breakdown strength and a superior energy-storage capability. Key to the process is the sequential deposition of uniform dispersions of the single component source, which generate a blended PVDF-BTO-PVDF structure prior to full evaporation of solvent, and thermal treatment of the dielectric. The result is like sandwich structure with partial 0-3 character. The central layer designed to provide the high electric displacement, is composed of high volume fraction 6-10 nm BTO nanocrystals produced by a TEG-sol method. The outer layers of the structure are predominantly PVDF, with a significantly lower volume fraction of BTO, taking advantage of the higher dielectric strength for pure PVDF at the electrode-nanocomposite interface. The film is mechanically flexible, and can be removed from the substrate, with total thicknesses in the range 1.2 - 1.5 μm. Parallel plate capacitance devices improved dielectric performances, compared to reported values for BTO-PVDF 0-3 nanocomposites, with a maximal discharged energy density of 19.4J/cm3 and dielectric breakdown strengths of up to 495 kV/mm.

Epitaxial YBa2Cu3O7-x nanocomposite films and coated conductors from BaMO3 (M = Zr, Hf) colloidal solutions

NASA Astrophysics Data System (ADS)

Obradors, X.; Puig, T.; Li, Z.; Pop, C.; Mundet, B.; Chamorro, N.; Vallés, F.; Coll, M.; Ricart, S.; Vallejo, B.; Pino, F.; Palau, A.; Gázquez, J.; Ros, J.; Usoskin, A.

2018-04-01

Superconducting nanocomposites are the best material choice to address the performance required in power applications and magnets working under high magnetic fields. However, it is still challenging to sort out how to achieve the highest superconducting performance using attractive and competitive manufacturing processes. Colloidal solutions have been recently developed as a novel and very promising low cost route to manufacture nanocomposite coated conductors. Well dispersed and stabilized preformance nanoparticle solutions are first prepared with high concentrations and then mixed with the YBa2Cu3O7 metalorganic precursor solutions to generate colloidal solutions to grow the nanocomposite films. Here we demonstrate, for the first time, that non-reactive BaZrO3 and BaHfO3 perovskite preformed nanoparticles are suitable for growing high quality thin and thick films, and coated conductors with a homogeneous distribution and controlled particle size using this fabrication method. Additionally, we extend the nanoparticle content of the nanocomposites up to 20%-25% mol without any degradation of the superconducting properties. Thick nanocomposite films, up to 0.8 μm, have been prepared with a single deposition of low-fluorine solutions using an ink jet printing dispenser and we demonstrate that the preformed nanoparticles display only a very limited coarsening during the growth process and so high critical current densities J c (B) under high magnetic fields. These films show the highest critical currents achieved so far based on the colloidal solution approach, I c = 220 A/cm-w at 77 K and self-field, and they still have a high potential for further increase in the film thickness. Finally, we also show that nanocomposite YBa2Cu3O7-BaZrO3 coated conductors based on an alternating beam assisted deposited YSZ buffer layer on stainless steel metallic substrates can be developed based on these novel colloidal solutions. Non-reactive preformed oxide perovskite

Active nanocomposite films based on soy proteins-montmorillonite- clove essential oil for the preservation of refrigerated bluefin tuna (Thunnus thynnus) fillets.

PubMed

Echeverría, Ignacio; López-Caballero, María Elvira; Gómez-Guillén, María Carmen; Mauri, Adriana Noemi; Montero, María Pilar

2018-02-02

This manuscript evaluates the potential application of active nanocomposite films based on soy protein isolate (SPI)-montmorillonite (MMT)-clove essential oil (CEO) to the preservation of muscle fillets of bluefin tuna (Thunnus thynnus) during refrigerated storage, and furthermore analyzes whether the clay diffuses from the package to food. SPI films with: CEO (SPI-CEO), MMT (SPI-MMT), or both CEO and MMT (SPI-MMT-CEO), were prepared and used to cover tuna fillets during 17days of storage at 2°C. Polyethylene films were also used as control. Protein films nanoreinforced with 10g MMT/100g SPI and activated with CEO were able to decrease microbial growth (evaluated by TVBN and microorganism counts) and lipid autooxidation (evaluated according to the TBA index, FTIR and color parameters) of tuna fillets during the storage period studied. The presence of clay seemed to favor the release of the active principles of clove oil by prolonging its antimicrobial (especially effective to inhibit Pseudomonas spp.) and antioxidant activity over time without observing the diffusion of the clay's own metals (Si and Al) from the nanocomposite materials to the muscle of fish. These results are encouraging for the use of nanocomposite films in food packaging. Copyright © 2017 Elsevier B.V. All rights reserved.

Polyoxometalate-Graphene Nanocomposite Modified Electrode for Electrocatalytic Detection of Ascorbic Acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Weiying; Du, Dan; Gunaratne, Don

Phosphomolybdate functionalized graphene nanocomposite (PMo 12-GS) has been successfully formed on a glassy carbon electrode (GCE) for the detection of ascorbic acid (AA). The obtained PMo 12-GS modified GCE, was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy and compared with GCE, GS modified GCE, and PMo 12 modified GCE. It shows an increased current and a decrease in over-potential of ~210 mV. The amperometric signals are linearly proportional to the AA concentration in a wide concentration range from 1×10 -6 M to 8×10 -3 M, with a detection limit ofmore » 0.5×10 -6 M. Finally, the PMo 12-GS modified electrode was employed for the determination of the AA level in vitamin C tablets, with recoveries between 96.3 and 100.8 %.« less

Chitosan nanocomposite films based on Ag-NP and Au-NP biosynthesis by Bacillus Subtilis as packaging materials.

PubMed

Youssef, Ahmed M; Abdel-Aziz, Mohamed S; El-Sayed, Samah M

2014-08-01

Chitosan-silver (CS-Ag) and Chitosan-gold (CS-Au) nanocomposites films were synthesized by a simple chemical method. A local bacterial isolate identified as Bacillus subtilis ss subtilis was found to be capable to synthesize both silver nanoparticles (Ag-NP) and gold nanoparticles (Au-NP) from silver nitrate (AgNO3) and chloroauric acid (AuCl(4-)) solutions, respectively. The biosynthesis of both Ag-NP and Au-NP characterize using UV/vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD), and then added to chitosan by different ratios (0.5, 1 and 2%). The prepared chitosan nanocomposites films were characterize using UV, XRD, SEM and TEM. Moreover, the antibacterial activity of the prepared films was evaluated against gram positive (Staphylococcus aureus) and gram negative bacteria (Pseudomonas aerugenosa), fungi (Aspergillus niger) and yeast (Candida albicans). Therefore, these materials can be potential used as antimicrobial agents in packaging applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Highly sensitive and selective detection of dopamine based on hollow gold nanoparticles-graphene nanocomposite modified electrode.

PubMed

Zhu, Wencai; Chen, Ting; Ma, Xuemei; Ma, Houyi; Chen, Shenhao

2013-11-01

Highly dispersed hollow gold-graphene (HAu-G) nanocomposites were synthesized by a two-step method. The immobilization of hollow gold nanoparticles (HAu NPs) onto the surface of graphene sheets was achieved by mixing an aqueous solution of HAu NPs with a poly(N-vinylpyrrolidone)-functionalized graphene dispersion at room temperature. A glassy carbon electrode (GCE) was modified with the nanocomposites, and the as-prepared modified electrode displayed high electrocatalytic activity and extraordinary electronic transport properties. Amperometric detection of dopamine (DA) performed with the HAu-G modified electrode exhibits a good linearity between 0.08 and 600 μM with a low detection limit of 0.05 μM (S/N=3) and also possesses good reproducibility and operational stability. The interference of ascorbic acid (AA) and uric acid (UA) can be excluded when using differential pulse voltammetric technique. In addition, this type of modified electrode can also be applied to the determination of DA content in dopamine hydrochloride injection. It is obvious that the HAu-G modified electrode provides a new way to detect dopamine sensitively and selectively. Copyright © 2013 Elsevier B.V. All rights reserved.

AC/DC electrical conduction and dielectric properties of PMMA/PVAc/C60 down-shifting nanocomposite films

NASA Astrophysics Data System (ADS)

El-Bashir, S. M.; Alwadai, N. M.; AlZayed, N.

2018-02-01

Polymer nanocomposite films were prepared by doping fullerene C60 in polymer blend composed of polymethacrylate/polyvinyl acetate blends (PMMA/PVAc) using solution cast technique. The films were characterized by differential scanning calorimeter (DSC), Transmission electron microscope (TEM), DC/AC electrical conductivity and dielectric measurements in the frequency range (100 Hz- 1 MHz). The glass transition temperature, Tg, was increased by increasing the concentration of fullerene C60; this property reflects the increase of thermal stability by increasing the nanofiller content. The DC and AC electrical conductivities were enhanced by increasing C60 concentration due to the electron hopping or tunneling between filled and empty localized states above Tg. The relaxation time was determined from the αβ -relaxations and found to be attenuated by increasing the temperature as a typical behavior of amorphous polymers. The calculated values of thermodynamic parameters revealed the increase of molecular stability by increasing the doping concentration; this feature supports the application of PMMA/PVAc/C60 nanocomposite films in a wide scale of solar energy conversion applications such as luminescent down-shifting (LDS) coatings for photovoltaic cells.

C-Ni-Pd and CNT-Ni-Pd film's molecular and crystalline structure investigations by FTIR spectroscopy and XRD diffraction

NASA Astrophysics Data System (ADS)

Stepińska, Izabela; Czerwosz, ElŻbieta; Diduszko, Ryszard; Kozłowski, Mirosław; Wronka, Halina

2017-08-01

In this work molecular and crystalline structure of new type of nanocomposite films were investigated. These films compose of CNT decorated with palladium nanograins. They were prepared on a base of C-Ni films modified in CVD process. C-Ni nanocomposite films were obtained by PVD process and their modification by CVD leads to a growth of CNT film. CNTs-Ni or C-Ni films were treated with additional PVD process with palladium. Nickel and palladium acetate and fulleren C60 are precursors of films in PVD process. FTIR spectroscopy was used to studied the molecular structure of film in every stage of preparation . The crystalline structure of these films was studied by X-ray diffraction. SEM (scanning electron microscopy) was applied to investigate film's surface topography.

New strain states and radical property tuning of metal oxides using a nanocomposite thin film approach

DOE PAGES

MacManus-Driscoll, Judith; Suwardi, Ady; Kursumovic, Ahmed; ...

2015-05-05

Auxetic-like strain states were generated in self-assembled nanocomposite thin films of (Ba 0.6Sr 0.4TiO 3) 1–x – (Sm 2O 3) x(BSTO – SmO). A switch from auxetic-like to elastic-like strain behavior was observed for x > 0.50, when the SmO switched from being nanopillars in the BSTO matrix to being the matrix with BSTO nanopillars embedded in it. A simple model was adopted to explain how in-plane strain varies with x. At high x (0.75), strongly enhanced ferroelectric properties were obtained compared to pure BSTO films. Furthermore, the nanocomposite method represents a powerful new way to tune the properties ofmore » a wide range of strongly correlated metal oxides whose properties are very sensitive to strain.« less

Electric Transport Phenomena of Nanocomposite Organic Polymer Thin Films

NASA Astrophysics Data System (ADS)

Jira, Nicholas C.; Sabirianov, Ildar; Ilie, Carolina C.

We discuss herein the nanocomposite organic thin film diodes for the use of plasmonic solar cells. This experimental work follows the theoretical calculations done for plasmonic solar cells using the MNPBEM toolbox for MatLab. These calculations include dispersion curves and amount of light scattering cross sections for different metallic nanoparticles. This study gives us clear ideas on what to expect from different metals, allowing us to make the best choice on what to use to obtain the best results. One specific technique for light trapping in thin films solar cells utilizes metal nanoparticles on the surface of the semiconductor. The characteristics of the metal, semiconductor interface allows for light to be guided in between them causing it to be scattered, allowing for more chances of absorption. The samples were fabricated using organic thin films made from polymers and metallic nanoparticles, more specifically Poly(1-vinylpyrrolidone-co-2-dimethylaminoethyl methacrylate) copolymer and silver or gold nanoparticles. The two fabrication methods applied include spin coating and Langmuir-Blodgett technique. The transport properties are obtained by analyzing the I-V curves. We will also discuss the resistance, resistivity, conductance, density of charge carriers. SUNY Oswego SCAC Grant.

Manipulation of ZnO composition affecting electrical properties of MEH-PPV: ZnO nanocomposite thin film via spin coating for OLEDs application

NASA Astrophysics Data System (ADS)

Azhar, N. E. A.; Shariffudin, S. S.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

2018-05-01

Recent investigations of the promising materials for optoelectronic have been demonstrated by introducing n-type inorganic material into conjugated polymer. Morphology, optical and electrical of nanocomposites thin films based on poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and zinc oxide (ZnO) nanotetrapods with various ZnO composition (0 wt% to 0.4 wt%) have been investigated. The MEH-PPV: ZnO nanocomposite thin film was deposited using spin-coating method. Surface morphology was characterized using field emission scanning electron microscopy and shows the uniform dispersion of MEH-PPV and ZnO phases for sample deposited at 0.2 wt%. The photoluminescence (PL) spectra shows the visible emission intensities increased when the ZnO composition increased. The current-voltage (I-V) measurement shows the highest conductivity of nanocomposite thin film deposited at 0.2 wt% of ZnO is 7.40 × 10-1 S. cm-1. This study will provide better performance and suitable for optoelectronic device especially OLEDs application.

Swift heavy ion induced modification in morphological and physico-chemical properties of tin oxide nanocomposites

NASA Astrophysics Data System (ADS)

Jaiswal, Manoj Kumar; Kanjilal, D.; Kumar, Rajesh

2013-11-01

Nanocomposite thin films of tin oxide (SnO2)/titanium oxide (TiO2) were grown on silicon (1 0 0) substrates by electron beam evaporation deposition technique using sintered nanocomposite pellet of SnO2/TiO2 in the percentage ratio of 95:5. Sintering of the nanocomposite pellet was done at 1300 °C for 24 h. The thicknesses of these films were measured to be 100 nm during deposition using piezo-sensor attached to the deposition chamber. TiO2 doped SnO2 nanocomposite films were irradiated by 100 MeV Au8+ ion beam at fluence range varying from 1 × 1011 ions/cm2 to 5 × 1013 ions/cm2 at Inter University Accelerator Center (IUAC), New Delhi, India. Chemical properties of pristine and ion irradiation modified thin films were characterized by Fourier Transform Infrared (FTIR) spectroscopy. FTIR peak at 610 cm-1 confirms the presence of O-Sn-O bridge of tin (IV) oxide signifying the composite nature of pristine and irradiated thin films. Atomic Force Microscope (AFM) in tapping mode was used to study the surface morphology and grain growth due to swift heavy ion irradiation at different fluencies. Grain size calculations obtained from sectional analysis of AFM images were compared with results obtained from Glancing Angle X-ray Diffraction (GAXRD) measurements using Scherrer’s formulae. Phase transformation due to irradiation was observed from Glancing Angle X-ray Diffraction (GAXRD) results. The prominent 2θ peaks observed in GAXRD spectrum are at 30.67°, 32.08°, 43.91°, 44.91° and 52.35° in the irradiated films.

Au-TiO2/Chit modified sensor for electrochemical detection of trace organophosphates insecticides.

PubMed

Qu, Yunhe; Min, Hong; Wei, Yinyin; Xiao, Fei; Shi, Guoyue; Li, Xiaohua; Jin, Litong

2008-08-15

In this paper, Au-TiO2/Chit modified electrode was prepared with Au-TiO2 nanocomposite (Au-TiO2) and Chitosan (Chit) as a conjunct. The Au-TiO2 nanocomposite and the films were characterized by electrochemical and spectroscopy methods. A set of experimental conditions was also optimized for the film's fabrication. The electrochemical and electrocatalytic behaviors of Au-TiO2/Chit modified electrode to trace organophosphates (OPs) insecticides such as parathion were discussed in this work. By differential pulse voltammetry (DPV) measurement, the current responses of Au-TiO2/Chit modified electrode were linear with parathion concentration ranging from 1.0 ng/ml to 7.0 x 10(3)ng/ml with the detection limit of 0.5 ng/ml. In order to evaluate the performance of the detection system, we also examined the real samples successfully in this work. It exhibited a sensitive, rapid and easy-to-use method for the fast determination of trace OPs insecticides.

Preparation of melt-spun antimicrobially modified LDH/polyolefin nanocomposite fibers.

PubMed

Kutlu, Burak; Schröttner, Percy; Leuteritz, Andreas; Boldt, Regine; Jacobs, Enno; Heinrich, Gert

2014-08-01

Layered double hydroxide (LDH) was synthesized and organically modified with camphorsulfonic acid (CSA) and ciprofloxacin. The thermal stability of CSA was improved remarkably under LDH shielding. A minimal inhibitory concentration of free CSA against tested bacteria was determined in order to define the essential quantity in LDH modification. The modified LDHs were melt-compounded with high density polyethylene and the prepared nanocomposites were further melt-spun using a piston-type spinning device. The melt-spun fibers were tested for their antimicrobial activity against Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Enterobacter cloacae, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes. CSA integrated fibers show susceptibility against Gram-positive bacteria and ciprofloxacin integrated fibers showed activity against both Gram-positive and Gram-negative bacteria. Copyright © 2014 Elsevier B.V. All rights reserved.

Preparation and characterization of the nanocomposites from chemically modified nanocellulose and poly(lactic acid)

Treesearch

Liqing Wei; Shupin Luo; Armando G. McDonald; Umesh P. Agarwal; Kolby C. Hirth; Laurent M. Matuana; Ronald C. Sabo; Nicole M. Stark

2017-01-01

Cellulose nanocrystals (CNCs) are renewable and sustainable filler for polymeric nanocomposites. However, their high hydrophilicity limits their use with hydrophobic polymer for composite materials. In this study, freeze-dried CNCs were modified by transesterification with canola oil fatty acid methyl ester to reduce the hydrophilicity. The transesterified CNCs (CNCFE...

Au-C allotrope nano-composite films at extreme conditions generated by intense ultra-short laser

NASA Astrophysics Data System (ADS)

Khan, Saif A.; Saravanan, K.; Tayyab, M.; Bagchi, S.; Avasthi, D. K.

2016-07-01

Structural evolution of gold-carbon allotrope nano-composite films under relativistically intense, ultra-short laser pulse irradiation is studied in this work. Au-C nano-composite films, having 4 and 10 at.% of Au, were deposited by co-sputtering technique on silicon substrates. Au-C60 NC films with 2.5 at.% Au were deposited on 12 μm thick Al foil using co-evaporation technique. These samples were radiated with single pulse from 45 fs, 10 TW Ti:Sapphire Laser at RRCAT at an intensity of 3 × 1018 W cm-2. The morphological and compositional changes were investigated using scanning electron microscopy (SEM) and Rutherford back-scattering spectrometry (RBS) techniques. Laser pulse created three morphologically distinct zones around the point of impact on samples with silicon substrates. The gold content in 600 μm circular region around a point of impact is found to reduce by a factor of five. Annular rings of ∼70 nm in diameter were observed in case of Au-C NC film after irradiation. Laser pulse created a hole of about 400 μm in the sample with Al foil as substrate and wavy structures of 6 μm wavelength are found to be created around this hole. The study shows radial variation in nano-structure formation with varying local intensity of laser pulse.

Structure-processing-property correlations in thin films of conjugated polymer nanocomposites and blends

NASA Astrophysics Data System (ADS)

Sreeram, Arvind

(IL) could be obtained in a single step reaction. The incorporation of IL in the film, not only greatly improved its mechanical properties, by acting as a plasticizer, but also imparted a dual mechanism of charge transport. The segments of conjugated double bonds imparted electronic conductivity to the films, and the IL resulted in ionic conductivity. The presence of both electronic and ionic conduction pathways in the films was confirmed by electrochemical impedance spectroscopy (EIS). These IL-imbibed conjugated polymer films are promising as materials for electrochemical energy conversion and storage. In the third part of this work, conjugated polymer films containing multiwalled carbon nanotubes (MWNT) and graphene nanoplatelets (GNP) were synthesized and characterized. PPV--MWNT nanocomposite films and PA--GNP nanocomposite films were characterized using a variety of analytical techniques including transmission electron microscopy, quasistatic and dynamic nanoindentaiton, electrochemical impedance spectroscopy, and cyclic voltammetry. Potential application of these films is in electrochemical supercapacitors.

Stress transfer and matrix-cohesive fracture mechanism in microfibrillated cellulose-gelatin nanocomposite films.

PubMed

Quero, Franck; Padilla, Cristina; Campos, Vanessa; Luengo, Jorge; Caballero, Leonardo; Melo, Francisco; Li, Qiang; Eichhorn, Stephen J; Enrione, Javier

2018-09-01

Microfibrillated cellulose (MFC) obtained from eucalyptus was embedded in gelatin from two sources; namely bovine and salmon gelatin. Raman spectroscopy revealed that stress is transferred more efficiently from bovine gelatin to the MFC when compared to salmon gelatin. Young's modulus, tensile strength, strain at failure and work of fracture of the nanocomposite films were improved by ∼67, 131, 43 y 243% respectively when using salmon gelatin as matrix material instead of bovine gelatin. Imaging of the tensile fracture surface of the MFC-gelatin nanocomposites revealed that crack formation occurs predominantly within bovine and salmon gelatin matrices rather than within the MFC or at the MFC/gelatin interface. This suggests that the mechanical failure mechanism in these nanocomposite materials is predominantly governed by a matrix-cohesive fracture mechanism. Both strength and flexibility are desirable properties for composite coatings made from gelatin-based materials, and so the findings of this study could assist in their utilization in the food and pharmaceutical industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

Influence of Content of Al2O3 on Structure and Properties of Nanocomposite Nb-B-Al-O films

NASA Astrophysics Data System (ADS)

Liu, Na; Dong, Lei; Dong, Lei; Yu, Jiangang; Pan, Yupeng; Wan, Rongxin; Gu, Hanqing; Li, Dejun

2015-11-01

Nb-B-Al-O nanocomposite films with different power of Al2O3 were successfully deposited on the Si substrate via multi-target magnetron co-sputtering method. The influences of Al2O3's content on structure and properties of obtained nanocomposite films through controlling Al2O3's power were investigated. Increasing the power of Al2O3 can influence the bombarding energy and cause the momentum transfer of NbB2. This can lead to the decreasing content of Al2O3. Furthermore, the whole films showed monocrystalline NbB2's (100) phase, and Al2O3 shaded from amorphous to weak cubic-crystalline when decreasing content of Al2O3. This structure and content changes were proof by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). When NbB2 grains were far from each other in lower power of Al2O3, the whole films showed a typical nanocomposite microstructure with crystalline NbB2 grains embedded in a matrix of an amorphous Al2O3 phase. Continuing increasing the power of Al2O3, the less content of Al2O3 tended to cause crystalline of cubic-Al2O3 between the close distances of different crystalline NbB2 grains. The appearance of cubic-crystallization Al2O3 can help to raise the nanocomposite films' mechanical properties to some extent. The maximum hardness and elastic modulus were up to 21.60 and 332.78 GPa, which were higher than the NbB2 and amorphous Al2O3 monolithic films. Furthermore, this structure change made the chemistry bond of O atom change from the existence of O-Nb, O-B, and O-Al bonds to single O-Al bond and increased the specific value of Al and O. It also influenced the hardness in higher temperature, which made the hardness variation of different Al2O3 content reduced. These results revealed that it can enhance the films' oxidation resistance properties and keep the mechanical properties at high temperature. The study highlighted the importance of controlling the Al2O3's content to prepare

Elastic properties of nc-TiN /a-Si3N4 and nc-TiN /a-BN nanocomposite films by surface Brillouin scattering

NASA Astrophysics Data System (ADS)

Manghnani, Murli H.; Tkachev, Sergey N.; Zinin, Pavel V.; Glorieoux, Christ; Karvankova, Pavla; Veprek, Stan

2005-03-01

The hardness of nanocomposite (nc) films developed recently appears to reach the hardness of diamond. High hardness is commonly attributed to the granular structure of nanocomposites (Hall-Petch effect) [E. O. Hall, Proc. Phys. Soc. Lond. B 64, 747 (1951); N. J. Petch, J. Iron Steel Inst. 174, 25 (1953)]. However, grain size in nanocomposites is generally small (5-15nm) and falls in the region where the Hall-Petch effect does not apply. The objective of the present study is to report the elastic properties of the superhard nanocomposites determined by means of surface Brillouin scattering (SBS), and to compare the results with those obtained by nanoindentation. Two types of nanocomposite films were studied: nc-TiN /a-Si3N4 and nc-TiN /a-BN. The SBS measurements presented yield values of Young's modulus significantly larger than those obtained from the slope of unloading indentation curve. This discrepancy is attributed to the lack of the validity of the assumptions behind the Sneddon's derivation of the formula used for the calculation of the Young's modulus from the indentation data.

Device level optimization of poly(vinylidene fluoride-trifluoroethylene)–zinc oxide polymer nanocomposite thin films for ferroelectric applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

C K, Subash, E-mail: cksubash08@gmail.com; Valiyaneerilakkal, Uvais; Varghese, Soney

Polymer nanocomposite was prepared using poly(vinylidene fluoride-trifluoroethylene) and zinc oxide (ZnO) nanopowder, which are ferroelectric in nature. Nanocomposite was prepared in various concentrations(0.2, 0.4, 0.8, and 1 wt. %) using probe ultra-sonication, followed by spin coating and annealing at 120 °C for 2 h to improve the formation of β-phase. Metal-ferroelectric-metal capacitor was fabricated using this optimized thin film as a ferroelectric layer. Device level optimization was carried out by polarization-electric field (P-E) hysteresis studies of this film, which shows polarization enhancement of composite. Various characterization techniques like atomic force microscopy, Fourier transform infra-red spectroscopy (FT-IR), Differential scanning calorimetry, and X-ray diffractionmore » were used to study the β-phase formation of nancomposite. The capacitance–voltage (C-V) and current-voltage (I-V) characteristics were studied through varying frequency and temperature. C-V measurements show an increase of 79% in the capacitance of polymer nanocomposite, which can be used for the fabrication of ferroelectric devices.« less

Antimicrobial nanostructured starch based films for packaging.

PubMed

Abreu, Ana S; Oliveira, M; de Sá, Arsénio; Rodrigues, Rui M; Cerqueira, Miguel A; Vicente, António A; Machado, A V

2015-09-20

Montmorillonite modified with a quaternary ammonium salt C30B/starch nanocomposite (C30B/ST-NC), silver nanoparticles/starch nanocomposite (Ag-NPs/ST-NC) and both silver nanoparticles/C30B/starch nanocomposites (Ag-NPs/C30B/ST-NC) films were produced. The nanoclay (C30B) was dispersed in a starch solution using an ultrasonic probe. Different concentrations of Ag-NPs (0.3, 0.5, 0.8 and 1.0mM) were synthesized directly in starch and in clay/starch solutions via chemical reduction method. Dispersion of C30B silicate layers and Ag-NPs in ST films characterized by X-ray and scanning electron microscopy showed that the presence of Ag-NPs enhanced clay dispersion. Color and opacity measurements, barrier properties (water vapor and oxygen permeabilities), dynamic mechanical analysis and contact angle were evaluated and related with the incorporation of C30B and Ag-NPs. Films presented antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans without significant differences between Ag-NPs concentrations. The migration of components from the nanostructured starch films, assessed by food contact tests, was minor and under the legal limits. These results indicated that the starch films incorporated with C30B and Ag-NPs have potential to be used as packaging nanostructured material. Copyright © 2015 Elsevier Ltd. All rights reserved.

Natural Rubber/Dendrimer Modified Montmorillonite Nanocomposites: Mechanical and Flame-Retardant Properties

PubMed Central

Zhang, Chenyang; Wang, Jincheng

2017-01-01

A series of flame-retardant nanocomposites were established based on compounding of natural rubber (NR) and dendrimer modified flame-retardant organic montmorillonite (FR-DOMt). The merits of these nanocomposites were focused on their better mechanical and flame-retardant properties. X-ray diffractometer (XRD) together with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis revealed that exfoliation, intercalation, or aggregation status in the NRmatrix can be achieved by addition of different amounts of FR-DOMt. The sound effects of blend ratio of FR-DOMt on mechanical, thermal stability, and flame-retardant (FR) properties of NR were studied. The NR/FR-DOMt-20 composite possessed the highest tensile strength, and this resulted from complicated interactions between layered silicates and elastomers. In addition, with loading of 20 phr of FR-DOMt, the flammability parameters of NR, such as heat release rate (HRR), smoke evolution area (SEA), and carbon monoxide (CO) concentration, were obviously reduced from cone calorimeter analysis. PMID:29283385

Synthesis of bio-based nanocomposites for controlled release of antimicrobial agents in food packaging

NASA Astrophysics Data System (ADS)

DeGruson, Min Liu

The utilization of bio-based polymers as packaging materials has attracted great attention in both scientific and industrial areas due to the non-renewable and nondegradable nature of synthetic plastic packaging. Polyhydroxyalkanoate (PHA) is a biobased polymer with excellent film-forming and coating properties, but exhibits brittleness, insufficient gas barrier properties, and poor thermal stability. The overall goal of the project was to develop the polyhydroxyalkanoate-based bio-nanocomposite films modified by antimicrobial agents with improved mechanical and gas barrier properties, along with a controlled release rate of antimicrobial agents for the inhibition of foodborne pathogens and fungi in food. The ability for antimicrobial agents to intercalate into layered double hydroxides depended on the nature of the antimicrobial agents, such as size, spatial structure, and polarity, etc. Benzoate and gallate anions were successfully intercalated into LDH in the present study and different amounts of benzoate anion were loaded into LDH under different reaction conditions. Incorporation of nanoparticles showed no significant effect on mechanical properties of polyhydroxybutyrate (PHB) films, however, significantly increased the tensile strength and elongation at break of polyhydroxybutyrate-co-valerate (PHBV) films. The effects of type and concentration of LDH nanoparticles (unmodified LDH and LDH modified by sodium benzoate and sodium gallate) on structure and properties of PHBV films were then studied. The arrangement of LDH in the bio-nanocomposite matrices ranged from exfoliated to phase-separated depending on the type and concentration of LDH nanoparticles. Intercalated or partially exfoliated structures were obtained using modified LDH, however, only phase-separated structures were formed using unmodified LDH. The mechanical (tensile strength and elongation at break) and thermo-mechanical (storage modulus) properties were significantly improved with low

Update on dental nanocomposites.

PubMed

Chen, M-H

2010-06-01

Dental resin-composites are comprised of a photo-polymerizable organic resin matrix and mixed with silane-treated reinforcing inorganic fillers. In the development of the composites, the three main components can be modified: the inorganic fillers, the organic resin matrix, and the silane coupling agents. The aim of this article is to review recent studies of the development of dental nanocomposites and their clinical applications. In nanocomposites, nanofillers are added and distributed in a dispersed form or as clusters. For increasing the mineral content of the tooth, calcium and phosphate ion-releasing composites and fluoride-releasing nanocomposites were developed by the addition of DCPA-whiskers or TTCP-whiskers or by the use of calcium fluoride or kaolinite. For enhancing mechanical properties, nanocomposites reinforced with nanofibers or nanoparticles were investigated. For reducing polymerization shrinkage, investigators modified the resin matrix by using methacrylate and epoxy functionalized nanocomposites based on silsesquioxane cores or epoxy-resin-based nanocomposites. The effects of silanization were also studied. Clinical consideration of light-curing modes and mechanical properties of nanocomposites, especially strength durability after immersion, was also addressed.

Resistive switching effect of N-doped MoS2-PVP nanocomposites films for nonvolatile memory devices

NASA Astrophysics Data System (ADS)

Wu, Zijin; Wang, Tongtong; Sun, Changqi; Liu, Peitao; Xia, Baorui; Zhang, Jingyan; Liu, Yonggang; Gao, Daqiang

2017-12-01

Resistive memory technology is very promising in the field of semiconductor memory devices. According to Liu et al, MoS2-PVP nanocomposite can be used as an active layer material for resistive memory devices due to its bipolar resistive switching behavior. Recent studies have also indicated that the doping of N element can reduce the band gap of MoS2 nanosheets, which is conducive to improving the conductivity of the material. Therefore, in this paper, we prepared N-doped MoS2 nanosheets and then fabricated N-doped MoS2-PVP nanocomposite films by spin coating. Finally, the resistive memory [C. Tan et al., Chem. Soc. Rev. 44, 2615 (2015)], device with ITO/N-doped MoS2-PVP/Pt structure was fabricated. Study on the I-V characteristics shows that the device has excellent resistance switching effect. It is worth mentioning that our device possesses a threshold voltage of 0.75 V, which is much better than 3.5 V reported previously for the undoped counterparts. The above research shows that N-doped MoS2-PVP nanocomposite films can be used as the active layer of resistive switching memory devices, and will make the devices have better performance.

Synthesis and characterization of new nanocomposites films using alanine-Cu-functionalized graphene oxide as nanofiller and PVA as polymeric matrix for improving of their properties

NASA Astrophysics Data System (ADS)

Abdolmaleki, Amir; Mallakpour, Shadpour; Karshenas, Azam

2017-09-01

In the synthesis of polymer-graphene nanocomposites, for improving properties of nanocomposites, two factors dispersion and strong interfacial interactions between graphene and the polymer, are essential. In the present work, poly(vinyl alcohol) PVA/GO-Cu-alanine nanocomposite films were manufactured using concentrations 0, 1, 3 and 5 wt% of GO-Cu-alanine in water solution. For this purpose, L-alanine amino acid was located on the surface and edges of GO through copper(II) ion as a coordinating function. Then, flexible PVA/GO-Cu-alanine nanocomposite films were fabricated using GO-Cu-alanine as filler and PVA as matrix. Due to the existence of affective interaction between GO-Cu-alanine and PVA matrix, the acquired PVA/GO-Cu-alanine nanocomposites demonstrated great thermal and mechanical properties. Properties of manufactured materials were characterized by Fourier transform infrared, X-ray photoelectron spectroscopies (XPS), X-ray diffraction (XRD), Thermal gravimetric analysis, elemental analysis, field emission scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX).

Structure and magnetic properties of spinel-perovskite nanocomposite thin films on SrTiO3 (111) substrates

NASA Astrophysics Data System (ADS)

Kim, Dong Hun; Yang, Junho; Kim, Min Seok; Kim, Tae Cheol

2016-09-01

Epitaxial CoFe2O4-BiFeO3 nanocomposite thin films were synthesized on perovskite structured SrTiO3 (001) and (111) substrates by combinatorial pulsed laser deposition and characterized using scanning electron microscopy, x-ray diffraction, and vibrating sample magnetometer. Triangular BiFeO3 nanopillars were formed in a CoFe2O4 matrix on (111) oriented SrTiO3 substrates, while CoFe2O4 nanopillars with rectangular or square top surfaces grew in a BiFeO3 matrix on (001) substrates. The magnetic hysteresis loops of nanocomposites on (111) oriented SrTiO3 substrates showed isotropic properties due to the strain relaxation while those of films on SrTiO3 (001) substrates exhibited a strong out-of-plane anisotropy originated from shape and strain effects.

The study of VOPc thin film transistors on modified substrates

NASA Astrophysics Data System (ADS)

Song, De; Xu, Qi; Cheng, Hongcang; Li, Bao-zeng; Shang, Yubin

2018-02-01

The vanadyl phthalocyanine (VOPc) organic thin film transistors (OTFTs) were fabricated on the various organosilane self-assembled monolayer (SAM) modified substrates. And the effect of the surface properties on the performance of these transistors was studied. The atomic force morphologies and X-ray diffraction (XRD) spectrums of vanadyl phthalocyanine films on different SAM-modified surfaces were studied. They reveal that the terminal functional groups of organosilane affect the growth of VOPc film and device performance. The VOPc film on octadecyltrichlorosilane (OTS) modified substrate has larger crystal size and effective crystal thickness than those on phenyltrichlorosilane (PTS), 1H,1H,2H,2H-Perfluorodec-yltrichlorosilane (FDTS) as well as non-modified substrate, which contributes the mobility of corresponding device several and several dozen times relative to other ones. The effective crystal thickness and crystal grain size of VOPc film on PTS is between that on OTS treated and that on non-modified substrate due to the stronger attractive force between VOPc and SiO2. The VOPc films' performance and effective crystal thickness on FDTS treated are worse than that on PTS due to the existents of attractive force between -CF3 and VOPc.

Supported porous carbon and carbon-CNT nanocomposites for supercapacitor applications

NASA Astrophysics Data System (ADS)

Schopf, Dimitri; Es-Souni, Mohammed

2016-03-01

Supported porous carbon and porous carbon-MWCNT-nanocomposite films are produced by pyrolysis of porous polyvinylidene fluoride (PVDF) or porous PVDF-MWCNT-nanocomposite films on thermally resistant substrates. All films are characterized by SEM, RAMAN and XRD. The application of these films as supercapacitors is explored with outstanding supercapacitance values ranging from 80 to 120 F g-1 (up to 70 mF cm-2) in a three-electrode set-up in 1 M KOH, depending on microstructure. Additionally, the implementation of porous nanocarbon-MWCNT-nanocomposite films as electrodes in a symmetrical supercapacitor device is investigated. In all cases, long-term charge-discharge stability is demonstrated.

Photo and Thermal Behavior of New Reinforced Polyamide-nanocomposite Montmorillonite on 2,3-Pyrazin Dicarboxylic Acid

NASA Astrophysics Data System (ADS)

Faghihi, Khalil; Samiei, Mojtaba; Hajibeygi, Mohsen

2012-06-01

Two new samples of reinforce polyamidemontmorillonite nanocomposites were synthesized by a convenient solution intercalation technique. Polyamide (PA) 3 as a source of polymer matrix was synthesized by the direct polycondensation reaction of pyrazine 2,3-dicarboxylic acid 1 with 4,4'-diamino diphenyl ether 2 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). The resulting nanocomposite films were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results showed that organo-modified clay was dispersed homogeneously in PA matrix. TGA indicated an enhancement of thermal stability of new nanocomposites compared with the pure polymer.

Photocatalytic degradation of metronidazole and methylene blue by PVA-assisted Bi2WO6-CdS nanocomposite film under visible light irradiation

NASA Astrophysics Data System (ADS)

Rajendran, Ranjith; Varadharajan, Krishnakumar; Jayaraman, Venkatesan; Singaram, Boobas; Jeyaram, Jayaprakash

2018-02-01

The enhanced photocatalytic performance of nanocomposite is synthesized via the hydrothermal method and characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS) and photoluminescence spectroscopy (PL). Under visible light irradiation, PVA assisted Bi2WO6-CdS nanocomposite film displayed enhanced photocatalytic efficiency and inhibition of photocorrosion as compared with pure CdS, pure Bi2WO6 and Bi2WO6-CdS composite. The PVA assisted Bi2WO6-CdS composite film catalyst showed stable catalytic performance until seven successive runs with 92% of methylene blue(MB) degradation, and easy to recover after degradation of organic pollutant. PVA assisted Bi2WO6-CdS nanocomposite film has optimal band edge position for superior photocatalytic degradation. Furthermore, the trapping experiment was carried out using different scavenger for active species. Among the active species, OH· are the most responsive species which play a vital role in the degradation of metronidazole and MB.

Smart Nacre-inspired Nanocomposites.

PubMed

Peng, Jingsong; Cheng, Qunfeng

2018-03-15

Nacre-inspired nanocomposites with excellent mechanical properties have achieved remarkable attention in the past decades. The high performance of nacre-inspired nanocomposites is a good basis for the further application of smart devices. Recently, some smart nanocomposites inspired by nacre have demonstrated good mechanical properties as well as effective and stable stimuli-responsive functions. In this Concept, we summarize the recent development of smart nacre-inspired nanocomposites, including 1D fibers, 2D films and 3D bulk nanocomposites, in response to temperature, moisture, light, strain, and so on. We show that diverse smart nanocomposites could be designed by combining various conventional fabrication methods of nacre-inspired nanocomposites with responsive building blocks and interface interactions. The nacre-inspired strategy is versatile for different kinds of smart nanocomposites in extensive applications, such as strain sensors, displays, artificial muscles, robotics, and so on, and may act as an effective roadmap for designing smart nanocomposites in the future. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Morphological and antibacterial properties of modified paper by PS nanocomposites for packaging applications.

PubMed

Youssef, Ahmed M; Kamel, S; El-Samahy, M A

2013-10-15

With the increasing sustainability trend with packaging materials, paper and polymer nanocomposites represent a novel class of packaging materials. This study evaluates the potential achievement of alternative sustainable materials as antibacterial packaging application. Paper sheet from rice straw coated with 5 or 10% polystyrene (PS) nanocomposites using titanium dioxide nanoparticles (TiO2-NPs) doped or undoped with sliver nanoparticles (Ag-NPs) were prepared. The morphology of the uncoated and coated paper sheets was studied by SEM. The treated paper sheets were analyzed for their elemental composition using EDAX. The Barrier, air permeability, cob test, as well as mechanical properties and tensile strength were also evaluated. The inhibitory effect of modified paper sheets against Pseudomonas, Staphylococcus aureus, Candida, and Staphylococcus were investigated. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characteristic time scales of coalescence of silver nanocomposite and nanoparticle films induced by continuous wave laser irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paeng, Dongwoo; Grigoropoulos, Costas P., E-mail: cgrigoro@berkeley.edu; Lee, Daeho

2014-08-18

In-situ optical probing has been performed to analyze and compare the characteristic coalescence time scales of silver ion-doped polyvinylalcohol nanocomposite (Ag-PVA NC) and polyvinylpyrrolidone-capped silver nanoparticle (Ag-PVP NP) films subjected to continuous wave laser irradiation. The Ag-PVA NC yielded conductive metallic patterns by photothermal reduction of PVA, formation of nanoparticles from silver ions and their subsequent coalescence. On the other hand, Ag-PVP NP thin films produced conductive patterns through only coalescence of nanoparticles. Upon laser irradiation, Ag-PVA NC and Ag-PVP NP films exhibited different coalescence characteristics.

Surface-modified Ba(Zr0.3Ti0.7)O3 nanofibers by polyvinylpyrrolidone filler for poly(vinylidene fluoride) composites with enhanced dielectric constant and energy storage density.

PubMed

Liu, Shaohui; Xue, Shuangxi; Xiu, Shaomei; Shen, Bo; Zhai, Jiwei

2016-05-17

Ferroelectric-relaxor behavior of Ba(Zr0.3Ti0.7)O3 nanofibers (BZT NF) with a large aspect ratio were prepared via electrospinning and surface modified by PVP as dielectric fillers. The nanocomposite flexible films based on surface modified BZT NF and polyvinylidene fluoride (PVDF) were fabricated via a solution casting. The results show that the surface-modified BZT NF fillers are highly dispersed and well integrated in the PVDF nanocomposites. The nanocomposites exhibit enhanced dielectric constant and reduced loss tangents at a low volume fraction of surface-modified BZT NF. The polymer nanocomposites maintain a relatively high breakdown strength, which is favorable for enhancing energy storage density in the nanocomposites. The nanocomposite containing of 2.5 vol. % of PVP modified BZT NF exhibits energy density as high as 6.3 J/cm(3) at 3800 kV/cm, which is more than doubled that of the pure PVDF of 2.8 J/cm(3) at 4000 kV/cm. Such significant enhancement could be attributed to the combined effects of the surface modification and large aspect ratio of the BZT NF. This work may provide a route for using the surface modified ferroelectric-relaxor behavior of ceramic nanofibers to enhance the dielectric energy density in ceramic-polymer nanocomposites.

Ionic Conductivity Increased by Two Orders of Magnitude in Micrometer-Thick Vertical Yttria-Stabilized ZrO 2 Nanocomposite Films

DOE PAGES

Lee, Shinbuhm; Zhang, Wenrui; Khatkhatay, Fauzia; ...

2015-09-03

We design and create a unique cell geometry of templated micrometer-thick epitaxial nanocomposite films which contain ~20 nm diameter yttria-stabilized ZrO 2 (YSZ) nanocolumns, strain coupled to a SrTiO 3 matrix. We also enhanced the ionic conductivity of these nanocolumnsby over 2 orders of magnitude compared to plain YSZ films. Concomitant with the higher ionic conduction is the finding that the YSZ nanocolumns in the films have much higher crystallinity and orientation, compared to plain YSZ films. Hence, “oxygen migration highways” are formed in the desired out-of-plane direction. This improved structure is shown to originate from the epitaxial coupling ofmore » the YSZ nanocolumns to the SrTiO 3 film matrix and from nucleation of the YSZ nanocolumns on an intermediate nanocomposite base layer of highly aligned Sm-doped CeO 2 nanocolumns within the SrTiO 3 matrix. Furthermore, this intermediate layer reduces the lattice mismatch between the YSZ nanocolumns and the substrate. Vertical ionic conduction values as high as 10 –2 Ω –1 cm –1 were demonstrated at 360 °C (300 °C lower than plain YSZ films), showing the strong practical potential of these nanostructured films for use in much lower operation temperature ionic devices.« less

Polymer Nanocomposite Film with Metal Rich Surface Prepared by In Situ Single-Step Formation of Palladium Nanoparticles: An Interesting Way to Combine Specific Functional Properties.

PubMed

Thompson, David; Kranbuehl, David; Espuche, Eliane

2016-10-18

This paper presents a continuous single-step route that permits preparation of a thermostable polymer/metal nanocomposite film and to combine different functional properties in a unique material. More precisely, palladium nanoparticles are in situ generated in a polyimide matrix thanks to a designed curing cycle which is applied to a polyamic acid/metal precursor solution cast on a glass plate. A metal-rich surface layer which is strongly bonded to the bulk film is formed in addition to homogeneously dispersed metal nanoparticles. This specific morphology leads to obtaining an optically reflective film. The metal nanoparticles act as gas diffusion barriers for helium, oxygen, and carbon dioxide; they induce a tortuosity effect which allows dividing the gas permeation coefficients by a factor near to 2 with respect to the neat polyimide matrix. Moreover, the ability of the in situ synthesized palladium nanoparticles to entrap hydrogen is evidenced. The nanocomposite film properties can be modulated as a function of the location of the film metal-rich surface with respect to the hydrogen feed. The synthesized nanocomposite could represent a major interest for a wide variety of applications, from specific coatings for aerospace or automotive industry, to catalysis applications or sensors.

Disentangling vortex pinning landscape in chemical solution deposited superconducting YBa2Cu3O7-x films and nanocomposites

NASA Astrophysics Data System (ADS)

Palau, A.; Vallès, F.; Rouco, V.; Coll, M.; Li, Z.; Pop, C.; Mundet, B.; Gàzquez, J.; Guzman, R.; Gutierrez, J.; Obradors, X.; Puig, T.

2018-07-01

In-field angular pinning performances at different temperatures have been analysed on chemical solution deposited (CSD) YBa2Cu3O7-x (YBCO) pristine films and nanocomposites. We show that with this analysis we are able to quantify the vortex pinning strength and energies, associated with different kinds of natural and artificial pinning defects, acting as efficient pinning centres at different regions of the H-T phase diagram. A good quantification of the variety of pinning defects active at different temperatures and magnetic fields provides a unique tool to design the best vortex pinning landscape under different operating conditions. We have found that by artificially introducing a unique defect in the YBCO matrix, the stacking faults, we are able to modify three different contributions to vortex pinning (isotropic-strong, anisotropic-strong, and isotropic-weak). The isotropic-strong contribution, widely studied in CSD YBCO nanocomposites, is associated with nanostrained regions induced at the partial dislocations surrounding the stacking faults. Moreover, the stacking fault itself acts as a planar defect which provides a very effective anisotropic-strong pinning at H//ab. Finally, the large presence of Cu-O cluster vacancies found in the stacking faults have been revealed as a source of isotropic-weak pinning sites, very active at low temperatures and high fields.

The preparation of γ-crystalline non-electrically poled photoluminescant ZnO-PVDF nanocomposite film for wearable nanogenerators

NASA Astrophysics Data System (ADS)

Jana, Santanu; Garain, Samiran; Ghosh, Sujoy Kumar; Sen, Shrabanee; Mandal, Dipankar

2016-11-01

Polyvinylidene fluoride (PVDF) films are filled with various mass fractions (wt%) of zinc oxide nanoparticles (ZnO-NPs) to fabricate the high performance of a wearable polymer composite nanogenerator (PCNG). The ZnO-NPs can induced a fully γ-crystalline phase in PVDF, where traditional electrical poling is not necessary for the generation of piezoelectric properties. The PCNG delivers up to 28 V of open circuit voltage and 450 nA of short circuit current by simple repeated human finger imparting (under a pressure amplitude of 8.43 kPa) that generates sufficient power to turn on at least 48 commercial blue light emitting diodes (LEDs) instantly. Furthermore, it also successfully charged the capacitors, signifying practical applicability as a piezoelectric based nanogenerator for self-powering devices. The applicability of PCNG by wearable means is clarified when it gives rise to a sensible response, say up to 400 mV of output voltage synchronized with the PCNG embedded human finger in a bending and releasing gesture. UV-visible absorption spectral analysis revealed the possibility of estimating a change in the optical band gap value (E g), refractive index (n) and optical activation energy (E a) in different concentrations of ZnO-NP incorporated PVDF nanocomposite films, and it possesses a useful methodology where ZnO-NPs can be used as an optical probe. Near blue light emission is observed from photoluminescence spectra, which are clearly shown from a Commission Internationale de L’Eclairage (CIE) diagram. The piezoelectric charge coefficient of the nanocomposite film is estimated to be -6.4 pC/N, where even electrical poling treatment is not employed. In addition, dielectric properties have been studied to understand the role of molecular kinetic and interfacial polarization occurring in nanocomposite films at different applied frequencies.

Synthesis of PDLLA/PLLA-bentonite nanocomposite through sonication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sitompul, Johnner, E-mail: sitompul@che.itb.ac.id; Setyawan, Daru, E-mail: daru.setyawan@gmail.com; Kim, Daniel Young Joon, E-mail: daniel.kim12321@gmail.com

2016-04-19

This paper concerns the synthesis of poly(D,L-lactic acid)/poly(L-lactic acid) bentonite nanocomposites. Poly (D,L-lactic acid) (PDLLA) was synthesized using lactic acid through the ZnO-catalyzed direct polycondensation method at vacuum pressure and poly(L-lactic acid) (PLLA) was synthesized with L-lactide by ring-opening polymerization method. The PDLLA/PLLA-bentonite nanocomposite films were synthesized using the solvent casting method. The nanoclay, bentonite, was prepared using the solution-intercalation method by dissolving the nanoparticles into chloroform before sonication. In this study, PDLLA/PLLA-bentonite nanocomposite films were produced using variable amounts of nanoclay and sonication times during the mixing of PDLLA/PLLA and bentonite. The properties of the PDLLA/PLLA nanocomposites were thenmore » characterized using the X-ray Diffraction (XRD), Universal Testing Machine (UTM), Water Vapor Permeability (WVP) tests, and the enzymatic biodegradability test. The XRD test was used to measure the intercalation of nanoclay layers in the PDLLA/PLLA matrix and the PDLLA/PLLA-bentonite intercalated nanocomposite films. It was found through these various tests that adding bentonite to the PDLLA/PLLA increases tensile strength to 56.76 MP. Furthermore, the biodegradability increases as well as the barrier properties of the polymers The different sonication time used during the mixing of the polymer solution with bentonite also affected the properties of the PDLLA/PLLA-bentonite nanocomposite films.« less

Synthesis and Thermal and Photo Behaviors of New Polyamide/Organocaly Nanocomposites Containing Para Phenylenediacrylic Moiety

NASA Astrophysics Data System (ADS)

Faghihi, Khalil; Soleimani, Masoumeh; Shabanian, Meisam; Abootalebi, Ashraf Sadat

2011-06-01

New type of aromatic polyamide/montmorillonite nanocomposites were produced using solution process in N-methyl-2-pyrolidone. Amide chains were synthesized from 4,4'-diaminodiphenyl sulfone and p-phenylenediacrylic acid in N-methyl-2-pyrolidone. The resulting nanocomposite films containing 5-15 mass % of organoclay were characterized for FT-IR, scanning electronmicroscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), optical transparency and water absorption measurements. The distribution of organoclay and nanostructure of the composites were investigated by (XRD) and SEM analyses. Thermogravimetric analysis indicated an increase in thermal stability of nanocomposites as compared to pristine polyamide. The percentage optical transparency and water absorption of these hybrids was found to be much reduced upon the addition of modified layered silicate indicating decreased permeability.

A novel glucose biosensor platform based on Ag@AuNPs modified graphene oxide nanocomposite and SERS application.

PubMed

Gupta, Vinod Kumar; Atar, Necip; Yola, Mehmet Lütfi; Eryılmaz, Merve; Torul, Hilal; Tamer, Uğur; Boyacı, Ismail Hakkı; Ustündağ, Zafer

2013-09-15

This study represents a novel template demonstration of a glucose biosensor based on mercaptophenyl boronic acid (MBA) terminated Ag@AuNPs/graphene oxide (Ag@AuNPs-GO) nanomaterials. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) method. The TEM image shows that Ag@AuNPs in the nanocomposite is in the range of diameters of 10-20 nm. The nanocomposite was used for the determination of glucose through the complexation between boronic acid and diol groups of glucose. Thus, a novel glucose biosensor was further fabricated by immobilizing glucose oxidase (GOD) into MBA terminated Ag@AuNPs-GO nanocomposite film (MBA-Ag@AuNPs-GO). The linearity range of glucose was obtained as 2-6mM with detection limit of 0.33 mM. The developed biosensor was also applied successfully for the determination of glucose in blood samples. The concentration value of glucose in blood samples was calculated to be 1.97±0.002 mM from measurements repeated for six times. Copyright © 2013 Elsevier Inc. All rights reserved.

Natural gum-assisted phthalocyanine immobilization in electroactive nanocomposites: physicochemical characterization and sensing applications.

PubMed

Zampa, Maysa F; de Brito, Ana Cristina F; Kitagawa, Igor L; Constantino, Carlos J L; Oliveira, Osvaldo N; da Cunha, Helder N; Zucolotto, Valtencir; dos Santos, José Ribeiro; Eiras, Carla

2007-11-01

Natural gums have been traditionally applied in cosmetics and the food industry, mainly as emulsification agents. Due to their biodegradability and excellent mechanical properties, new technological applications have been proposed involving their use with conventional polymers forming blends and composites. In this study, we take advantage of the polyelectrolyte character exhibited by the natural gum ChichA (Sterculia striata), extracted in the Northeastern region of Brazil, to produce electroactive nanocomposites. The nanocomposites were fabricated in the form of ultrathin films by combining a metallic phthalocyanine (nickel tetrasulfonated phthalocyanine, NiTsPc) and the ChichA gum in a tetralayer architecture, in conjunction with conventional polyelectrolytes. The presence of the gum led to an efficient adsorption of the phthalocyanine and enhanced the electrochemical response of the films. Upon combining the electrochemical and UV-vis absorption data, energy diagrams of the ChichA/NiTsPc-based system were obtained. Furthermore, modified electrodes based on gum/phthalocyanine films were able to detect dopamine at concentrations as low as 10-5 M.

Structural modification in the formation of starch - silver nanocomposites

NASA Astrophysics Data System (ADS)

Begum, S. N. Suraiya; Aswal, V. K.; Ramasamy, Radha Perumal

2016-05-01

Polymer based nanocomposites have gained wide applications in field of battery technology. Starch is a naturally occurring polysaccharide with sustainable properties such as biodegradable, non toxic, excellent film forming capacity and it also act as reducing agent for the metal nanoparticles. In our research various concentration of silver nitrate (AgNO3) was added to the starch solution and films were obtained using solution casting method. Surface electron microscope (SEM) of the films shows modifications depending upon the concentration of AgNO3. Small angle neutron scattering (SANS) analysis showed that addition of silver nitrate modifies the starch to disc like structures and with increasing the AgNO3 concentration leads to the formation of fractals. This research could benefit battery technology where solid polymer membranes using starch is used.

Dispersion of cellulose nanofibers in biopolymer based nanocomposites

NASA Astrophysics Data System (ADS)

Wang, Bei

The focus of this work was to understand the fundamental dispersion mechanism of cellulose based nanofibers in bionanocomposites. The cellulose nanofibers were extracted from soybean pod and hemp fibers by chemo-mechanical treatments. These are bundles of cellulose nanofibers with a diameter ranging between 50 to 100 nm and lengths of thousands of nanometers which results in very high aspect ratio. In combination with a suitable matrix polymer, cellulose nanofiber networks show considerable potential as an effective reinforcement for high quality specialty applications of bio-based nanocomposites. Cellulose fibrils have a high density of --OH groups on the surface, which have a tendency to form hydrogen bonds with adjacent fibrils, reducing interaction with the surrounding matrix. The use of nanofibers has been mostly restricted to water soluble polymers. This thesis is focused on synthesizing the nanocomposite using a solid phase matrix polypropylene (PP) or polyethylene (PE) by hot compression and poly (vinyl alcohol) (PVA) in an aqueous phase by film casting. The mechanical properties of nanofiber reinforced PVA film demonstrated a 4-5 fold increase in tensile strength, as compared to the untreated fiber-blend-PVA film. It is necessary to reduce the entanglement of the fibrils and improve their dispersion in the matrix by surface modification of fibers without deteriorating their reinforcing capability. Inverse gas chromatography (IGC) was used to explore how various surface treatments would change the dispersion component of surface energy and acid-base character of cellulose nanofibers and the effect of the incorporation of these modified nanofibers into a biopolymer matrix on the properties of their nano-composites. Poly (lactic acid) (PLA) and polyhydroxybutyrate (PHB) based nanocomposites using cellulose nanofibers were prepared by extrusion, injection molding and hot compression. The IGC results indicated that styrene maleic anhydride coated and ethylene

Carbon Nanotube-Reinforced Thermotropic Liquid Crystal Polymer Nanocomposites

PubMed Central

Kim, Jun Young

2009-01-01

This paper focuses on the fabrication via simple melt blending of thermotropic liquid crystal polyester (TLCP) nanocomposites reinforced with a very small quantity of modified carbon nanotube (CNT) and the unique effects of the modified CNT on the physical properties of the nanocomposites. The thermal, mechanical, and rheological properties of modified CNT-reinforced TLCP nanocomposites are highly dependent on the uniform dispersion of CNT and the interactions between the CNT and TLCP, which can be enhanced by chemical modification of the CNT, providing a design guide of CNT-reinforced TLCP nanocomposites with great potential for industrial uses.

Active packaging from chitosan-titanium dioxide nanocomposite film for prolonging storage life of tomato fruit.

PubMed

Kaewklin, Patinya; Siripatrawan, Ubonrat; Suwanagul, Anawat; Lee, Youn Suk

2018-06-01

The feasibility of active packaging from chitosan (CS) and chitosan containing nanosized titanium dioxide (CT) to maintain quality and extend storage life of climacteric fruit was investigated. The CT nanocomposite film and CS film were fabricated using a solution casting method and used as active packaging to delay ripening process of cherry tomatoes. Changes in firmness, weight loss, a*/b* color, lycopene content, total soluble solid, ascorbic acid, and concentration of ethylene and carbon dioxide of the tomatoes packaged in CT film, CS film, and control (without CT or CS films) were monitored during storage at 20°C. Classification of fruit quality as a function of different packaging treatments was visualized using linear discriminant analysis. Tomatoes packaged in the CT film evolved lower quality changes than those in the CS film and control. The results suggested that the CT film exhibited ethylene photodegradation activity when exposed to UV light and consequently delayed the ripening process and changes in the quality of the tomatoes. Copyright © 2018 Elsevier B.V. All rights reserved.

A self-cleaning coating based on commercial grade polyacrylic latex modified by TiO2/Ag-exchanged-zeolite-A nanocomposite

NASA Astrophysics Data System (ADS)

Nosrati, Rahimeh; Olad, Ali; Nofouzi, Katayoon

2015-08-01

The commercial grade polyacrylic latex was modified in order to prepare a self-cleaning coating. TiO2/Ag-exchanged-zeolite-A nanocomposite was prepared and used as additive in the matrix of polyacrylic latex to achieve a hydrophilic and photocatalytic coating. FTIR and UV-visible spectroscopy, X-ray diffraction patterns and FESEM were used to characterize the composition and structure of the nanocomposites and coatings. The acrylic coatings, were prepared by using of TiO2/Ag-exchanged-zeolite-A additive, had better UV and visible light absorption, hydrophilic, degradation of organic pollutants, stability in water and antimicrobial properties than pristine commercial grade polyacrylic latex coating. According to the results, the modified polyacrylic based coating containing 0.5 wt% of TiO2/Ag-exchanged-zeolite-A nanocomposite additive with TiO2 to Ag-exchanged-zeolite-A ratio of 1:2 was the best coating considering most of useful properties such as small band gap and low water contact angle. The water contact angle for unmodified polyacrylic latex coating was 68° which was decreased to less than 10° in modified coating after 24 h LED lamp illumination.

Nanocomposite films

DOEpatents

Mitlin, David; , Ophus, Colin; Evoy, Stephane; Radmilovic, Velimir; Mohammadi, Reza; Westra, Ken; Nelson-Fitzpatrick, Nathaniel; Lee, Zonghoon

2010-07-20

A thin-film composition of nanocrystal molybdenum in an amorphous metallic matrix may be formed by co-sputtering Mo with aluminum or nickel. NEMS cantilevers may be formed from the film. The films exhibit high nanoindentation hardness and a reduction in roughness and intrinsic stress, while maintaining resistivity in the metallic range.

Comparative study of the anchorage and the catalytic properties of nanoporous TiO2 films modified with ruthenium (II) and rhenium (I) carbonyl complexes

NASA Astrophysics Data System (ADS)

Oyarzún, Diego P.; Chardon-Noblat, Sylvie; Linarez Pérez, Omar E.; López Teijelo, Manuel; Zúñiga, César; Zarate, Ximena; Shott, Eduardo; Carreño, Alexander; Arratia-Perez, Ramiro

2018-02-01

In this article we study the anchoring of cis-[Ru(bpyC4pyr)(CO)2(CH3CN)2]2+, cis-[Ru(bpy)2(CO)2]2+ and cis-[Ru(bpyac)(CO)2Cl2], onto nanoporous TiO2 employing electropolymerization, electrostatic interaction and chemical bonding. Also, the [Re(bpyac)(CO)3Cl] rhenium(I) complex for chemical anchorage was analyzed. The characterization of TiO2/Ru(II) and TiO2/Re(I) nanocomposite films was performed by field emission scanning electron microscopy (FESEM), electron dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. In addition, for the more stable nanocomposites obtained, the catalytic properties (solar energy conversion and CO2 reduction) were evaluated. The efficiency improvement in redox process derived from the (photo)electrochemical evidence indicates that modified nanoporous TiO2 structures enhance the rate of charge transfer reactions.

Magnetization enhancement due to incorporation of non-magnetic nitrogen content in (Co{sub 84}Zr{sub 16})N{sub x} nano-composite films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Jitendra, E-mail: jitendra@ceeri.ernet.in; Akhtar, Jamil; Academy of Scientific and Innovative Research, New Delhi 110001

We report the magnetic, electronic, and structural properties of nano-composite (Co{sub 84}Zr{sub 16})N{sub x} or CZN films prepared by reactive co-sputter deposition method. As-deposited CZN films have shown enhancement in magnetization (M{sub s}) with incorporation of nitrogen content, which is related to the evolution of nano-composite phase. X-ray diffraction study has confirmed poly-crystalline growth of CZN films with fcc(331) and fcc(422) phases. High-resolution transmission electron microscope study reveals that CZN films are composed of ordered and crystalline ferromagnetic Co nano-clusters, which are embedded in the nano-composite matrix. Photoemission measurements show the change in the intensity near the Fermi level mostmore » likely due to defects and shift in the core-levels binding energy with nitrogen concentration. Raman spectroscopy data show an increase in the intensity of the Raman lines with nitrogen concentration upto 20%. However, the intensity is significantly lower for 30% sample. This indicates that less nitrogen or defect states are being substituted into the lattice above 20% and is consistent with the observed magnetic behavior. Our studies indicate that defects induced due to the incorporation of non-magnetic nitrogen content play a key role to enhance the magnetization.« less

Preparation and Properties of Nanocomposites from Pristine and Modified SWCNTs of Comparable Average Aspect Ratios

NASA Technical Reports Server (NTRS)

Smith, Joseph G.; Delozier, Donavon M.; Watson, Kent A.; Connell, John W.; Bekyarova, E.; Haddon, R.; Yu, A.

2008-01-01

Low color, flexible, space-durable polyimide films with inherent and robust electrical conductivity to dissipate electrostatic charge (ESC) have been under investigation as part of a materials development activity for future NASA space missions. The use of single-walled carbon nanotubes (SWCNTs) is one means to achieving this goal. Even though the concentration of SWCNTs needed to achieve ESC dissipation is typically low, it is dependent upon purity, size, dispersion, and functionalization. In this study, SWCNTs prepared by the electric arc discharge method were used to synthesize nanocomposites using the LaRC(TradeMark) CP2 backbone as the matrix. Pristine and functionalized SWCNTs were mixed with an alkoxysilane terminated amide acid of LaRC(TradeMark) CP2 and the soluble imide form of the polymer and the resultant nanocomposites evaluated for mechanical, thermal, and electrical properties. Due to the preparative conditions for the pristine and functionalized SWCNTs, the average aspect ratio for both was comparable. This permitted the assessment of SWCNT functionalization with respect to various interactions (e.g. van der Waals, hydrogen bonding, covalent bond formation, etc.) with the matrix and the macroscopic effects upon nanocomposite properties. The results of this study are described herein.

Interfacial characterization and supercapacitive properties of polyaniline-Gum arabic nanocomposite/graphene oxide LbL modified electrodes

NASA Astrophysics Data System (ADS)

Oliveira, Rafaela D.; Santos, Cleverson S.; Ferreira, Rodolfo T.; Marciniuk, Gustavo; Marchesi, Luís F.; Garcia, Jarem R.; Vidotti, Marcio; Pessoa, Christiana A.

2017-12-01

In this manuscript, we describe the synthesis and electrochemical characterization of polyaniline-gum arabic nanocomposites and graphene oxide (PANI-GA/GO) modified electrodes with a detailed study concerning their supercapacitive properties. The electrode modification was carried out by using the Layer-by-Layer technique (LbL), where the PANI-GA nanocomposite dispersion was used as polycation and the GO colloidal dispersion as polyanion. The bilayer growth was followed by both UV-vis spectroscopy and cyclic voltammetry, and an increase in the characteristic PANI absorption and in the electrochemical signal was verified, confirming the electrode build up. Galvanostatic charge-discharge curves (GCDC) were performed to evaluate the supercapacitive properties of the modified electrodes, these results showed the dependence of the specific capacitance with the number of bilayers, where values of CS around 15 mF cm-2 (i = 0.1 mA cm-2) were found. Electrochemical impedance spectroscopy confirmed the pseudocapacitive properties of the modified electrodes, showing an increase in the low-frequency capacitance with the number of bilayers. Hereby the (PANI-GA/GO)-LbL electrodes were shown to be good candidates for active materials in supercapacitors.

Preparation of Cu₂O-Reduced Graphene Nanocomposite Modified Electrodes towards Ultrasensitive Dopamine Detection.

PubMed

He, Quanguo; Liu, Jun; Liu, Xiaopeng; Li, Guangli; Deng, Peihong; Liang, Jing

2018-01-12

Cu₂O-reduced graphene oxide nanocomposite (Cu₂O-RGO) was used to modify glassy carbon electrodes (GCE), and applied for the determination of dopamine (DA). The microstructure of Cu₂O-RGO nanocomposite material was characterized by scanning electron microscope. Then the electrochemical reduction condition for preparing Cu₂O-RGO/GCE and experimental conditions for determining DA were further optimized. The electrochemical behaviors of DA on the bare electrode, RGO- and Cu₂O-RGO-modified electrodes were also investigated using cyclic voltammetry in phosphate-buffered saline solution (PBS, pH 3.5). The results show that the oxidation peaks of ascorbic acid (AA), dopamine (DA), and uric acid (UA) could be well separated and the peak-to-peak separations are 204 mV (AA-DA) and 144 mV (DA-UA), respectively. Moreover, the linear response ranges for the determination of 1 × 10 -8 mol/L~1 × 10 -6 mol/L and 1 × 10 -6 mol/L~8 × 10 -5 mol/L with the detection limit 6.0 × 10 -9 mol/L (S/N = 3). The proposed Cu₂O-RGO/GCE was further applied to the determination of DA in dopamine hydrochloride injections with satisfactory results.

Accelerating the design of molecularly imprinted nanocomposite membranes modified by Au@polyaniline for selective enrichment and separation of ibuprofen

NASA Astrophysics Data System (ADS)

Wu, Xiuling; Wu, Yilin; Dong, Hongjun; Zhao, Juan; Wang, Chen; Zhou, Shi; Lu, Jian; Yan, Yongsheng; Li, He

2018-01-01

A novel system for harvesting molecularly imprinted nanocomposite membranes (MINcMs) with Au-modified polyaniline (Au@polyaniline) nanocomposite structure was developed for selective enrichment and separation of ibuprofen. This unique nanocomposite structure obviously enhanced the adsorption capacity, perm-selectivity performance, and regeneration ability of MINcMs. The as-prepared MINcMs showed outstanding adsorption capacity (22.02 mg g-1) of ibuprofen, which was four times higher than that of non-imprinted nanocomposite membranes (NINcMs). Furthermore, the selectivity factor of MINcMs for ibuprofen reached up to 4.67 and the perm-selectivity factor β was about 8.74, which indicated MINcMs had a good selective separation performance of ibuprofen. We envision that this novel synthesis method will open a new direction to manipulation of molecularly imprinted membrane materials and provide a simple yet convenient way to selective separation of ibuprofen.

Nanocomposite films based on CMC, okra mucilage and ZnO nanoparticles: Physico mechanical and antibacterial properties.

PubMed

Mohammadi, Hamid; Kamkar, Abolfazl; Misaghi, Ali

2018-02-01

This work examined the physico mechanical parameters and antibacterial activity of CMC/okra mucilage (OM) blend films containing ZnO nanoparticles (NPs). Different proportions of CMC and okra mucilage (100/0; 70/30; 60/40 and 50/50 respectively), were mixed and casted to posterior analysis of formed films. The more colored films were obtained by higher contents of okra mucilage and adding ZnO nanoparticles. The incorporation of ZnO NPs into CMC film decreased the elongation at the break (EB) value of the films and increased the tensile strength (TS) value of the film. With increase in CMC concentration in the films, higher water vapor permeability and higher solubility in water were achieved. Microstructure analysis using SEM showed a smooth and compact surface morphology, homogeneous structure, and a rough surface for CMC, CMC+ZnO, and CMC/OM30%+ZnO, respectively. Nanocomposite films presented antibacterial activity against tested bacteria. Films contained okra mucilage showed more antibacterial activity. The inhibitory activities of resultant films were stronger against S. aureus than E. coli. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electrocatalytic oxidation of dopamine based on non-covalent functionalization of manganese tetraphenylporphyrin/reduced graphene oxide nanocomposite.

PubMed

Sakthinathan, Subramanian; Lee, Hsin Fang; Chen, Shen-Ming; Tamizhdurai, P

2016-04-15

In the present work, a reduced graphene oxide (RGO) supported manganese tetraphenylporphyrin (Mn-TPP) nanocomposite was electrochemically synthesized and used for the highly selective and sensitive detection of dopamine (DA). The nuclear magnetic resonance, scanning electron microscopy and elemental analysis were confirmed the successful formation of RGO/Mn-TPP nanocomposite. The prepared RGO/Mn-TPP nanocomposite modified electrode exhibited an enhanced electrochemical response to DA with less oxidation potential and enhanced response current. The electrochemical studies revealed that the oxidation of the DA at the composite electrode is a surface controlled process. The cyclic voltammetry, differential pulse voltammetry and amperometry methods were enable to detect DA. The working linear range of the electrode was observed from 0.3 to 188.8 μM, limit of detection was 8 nM and the sensitivity was 2.606 μA μM(-1) cm(-2). Here, the positively charged DA and negatively charged porphyrin modified RGO can accelerate the electrocatalysis of DA via electrostatic attraction, while the negatively charged ascorbic acid (AA) repulsed by the negatively charged electrode surface which supported for good selectivity. The good recovery results obtained for the determination of DA present in DA injection samples and human pathological sample further revealed the good practicality of RGO/Mn-TPP nanocomposite film modified electrode. Copyright © 2016 Elsevier Inc. All rights reserved.

Influences of modified bacterial cellulose nanofibers (BCNs) on structural, thermophysical, optical, and barrier properties of poly ethylene-co-vinyl acetate (EVA) nanocomposite.

PubMed

Ghadikolaei, Shila Shirdel; Omrani, Abdollah; Ehsani, Morteza

2018-04-14

The BCNs were chemically modified using acetic anhydride with the aim of improving its dispersion and interfacial adhesion. Acetylation of BCNs was confirmed by FT-IR spectroscopy. Morphology studies using TEM and SEM revealed that a reasonable dispersion of the modified BCNs in the EVA matrix was accomplished. The DSC data displayed a little shift in the T g to higher temperatures with the incorporation of both modified and unmodified BCNs. Increased thermal stability of the nanocomposites consisting acetylated BCNs was confirmed by TGA technique. DMA measurements highlighted that the storage modulus increased and the damping properties decreased for the nanocomposites with regard to the neat EVA. Copyright © 2018 Elsevier B.V. All rights reserved.

Hg(2+) detection using a disposable and miniaturized screen-printed electrode modified with nanocomposite carbon black and gold nanoparticles.

PubMed

Cinti, Stefano; Santella, Francesco; Moscone, Danila; Arduini, Fabiana

2016-05-01

A miniaturized screen-printed electrode (SPE) modified with a carbon black-gold nanoparticle (CBNP-AuNP) nanocomposite has been developed as an electrochemical sensor for the detection of inorganic mercury ions (Hg(2+)). The working electrode surface has been modified with nanocomposite constituted of CBNPs and AuNPs by an easy drop casting procedure that makes this approach extendible to an automatable mass production of modified SPEs. Square wave anodic stripping voltammetry (SWASV) was adopted to perform Hg(2+) detection, revealing satisfactory sensitivity and detection limit, equal to 14 μA ppb(-1) cm(-2) and 3 ppb, respectively. The applicability of the CBNP-AuNP-SPE for the determination of inorganic mercury has been assessed in river water by a simple filtration and acidification of the sample as well as in soil by means of a facile acidic extraction procedure assisted by ultrasound.

Preparation and properties of hybrid monodispersed magnetic α-Fe2O3 based chitosan nanocomposite film for industrial and biomedical applications.

PubMed

Singh, Jay; Srivastava, M; Dutta, Joydeep; Dutta, P K

2011-01-01

In this study, hydrothermally prepared magnetic α-Fe2O3 nanoparticles were dispersed in chitosan (CH) solution to fabricate nanocomposite film. X-ray diffraction (XRD) patterns indicated that the α-Fe2O3 nanoparticles were pure α-Fe2O3 with rhombohedral structures, and the fabrication of CH did not result in a phase change. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) results showed that the hexagonal and spherical monodispersed α-Fe2O3 nanoparticles were encapsulated into the spherical dumb shaped CH-α-Fe2O3 nanocomposite film with a mean diameter of ∼87 and ∼110 nm respectively. The α-Fe2O3 nanoparticles and CH-α-Fe2O3 nanocomposite film were also characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM). Magnetic measurements revealed that the saturated magnetization (Ms) and remanent magnetization (Mr) of the pure α-Fe2O3 nanoparticles reached 0.573 emu/g and 0.100 emu/g respectively and the nanoparticles showed the characteristics of weak ferromagnetic before and after coating with CH. Copyright © 2010 Elsevier B.V. All rights reserved.

Sustainable Energy-Storage Materials from Lignin-Graphene Nanocomposite-Derived Porous Carbon Film

DOE PAGES

Tran, Chau D.; Ho, Hoi Chun; Keum, Jong K.; ...

2017-05-30

We present a simple, green approach to fabricating porous free-standing carbon films. An alkaline solution of low-cost, renewable lignin and graphene oxide (GO) is cast, followed by simultaneous carbonization and activation. Lignin, which is the least valued product from several biomass processing industries, is an efficient source of carbon when used as an intercalating agent to separate graphene sheets derived from homogeneous GO/lignin nanocomposite films prepared from an aqueous alkaline (KOH) solution. After thermal treatment the GO/lignin films show complete dispersion of reduced GO sheets within amorphous lignin-derived carbon. Furthermore, the presence of KOH in the film produces activated carbon.more » The resulting activated carbon films display a specific surface area of up to 1744 m2 g 1 and consist of a balance of pore volumes with pore sizes below and above 1 nm. A two-electrode supercapacitor composed of these films in an aqueous electrolyte exhibits near-ideal capacitive behavior at an ultrahigh scan rate of 1 V s 1, while maintaining an excellent specific capacitance of 162 F g 1. Such outstanding performance of renewable carbon as a supercapacitor, in addition to the ease of electrode fabrication from a precursor containing 85 % lignin, offers a novel method for valorization of lignin-rich byproduct streams from biomass processing industries.« less

Sustainable Energy-Storage Materials from Lignin-Graphene Nanocomposite-Derived Porous Carbon Film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tran, Chau D.; Ho, Hoi Chun; Keum, Jong K.

We present a simple, green approach to fabricating porous free-standing carbon films. An alkaline solution of low-cost, renewable lignin and graphene oxide (GO) is cast, followed by simultaneous carbonization and activation. Lignin, which is the least valued product from several biomass processing industries, is an efficient source of carbon when used as an intercalating agent to separate graphene sheets derived from homogeneous GO/lignin nanocomposite films prepared from an aqueous alkaline (KOH) solution. After thermal treatment the GO/lignin films show complete dispersion of reduced GO sheets within amorphous lignin-derived carbon. Furthermore, the presence of KOH in the film produces activated carbon.more » The resulting activated carbon films display a specific surface area of up to 1744 m2 g 1 and consist of a balance of pore volumes with pore sizes below and above 1 nm. A two-electrode supercapacitor composed of these films in an aqueous electrolyte exhibits near-ideal capacitive behavior at an ultrahigh scan rate of 1 V s 1, while maintaining an excellent specific capacitance of 162 F g 1. Such outstanding performance of renewable carbon as a supercapacitor, in addition to the ease of electrode fabrication from a precursor containing 85 % lignin, offers a novel method for valorization of lignin-rich byproduct streams from biomass processing industries.« less

Use of Nanocomposites for Flexible Pressure Sensors =

NASA Astrophysics Data System (ADS)

Sepulveda, Alexandra Conceicao Teixeira

Polymer nanocomposites (PNCs) are defined as polymers bonded with nanoparticles to create materiais with improved properties. The development of this type of material is rapidly emerging as a multidisciplinary research activity, since their final properties can benefit many different fields of application, namely in the development of electrical devices as studied herein. A fabrication technique to produce conductive PNCs was developed in this work and used to fabricate flexible capacitive pressure sensors. The process is based on vertically aligned-carbon nanotubes (A-CNTs) embedded in a flexible and biocompatible matrix of polydimethylsiloxane (PDMS). Thin A-CNTs/PDMS nanocomposite films ( 400 mum) were produced using wetting of as-grown A-CNTs with uncured PDMS and the resulting nanocomposites were used to fabricate flexible pressure sensors. The sensing capability of this A-CNTs/PDMS nanocomposite is attributed to the distinctive combination of mechanical flexibility and electrical properties. The fabricated nanocomposites were characterized and mechanical and electrical properties evaluated. The PDMS is significantly modified by the reinforcing A-CNT fibers, demonstrating non-isotropic (as opposed to the isotropic neat PDMS) elastic properties ali different than the PDMS (Young's modulus of 0.8 MPa), including an anisotropy ratio of 4.8 and increases in the modulus of A-CNTs/PDMS nanocomposites over PDMS by more than 900 % and 100 %, in the CNTs longitudinal and transverse directions, respectively. Regarding the electrical measurements, A-CNTs/PDMS nanocomposites presented an electrical conductivity of 0.35 Sim. The rather low conductivity does not compromise the developed capacitive sensor, but since passive telemetry is required to measure and power the sensor, solutions to overcome this problem were also studied. The configuration of the developed flexible sensor is similar to typical silicon-based capacitive pressure sensors. It is composed of three thin

Low Temperature Reactive Sputtering of Thin Aluminum Nitride Films on Metallic Nanocomposites

PubMed Central

Ramadan, Khaled Sayed Elbadawi; Evoy, Stephane

2015-01-01

Piezoelectric aluminum nitride thin films were deposited on aluminum-molybdenum (AlMo) metallic nanocomposites using reactive DC sputtering at room temperature. The effect of sputtering parameters on film properties was assessed. A comparative study between AlN grown on AlMo and pure aluminum showed an equivalent (002) crystallographic texture. The piezoelectric coefficients were measured to be 0.5±0.1 C m-2 and 0.9±0.1 C m-2, for AlN deposited on Al/0.32Mo and pure Al, respectively. Films grown onto Al/0.32Mo however featured improved surface roughness. Roughness values were measured to be 1.3nm and 5.4 nm for AlN films grown on AlMo and on Al, respectively. In turn, the dielectric constant was measured to be 8.9±0.7 for AlN deposited on Al/0.32Mo seed layer, and 8.7±0.7 for AlN deposited on aluminum; thus, equivalent within experimental error. Compatibility of this room temperature process with the lift-off patterning of the deposited AlN is also reported. PMID:26193701

A novel rapid synthesis of Fe{sub 2}O{sub 3}/graphene nanocomposite using ferrate(VI) and its application as a new kind of nanocomposite modified electrode as electrochemical sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karimi, Mohammad Ali, E-mail: ma_karimi43@yahoo.com; Department of Chemistry & Nanoscience and Nanotechnology Research Laboratory; Banifatemeh, Fatemeh

2015-10-15

Highlights: • A novel rapid synthesis of rGO–Fe{sub 2}O{sub 3} nanocomposite was developed using Fe(VI). • Fe(VI) as an environmentally friendly oxidant was introduced for GO synthesis. • Synthesized rGO–Fe{sub 2}O{sub 3} nanocomposite was applied as electrochemical sensor. • A non-enzymatic sensor was developed for H{sub 2}O{sub 2}. - Abstract: In this study, a novel, simple and sensitive non-enzymatic hydrogen peroxide electrochemical sensor was developed using reduced graphene oxide/Fe{sub 2}O{sub 3} nanocomposite modified glassy carbon electrode. This nanocomposite was synthesized by reaction of sodium ferrate with graphene in alkaline media. This reaction completed in 5 min and the products weremore » stable and its deposition on the surface of electrode is investigated. It has been found the apparent charge transfer rate constant (ks) is 0.52 and transfer coefficient (α) is 0.61 for electron transfer between the modifier and glassy carbon electrode. Electrochemical behavior of this electrode and its ability to catalyze the electro-reduction of H{sub 2}O{sub 2} has been studied by cyclic voltammetry and chronoamperometry at different experimental conditions. The analytical parameters showed the good ability of electrode as a sensor for H{sub 2}O{sub 2} amperometric reduction.« less

Preparation and Characterization of Space Durable Polymer Nanocomposite Films from Functionalized Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Delozier, D. M.; Connell, J. W.; Smith, J. G.; Watson, K. A.

2003-01-01

Low color, flexible, space durable polyimide films with inherent, robust electrical conductivity have been under investigation as part of a continuing materials development activity for future NASA space missions involving Gossamer structures. Electrical conductivity is needed in these films to dissipate electrostatic charge build-up that occurs due to the orbital environment. One method of imparting conductivity is through the use of single walled carbon nanotubes (SWNTs). However, the incompatibility and insolubility of the SWNTs severely hampers their dispersion in polymeric matrices. In an attempt to improve their dispersability, SWNTs were functionalized by the reaction with an alkyl hydrazone. After this functionalization, the SWNTs were soluble in select solvents and dispersed more readily in the polymer matrix. The functionalized SWNTs were characterized by Raman spectroscopy and thermogravimetric analysis (TGA). The functionalized nanotubes were dispersed in the bulk of the films using a solution technique. The functionalized nanotubes were also applied to the surface of polyimide films using a spray coating technique. The resultant polyimide nanocomposite films were evaluated for nanotube dispersion, electrical conductivity, mechanical, and optical properties and compared with previously prepared polyimide-SWNT samples to assess the effects of SWNT functionalization.

Gentamicin modified chitosan film with improved antibacterial property and cell biocompatibility.

PubMed

Liu, Yang; Ji, Peihong; Lv, Huilin; Qin, Yong; Deng, Linhong

2017-05-01

Gentamicin modified chitosan film (CS-GT) was produced using a three-step procedure comprising: (i) the chitosan solution was air-dried to form a chitosan (CS) film, (ii) using citric acid to generate the amide and carboxyl groups on the surface of CS, (iii) the CS with surface carboxyl groups was modified by grafting of gentamicin. After modification, this CS-GT film has excellent hydrophilicity and biocompatibility. It is very evident that the gentamicin grafting treatment significantly improves the antibacterial properties of the CS film. Our preliminary results suggest that this novel gentamicin modified chitosan film, which can be prepared in large quantities and at low cost, should have potential application in biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Electronic excitation induced modifications of structural, electrical and optical properties of Cu-C60 nanocomposite thin films

NASA Astrophysics Data System (ADS)

Inani, H.; Singhal, R.; Sharma, P.; Vishnoi, R.; Ojha, S.; Chand, S.; Sharma, G. D.

2017-09-01

High energy ion irradiation significantly affects the size and shape of nanoparticles in composites. Low concentration metal fraction embedded in fullerene matrix in form of nanocomposites was synthesized by thermal co-evaporation method. Swift heavy ion irradiation was performed with 120 MeV Au ion beam on Cu-C60 nanocomposites at different fluences 1 × 1012, 3 × 1012, 6 × 1012, 1 × 1013 and 3 × 1013 ions/cm2. Absorption spectra demonstrated that absorption intensity of nanocomposite thin film was increased whereas absorption modes of fullerene C60 were diminished with fluence. Rutherford backscattering spectroscopy was also performed to estimate the thickness of the film and atomic metal fraction in matrix and found to be 45 nm and 3%, respectively. Transmission electron microscopy was performed for structural and particle size evaluation of Cu nanoparticles (NPs) in fullerene C60 matrix. A growth of Cu nanoparticles is observed at a fluence of 3 × 1013 ions/cm2 with a bi-modal distribution in fullerene C60. Structural evolution of fullerene C60 matrix with increasing fluence of 120 MeV Au ion beam is studied by Raman spectroscopy which shows the amorphization of matrix (fullerene C60) at lower fluence. The growth of Cu nanoparticles is explained using the phenomena of Ostwald ripening.

Impact of Sweet Potato Starch-Based Nanocomposite Films Activated With Thyme Essential Oil on the Shelf-Life of Baby Spinach Leaves

PubMed Central

Issa, Aseel; Ibrahim, Salam A.; Tahergorabi, Reza

2017-01-01

Salmonella Typhimurium (S. Typhi) and Escherichia coli (E. coli) have been responsible for an increasing number of outbreaks linked to fresh produce, such as baby spinach leaves, in the last two decades. More recently, antimicrobial biodegradable packaging systems have been attracting much attention in the food packaging industry as eco-friendly alternatives to conventional plastic packaging. The objective of this study was to evaluate the effect of antibacterial nanocomposite films on inoculated spinach leaves and on the sensory properties of these leaves during eight days of refrigerated storage. In this study, an antibacterial film comprised of sweet potato starch (SPS), montmorillonite (MMT) nanoclays and thyme essential oil (TEO) as a natural antimicrobial agent was developed. Our results showed that the incorporation of TEO in the film significantly (p < 0.05) reduced the population of E. coli and S. Typhi on fresh baby spinach leaves to below detectable levels within five days, whereas the control samples without essential oil maintained approximately 4.5 Log colony forming unit (CFU)/g. The sensory scores for spinach samples wrapped in films containing TEO were higher than those of the control. This study thus suggests that TEO has the potential to be directly incorporated into a SPS film to prepare antimicrobial nanocomposite films for food packaging applications. PMID:28587199

Structural and electromagnetic properties of NiAlxFe2-xO4/SiO2 nanocomposite films deposited using a sol-gel spin-coating method

NASA Astrophysics Data System (ADS)

Wang, Li; Li, Xuejian; Li, Ji; Liu, Mei; Xu, Shichong; Li, Haibo

2017-12-01

NiAlxFe2-xO4/SiO2 (0 ≤ x ≤ 1.0) nanocomposite films deposited on Si(1 0 0) substrates were prepared by a sol-gel spin-coating method. The influences of Al3+ content and annealing temperature on the structural and electromagnetic properties of the nanocomposite films were investigated. The results indicated that NiAlxFe2-xO4 in the nanocomposite films crystallized after annealing at 1073 K and above. When the doping content x increased from 0 to 1.0, the lattice constants and the average crystallite sizes of the NiAlxFe2-xO4 nanoparticles decreased. The saturation magnetization and coercivity of the films were inversely proportional to the Al3+ content. The maximum value of saturation magnetization (361.6 emu/cm3) and the minimum value of coercivity (18.6 kA/m) were obtained for x of 0.2. When the annealing temperature increased from 1073 to 1473 K, the lattice constant and the average crystallite size of the NiAl0.2Fe1.8O4 nanoparticles increased from 0.8322 to 0.8349 nm and 4 to 28 nm, respectively, and the saturation magnetization and coercivity of the films increased from 214.8 to 464.5 emu/cm3 and 8.2 to 26.9 kA/m, respectively. Moreover, the DC resistivity of the films increased with increasing Al3+ content and annealing temperature.

Advances in rubber/halloysite nanotubes nanocomposites.

PubMed

Jia, Zhixin; Guo, Baochun; Jia, Demin

2014-02-01

The research advances in rubber/halloysite nanotubes (rubber/HNTs) nanocomposites are reviewed. HNTs are environmentally-friendly natural nanomaterials, which could be used to prepare the rubber-based nanocomposites with high performance and low cost. Unmodified HNTs could be adopted to prepare the rubber/HNTs composites with improved mechanical properties, however, the rubber/HNTs nanocomposites with fine morphology and excellent properties were chiefly prepared with various modifiers by in situ mixing method. A series of rubber/HNTs nanocomposites containing several rubbers (SBR, NR, xSBR, NBR, PU) and different modifiers (ENR, RH, Si69, SA, MAA, ILs) have been investigated. The results showed that all the rubber/HNTs nanocomposites achieved strong interfacial interaction via interfacial covalent bonds, hydrogen bonds or multiple interactions, realized significantly improved dispersion of HNTs at nanoscale and exhibited excellent mechanical performances and other properties.

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Yifan; Kawase, Ayako; Song, Min-Kyu

In this paper, we have investigated the chemical bonding interaction of S in a CTAB (cetyltrimethylammonium bromide, CH 3(CH 2) 15N +(CH 3) 3Br –)-modified sulfur–graphene oxide (S–GO) nanocomposite used as the cathode material for Li/S cells by S K-edge X-ray absorption spectroscopy (XAS). The results show that the introduction of CTAB to the S–GO nanocomposite and changes in the synthesis recipe including alteration of the S precursor ratios and the sequence of mixing ingredients lead to the formation of different S species. CTAB modifies the cathode materials through bonding with Na 2S x in the precursor solution, which ismore » subsequently converted to C–S bonds during the heat treatment at 155 °C. Moreover, GO bonds with CTAB and acts as the nucleation center for S precipitation. Finally, all these interactions among S, CTAB, and GO help to immobilize the sulfur in the cathode and may be responsible for the enhanced cell cycle life of CTAB–S–GO nanocomposite-based Li/S cells.« less

X-ray Absorption Spectroscopic Characterization of the Synthesis Process: Revealing the Interactions in Cetyltrimethylammonium Bromide-Modified Sulfur–Graphene Oxide Nanocomposites

DOE PAGES

Ye, Yifan; Kawase, Ayako; Song, Min-Kyu; ...

2016-04-22

In this paper, we have investigated the chemical bonding interaction of S in a CTAB (cetyltrimethylammonium bromide, CH 3(CH 2) 15N +(CH 3) 3Br –)-modified sulfur–graphene oxide (S–GO) nanocomposite used as the cathode material for Li/S cells by S K-edge X-ray absorption spectroscopy (XAS). The results show that the introduction of CTAB to the S–GO nanocomposite and changes in the synthesis recipe including alteration of the S precursor ratios and the sequence of mixing ingredients lead to the formation of different S species. CTAB modifies the cathode materials through bonding with Na 2S x in the precursor solution, which ismore » subsequently converted to C–S bonds during the heat treatment at 155 °C. Moreover, GO bonds with CTAB and acts as the nucleation center for S precipitation. Finally, all these interactions among S, CTAB, and GO help to immobilize the sulfur in the cathode and may be responsible for the enhanced cell cycle life of CTAB–S–GO nanocomposite-based Li/S cells.« less

Monitoring of microbial cell viability using nanostructured electrodes modified with Graphene/Alumina nanocomposite.

PubMed

Hassan, Rabeay Y A; Mekawy, Moataz M; Ramnani, Pankaj; Mulchandani, Ashok

2017-05-15

Microbial infections are rapidly increasing; however most of the existing microbiological and molecular detection methods are time consuming and/or cannot differentiate between the viable and dead cells which may overestimate the risk of infections. Therefore, a bioelectrochemical sensing platform with a high potential to the microbial-electrode interactions was designed based on decorated graphene oxide (GO) sheet with alumina (Al 2 O 3 ) nanocrystals. GO-Al 2 O 3 nanocomposite was synthesized using self-assembly of GO and Al 2 O 3 and characterized using the scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), Raman-spectroscopy, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Enhancement of electrocatalytic activity of the composite-modified electrode was demonstrated. Thus, using the GO-Al 2 O 3 nanocomposite modified electrode, the cell viability was determined by monitoring the bioelectrochemical response of the living microbial cells (bacteria and yeast) upon stimulation with carbon source. The bioelectrochemical assay was optimized to obtain high sensitivity and the method was applied to monitor cell viability and screen susceptibility of metabolically active cells (E. coli, B. subtilis, Enterococcus, P. aeruginosa and Salmonella typhi) to antibiotics such as ampicillin and kanamycin. Therefore, the developed assay is suitable for cell proliferation and cytotoxicity testing. Copyright © 2017 Elsevier B.V. All rights reserved.

Efficient upconversion polymer-inorganic nanocomposite thin film emitters prepared by the double beam matrix assisted pulsed laser evaporation (DB-MAPLE)

NASA Astrophysics Data System (ADS)

Darwish, Abdalla M.; Burkett, Allan; Blackwell, Ashley; Taylor, Keylantra; Walker, Vernell; Sarkisov, Sergey; Koplitz, Brent

2014-09-01

We report on fabrication and investigation of optical and morphological properties of highly efficient (a quantum yield of 1%) upconversion polymer-inorganic nanocomposite thin film emitters prepared by the new technique of double beam matrix assisted pulsed laser evaporation (DB-MAPLE). Polymer poly(methyl methacrylate) (PMMA) host was evaporated on a silicon substrate using a 1064-nm pulsed laser beam using a target made of frozen (to the temperature of liquid nitrogen) solution of PMMA in chlorobenzene. Concurrently, the second 532-nm pulsed beam from the same laser was used to impregnate the polymer host with the inorganic nanoparticulate made of the rare earth upconversion compounds NaYF4: Yb3+, Er3+, NaYF4: Yb3+, Ho3+, and NaYF4: Yb3+, Tm3+. The compounds were initially synthesized using the wet process, baked, and compressed in solid pellet targets. The proposed DB-MAPLE method has the advantage of making highly homogeneous nanocomposite films with precise control of the doping rate due to the optimized overlapping of the plumes produced by the ablation of the organic and inorganic target with the infrared and visible laser beams respectively. X-ray diffraction, electron and atomic force microscopy, and optical fluorescence spectroscopy indicated that the inorganic nanoparticulate preserved its crystalline structure and upconversion properties (strong emission in green, red, and blue bands upon illumination with 980-nm laser diode) after being transferred from the target in the polymer nanocomposite film. The produced films can be used in applications varying from the efficiency enhancement of the photovoltaic cells, optical sensors and biomarkers to anti-counterfeit labels.

Preparation of Cu2O-Reduced Graphene Nanocomposite Modified Electrodes towards Ultrasensitive Dopamine Detection

PubMed Central

He, Quanguo; Liu, Jun; Liu, Xiaopeng; Li, Guangli; Deng, Peihong; Liang, Jing

2018-01-01

Cu2O-reduced graphene oxide nanocomposite (Cu2O-RGO) was used to modify glassy carbon electrodes (GCE), and applied for the determination of dopamine (DA). The microstructure of Cu2O-RGO nanocomposite material was characterized by scanning electron microscope. Then the electrochemical reduction condition for preparing Cu2O-RGO/GCE and experimental conditions for determining DA were further optimized. The electrochemical behaviors of DA on the bare electrode, RGO- and Cu2O-RGO-modified electrodes were also investigated using cyclic voltammetry in phosphate-buffered saline solution (PBS, pH 3.5). The results show that the oxidation peaks of ascorbic acid (AA), dopamine (DA), and uric acid (UA) could be well separated and the peak-to-peak separations are 204 mV (AA-DA) and 144 mV (DA-UA), respectively. Moreover, the linear response ranges for the determination of 1 × 10−8 mol/L~1 × 10−6 mol/L and 1 × 10−6 mol/L~8 × 10−5 mol/L with the detection limit 6.0 × 10−9 mol/L (S/N = 3). The proposed Cu2O-RGO/GCE was further applied to the determination of DA in dopamine hydrochloride injections with satisfactory results. PMID:29329206

Chitosan-Iron Oxide Coated Graphene Oxide Nanocomposite Hydrogel: A Robust and Soft Antimicrobial Biofilm.

PubMed

Konwar, Achyut; Kalita, Sanjeeb; Kotoky, Jibon; Chowdhury, Devasish

2016-08-17

We report a robust biofilm with antimicrobial properties fabricated from chitosan-iron oxide coated graphene oxide nanocomposite hydrogel. For the first time, the coprecipitation method was used for the successful synthesis of iron oxide coated graphene oxide (GIO) nanomaterial. After this, films were fabricated by the gel-casting technique aided by the self-healing ability of the chitosan hydrogel network system. Both the nanomaterial and the nanocomposite films were characterized by techniques such as scanning electron microscopy, FT-IR spectroscopy, X-ray diffraction, and vibrating sample magnetometry. Measurements of the thermodynamic stability and mechanical properties of the films indictaed a significant improvement in their thermal and mechanical properties. Moreover, the stress-strain profile indicated the tough nature of the nanocomposite hydrogel films. These improvements, therefore, indicated an effective interaction and good compatibility of the GIO nanomaterial with the chitosan hydrogel matrix. In addition, it was also possible to fabricate films with tunable surface properties such as hydrophobicity simply by varying the loading percentage of GIO nanomaterial in the hydrogel matrix. Fascinatingly, the chitosan-iron oxide coated graphene oxide nanocomposite hydrogel films displayed significant antimicrobial activities against both Gram-positive and Gram-negative bacterial strains, such as methicillin-resistant Staphylococcus aureus, Staphylococcus aureus, and Escherichia coli, and also against the opportunistic dermatophyte Candida albicans. The antimicrobial activities of the films were tested by agar diffusion assay and antimicrobial testing based on direct contact. A comparison of the antimicrobial activity of the chitosan-GIO nanocomposite hydrogel films with those of individual chitosan-graphene oxide and chitosan-iron oxide nanocomposite films demonstrated a higher antimicrobial activity for the former in both types of tests. In vitro hemolysis

Simultaneous electrochemical determination of dopamine and paracetamol on multiwalled carbon nanotubes/graphene oxide nanocomposite-modified glassy carbon electrode.

PubMed

Cheemalapati, Srikanth; Palanisamy, Selvakumar; Mani, Veerappan; Chen, Shen-Ming

2013-12-15

In the present study, multiwalled carbon nanotubes (MWCNT)/graphene oxide (GO) nanocomposite was prepared by homogenous dispersion of MWCNT and GO and used for the simultaneous voltammetric determination of dopamine (DA) and paracetamol (PA). The TEM results confirmed that MWCNT walls were wrapped well with GO sheets. The MWCNT/GO nanocomposite showed superior electrocatalytic activity towards the oxidation of DA and PA, when compared with either pristine MWCNT or GO. The major reason for the efficient simultaneous detection of DA and PA at nanocomposite was the synergistic effect between MWCNT and GO. The electrochemical oxidation of DA and PA was investigated by cyclic voltammetry, differential pulse voltammetry and amperometry. The nanocomposite modified electrode showed electrocatalytic oxidation of DA and PA in the linear response range from 0.2 to 400 µmol L(-1) and 0.5 to 400 µmol L(-1) with the detection limit of 22 nmol L(-1) and 47 nmol L(-1) respectively. The proposed sensor displayed good selectivity, sensitivity, stability with appreciable consistency and precision. © 2013 Elsevier B.V. All rights reserved.

Proliferation and osteogenic differentiation of rat BMSCs on a novel Ti/SiC metal matrix nanocomposite modified by friction stir processing

PubMed Central

Zhu, Chenyuan; Lv, Yuting; Qian, Chao; Qian, Haixin; Jiao, Ting; Wang, Liqiang; Zhang, Fuqiang

2016-01-01

The aims of this study were to fabricate a novel titanium/silicon carbide (Ti/SiC) metal matrix nanocomposite (MMNC) by friction stir processing (FSP) and to investigate its microstructure and mechanical properties. In addition, the adhesion, proliferation and osteogenic differentiation of rat bone marrow stromal cells (BMSCs) on the nanocomposite surface were investigated. The MMNC microstructure was observed by both scanning and transmission electron microscopy. Mechanical properties were characterized by nanoindentation and Vickers hardness testing. Integrin β1 immunofluorescence, cell adhesion, and MTT assays were used to evaluate the effects of the nanocomposite on cell adhesion and proliferation. Osteogenic and angiogenic differentiation were evaluated by alkaline phosphatase (ALP) staining, ALP activity, PCR and osteocalcin immunofluorescence. The observed microstructures and mechanical properties clearly indicated that FSP is a very effective technique for modifying Ti/SiC MMNC to contain uniformly distributed nanoparticles. In the interiors of recrystallized grains, characteristics including twins, fine recrystallized grains, and dislocations formed concurrently. Adhesion, proliferation, and osteogenic and angiogenic differentiation of rat BMSCs were all enhanced on the novel Ti/SiC MMNC surface. In conclusion, nanocomposites modified using FSP technology not only have superior mechanical properties under stress-bearing conditions but also provide improved surface and physicochemical properties for cell attachment and osseointegration. PMID:27958394

Proliferation and osteogenic differentiation of rat BMSCs on a novel Ti/SiC metal matrix nanocomposite modified by friction stir processing

NASA Astrophysics Data System (ADS)

Zhu, Chenyuan; Lv, Yuting; Qian, Chao; Qian, Haixin; Jiao, Ting; Wang, Liqiang; Zhang, Fuqiang

2016-12-01

The aims of this study were to fabricate a novel titanium/silicon carbide (Ti/SiC) metal matrix nanocomposite (MMNC) by friction stir processing (FSP) and to investigate its microstructure and mechanical properties. In addition, the adhesion, proliferation and osteogenic differentiation of rat bone marrow stromal cells (BMSCs) on the nanocomposite surface were investigated. The MMNC microstructure was observed by both scanning and transmission electron microscopy. Mechanical properties were characterized by nanoindentation and Vickers hardness testing. Integrin β1 immunofluorescence, cell adhesion, and MTT assays were used to evaluate the effects of the nanocomposite on cell adhesion and proliferation. Osteogenic and angiogenic differentiation were evaluated by alkaline phosphatase (ALP) staining, ALP activity, PCR and osteocalcin immunofluorescence. The observed microstructures and mechanical properties clearly indicated that FSP is a very effective technique for modifying Ti/SiC MMNC to contain uniformly distributed nanoparticles. In the interiors of recrystallized grains, characteristics including twins, fine recrystallized grains, and dislocations formed concurrently. Adhesion, proliferation, and osteogenic and angiogenic differentiation of rat BMSCs were all enhanced on the novel Ti/SiC MMNC surface. In conclusion, nanocomposites modified using FSP technology not only have superior mechanical properties under stress-bearing conditions but also provide improved surface and physicochemical properties for cell attachment and osseointegration.

Structural modification in the formation of starch – silver nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Begum, S. N. Suraiya; Ramasamy, Radha Perumal, E-mail: perumal.ramasamy@gmail.com; Aswal, V. K.

Polymer based nanocomposites have gained wide applications in field of battery technology. Starch is a naturally occurring polysaccharide with sustainable properties such as biodegradable, non toxic, excellent film forming capacity and it also act as reducing agent for the metal nanoparticles. In our research various concentration of silver nitrate (AgNO{sub 3}) was added to the starch solution and films were obtained using solution casting method. Surface electron microscope (SEM) of the films shows modifications depending upon the concentration of AgNO{sub 3}. Small angle neutron scattering (SANS) analysis showed that addition of silver nitrate modifies the starch to disc like structuresmore » and with increasing the AgNO{sub 3} concentration leads to the formation of fractals. This research could benefit battery technology where solid polymer membranes using starch is used.« less

Thermal-induced structural and optical investigations of Agsbnd ZnO nanocomposite thin films

NASA Astrophysics Data System (ADS)

Singh, S. K.; Singhal, R.

2018-07-01

In the present paper, we have successfully synthesized Agsbnd ZnO nanocomposite thin films by RF-magnetron sputtering technique at room temperature. Systematic investigations of thermal-induced structural and optical modifications in Agsbnd ZnO thin films have been observed and described. The Agsbnd ZnO thin films were annealed at three different temperatures of 300 °C, 400 °C and 500 °C in vacuum to prevent the oxidation of Ag. The presence and formation of Ag nanoparticles were estimated by transmission electron microscopy. X-ray diffraction analysis revealed the structural information about the crystalline quality of ZnO. The crystallinity as well as the crystallite size of the films have been found to be improved with annealing temperatures. The estimated crystallite size was ∼15.8 nm for as-deposited film and 19.0 nm for the film at a higher temperature. The chemical composition and structural analysis of as-deposited film were carried out by X-ray photoelectron spectroscopy. A very sharp absorption band appeared at ∼540 nm for Ag NPs that is associated with the surface plasmon resonance band of Ag. A noticeable red shift of about ∼12 nm has been recorded for films annealed at 500 °C. Atomic force microscopy has been utilized to examine the surface morphology of the as-deposited and annealed films. The grain size was found to be increase with increasing annealing temperature, while no significant changes were observed in the roughness of Agsbnd ZnO thin films. Raman spectroscopy revealed lattice defects and disordering in the films after the thermal annealing.

Anomalous Drag Reduction and Hydrodynamic Interactions of Nanoparticles in Polymer Nanocomposite Thin Films

NASA Astrophysics Data System (ADS)

Basu, Jaydeep; Begam, Nafisa; Chandran, Sivasurender; Sprung, Michael

2015-03-01

One of the central dogma of fluid physics is the no-slip boundary condition whose validity has come under intense scrutiny, especially in the fields of micro and nanofluidics. Although various studies show the violation of the no-slip condition its effect on flow of colloidal particles in viscous media has been rarely explored. Here we report unusually large reduction of effective drag experienced by polymer grafted nanoparticles moving through a highly viscous film of polymer, well above its glass transition temperature. The extent of drag reduction increases with decreasing temperature and polymer film thickness. We also observe apparent divergence of the wave vector dependent hydrodynamic interaction function of these nanoparticles with an anomalous power law exponent of ~ 2 at the lowest temperatures and film thickness. Such strong hydrodynamic interactions are not expected in polymer melts where these interactions are known to be screened to molecular dimensions. We provide evidence for the presence of large hydrodynamic slip at the nanoparticle-polymer interface and demonstrate its tunability with temperature and confinement. Our study suggests novel physics emerging in dynamics nanoparticles due to confinement and interface wettability in thin films of polymer nanocomposites.

Influence of Food with High Moisture Content on Oxygen Barrier Property of Polyvinyl Alcohol (PVA)/Vermiculite Nanocomposite Coated Multilayer Packaging Film.

PubMed

Kim, Jung Min; Lee, Min Hyeock; Ko, Jung A; Kang, Dong Ho; Bae, Hojae; Park, Hyun Jin

2018-02-01

This study investigates the potential complications in applying nanoclay-based waterborne coating to packaging films for food with high moisture content. Multilayer packaging films were prepared by dry laminating commercially available polyvinyl alcohol (PVA)/vermiculite nanocomposite coating films and linear low-density polyethylene film, and the changes in oxygen barrier properties were investigated according to different relative humidity using 3 types of food simulants. When the relative humidity was above 60%, the oxygen permeability increased sharply, but this was reversible. Deionized water and 3% acetic acid did not cause any large structural change in the PVA/vermiculite nanocomposite but caused a reversible deterioration of the oxygen barrier properties. In contrast, 50% ethanol, a simulant for the semifatty food, induced irreversible structural changes with deterioration of the oxygen barrier property. These changes are due to the characteristics of PVA rather than vermiculite. We believe this manuscript would be of interest to the wide group of researchers, organizations, and companies in the field of developing nanoclay-based gas barrier packaging for foods with high moisture content. Hence, we wish to diffuse our knowledge to the scientific community. © 2018 Institute of Food Technologists®.

Preparation and physical properties of tara gum film reinforced with cellulose nanocrystals.

PubMed

Ma, Qianyun; Hu, Dongying; Wang, Lijuan

2016-05-01

Cellulose nanocrystals (CNC) prepared from microcrystalline cellulose were blended in tara gum solution to prepare nanocomposite films. The morphology, crystallinity, and thermal properties of the CNC and films were evaluated by using transmission electron microscopy, X-ray diffractometry, and thermogravimetric analysis, respectively. The resultant CNC was rod-shaped with diameters of around 8.6 nm. The effect of CNC content on physical and thermal properties of films was studied. The composite film tensile strength increased from 27.86 to 65.73 MPa, elastic modulus increased from 160.98 MPa to 882.49 MPa and the contact angle increased from 55.8° to 98.7° with increasing CNC content from 0 to 6 wt%. However, CNC addition increased the thermal stability slightly and CNC content above 6 wt% decreased the tensile strength by CNC aggregation in the matrix. The nanocomposite film containing 6 wt% CNC possessed the highest light transmittance, mechanical properties, and lowest oxygen permeability. CNC addition is a suitable method to modify tara gum matrix polymer properties. Copyright © 2016 Elsevier B.V. All rights reserved.

Enzymatic biosensor based on entrapment of d-amino acid oxidase on gold nanofilm/MWCNTs nanocomposite modified glassy carbon electrode by sol-gel network: Analytical applications for d-alanine in human serum.

PubMed

Shoja, Yalda; Rafati, Amir Abbas; Ghodsi, Javad

2017-05-01

Sensing and determination of d-alanine is studied by using an enzymatic biosensor which was constructed on the basis of d-amino acid oxidase (DAAO) immobilization by sol-gel film onto glassy carbon electrode surface modified with nanocomposite of gold nanofilm (Au-NF) and multiwalled carbon nanotubes (MWCNTs). The Au-NF/MWCNT nanocomposite was prepared by applying the potentiostatic technique for electrodeposition of Au-NF on the MWCNT immobilized on glassy carbon electrode surface. The modified electrode is investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), linear sweep voltammetry (LSV) and cyclic voltammetry(CV) techniques. The linear sweep voltammetry was used for determination of d-alanine and the results showed an excellent linear relationship between biosensor response and d-alanine concentration ranging from 0.25μM to 4.5μM with correction coefficient of 0.999 (n=20). Detection limit for the fabricated sensor was calculated about 20nM (for S/N=3) and sensitivity was about 56.1μAμM -1 cm -2 . The developed biosensor exhibited rapid and accurate response to d-alanine, a good stability (4 weeks) and an average recovery of 98.9% in human serum samples. Copyright © 2017 Elsevier Inc. All rights reserved.

Immobilization of biomolecules on cysteamine-modified polyaniline film for highly sensitive biosensing.

PubMed

Cai, Qi; Xu, Baojian; Ye, Lin; Di, Zengfeng; Zhang, Jishen; Jin, Qinghui; Zhao, Jianlong; Xue, Jian; Chen, Xianfeng

2014-03-01

We present a new cysteamine (CS)-modified polyaniline (PANI) film for highly efficient immobilization of biomolecules in biosensing technology. This electrochemical deposited PANI film treated with CS and glutaraldehyde could be employed as an excellent substrate for biomolecules immobilization. The parameters of PANI growth were optimized to obtain suitable surface morphology of films for biomolecules combination with the help of electron and atomic force microscopy. Cyclic voltammetry (CV) was utilized to illustrate the different electrochemical activities of each modified electrode. Due to the existence of sulfydryl group and amino group in CS, surface modification with CS was proven to reduce oxidized units on PANI film remarkably, as evidenced by both ATR-FTIR and Raman spectroscopy characterizations. Furthermore, bovine serum albumin (BSA) was used as the model protein to investigate the immobilization efficiency of biomolecules on the PANI film, comparative study using quartz crystal microbalance (QCM) showed that BSA immobilized on CS-modified PANI could be increased by at least 20% than that without CS-modified PANI in BSA solution with the concentration of 0.1-1mg/mL. The CS-modified PANI film would be significant for the immobilization and detection of biomolecules and especially promising in the application of immunosensor for ultrasensitive detection. © 2013 Published by Elsevier B.V.

Design of amine modified polymer dispersants for liquid-phase exfoliation of transition metal dichalcogenide nanosheets and their photodetective nanocomposites

NASA Astrophysics Data System (ADS)

Lee, Jinseong; Hahnkee Kim, Richard; Yu, Seunggun; Babu Velusamy, Dhinesh; Lee, Hyeokjung; Park, Chanho; Cho, Suk Man; Jeong, Beomjin; Sol Kang, Han; Park, Cheolmin

2017-12-01

Liquid-phase exfoliation (LPE) of transition metal dichalcogenide (TMD) nanosheets is a facile, cost-effective approach to large-area photoelectric devices including photodetectors and non-volatile memories. Non-destructive exfoliation of nanosheets using macromolecular dispersing agents is beneficial in rendering the TMD nanocomposite films suitable for mechanically flexible devices. Here, an efficient LPE of molybdenum disulfide (MoS2) with an amine modified poly(styrene-co-maleic anhydride) co-polymer (AM-PSMA) is demonstrated, wherein the maleic anhydrides were converted into maleic imides with primary amines using N-Boc-(CH2) n -NH2. The exfoliation of nanosheets was facilitated through Lewis acid-base interaction between the primary amine and transition metal. The results demonstrate that the exfoliation depends upon both the fraction of primary amines in the polymer chain and their distance from the polymer backbone. Under optimized conditions of primary amine content and its distance from the backbone, AM-PSMA gave rise to a highly concentrated MoS2 nanosheet suspension that was stable for over 10 d. Exfoliation of several other TMDs was also achieved using the optimized AM-PSMA, indicating the scope of AM-PSMA applications. Furthermore, a flexible composite film of AM-PSMA and MoS2 nanosheets fabricated by vacuum-assisted filtration showed excellent photoconductive performances including a high I on/I off ratio of 102 and a fast photocurrent switching of 300 ms.

New Poly(amide-imide)/Nanocomposites Reinforced Silicate Nanoparticles Based on N-pyromellitimido-L-phenyl Alanine Containing Ether Moieties

NASA Astrophysics Data System (ADS)

Faghihi, Khalil; Shabanian, Meisam; Dadfar, Ehsan

2012-02-01

A series of Poly(amide-imide)/montmorillonite nanocomposites containing N-pyromellitimido-L-phenyl alanine moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide) (PAI) 5 as a source of polymer matrix was synthesized by the direct polycondensation reaction of N-pyromellitimido-L-phenyl alanine 3 with 4,4'-diamino diphenyl ether 4 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). The resulting nanocomposite films were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results showed that organo-modified clay was dispersed homogeneously in PAI matrix. TGA indicated an enhancement of thermal stability of new nanocomposites compared with the pure polymer.

Whey protein isolate/cellulose nanofibre/TiO2 nanoparticle/rosemary essential oil nanocomposite film: Its effect on microbial and sensory quality of lamb meat and growth of common foodborne pathogenic bacteria during refrigeration.

PubMed

Alizadeh Sani, Mahmood; Ehsani, Ali; Hashemi, Mohammad

2017-06-19

The use of biodegradable nanocomposite films in active packaging is of great importance since they can have a controlled release of antimicrobial compounds. This study was conducted to evaluate the efficacy of whey protein isolate (WPI)/cellulose nanofibre (CNF) nanocomposite films containing 1.0% (w/w) titanium dioxide (TiO 2 ) and 2.0% (w/v) rosemary essential oil (REO) in preserving the microbial and sensory quality of lamb meat during the storage at 4±1°C. Initially, the best concentration of each compound to be added to the film was determined by micro-dilution and disc diffusion methods. The microbial and sensory properties of lamb meat were controlled in two groups (control and treatment) over 15days of storage. Then, the samples were analysed for total viable count (TVC), Pseudomonas spp. count, Enterobacteriaceae count, Lactic acid bacteria (LAB) count, inoculated Staphylococcus aureus count, Listeria monocytogenes count, and Escherichia coli O 157 :H 7 count. Microbial analysis and nine-point hedonic scale was applied for the sensory analysis. Results indicated that the use of nanocomposite films significantly reduced the bacterial counts of treatment group. Higher inhibition effect was observed on Gram-positive bacteria than on Gram-negative bacteria (P<0.05). The microbial and sensory evaluations also showed that the use of nanocomposite films significantly increased the shelf life of treated meat (15days) compared to the control meat (6days). Based on the results of this study, the edible nanocomposite films were effective in preserving the microbial and sensory qualities of lamb meat; therefore, this application is recommended in meat especially red meat. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation and characterization of a poly (1, 4-phenylenevinylene) derivative-based hybrid thin film nanocomposites with enhanced performance

NASA Astrophysics Data System (ADS)

Belhaj, Marwa; Jemmeli, Dhouha; Dridi, Cherif; Ben Salem, Balkiss; Jaballah, Najmeddine; Majdoub, Mustapha; Yatskiv, Roman; Grym, Jan

2018-05-01

In this study, a poly (1, 4-phenylenevinylene) derivative (PPV-C6) was synthesized via Gilch polycondensation, and its electrochemical and optical characteristics were determined by cyclic voltammetry analysis, ultraviolet-visible, and photoluminescence spectroscopy. The polymer exhibited semiconductor behavior with an optical band gap of about 2.02 eV. Thin-film hybrid nanocomposites were prepared based on PPV-C6 with a large range of concentrations of sol-gel synthesized surfactant-free ZnO nanoparticles (n-ZnO). We investigated the photophysical properties of nanocomposites with different weight ratios of n-ZnO. The optical absorption spectra of PPV-C6: n-ZnO nanocomposites exhibited moderate variation in terms of the optical band gap energy with respect to the pristine polymer. Photoluminescence spectra indicated that the optimum n-ZnO concentration was about 50 wt% to achieve photoluminescence quenching, which corresponded to the most homogeneous surface and efficient charge transfer due to optimal exciton dissociation. We established good correlations between the investigated properties.

Fabrication of Amine-Modified Magnetite-Electrochemically Reduced Graphene Oxide Nanocomposite Modified Glassy Carbon Electrode for Sensitive Dopamine Determination

PubMed Central

He, Quanguo; Liu, Jun; Liu, Xiaopeng; Li, Guangli; Chen, Dongchu; Deng, Peihong; Liang, Jing

2018-01-01

Amine-modified magnetite (NH2–Fe3O4)/reduced graphene oxide nanocomposite modified glassy carbon electrodes (NH2–Fe3O4/RGO/GCEs) were developed for the sensitive detection of dopamine (DA). The NH2-Fe3O4/RGO/GCEs were fabricated using a drop-casting method followed by an electrochemical reduction process. The surface morphologies, microstructure and chemical compositions of the NH2–Fe3O4 nanoparticles (NPs), reduced graphene oxide (RGO) sheets and NH2–Fe3O4/RGO nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy. The electrochemical behaviors of DA on the bare and modified GCEs were investigated in phosphate buffer solution (PBS) by cyclic voltammetry (CV). Compared with bare electrode and RGO/GCE, the oxidation peak current (ipa) on the NH2–Fe3O4/RGO/GCE increase significantly, owing to the synergistic effect between NH2–Fe3O4 NPs and RGO sheets. The oxidation peak currents (ipa) increase linearly with the concentrations of DA in the range of 1 × 10−8 mol/L – 1 × 10−7 mol/L, 1 × 10−7 mol/L – 1 × 10−6 mol/L and 1 × 10−6 mol/L – 1 × 10−5 mol/L. The detection limit is (4.0 ± 0.36) ×10−9 mol/L (S/N = 3). Moreover, the response peak currents of DA were hardly interfered with the coexistence of ascorbic acid (AA) and uric acid (UA). The proposed NH2–Fe3O4/RGO/GCE is successfully applied to the detection of dopamine hydrochloride injections with satisfactory results. Together with low cost, facile operation, good selectivity and high sensitivity, the NH2–Fe3O4/RGO/GCEs have tremendous prospects for the detection of DA in various real samples. PMID:29584682

Anisotropic elasticity of quasi-one-component polymer nanocomposites.

PubMed

Voudouris, Panayiotis; Choi, Jihoon; Gomopoulos, Nikos; Sainidou, Rebecca; Dong, Hongchen; Matyjaszewski, Krzysztof; Bockstaller, Michael R; Fytas, George

2011-07-26

The in-plane and out-of-plane elastic properties of thin films of "quasi-one-component" particle-brush-based nanocomposites are compared to those of "classical" binary particle-polymer nanocomposite systems with near identical overall composition using Brillouin light scattering. Whereas phonon propagation is found to be independent of the propagation direction for the binary particle/polymer blend systems, a pronounced splitting of the phonon propagation velocity along the in-plane and out-of-plane film direction is observed for particle-brush systems. The anisotropic elastic properties of quasi-one-component particle-brush systems are interpreted as a consequence of substrate-induced order formation into layer-type structures and the associated breaking of the symmetry of the film. The results highlight new opportunities to engineer quasi-one-component nanocomposites with advanced control of structural and physical property characteristics based on the assembly of particle-brush materials.

Sliding friction of nanocomposite WC1-x/C coatings: transfer film and its influence on tribology.

PubMed

Liu, Y; Gubisch, M; Spiess, L; Schaefer, J A

2009-06-01

The transfer film on steel spheres formed in reciprocating sliding against nanocomposite coatings based on nanocrystalline WC1-x in amorphous carbon matrix is characterized and correlated with the tribological properties measured by a precision microtribometer. With the presence of transfer film, a coefficient of friction approximately 0.13 and a depth wear rate approximately 0.35 x 10(-10) m/N.Pass were obtained. The central zone of the transfer film covering approximately 25% of the Hertz contact area is intact while cracks and wear debris are found in the vast peripheral area. It is also heavily oxidized due to the absence of carbon, which is located at the peripherals and acts as lubricants. We propose that the oxidation of WC and adhesion of the oxides to the surface of sphere is the main mechanism for the buildup of the transfer films. With the thickening of the film, the internal stress increases. Under the shear stress, spalling and cracking of the transfer film take place. The overall tribological performance of the coatings is therefore a competing process of buildup and spalling of transfer films.

Nutraceutically inspired pectin-Mg(OH)₂ nanocomposites for bioactive packaging applications.

PubMed

Moreira, Francys K V; De Camargo, Lais A; Marconcini, José M; Mattoso, Luiz H C

2013-07-24

This paper reports on the development of bioactive edible films based on pectin as a dietary matrix and magnesium hydroxide (Mg(OH)2) nanoplates as a reinforcing filler. Nanocomposites of high-methoxyl (HM) and low-methoxyl (LM) pectins were prepared using the casting method at concentrations of Mg(OH)2 ranging from 0.5 to 5 wt %. Atomic force microscopy and FTIR spectroscopy were employed to characterize the nanocomposite structure. The tensile properties and thermal stability of the nanocomposites were also examined to ascertain the effect of Mg(OH)2 inclusion and degree of methoxylation. The results provided evidence that the Mg(OH)2 nanoplates were uniformly dispersed and interacted strongly with the film matrix. The mechanical and thermal properties were significantly improved in the nanocomposite films compared to the control. Mg(OH)2 nanoplates were more effective in improving properties of LM pectin. Preliminary migration studies using arugula leaves confirmed that pectin-Mg(OH)2 nanocomposites can release magnesium hydroxide by contact, demonstrating their potential for magnesium supplementation in bioactive packaging.

Crab shell chitin whiskers reinforced natural rubber nanocomposites. 3. Effect of chemical modification of chitin whiskers.

PubMed

Gopalan Nair, Kalaprasad; Dufresne, Alain; Gandini, Alessandro; Belgacem, Mohamed Naceur

2003-01-01

The purpose of this study was to chemically modify the surface of chitin whiskers and to investigate the effect of the incorporation of these modified whiskers into a natural rubber (NR) matrix on the properties of the ensuing nanocomposite. Different chemical coupling agents were tested, namely, phenyl isocyanate (PI), alkenyl succinic anhydride (ASA) (Accosize 18 from American Cyanamid), and 3-isopropenyl-alpha,alpha'-dimethylbenzyl isocyanate (TMI). The extent of chemical modification was evaluated by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and surface energy analysis. After chemical modification, nanocomposite films were obtained using a toluene natural rubber solution in which the whiskers were dispersed. Their mechanical properties were found to be inferior to those of unmodified chitin/NR composites presented in our previous study. In fact, even though there is an increase in filler-matrix interaction as a result of chemical modification of the chitin whiskers, this does not contribute to the improvement in the mechanical properties of the resulting nanocomposite. It is concluded that this loss of performance is due to the partial destruction of the three-dimensional network of chitin whiskers assumed to be present in the unmodified composites.

Properties of solid solutions, doped film, and nanocomposite structures based on zinc oxide

NASA Astrophysics Data System (ADS)

Lashkarev, G. V.; Shtepliuk, I. I.; Ievtushenko, A. I.; Khyzhun, O. Y.; Kartuzov, V. V.; Ovsiannikova, L. I.; Karpyna, V. A.; Myroniuk, D. V.; Khomyak, V. V.; Tkach, V. N.; Timofeeva, I. I.; Popovich, V. I.; Dranchuk, N. V.; Khranovskyy, V. D.; Demydiuk, P. V.

2015-02-01

A study of the properties of materials based on the wide bandgap zinc oxide semiconductor, which are promising for application in optoelectronics, photovoltaics and nanoplasmonics. The structural and optical properties of solid solution Zn1-xCdxO films with different cadmium content, are studied. The samples are grown using magnetron sputtering on sapphire backing. Low-temperature photoluminescence spectra revealed emission peaks associated with radiative recombination processes in those areas of the film that have varying amounts of cadmium. X-ray phase analysis showed the presence of a cadmium oxide cubic phase in these films. Theoretical studies of the solid solution thermodynamic properties allowed for a qualitative interpretation of the observed experimental phenomena. It is established that the growth of the homogeneous solid solution film is possible only at high temperatures, whereas regions of inhomogeneous composition can be narrowed through elastic deformation, caused by the mismatch of the film-backing lattice constants. The driving forces of the spinodal decomposition of the Zn1-xCdxO system are identified. Fullerene-like clusters of Znn-xCdxOn are used to calculate the bandgap and the cohesive energy of ZnCdO solid solutions. The properties of transparent conductive ZnO films, doped with Group III donor impurities (Al, Ga, In), are examined. It is shown that oxygen vacancies are responsible for the hole trap centers in the zinc oxide photoconductivity process. We also examine the photoluminescence properties of metal-ZnO nanocomposite structures, caused by surface plasmons.

Colorless polyimide/organoclay nanocomposite substrates for flexible organic light-emitting devices.

PubMed

Kim, Jin-Hoe; Choi, Myeon-Chon; Kim, Hwajeong; Kim, Youngkyoo; Chang, Jin-Hae; Han, Mijeong; Kim, Il; Ha, Chang-Sik

2010-01-01

We report the preparation and application of indium tin oxide (ITO) coated fluorine-containing polyimide/organoclay nanocomposite substrate. Fluorine-containing polyimide/organoclay nanocomposite films were prepared through thermal imidization of poly(amic acid)/organoclay mixture films, whilst on which ITO thin films were coated on the films using a radio-frequency planar magnetron sputtering by varying the substrate temperature and the ITO thickness. Finally the ITO coated fluorine-containing polyimide/organoclay nanocomposite substrate was employed to make flexible organic light-emitting devices (OLED). Results showed that the lower sheet resistance was achieved when the substrate temperature was high and the ITO film was thick even though the optical transmittance was slightly lowered as the thickness increased. approximately 10 nm width ITO nanorods were found for all samples but the size of clusters with the nanorods was generally increased with the substrate temperature and the thickness. The flexible OLED made using the present substrate was quite stable even when the device was extremely bended.

Metal (Ag/Ti)-Containing Hydrogenated Amorphous Carbon Nanocomposite Films with Enhanced Nanoscratch Resistance: Hybrid PECVD/PVD System and Microstructural Characteristics.

PubMed

Constantinou, Marios; Nikolaou, Petros; Koutsokeras, Loukas; Avgeropoulos, Apostolos; Moschovas, Dimitrios; Varotsis, Constantinos; Patsalas, Panos; Kelires, Pantelis; Constantinides, Georgios

2018-03-30

This study aimed to develop hydrogenated amorphous carbon thin films with embedded metallic nanoparticles (a-C:H:Me) of controlled size and concentration. Towards this end, a novel hybrid deposition system is presented that uses a combination of Plasma Enhanced Chemical Vapor Deposition (PECVD) and Physical Vapor Deposition (PVD) technologies. The a-C:H matrix was deposited through the acceleration of carbon ions generated through a radio-frequency (RF) plasma source by cracking methane, whereas metallic nanoparticles were generated and deposited using terminated gas condensation (TGC) technology. The resulting material was a hydrogenated amorphous carbon film with controlled physical properties and evenly dispersed metallic nanoparticles (here Ag or Ti). The physical, chemical, morphological and mechanical characteristics of the films were investigated through X-ray reflectivity (XRR), Raman spectroscopy, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM) and nanoscratch testing. The resulting amorphous carbon metal nanocomposite films (a-C:H:Ag and a-C:H:Ti) exhibited enhanced nanoscratch resistance (up to +50%) and low values of friction coefficient (<0.05), properties desirable for protective coatings and/or solid lubricant applications. The ability to form nanocomposite structures with tunable coating performance by potentially controlling the carbon bonding, hydrogen content, and the type/size/percent of metallic nanoparticles opens new avenues for a broad range of applications in which mechanical, physical, biological and/or combinatorial properties are required.

Nanocomposite film of TiO{sub 2} nanotube and polyoxometalate towards photocatalytic degradation of nitrobenzene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Zhixia; Zhao, Mingliang; Li, Fengyan, E-mail: lify525@nenu.edu.cn

2014-12-15

Highlights: • The film of POMs and TiO{sub 2} nanotubes was prepared by electrodeposition. • The photocatalytic activity of the composite film for nitrobenzene was investigated. • The composite film showed higher photocatalytic activity than pure TiO{sub 2} nanotubes. • The introduction of POMs into TiO{sub 2} could retard electron–hole recombination. - Abstract: The composite film based on polyoxometalates (POMs)-modified TiO{sub 2} nanotubes was prepared by electrodeposition method for the photocatalytic degradation of nitrobenzene. The composite film was characterized by field-emission scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, which indicated that the POMs weremore » well introduced into the TiO{sub 2} nanotubes. Furthermore, the photocatalytic properties of the TiO{sub 2} nanotubes and POMs-modified TiO{sub 2} nanotubes were evaluated by the decomposition of nitrobenzene. POMs-modified TiO{sub 2} nanotubes showed much higher photocatalytic activity than pure TiO{sub 2} nanotubes. These results provide a promising route to effectively photocatalytic degradation of nitrobenzene by POMs-modified TiO{sub 2} nanotubes.« less

Adhesive and morphological characteristics of surface chemically modified polytetrafluoroethylene films

NASA Astrophysics Data System (ADS)

Hopp, B.; Kresz, N.; Kokavecz, J.; Smausz, T.; Schieferdecker, H.; Döring, A.; Marti, O.; Bor, Z.

2004-01-01

In the present paper, we report an experimental determination of adhesive and topographic characteristics of chemically modified surface of polytetrafluoroethylene (PTFE) films. The surface chemistry was modified by ArF excimer laser irradiation in presence of triethylene-tetramine photoreagent. The applied laser fluence was varied in the range of 0.4-9 mJ/cm 2, and the number of laser pulses incident on the same area was 1500. To detect the changes in the adhesive features of the treated Teflon samples, we measured receding contact angle for distilled water and adhesion strength, respectively. It was found that the receding contact angle decreased from 96° to 30-37° and the adhesion strength of two-component epoxy glue to the treated sample surface increased from 0.03 to 9 MPa in the applied laser fluence range. Additionally, it was demonstrated that the adhesion of human cells to the modified Teflon samples is far better than to the untreated ones. The contact mode and pulsed force mode atomic force microscopic investigations of the treated samples demonstrated that the measured effective contact area of the irradiated films does not differ significantly from that of the original films, but the derived adhesion force is stronger on the modified samples than on the untreated ones. Hence, the increased adhesion of the treated Teflon films is caused by the higher surface energy.

Modification of cellulose acetate nanocomposite with TiO{sub 2}-organoclay as nanofiller and its self-photodegradation study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luthfiyah, Siti Zahrotul; Krisnandi, Yuni K., E-mail: yuni.krisnandi@sci.ui.ac.id; Andhika, Kadek

2016-04-19

Nanocomposite cellulose acetate has been synthesized using organoclay nanofiller modified with TiO{sub 2}. Tapanuli bentonite was previously subjected to purification and sodium exchangeprocesses, then modified with TiO{sub 2},that was added as much as 0%, 1%, 3%, 5%, and 10% weight of the total composite. FTIR analysis showed intercalation with Hexadecyl Ammonium Bromide (HDTMABr) surfactant was successfully carried out, indicated by new absorption bands at 2636 cm{sup −1} and 2569 cm{sup −1}. XRD diffractogram shows the increase in basal spasing on the modification of bentonite from 15.7 Å to 19.7 Å after modification. Fabrication of nanocomposite film was carried out using acetone asmore » solvent and through solvent casting method. Nanocomposite application in photodegradation test was carried out under direct sunlight irradiation, UV light, and without irradiation for six days. It is found that the greater the amount of TiO{sub 2} in the composites, the more weight loss occured, due to photodegredation. Percent weight loss in the UV light irradiation are 1.11%, 2.15%, 2.73%, 3.18%, and 3.96%, while under direct sunlight irradiation, the weight loss was 1.03%, 3.03%, 3.88%, 4.53%, and 5.57%. Modification of nanocomposite with the addition of photocatalytic TiO{sub 2} has shown to give the nanocomposite the ability of self-photodegradation.« less

Viscoelastic and Mechanical Properties of Thermoset PMR-type Polyimide-Clay Nanocomposites

NASA Technical Reports Server (NTRS)

Abdalla, Mohamed O.; Dean, Derrick; Campbell, Sandi

2002-01-01

High temperature thermoset polyimide-clay nanocomposites were prepared by blending 2.5 and 5 wt% of an unmodified Na(+-) montmorillonite (PGV) and two organically modified FGV (PGVCl0COOH, PGVC12) with a methanol solution of PMR-15 precursor. The methanol facilitated the dispersal of the unmodified clay. Dynamic mechanical analysis results showed a significant increase in the thermomechanical properties (E' and E") of 2.5 wt% clay loaded nanocomposites in comparison with the neat polyimide. Higher glass transition temperatures were observed for 2.5 wt% nanocomposites compared to the neat polyimide. Flexural properties measurements for the 2.5 wt% nanocomposites showed a significant improvement in the modulus and strength, with no loss in elongation. This trend was not observed for the 5 wt% nanocomposites. An improvement in the CTE was observed for the PGV/PMR-15 nanocomposites, while a decrease was observed for the organically modified samples. This was attributed to potential variations in the interface caused by modifier degradation.

High-performance polymer/layered silicate nanocomposites

NASA Astrophysics Data System (ADS)

Heidecker, Matthew J.

High-performance layered-silicate nanocomposites of Polycarbonate (PC), poly(ethylene terephthalate) (PET), and their blends were produced via conventional melt-blending techniques. The focus of this thesis was on the fundamentals of dispersion, control of thermal stability, maintenance of melt-blending processing conditions, and on optimization of the composites' mechanical properties via the design of controlled and thermodynamically favorable nano-filler dispersions within the polymer matrices. PET and PC require high temperatures for melt-processing, rendering impractical the use of conventional/commercial organically-modified layered-silicates, since the thermal degradation temperatures of their ammonium surfactants lies below the typical processing temperatures. Thus, different surfactant chemistries must be employed in order to develop melt-processable nanocomposites, also accounting for polymer matrix degradation due to water (PET) or amine compounds (PC). Novel high thermal-stability surfactants were developed and employed in montmorillonite nanocomposites of PET, PC, and PC/PET blends, and were compared to the respective nanocomposites based on conventional quaternary-ammonium modified montmorillonites. Favorable dispersion was achieved in all cases, however, the overall material behavior -- i.e., the combination of crystallization, mechanical properties, and thermal degradation -- was better for the nanocomposites based on the thermally-stable surfactant fillers. Studies were also done to trace, and ultimately limit, the matrix degradation of Polycarbonate/montmorillonite nanocomposites, through varying the montmorillonite surfactant chemistry, processing conditions, and processing additives. Molecular weight degradation was, maybe surprisingly, better controlled in the conventional quaternary ammonium based nanocomposites -- even though the thermal stability of the organically modified montmorillonites was in most cases the lowest. Dependence of the

The study of poly(L-lactide) grafted silica nanoparticles on the film blowing of poly(L-lactide)

NASA Astrophysics Data System (ADS)

Wu, Feng; Liu, Zhengying; Yang, Mingbo

2015-05-01

PLA nanocomposites are prepared by us, and to better develop the function of silica nanoparticle, the surface of silica nanoparticles are modified by introducing PLA chains via "grafting to" method in our research. According to the results of 1H NMR and TGA, it shows that the PLA grafted Silica nanoparticles are successfully synthesized by controlling the reaction condition, and the molecular weight of the grafted PLA chains is relatively as high as 22 400 g/mol. PLA Nanocomposites with modified nanoparticles are prepared using a convenient melt blending method to guarantee well-distribution of the particles. The well-dispersion state of silica nanospheres is confirmed by Scan Electrical Micrograph (SEM) technology. From the dynamic shear rheology tests, the strain and time sweep both reveal that stability networks are formed in these nanocomposites. And the frequency sweep shows that the nanoparticles with long grafted chains dramatically enhanced the storage and viscosity of the pure PLA. The rheology testing suggests that strong particle-matrix interactions between molecularly/nano-level dispersed grafted silica and PLA chains formed; and the elongational viscosity of PLA has been markedly improved with the addition of the nanoparticle. The effect of modified nanoparticles on the thermal properties of PLA has also been studied by us using Differential Scanning Calorimetry (DSC). It reveals that the crystallization rate of PLA has been improved as the long grafted chains play as the nucleation sites for PLA. Finally based on these rheology and crystallization researches, the nanocomposites are used to prepare PLA blowing films. Compared to pure PLA and PLA/unmodified silica nanocomposites, the results show that the stability of the film blowing has been greatly improved and the blow-up ratio has been increased with the addition of PLA grafted nanoparticles. The modified nanoparticles hold significant candidates to improve the thermal stability and the

Size-controlled growth and antibacterial mechanism for Cu:C nanocomposite thin films.

PubMed

Javid, Amjed; Kumar, Manish; Yoon, Seokyoung; Lee, Jung Heon; Han, Jeon Geon

2016-12-21

The interdependence of 'size' and 'volume-fraction' hinders the identification of their individual role in the interface properties of metal nanoparticles (NPs) embedded in a matrix. Here, the case of Cu NPs embedded in a C matrix is presented for their profound antibacterial activity. Cu:C nanocomposite thin films with fixed Cu content (≈12 atomic%) are prepared using a plasma process where plasma energy controls the size of Cu NPs (from 9 nm to 16 nm). An inverse relationship between the size-effect on antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria is established through the real time monitoring of an aliquot by inductively coupled plasma mass spectrometry, which confirmed the inverse relationship of Cu ion release from the nanocomposite with varied Cu NP sizes. It was found that enhancing the total power density increases the plasma density as well as effective kinetic energy of the plasma species, which in turn creates a large number of nucleation sites and restricts the island kind of growth of Cu NPs. The mechanism of NP size-control is illustrated on the basis of ion density and nucleation and the growth regime of plasma species. This physical approach to NP size reduction anticipates a contamination-free competitive recipe of size-control to capping based chemical methods.

Optical limiting in gelatin stabilized Cu-PVP nanocomposite colloidal suspension

NASA Astrophysics Data System (ADS)

Tamgadge, Y. S.; Gedam, P. P.; Thakare, N. B.; Talwatkar, S. S.; Sunatkari, A. L.; Muley, G. G.

2018-05-01

This article illustrates investigations on optical limiting properties of Cu-PVP nanocomposite colloidal suspension. Gelatin stabilized Cu nanoparticles have been synthesized using chemical reduction method and thin films in PVP matrix have been obtained using spin coating technique. Thin films have been characterized by X-ray diffraction (XRD), Ultraviolet-visible (UV-vis) spectroscopy, etc. for structural and linear optical studies. Optical limiting properties of Colloidal Cu-PVP nanocomposites have been investigated at 808 nm diode CW laser. Minimum optical limiting threshold was found for GCu3-PVP nanocomposites sample. The strong optical limiting is thermal in origin as CW laser is used and effects are attributed to thermal lensing effect.

Thermal-induced SPR tuning of Ag-ZnO nanocomposite thin film for plasmonic applications

NASA Astrophysics Data System (ADS)

Singh, S. K.; Singhal, R.

2018-05-01

The formation of silver (Ag) nanoparticles in a ZnO matrix were successfully synthesized by RF-magnetron sputtering at room temperature. As prepared Ag-ZnO nanocomposite (NCs) thin films were annealed in vacuum at three different temperatures of 300 °C, 400 °C and 500 °C, respectively. The structural modifications for as-deposited and annealed films were estimated by X-ray diffraction and TEM techniques. The crystalline behavior preferably along the c-axis of the hexagonal wurtzite structure was observed in as-deposited Ag-ZnO film and improved significantly with increasing the annealing temperature. The crystallite size of as-deposited film was measured to be 13.6 nm, and increases up to 28.5 nm at higher temperatures. The chemical composition and surface structure of the as-deposited films were estimated by X-ray photoelectron spectroscopy. The presence of Ag nanoparticles with average size of 8.2 ± 0.2 nm, was confirmed by transmission electron microscopy. The strong surface plasmon resonance (SPR) band was observed at the wavelength of ∼565 nm for as-deposited film and a remarkable red shift of ∼22 nm was recorded after the annealing treatment as confirmed by UV-visible spectroscopy. Atomic force microscopy confirmed the grain growth from 60.38 nm to 79.42 nm for as-deposited and higher temperature annealed film respectively, with no significant change in the surface roughness. Thermal induced modifications such as disordering and lattice defects in Ag-ZnO NCs thin films were carried out by Raman spectroscopy. High quality Ag-ZnO NCs thin films with minimum strain and tunable optical properties could be useful in various plasmonic applications.

Self-assembly of mesoscopically ordered chromatic polydiacetylene/silica nanocomposites

NASA Technical Reports Server (NTRS)

Lu, Y.; Yang, Y.; Sellinger, A.; Lu, M.; Huang, J.; Fan, H.; Haddad, R.; Lopez, G.; Burns, A. R.; Sasaki, D. Y.;

All-cellulose nanocomposite film made from bagasse cellulose nanofibers for food packaging application.

PubMed

Ghaderi, Moein; Mousavi, Mohammad; Yousefi, Hossein; Labbafi, Mohsen

2014-04-15

All-cellulose nanocomposite (ACNC) film was produced from sugarcane bagasse nanofibers using N,N-dimethylacetamide/lithium chloride solvent. The average diameter of bagasse fibers (14 μm) was downsized to 39 nm after disk grinding process. X-ray diffraction showed that apparent crystallinity and crystallite size decreased relatively to an increased duration of dissolution time. Thermogravimetric analysis confirmed that thermal stability of the ACNC was slightly less than that of the pure cellulose nanofiber sheet. Tensile strength of the fiber sheet, nanofiber sheet and ACNC prepared with 10 min dissolution time were 8, 101 and 140 MPa, respectively. Water vapor permeability (WVP) of the ACNC film increased relatively to an increased duration of dissolution time. ACNC can be considered as a multi-performance material with potential for application in cellulose-based food packaging owing to its promising properties (tough, bio-based, biodegradable and acceptable levels of WVP). Copyright © 2014 Elsevier Ltd. All rights reserved.

Thermal and mechanical properties of palm oil-based polyurethane acrylate/clay nanocomposites prepared by in-situ intercalative method and electron beam radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salih, A. M.; Ahmad, Mansor Bin; Ibrahim, Nor Azowa

2014-02-12

Palm oil based-polyurethane acrylate (POBUA)/clay nanocomposites were prepared via in-situ intercalative polymerization using epoxidized palm oil acrylate (EPOLA) and 4,4' methylene diphenyl diisocyante (MDI). Organically modified Montmorillonite (ODA-MMT) was incorporated in EPOLA (1, 3 and 5%wt), and then subjected to polycondensation reaction with MDI. Nanocomposites solid films were obtained successfully by electron beam radiation induced free radical polymerization (curing). FTIR results reveal that the prepolymer was obtained successfully, with nanoclay dispersed in the matrix. The intercalation of the clay in the polymer matrix was investigated by XRD and the interlayer spacing of clay was found to be increased up tomore » 37 Å, while the structure morphology of the nanocomposites was investigated by TEM and SEM. The nanocomposites were found to be a mixture of exfoliated and intercalated morphologies. The thermal stability of the nanocomposites was significantly increased by incorporation of nanoclay into the polymer matrix. DSC results reveal that the Tg was shifted to higher values, gradually with increasing the amount of filler in the nanocomposites. Tensile strength and Young's modulus of the nanocomposites showed remarkable improvement compared to the neat POBUA.« less

Enhancement of mechanical properties of epoxy/graphene nanocomposite

NASA Astrophysics Data System (ADS)

Berhanuddin, N. I. C.; Zaman, I.; Rozlan, S. A. M.; Karim, M. A. A.; Manshoor, B.; Khalid, A.; Chan, S. W.; Meng, Q.

2017-10-01

Graphene is a novel class of nanofillers possessing outstanding characteristics including most compatible with most polymers, high absolute strength, high aspect ratio and cost effectiveness. In this study, graphene was used to reinforce epoxy as a matrix, to enhance its mechanical properties. Two types of epoxy composite were developed which are epoxy/graphene nanocomposite and epoxy/modified graphene nanocomposite. The fabrication of graphene was going through thermal expansion and sonication process. Chemical modification was only done for modified graphene where 4,4’-Methylene diphenyl diisocyanate (MDI) is used. The mechanical properties of both nanocomposite, such as Young’s modulus and maximum stress were investigated. Three weight percentage were used for this study which are 0.5 wt%, 1.0 wt% and 1.5 wt%. At 0.5 wt%, modified and unmodified shows the highest value compared to neat epoxy, where the value were 8 GPa, 6 GPa and 0.675 GPa, respectively. For maximum stress, neat epoxy showed the best result compared to both nanocomposite due to the changes of material properties when adding the filler into the matrix. Therefore, both nanocomposite increase the mechanical properties of the epoxy, however modification surface of graphene gives better improvement.

Physicochemical and Mechanical Properties of Bambara Groundnut Starch Films Modified with Stearic Acid.

PubMed

Oyeyinka, Samson A; Singh, Suren; Amonsou, Eric O

2017-01-01

The physicochemical and mechanical properties of biofilm prepared from bambara starch modified with varying concentrations of stearic acid (0%, 2.5%, 3.5%, 5%, 7%, and 10%) were studied. By scanning electron microscopy, bambara starch films modified with stearic acid (≥3.5%) showed a progressively rough surface compared to those with 2.5% stearic acid and the control. Fourier transform infrared spectroscopy spectra revealed a peak shift of approximately 31 cm -1 , suggesting the promotion of hydrogen bond formation between hydroxyl groups of starch and stearic acid. The addition of 2.5% stearic acid to bambara starch film reduced water vapor permeability by approximately 17%. Bambara starch films modified with higher concentration of stearic acid were more opaque and showed significantly high melting temperatures. However, mechanical properties of starch films were generally negatively affected by stearic acid. Bambara starch film may be modified with 2.5% stearic acid for improved water vapor permeability and thermal stability with minimal effect on tensile strength. © 2016 Institute of Food Technologists®.

Process for the preparation of metal-containing nanostructured films

NASA Technical Reports Server (NTRS)

Lu, Yunfeng (Inventor); Wang, Donghai (Inventor)

2006-01-01

Metal-containing nanostructured films are prepared by electrodepositing a metal-containing composition within the pores of a mesoporous silica template to form a metal-containing silica nanocomposite. The nanocomposite is annealed to strengthen the deposited metal-containing composition. The silica is then removed from the nanocomposite, e.g., by dissolving the silica in an etching solution to provide a self-supporting metal-containing nanostructured film. The nanostructured films have a nanowire or nanomesh architecture depending on the pore structure of the mesoporous silica template used to prepare the films.

Synthesis and applications of MANs/poly(MMA-co-BA) nanocomposite latex by miniemulsion polymerization

PubMed Central

Chen, Huayao; Zhou, Xinhua; Gunasekaran, Sundaram

2017-01-01

We have synthesized core-shell structured 3-methacryloxypropyltrimethoxysilane (MPS) functionalized antimony-doped tin oxide nanoparticles (MANs)–poly(methyl methacrylate-co-butyl acrylate) (PMMA-co-BA, PMB) nanocomposite latex particles via miniemulsion polymerization method. Polymerizable anionic surfactant DNS-86 (allyloxy polyoxyethylene(10) nonyl ammonium sulfate) was first introduced to synthesize core-shell nanocomposite. The morphologies of synthesized MANs and MANs/PMB latex nanocomposite particles were studied with transmission electron microscopy, which revealed particles, on average 70 nm in size, with a core-shell structure. Owing to the uniformity and hydrophobicity of MANs, the MANs-embedded PMB latex nanocomposite can be tailored more precisely than other nanoparticles-embedded nanocomposites. Films incorporating 10 wt% of MANs in the MAN/PMB latex nanocomposite exhibit good transmittance in the visible region, and excellent opacity in the near infrared region. The MANs/PMB nanocomposite film also appears suitable for heat insulation applications. PMID:29291076

Enhanced antibacterial performance of hybrid semiconductor nanomaterials: ZnO/SnO 2 nanocomposite thin films

NASA Astrophysics Data System (ADS)

Talebian, Nasrin; Nilforoushan, Mohammad Reza; Zargar, Elahe Badri

2011-10-01

The nano-sized coupled oxides ZnO/SnO 2 thin films in a molar ratio of 2:1 (Z2S), 1:1 (ZS) and 1:2 (ZS2) were prepared using sol-gel dip coating method and characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-vis spectroscopy. Escherichia coli ( E. coli, ATCC 25922) was selected as a model for the Gram-negative bacteria to evaluate antibacterial property of composite samples compared with single ZnO (Z) and single SnO 2 (S) films. The antibacterial activity has been studied applying the so-called antibacterial drop test under UV illumination. The bactericidal activity was estimated by relative number of bacteria survived calculated from the number of viable cells which form colonies on the nutrient agar plates. The influence of the SnO 2-ZnO nanocomposite composition on the structural features and on the antibacterial properties of the thin films are reported and discussed. It is found that all coatings exhibited a high antibacterial activity. The coupled oxide photocatalyst Z2S has better photocatalytic activity to bacteria inactivation than ZS, ZS2, Z and S films. Furthermore, nanostructured films were active even in the absence of irradiation.

Solution Coating of Pharmaceutical Nanothin Films and Multilayer Nanocomposites with Controlled Morphology and Polymorphism.

PubMed

Horstman, Elizabeth M; Kafle, Prapti; Zhang, Fengjiao; Zhang, Yifu; Kenis, Paul J A; Diao, Ying

2018-03-28

Nanosizing is rapidly emerging as an alternative approach to enhance solubility and thus the bioavailability of poorly aqueous soluble active pharmaceutical ingredients (APIs). Although numerous techniques have been developed to perform nanosizing of API crystals, precise control and modulation of their size in an energy and material efficient manner remains challenging. In this study, we present meniscus-guided solution coating as a new technique to produce pharmaceutical thin films of nanoscale thickness with controlled morphology. We demonstrate control of aspirin film thickness over more than 2 orders of magnitude, from 30 nm to 1.5 μm. By varying simple process parameters such as the coating speed and the solution concentration, the aspirin film morphology can also be modulated by accessing different coating regimes, namely the evaporation regime and the Landau-Levich regime. Using ellipticine-a poorly water-soluble anticancer drug-as another model compound, we discovered a new polymorph kinetically trapped during solution coating. Furthermore, the polymorphic outcome can be controlled by varying coating conditions. We further performed layer-by-layer coating of multilayer nanocomposites, with alternating thin films of ellipticine and a biocompatible polymer, which demonstrate the potential of additive manufacturing of multidrug-personalized dosage forms using this approach.

Effect of annealing temperature on optical and electrical properties of ZrO2-SnO2 based nanocomposite thin films

NASA Astrophysics Data System (ADS)

Anitha, V. S.; Lekshmy, S. Sujatha; Berlin, I. John; Joy, K.

2014-01-01

Transparent nanocomposite ZrO2-SnO2 thin films were prepared by sol-gel dip-coating technique. Films were annealed at 500°C, 800°C and 1200°C respectively. X-ray diffraction(XRD) spectra showed a mixture of three phases: tetragonal ZrO2 and SnO2 and orthorhombic ZrSnO4. The grain size of all the three phases' increased with annealing temperature. An average transmittance greater than 85%(in UV-Visible region) is observed for all the films. The band gap for the films decreased from 4.79 eV to 4.62 eV with increase in annealing temperature from 500 to 1200 °C. The electrical resistivity increased with increase in annealing temperature. Such composite ZrO2-SnO2 films can be used in many applications and in optoelectronic devices.

Impact of magnetite nanoparticle incorporation on optical and electrical properties of nanocomposite LbL assemblies.

PubMed

Yashchenok, Alexey M; Gorin, Dmitry A; Badylevich, Mikhail; Serdobintsev, Alexey A; Bedard, Matthieu; Fedorenko, Yanina G; Khomutov, Gennady B; Grigoriev, Dmitri O; Möhwald, Helmuth

2010-09-21

Optical and electrical properties of polyelectrolyte/iron oxide nanocomposite planar films on silicon substrates were investigated for different amount of iron oxide nanoparticles incorporated in the films. The nanocomposite assemblies prepared by the layer-by-layer assembly technique were characterized by ellipsometry, atomic force microscopy, and secondary ion mass-spectrometry. Absorption spectra of the films reveal a shift of the optical absorption edge to higher energy when the number of deposited layers decreases. Capacitance-voltage and current-voltage measurements were applied to study the electrical properties of metal-oxide-semiconductor structures prepared by thermal evaporation of gold electrodes on nanocomposite films. The capacitance-voltage measurements show that the dielectric constant of the film increases with the number of deposited layers and the fixed charge and the trapped charge densities have a negative sign.

Self-Assembled Heteroepitaxial Oxide Nanocomposite for Photoelectrochemical Solar Water Oxidation

PubMed Central

2016-01-01

We report on spontaneously phase ordered heteroepitaxial SrTiO3 (STO):ZnFe2O4 (ZFO) nanocomposite films that give rise to strongly enhanced photoelectrochemical solar water oxidation, consistent with enhanced photoinduced charge separation. The STO:ZFO nanocomposite yielded an enhanced photocurrent density of 0.188 mA/cm2 at 1.23 V vs a reversible hydrogen electrode, which was 7.9- and 2.6-fold higher than that of the plain STO film and ZFO film cases under 1-sun illumination, respectively. The photoelectrode also produced stable photocurrent and Faradaic efficiencies of H2 and O2 formation that were more than 90%. Incident-photon-to-current-conversion efficiency measurements, Tauc plots, Mott–Schottky plots, and electrochemical impedance spectroscopy measurements proved that the strongly enhanced photogenerated charge separation resulted from vertically aligned pseudosingle crystalline components, epitaxial heterojunctions, and a staggered band alignment of the components of the nanocomposite films. This study presents a completely new avenue for efficient solar energy conversion applications. PMID:27212792

High-Pressure Study of Bio-inspired Multi-Functional Nanocomposites Using Atomic Force Microscopy Methods

NASA Astrophysics Data System (ADS)

Diaz Gonzalez, Alfredo J.

was performed using the correlation of conductive atomic force microscopy and contact resonance force microscopy to measure the local variations. The analysis shows that in thin and transparent films, there is segregation in the response of Cloisite Na+ based nanocomposites compared to the bare polymer or Laponite RD nanocomposite, hence the investigation focuses on Laponite RD. For Laponite RD, we investigate the 3-D distribution of nanoclay in the coating. The distribution of nanoclay at the surface is elucidated by mapping the dissipative and conservative interactions between tip and sample in bimodal AFM. Measuring the strain produced by the tip, the 3-D structure is inferred using models for mechanical properties of nanocomposites. Single platelet measurements are used to infer the inter-platelet distance. It is known that the free amplitude of the higher eigenmode can be modulated to produce large forces in bimodal AFM. The pressure estimated for the typical cantilever parameters used are in the range 1.2-3.3 GPa, which is used to apply high-pressure to the subsurface structure of the nanocomposite. We show that the tip-surface interaction modifies the subsurface morphology of the nanocomposite and results in changes of the out-of-plane current. Also, the structural modification caused by the bimodal AFM treatment results in local changes in mechanical properties. This behavior is obtained for the Laponite RD nanocomposite, but it is not observed for the Cloisite Na+ nanocomposite or the bare polymer. Laponite RD has a platelet size similar to the tip, while Cloisite Na+ is much larger leading to a reduction in pressure. By modelling the transmission probability of electrons, geometrical changes in the structure are examined and shown to modify the tunneling of the electrons through the coating. Specifically, parallel compression of the nanoclay (modelled as barriers for electrons) leads to a change in the transmission probability of the electrons. Depending on

Vapor phase polymerization deposition of conducting polymer/graphene nanocomposites as high performance electrode materials.

PubMed

Yang, Yajie; Li, Shibin; Zhang, Luning; Xu, Jianhua; Yang, Wenyao; Jiang, Yadong

2013-05-22

In this paper, we report chemical vapor phase polymerization (VPP) deposition of novel poly(3,4-ethylenedioxythiophene) (PEDOT)/graphene nanocomposites as solid tantalum electrolyte capacitor cathode films. The PEDOT/graphene films were successfully prepared on porous tantalum pentoxide surface as cathode films through the VPP procedure. The results indicated that the high conductivity nature of PEDOT/graphene leads to the decrease of cathode films resistance and contact resistance between PEDOT/graphene and carbon paste. This nanocomposite cathode film based capacitor showed ultralow equivalent series resistance (ESR) ca. 12 mΩ and exhibited better capacitance-frequency performance than the PEDOT based capacitor. The leakage current investigation revealed that the device encapsulation process does not influence capacitor leakage current, indicating the excellent mechanical strength of PEDOT-graphene films. The graphene showed a distinct protection effect on the dielectric layer from possible mechanical damage. This high conductivity and mechanical strength graphene based conducting polymer nanocomposites indicated a promising application future for organic electrode materials.

A flexible mesoporous Li4Ti5O12-rGO nanocomposite film as free-standing anode for high rate lithium ion batteries

NASA Astrophysics Data System (ADS)

Zhu, Kunxu; Gao, Hanyang; Hu, Guoxin

2018-01-01

Advanced flexible electrode is crucial in the development of flexible energy storage devices for emerging wearable and portable electronics. Herein, a free-standing flexible mesoporous Li4Ti5O12-rGO (LTO-rGO) nanocomposite film is rationally designed and fabricated for lithium ion batteries (LIBs). This efficient synthesis involves the growth of lithium titanate hydrate (LTH) precursors on the graphene oxide (GO) by a hydrothermal reaction, assembly into LTH-GO film by vacuum filtration with some extra GO added, and subsequent conversion into LTO-rGO nanocomposite film through calcination. When rGO content in the LTO-rGO film is set, the addition sequence of GO is found to affect its textural and mechanical properties. The resultant free-standing LTO-rGO electrode, taking advantages of high Li4Ti5O12 loading of 73.9%, mesoporous layer-stacked channels with good electron/ion conductivity, good mechanical strength, and enlarged electrode/electrolyte contact area, delivers excellent electrochemical performance (e.g., specific capacity of 135.4 mAh g-1 at 40 C) over the electrode of conventional configuration. Moreover, no organic but all inorganic reagents are used in the synthesis, offering an eco-friendly, cost-efficient, and easily scalable way to fabricate binder-free flexible electrode for LIBs.

Electrospun PVA/Bentonite Nanocomposites Mats for Drug Delivery

PubMed Central

Ferrández-Rives, Mariola; Gómez Ribelles, José Luis

2017-01-01

Electrospun mats and films of polyvinyl alcohol (PVA) hydrogel are produced for drug delivery. To provide mechanical consistency to the gel a reinforcement by nanoclays is introduced in the polymer matrix. Four different suspensions of nanoparticles in the polymer solution are prepared in an adequate solvent. These suspensions are subjected to an electrospinning process to produce the nanofiber mat, while films are produced by casting. The influence of the process parameters over the nanofibers microstructure is analyzed by scanning electron microscopy (SEM). The effectiveness of nanoclay encapsulation in the nanocomposites is tested by a thermogravimetric analysis. A crosslinking reaction in solution is carried out to prevent the dissolution of the nanocomposites in aqueous media. A model protein (bovine serum albumin, BSA) is absorbed in the nanocomposites to characterize the release kinetics in phosphate-buffered saline (PBS). PMID:29261123

Structural and optical properties of SiC-SiO2 nanocomposite thin films

NASA Astrophysics Data System (ADS)

Bozetine, I.; Keffous, A.; Kaci, S.; Menari, H.; Manseri, A.

2018-03-01

This study deals with the deposition of thin films of a SiC-SiO2nanocomposite deposited on silicon substrates. The deposition is carried out by a co-sputtering RF magnetron 13.56 MHz, using two targets a polycristallin 6H-SiC and sprigs of SiO2. In order to study the influence of the deposition time on the morphology, the structural and optical properties of the thin films produced, two series of samples were prepared, namely a series A with a 30 min deposition time and a series B of one hour duration. The samples were investigated using different characterization techniques such as Scanning Electron Microscope (SEM), X-ray Diffraction (DRX), Fourier Transform Infrared Spectroscopy (FTIR), Secondary Ion Mass Spectrometry (SIMS) and photoluminescence. The results obtained, reveal an optical gap varies between 1.4 and 2.4 eV depending on the thickness of the film; thus depending on the deposition time. The SIMS profile recorded the presence of oxygen (16O) on the surface, which the signal beneath the silicon signal (28Si) and carbon (12C) signals, which confirms that the oxide (SiO2) is the first material deposited at the interface film - substrate with an a-OSiC structure. The photoluminescence (PL) measurement exhibits two peaks, centred at 390 nm due to the oxide and at 416 nm due probably to the nanocrystals of SiC crystals, note that when the deposition time increases, the intensity of the PL drops drastically, result in agreement with dense and smooth film.

A label-free electrochemical impedance immunosensor based on AuNPs/PAMAM-MWCNT-Chi nanocomposite modified glassy carbon electrode for detection of Salmonella typhimurium in milk.

PubMed

Dong, Jing; Zhao, Han; Xu, Minrong; Ma, Qiang; Ai, Shiyun

2013-12-01

A sensitive and stable label-free electrochemical impedance immunosensor for the detection of Salmonella typhimurium was developed by immobilising anti-Salmonella antibodies onto the gold nanoparticles and poly(amidoamine)-multiwalled carbon nanotubes-chitosan nanocomposite film modified glassy carbon electrode (AuNPs/PAMAM-MWCNT-Chi/GCE). Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to verify the stepwise assembly of the immunosensor. Co-addition of MWCNT, PAMAM and AuNPs greatly enhanced the sensitivity of the immunosensor. The immobilisation of antibodies and the binding of Salmonella cells to the modified electrode increased the electron-transfer resistance (Ret), which was directly measured with EIS using [Fe(CN)6](3-/4-) as a redox probe. A linear relationship of Ret and Salmonella concentration was obtained in the Salmonella concentration range of 1.0×10(3) to 1.0×10(7) CFU mL(-1) with a detection limit of 5.0×10(2) CFU mL(-1). Additionally, the proposed method was successfully applied to determine S. typhimurium content in milk samples with satisfactory results. Copyright © 2013 Elsevier Ltd. All rights reserved.

A novel lable-free electrochemical immunosensor for carcinoembryonic antigen based on gold nanoparticles-thionine-reduced graphene oxide nanocomposite film modified glassy carbon electrode.

PubMed

Kong, Fen-Ying; Xu, Mao-Tian; Xu, Jing-Juan; Chen, Hong-Yuan

2011-10-15

In this paper, gold nanoparticle-thionine-reduced graphene oxide (GNP-THi-GR) nanocomposites were prepared to design a label-free immunosensor for the sensitive detection of carcinoembryonic antigen (CEA). The nanocomposites with good biocompatibility, excellent redox electrochemical activity and large surface area were coated onto the glassy carbon electrode (GCE) surface and then CEA antibody (anti-CEA) was immobilized on the electrode to construct the immunosensor. The morphologies and electrochemistry of the formed nanocomposites were investigated by using scanning electron microscopy (SEM), ultraviolet-visible (UV-vis) spectrometry, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). CV and differential pulse voltammetry (DPV) studies demonstrated that the formation of antibody-antigen complexes decreased the peak current of THi in the GNP-THi-GR nanocomposites. The decreased currents were proportional to the CEA concentration in the range of 10-500 pg/mL with a detection limit of 4 pg/mL. The proposed method was simple, fast and inexpensive for the determination of CEA at very low levels. Copyright © 2011 Elsevier B.V. All rights reserved.

Carbon Nanotube-Poly(vinylalcohol) Nanocomposite Film Devices: Applications for Femtosecond Fiber Laser Mode Lockers and Optical Amplifier Noise Suppressors

NASA Astrophysics Data System (ADS)

Sakakibara, Youichi; Rozhin, Aleksey G.; Kataura, Hiromichi; Achiba, Yohji; Tokumoto, Madoka

2005-04-01

We fabricated single-wall carbon nanotube (SWNT)/poly(vinylalcohol) (PVA) nanocomposite freestanding films and examined their application in devices in which the saturable absorption of SWNTs at near-infrared optical telecommunication wavelengths can be utilized. In a passively mode-locked fiber laser, we integrated a 30-μm-thick SWNT/PVA film into a fiber connection adaptor with the film sandwiched by a pair of fiber ferrules. A ring fiber laser with a SWNT/PVA saturable absorber was operated very easily in the mode-locked short-pulse mode with a pulse width of about 500 fs. Reproducible stable device performance was confirmed. In examining noise suppression for optical amplifiers, mixed light of semiconductor amplified spontaneous emission (ASE) source and 370 fs laser pulses was passed through a 100-μm-thick SWNT/PVA film. The transmission loss of the femtosecond pulse light was smaller than that of the ASE light. This proved that the SWNT/PVA film has the ability to suppress ASE noise.

Multifunctional zirconium oxide doped chitosan based hybrid nanocomposites as bone tissue engineering materials.

PubMed

Bhowmick, Arundhati; Jana, Piyali; Pramanik, Nilkamal; Mitra, Tapas; Banerjee, Sovan Lal; Gnanamani, Arumugam; Das, Manas; Kundu, Patit Paban

2016-10-20

This paper reports the development of multifunctional zirconium oxide (ZrO2) doped nancomposites having chitosan (CTS), organically modified montmorillonite (OMMT) and nano-hydroxyapatite (HAP). Formation of these nanocomposites was confirmed by various characterization techniques such as Fourier transform infrared spectroscopy and powder X-ray diffraction. Scanning electron microscopy images revealed uniform distribution of OMMT and nano-HAP-ZrO2 into CTS matrix. Powder XRD study and TEM study revealed that OMMT has partially exfoliated into the polymer matrix. Enhanced mechanical properties in comparison to the reported literature were obtained after the addition of ZrO2 nanoparticle into the nanocomposites. In rheological measurements, CMZH I-III exhibited greater storage modulus (G') than loss modulus (G″). TGA results showed that these nanocomposites are thermally more stable compare to pure CTS film. Strong antibacterial zone of inhibition and the lowest minimum inhibition concentration (MIC) value of these nanocomposites against bacterial strains proved that these materials have the ability to prevent bacterial infection in orthopedic implants. Compatibility of these nanocomposites with pH and blood of human body was established. It was observed from the swelling study that the swelling percentage was increased with decreasing the hydrophobic OMMT content. Human osteoblastic MG-63 cell proliferations were observed on the nanocomposites and cytocompatibility of these nanocomposites was also established. Moreover, addition of 5wt% OMMT and 5wt% nano-HAP-ZrO2 into 90wt% CTS matrix provides maximum tensile strength, storage modulus, aqueous swelling and cytocompatibility along with strong antibacterial effect, pH and erythrocyte compatibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chiral permselectivity in surface-modified nanoporous opal films.

PubMed

Cichelli, Julie; Zharov, Ilya

2006-06-28

Nanoporous 7 mum thin opal films comprising 35 layers of 200 nm diameter SiO2 spheres were assembled on Pt electrodes and modified with chiral selector moieties on the silica surface. Diffusion of chiral redox species through the opals was studied by cyclic voltammetry. The chiral opal films demonstrate high selectivity for transport of one enantiomer over the other. This chiral permselectivity is attributed to the surface-facilitated transport utilizing noncovalent interactions between the chiral permeant molecules and surface-bound chiral selectors.

Biomimetic modified clinical-grade POSS-PCU nanocomposite polymer for bypass graft applications: a preliminary assessment of endothelial cell adhesion and haemocompatibility.

PubMed

Solouk, Atefeh; Cousins, Brian G; Mirahmadi, Fereshteh; Mirzadeh, Hamid; Nadoushan, Mohammad Reza Jalali; Shokrgozar, Mohammad Ali; Seifalian, Alexander M

2015-01-01

To date, there are no small internal diameter (<5mm) vascular grafts that are FDA approved for clinical use due to high failure rates from thrombosis and unwanted cell proliferation. The ideal conditions to enhance bioengineered grafts would be the blood contacting lumen of the bypass graft fully covered by endothelial cells (ECs). As a strategy towards this aim, we hypothesized that by immobilising biomolecules on the surface of the polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane (POSS-PCU) nanocomposite polymers, which contain binding sites and ligands for cell surface receptors similar to extracellular matrix (ECM) will positively influence the attachment and proliferation of ECs. Since, the surface of POSS-PCU is inert and not directly suitable for immobilisation of biomolecules, plasma graft polymerisation is a suitable method to modify the surface properties ready for immobilisation and biofunctionalisation. POSS-PCU was activated by plasma treatment in air/O2 to from hydroperoxides (-OH, -OOH), and then carboxylated via plasma polymerisation of a 30% acrylic acid solution (Poly-AA) using a two-step plasma treatment (TSPT) process. Collagen type I, a major component of ECM, was covalently immobilised to mimic the ECM structures to ECs (5mg/ml) using a two-step chemical reaction using EDC chemistry. Successful immobilisation of poly-AA and collagen on to the nanocomposites was confirmed using Toluidine Blue staining and the Bradford assay. Un-treated POSS-PCU served as a simple control. The impact of collagen grafting on the physical, mechanical and biological properties of POSS-PCU was evaluated via contact angle (θ) measurements, scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical thermal analysis (DMTA), ECs adhesion and proliferation followed by platelet adhesion and haemolysis ratio (HR) tests. Poly-AA content on each of the plasma treated nanocomposite films increased on Low, Med and High samples due

Preparation of Modified Films with Protein from Grouper Fish

PubMed Central

Tecante, A.; Granados-Navarrete, S.; Martínez-García, C.

2016-01-01

A protein concentrate (PC) was obtained from Grouper fish skin and it was used to prepare films with different amounts of sorbitol and glycerol as plasticizers. The best performing films regarding resistance were then modified with various concentrations of CaCl2, CaSO4 (calcium salts), and glucono-δ-lactone (GDL) with the purpose of improving their mechanical and barrier properties. These films were characterized by determining their mechanical properties and permeability to water vapor and oxygen. Formulations with 5% (w/v) protein and 75% sorbitol and 4% (w/v) protein with a mixture of 15% glycerol and 15% sorbitol produced adequate films. Calcium salts and GDL increased the tensile fracture stress but reduced the fracture strain and decreased water vapor permeability compared with control films. The films prepared represent an attractive alternative for being used as food packaging materials. PMID:27597950

Dynamic piezoresistive response of hybrid nanocomposites

NASA Astrophysics Data System (ADS)

Gbaguidi, Audrey; Anees, Muhammad; Namilae, Sirish; Kim, Daewon

2017-04-01

Hybrid nanocomposites with carbon nanotubes and graphitic platelets as fillers are known to exhibit remarkable electrical and mechanical properties with many potential strain and damage sensing applications. In this work, we fabricate hybrid nanocomposites with carbon nanotube sheet and coarse graphite platelets as fillers with epoxy matrix. We then examine the electromechanical behavior of these nanocomposites under dynamic loading. The electrical resistivity responses of the nanocomposites are measured in frequency range of 1 Hz to 50 Hz with different levels of induced strains. Axial cycling loading is applied using a uniaxial electrodynamic shaker, and transverse loading is applied on end-clamped specimen using modified speakers. In addition, a dynamic mechanical analysis of nanocomposite specimen is performed to characterize the thermal and dynamic behavior of the nanocomposite. Our results indicate that these hybrid nanocomposites exhibit a distinct piezoresistive response under a wide range of dynamic loading conditions, which can be beneficial for potential sensing applications.

Enhanced energy density and thermostability in polyimide nanocomposites containing core-shell structured BaTiO3@SiO2 nanofibers

NASA Astrophysics Data System (ADS)

Wang, Junchuan; Long, Yunchen; Sun, Ying; Zhang, Xueqin; Yang, Hong; Lin, Baoping

2017-12-01

High energy density polymer nanocomposites with high-temperature resistance are quite desirable for film capacitors and many other power electronics. In this study, polyimide-based (PI) nanocomposite films containing the core-shell structured barium titanate@silicon dioxide (BT@SiO2) nanofibers have been successfully synthesized by the solution casting method. In the BT@SiO2/PI nanocomposite films, the dielectric permittivity as well as the breakdown strength increase significantly. The SiO2 shell layers with moderate dielectric permittivity could effectively mitigate the local field concentration induced by the large mismatch between the dielectric permittivity of BT and PI, which contributes to the enhancement of the breakdown strength of the PI nanocomposite films. As a result, the PI nanocomposite film filled with 3 vol% BT@SiO2 nanofibers exhibits a maximal energy density of 2.31 J cm-3 under the field of 346 kV/mm, which is 62% over the pristine PI (1.42 J cm-3 at 308 kV/mm) and about 200% greater than the best commercial polymer, i.e. biaxially oriented polypropylenes (BOPP) (≈1.2 J cm-3). The thermogravimetric analysis results indicate that the BT@SiO2/PI nanocomposite films have good thermal stability below 500 °C.

Nonenzymatic amperometric determination of glucose by CuO nanocubes-graphene nanocomposite modified electrode.

PubMed

Luo, Liqiang; Zhu, Limei; Wang, Zhenxin

2012-12-01

Here, we report a nonenzymatic amperometric glucose sensor based on copper oxide (CuO) nanocubes-graphene nanocomposite modified glassy carbon electrode (CuO-G-GCE). In this case, the graphene sheets were cast on the GCE directly. CuO nanocubes were obtained by oxidizing electrochemically deposited Cu on the graphene. The morphology of CuO-G nanocomposite was characterized by scanning electron microscopy. The CuO-G-GCE-based sensor exhibited excellent electrocatalytic activity and high stability for glucose oxidation. Under optimized conditions, the linearity between the current response and the glucose concentration was obtained in the range of 2μM to 4mM with a detection limit of 0.7μM (S/N=3), and a high sensitivity of 1360μAmM(-1)cm(-2). The proposed electrode showed a fast response time (less than 5s) and a good reproducibility. The as-made sensor was applied to determine the glucose levels in clinic human serum samples with satisfactory results. In addition, the effects of common interfering species, including ascorbic acid, uric acid, dopamine and other carbohydrates, on the amperometric response of the sensor were investigated and discussed in detail. Copyright © 2012 Elsevier B.V. All rights reserved.

Direct electrochemistry of hemoglobin on graphene and titanium dioxide nanorods composite modified electrode and its electrocatalysis.

PubMed

Sun, Wei; Guo, Yaqing; Ju, Xiaomei; Zhang, Yuanyuan; Wang, Xiuzhen; Sun, Zhenfan

2013-04-15

A biocompatible sensing platform based on graphene (GR) and titanium dioxide (TiO₂) nanorods for the immobilization of hemoglobin (Hb) was adopted in this paper. The GR-TiO₂-Hb composite-modified carbon ionic liquid electrode was constructed through a simple casting method with Nafion as the film forming material. UV-Vis and FT-IR spectra confirmed that Hb retained its native structure in the composite film. Direct electron transfer of Hb incorporated into the composite was realized with a pair of quasi-reversible redox waves appeared, indicating that the presence of GR-TiO₂ nanocomposite on the electrode surface could facilitate the electron transfer rate between the electroactive center of Hb and the substrate electrode. Hb modified electrode showed excellent electrocatalytic activity to the reduction of trichloroacetic acid in the concentration range from 0.6 to 21.0 mmol L⁻¹. These results indicated that GR-TiO₂ nanocomposite could be a friendly biocompatible interface for immobilizing biomolecules and keeping their native structure. The fabricated biosensor displayed the advantages such as high sensitivity, good reproducibility and long-term stability. Copyright © 2012 Elsevier B.V. All rights reserved.

Influence of gamma irradiation on structural, thermal and antibacterial properties of HPMC/ZnO nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, B. Lakshmeesha; Madhukumar, R.; Latha, S.

This work was carried out to evaluate the effect of gamma irradiation on the structural, thermal and antibacterial properties of HPMC/ZnO nanocomposite films exposed to Cobalt-60 (Average energy: 1.25 MeV). The X-ray diffraction study revealed that the crystallite size (L in Å) decreased as irradiation dose increased. The crystallinity (X{sub c}) of the nanocomposites initially increased and at higher doses it was decreased. The thermal stability of the nanocomposites increased up to 50 kGy and after that decreased as the irradiation dose increased. But, HPMC/ZnO nanocomposite films, showed a promising range of antimicrobial activity against tested micro-organisms making nanocomposites suitablemore » for food packing and other biomedical applications.« less

Highly sensitive and selective dopamine biosensor based on a phenylethynyl ferrocene/graphene nanocomposite modified electrode.

PubMed

Liu, Meiling; Wang, Linping; Deng, Jianhui; Chen, Qiong; Li, Yuzhen; Zhang, Youyu; Li, Haitao; Yao, Shouzhuo

2012-10-07

A new ferrocene derivative (1-[(4-amino) phenylethynyl]ferrocene, Fc-NH(2)) was synthesized for the first time. The ferrocene derivative molecule contained the phenylethynyl skeleton, ferrocene and amino groups with excellent electrochemical properties. The graphene/Fc-NH(2) nanocomposite was prepared by mixing graphene solution and Fc-NH(2) solution in one pot and the nanocomposite was utilized to construct a Nafion/graphene/Fc-NH(2) modified glassy carbon electrode (GCE). The ferrocene derivative immobilized on the graphene can enhance the charge-transport ability of the nanocomposite, stabilize the graphene and prevent the leakage of ferrocene. The detection signal of dopamine (DA) was significantly amplified on the Nafion/graphene/Fc-NH(2)/GCE. It was experimentally demonstrated that the signal enhancement results from the synergy amplification effect of graphene and the Fc-NH(2). The oxidation peak currents of DA were linearly related to the concentrations in the range of 5 × 10(-8) to 2 × 10(-4) M with the detection limit of 20 nM in the absence of uric acid (UA) and ascorbic acid (AA). In the presence of 10(-3) M AA and 10(-4) M UA, the linear response range was 1 × 10(-7) to 4 × 10(-4) M, and the detection limit was 50 nM at S/N = 3. Using the proposed Nafion/Fc-NH(2)/graphene/GCE, DA was successfully determined in real samples with the standard addition method.

Characterization of cobalt(II) chloride-modified condensation polyimide films

NASA Technical Reports Server (NTRS)

Rancourt, J. D.; Taylor, L. T.

1988-01-01

The effect of solvent extraction on the properties of cobalt(II) chloride-modified polyimide films was investigated. Solvent-cast films were prepared from solutions of cobalt chloride in poly(amide acid)/N,N-dimethylacetamide (DMAc) and were subsequently dried and cured in static air, forced air, or inert gas ovens with controlled humidity. The films were extracted by either of the three processes (1) soaking in a tray with distilled water at room temperature, (2) soxhlett extraction with distilled water, or (3) soxhell extraction with DMAc. Extraction with DMAc was found to remove both cobalt and chlorine from the films and to slightly increase bulk thermal stability and both surface resistivity and electrical resistivity.

Transparent cellulose/polyhedral oligomeric silsesquioxane nanocomposites with enhanced UV-shielding properties.

PubMed

Feng, Ye; Zhang, Jinming; He, Jiasong; Zhang, Jun

2016-08-20

The solubility of eight types of polyhedral oligomeric silsesquioxane (POSS) derivatives in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) and the dispersion of POSS in cellulose matrix were examined. Only a special POSS containing both aminophenyl and nitrophenyl groups (POSS-AN, NH2:NO2=2:6) was selected to prepare nanocomposites, because of its good solubility in AmimCl and high stability during the preparation process. POSS-AN nanoparticles were uniformly dispersed in a cellulose matrix with a size of 30-40nm, and so the resultant cellulose/POSS-AN nanocomposite films were transparent. The mechanical properties of the films achieved a maximum tensile strength of 190MPa after addition of 2wt% POSS-AN. Interestingly, all of the cellulose/POSS-AN films exhibited high UV-absorbing capability. For the 15wt% cellulose/POSS-AN film, the transmittance of UVA (315-400nm) and UVB (280-315nm) was only 9.1% and nearly 0, respectively. The UV aging and shielding experiments showed that the transparent cellulose/POSS-AN nanocomposite films possessed anti-UV aging and UV shielding properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optical, electrochemical and hydrophilic properties of Y2O3 doped TiO2 nanocomposite films.

PubMed

Zhang, Xiangchao; Yang, Huaming; Tang, Aidong

2008-12-25

The 5% Y2O3 doped TiO2 nanocomposite film (YTF) deposited on ITO glass substrate has been synthesized by the sol-gel dip-coating method. The as-synthesized samples were characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), voltage-current (V-I), electrochemical impedance spectroscopy (EIS) and ultraviolet-visible (UV-vis) analysis technologies. The crystalline structure, surface morphology and surface chemical composition of YTF sample have been primarily investigated. The results demonstrate that YTF is anatase crystalline phase with thickness of 480 nm and consists of spherical shape particles with a grain size of about 15.8 nm. The binding energy appears as a chemical shift, and relatively more Y and Ti species are present on the surface, indicating that active surfaces of the nanocomposite film have been enhanced with more oxygen vacancies Vö due to doping Y2O3 to TiO2. The absorption edge of YTF has a red shift, and the optical properties of YTF in visible light region have been obviously improved. The water contact angle is about 8 degrees after daylight lamp irradiation 60 min. An equivalent circuit model provided a reliable description for the electrochemical systems. Based on the Mott-Schottky equation, the donor concentration (ND) for YTF is 1.05 x 10(20) cm(-3), which enhances 1 order of magnitude than that for pure TiO2 film (TF), the flat-band potential (V(fb)) and the space charge layer (d(sc)) obviously decreased. With the incorporation of Y2O3 into TiO2, the optical, electrochemical and photoinduced hydrophilic properties of YTF in visible light region have obviously improved, indicating that YTF shows promising applications in solar energy conversion, self-cleaning and other potential fields.

Photonic structures based on hybrid nanocomposites

NASA Astrophysics Data System (ADS)

Husaini, Saima

In this thesis, photonic structures embedded with two types of nanomaterials, (i) quantum dots and (ii) metal nanoparticles are studied. Both of these exhibit optical and electronic properties different from their bulk counterpart due to their nanoscale physical structure. By integrating these nanomaterials into photonic structures, in which the electromagnetic field can be confined and controlled via modification of geometry and composition, we can enhance their linear and nonlinear optical properties to realize functional photonic structures. Before embedding quantum dots into photonic structures, we study the effect of various host matrices and fabrication techniques on the optical properties of the colloidal quantum dots. The two host matrices of interest are SU8 and PMMA. It is shown that the emission properties of the quantum dots are significantly altered in these host matrices (especially SU8) and this is attributed to a high rate of nonradiative quenching of the dots. Furthermore, the effects of fabrication techniques on the optical properties of quantum dots are also investigated. Finally a microdisk resonator embedded with quantum dots is fabricated using soft lithography and luminescence from the quantum dots in the disk is observed. We investigate the absorption and effective index properties of silver nanocomposite films. It is shown that by varying the fill factor of the metal nanoparticles and fabrication parameters such as heating time, we can manipulate the optical properties of the metal nanocomposite. Optimizing these parameters, a silver nanocomposite film with a 7% fill factor is prepared. A one-dimensional photonic crystal consisting of alternating layers of the silver nanocomposite and a polymer (Polymethyl methacrylate) is fabricated using spin coating and its linear and nonlinear optical properties are investigated. Using reflectivity measurements we demonstrate that the one-dimensional silver-nanocomposite-dielectric photonic crystal

Highly-efficient photocatalytic degradation of methylene blue by PoPD-modified TiO 2 nanocomposites due to photosensitization-synergetic effect of TiO2 with PoPD.

PubMed

Yang, Chuanxi; Dong, Wenping; Cui, Guanwei; Zhao, Yingqiang; Shi, Xifeng; Xia, Xinyuan; Tang, Bo; Wang, Weiliang

2017-06-21

Poly-o-phenylenediamine modified TiO 2 nanocomposites were successfully synthesized via an 'in situ' oxidative polymerization method. The modified nanocomposites were characterized by BET, XRD, TEM, FT-IR, TGA, XPS, EA and UV-Vis DRS. The photocatalytic degradation of methylene blue was chosen as a model reaction to evaluate the photocatalytic activities of TiO 2 and PoPD/TiO 2 . The results indicated that PoPD/TiO 2 nanocomposites exhibited good photocatalytic activity and stability. The photocatalytic activity of PoPD/TiO 2 increased as the initial pH increased because of electrostatic adsorption between the photocatalyst and MB as well as the generation of ·OH, whereas it exhibited an earlier increasing and later decreasing trend as the concentration of the photocatalyst increased owing to the absorption of visible light. The photocatalytic stability of the PoPD/TiO 2 nanocomposite was dependent on the stability of its structure. Based on radical trapping experiments and ESR measurements, the origin of oxidizing ability of PoPD/TiO 2 nanocomposites on photocatalytic degradation of MB was proposed, which taking into account of ·OH and ·O 2 - were the first and second important ROS, respectively. The possible photocatalytic mechanism and photocatalytic activity enhanced mechanism has been proposed, taking into account the photosensitization effect and synergetic effect of TiO 2 with PoPD.

Elastic Modulus and Thermal Conductivity of Thiolene/TiO2 Nanocomposites

PubMed Central

2017-01-01

Metal oxide based polymer nanocomposites find diverse applications as functional materials, and in particular thiol-ene/TiO2 nanocomposites are promising candidates for dental restorative materials. The important mechanical and thermal properties of the nanocomposites, however, are still not well understood. In this study, the elastic modulus and thermal conductivity of thiol-ene/TiO2 nanocomposite thin films with varying weight fractions of TiO2 nanoparticles are investigated by using Brillouin light scattering spectroscopy and 3ω measurements, respectively. As the TiO2 weight fraction increases from 0 to 90%, the effective elastic longitudinal modulus of the films increases from 6.2 to 37.5 GPa, and the effective thermal conductivity from 0.04 to 0.76 W/m K. The former increase could be attributed to the covalent cross-linking of the nanocomposite constituents. The latter one could be ascribed to the addition of high thermal conductivity TiO2 nanoparticles and the formation of possible conductive channels at high TiO2 weight fractions. The linear dependence of the thermal conductivity on the sound velocity, reported for amorphous polymers, is not observed in the present nanocomposite system. PMID:29755637

Carbon nanotube-polymer nanocomposite infrared sensor.

PubMed

Pradhan, Basudev; Setyowati, Kristina; Liu, Haiying; Waldeck, David H; Chen, Jian

2008-04-01

The infrared photoresponse in the electrical conductivity of single-walled carbon nanotubes (SWNTs) is dramatically enhanced by embedding SWNTs in an electrically and thermally insulating polymer matrix. The conductivity change in a 5 wt % SWNT-polycarbonate nanocomposite is significant (4.26%) and sharp upon infrared illumination in the air at room temperature. While the thermal effect predominates in the infrared photoresponse of a pure SWNT film, the photoeffect predominates in the infrared photoresponse of SWNT-polycarbonate nanocomposites.

Dielectric, ferroelectric, and thermodynamic properties of silicone oil modified PVDF films for energy storage application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Bingcheng; Wang, Xiaohui, E-mail: wxh@tsinghua.edu.cn, E-mail: llt-dms@mail.tsinghua.edu.cn; Li, Longtu, E-mail: wxh@tsinghua.edu.cn, E-mail: llt-dms@mail.tsinghua.edu.cn

Silicone oil modified poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) films were fabricated by the blending, casting, and hot-molding methods. The dielectric constant was increased for the 7.4 wt. % and 17.0 wt. % silicone oil modified P(VDF-HFP) films, while the dielectric loss for all blend films are decreased. D-E loops of 7.4 wt. % and 17.0 wt. % silicone oil modified P(VDF-HFP) films become slimmer than the pristine P(VDF-HFP) films. The maximum discharged energy density of 10.3 J/cm{sup 3} was obtained in 7.4 wt. % silicone oil modified P(VDF-HFP) films at the external electric field of 398 kV/mm. The Gibbs energy, miscibility, and phase behavior of binary mixture of P(VDF-HFP) silicone oil were investigated usingmore » molecular simulations and the extended Flory–Huggins model revealing favorable interactions and compatibility between P(VDF-HFP) and silicone oil.« less

Thermal stability increase in metallic nanoparticles-loaded cellulose nanocrystal nanocomposites.

PubMed

Goikuria, U; Larrañaga, A; Vilas, J L; Lizundia, E

2017-09-01

Due to the potential of CNC-based flexible materials for novel industrial applications, the aim of this work is to improve the thermal stability of cellulose nanocrystals (CNC) films through a straightforward and scalable method. Based of nanocomposite approach, five different metallic nanoparticles (ZnO, SiO 2 , TiO 2 , Al 2 O 3 and Fe 2 O 3 ) have been co-assembled in water with CNCs to obtain free-standing nanocomposite films. Thermogravimetric analysis (TGA) reveals an increased thermal stability upon nanoparticle. This increase in the thermal stability reaches a maximum of 75°C for the nanocomposites having 10wt% of Fe 2 O 3 and ZnO. The activation energies of thermodegradation process (E a ) determined according to Kissinger and Ozawa-Flynn-Wall methods further confirm the delayed degradation of CNC nanocomposites upon heating. Finally, the changes induced in the crystalline structure during thermodegradation were followed by wide angle X-ray diffraction (WAXD). It is also observed that thermal degradation proceeds at higher temperatures for nanocomposites having metallic nanoparticles. Overall, experimental findings here showed make nanocomposite approach a simple low-cost environmentally-friendly strategy to overcome the relatively poor thermal stability of CNCs when extracted via sulfuric acid assisted hydrolysis of cellulose. Copyright © 2017 Elsevier Ltd. All rights reserved.

Morphology and Admittance Spectroscopy of Cellulose Acetate/Graphene Quantum Dots Nanocomposites

NASA Astrophysics Data System (ADS)

Arthisree, D.; Joshi, Girish M.; Kumar, Annamalai Senthil

Graphene quantum dots (GQDs) are considered as fascinating materials feasible for biological, optoelectronic devices, energy and environmental applications. Casting nanocomposite films for technological application is a challenging research interest. Cellulose acetate (CA) is one of the most abundant, economic, environmental friendly and biodegradable biomaterials. It has been found that CA is a preferred composite matrix to prepare recasting films, due to its efficient antifouling feature. In the present investigation, we exhibited preparation of CA/GQD nanocomposite by solution blending as a function of GQD loading 0.1-0.5wt.%. Morphology and electrical properties were examined as a function of GQD loading. The nanocomposite was characterized by impedance spectroscopy, and the measured admittance (Y) was plotted against temperature across broadband frequency. The magnitude of Y exhibits direct relation under the varying temperature. The morphology of the nanocomposites was observed by atomic force microscope technique in contact mode. Collective observation from our results is that it can be revealed that CA/GQD nanocomposites are suitable for thermal sensing applications.

Graphene-conducting polymer nanocomposite as novel electrode for supercapacitors

NASA Astrophysics Data System (ADS)

Gómez, Humberto; Ram, Manoj K.; Alvi, Farah.; Villalba, P.; Stefanakos, Elias (Lee); Kumar, Ashok

A novel graphene-polyaniline nanocomposite material synthesized using chemical precipitation technique is reported as an electrode for supercapacitors. The graphene (G)-polyaniline (PANI) nanocomposite film was dissolved in N-Methyl-2-pyrrolidone (NMP) and characterized using Raman, FTIR, Scanning Electron Microscopy, Transmission Electron Microscopy, and cyclic voltammetry (CV) techniques. The interesting composite structure could be observed using different ratios of graphene and aniline monomer. The supercapacitor is fabricated using G-PANI in N-Methyl-2-pyrrolidone (NMP) and G-PANI-Nafion films on graphite electrodes. A specific capacitance of 300-500 F g -1 at a current density of 0.1 A g -1 is observed over graphene-PANI nanocomposite materials. The aim of this study is to tailor the properties of the capacitors through the optimization of their components, and packaging towards a qualification for portable systems applications. Based on experimental data shown in this work, conducting polymer nanocomposite capacitor technology could be viable, and could also surpass existing technologies when such a novel approach is used.

Synthesis and characterization of ZnO–CuO nanocomposites powder by modified perfume spray pyrolysis method and its antimicrobial investigation

NASA Astrophysics Data System (ADS)

Saravanakkumar, D.; Sivaranjani, S.; Kaviyarasu, K.; Ayeshamariam, A.; Ravikumar, B.; Pandiarajan, S.; Veeralakshmi, C.; Jayachandran, M.; Maaza, M.

2018-03-01

Pure ZnO, ZnO–CuO nanocomposites can be synthesized by using a modified perfume spray pyrolysis method (MSP). The crystallite size of the nanoparticles (NPs) has been observed by X-ray diffraction pattern and is nearly 36 nm. Morphological studies have been analyzed by using Field Emission Scanning Electron Microscopy (FESEM) and its elemental analysis was reported by Elemental X-ray Analysis (EDX); these studies confirmed that ZnO and CuO have hexagonal structure and monoclinic structure respectively. Fourier Transform Infrared (FTIR) spectra revealed that the presence of functional frequencies of ZnO and CuO were observed at 443 and 616 cm‑1. The average bandgap value at 3.25 eV using UV–vis spectra for the entitled composite has described a blue shift that has been observed here. The antibacterial study against both gram positive and negative bacteria has been studied by the disc diffusion method. To the best of our knowledge, it is the first report on ZnO–CuO nanocomposite synthesized by a modified perfume spray pyrolysis method.

Investigation of anticorrosion properties of nanocomposites of spray coated zinc oxide and titanium dioxide thin films on stainless steel (304L SS) in saline environment

NASA Astrophysics Data System (ADS)

P, Muhamed Shajudheen V.; S, Saravana Kumar; V, Senthil Kumar; Maheswari A, Uma; M, Sivakumar; Rani K, Anitha

2018-01-01

The present study reports the anticorrosive nature of nanocomposite thin films of zinc oxide and titanium dioxide on steel substrate (304L SS) using spray coating method. The morphology and chemical constituents of the nanocomposite thin film were characterized by field effect scanning electron microscopy and energy dispersive analysis of x-ray (EDAX) studies. From the EDAX studies, it was observed that nanocomposite coatings of desired stoichiometry can be synthesized using present coating technique. The cyclic voltametric techniques such as Tafel analysis and electrochemical impedance spectroscopy (EIS) analysis were conducted to study the anticorrosion properties of the coatings. The E corr values obtained from Tafel polarization curves of the sample coated with nanocomposites of ZnO and TiO2 in different ratios (5:1, 1:1 and 1:5) indicated that the corrosion resistance was improved compared to bare steel. The coating resistance values obtained from the Nyquist plot after fitting with equivalent circuit confirmed the improved anticorrosion performance of the coated samples. The sample coated with ZnO: TiO2 in the ratio 1:5 showed better corrosion resistance compared to other ratios. The Tafel and EIS studies were repeated after exposure to 5% NaCl for 390 h and the results indicated the anticorrosive nature of the coating in the aggressive environment. The root mean square deviation of surface roughness values calculated from the AFM images before and after salt spray indicated the stability of coating in the saline environment.

Effects of Plastizers on the Structure and Properties of Starch-Clay Nanocomposites

USDA-ARS?s Scientific Manuscript database

Biodegradable nanocomposites were successfully fabricated from corn starch and montmorillonite (MMT) nanoclays by melt extrusion processing. The structure and morphology of the nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and film propertie...

Flexible Electronic Substrate Film Fabricated Using Natural Clay and Wood Components with Cross-Linking Polymer.

PubMed

Takahashi, Kiyonori; Ishii, Ryo; Nakamura, Takashi; Suzuki, Asami; Ebina, Takeo; Yoshida, Manabu; Kubota, Munehiro; Nge, Thi Thi; Yamada, Tatsuhiko

2017-05-01

Requirements for flexible electronic substrate are successfully accomplished by green nanocomposite film fabricated with two natural components: glycol-modified biomass lignin and Li + montmorillonite clay. In addition to these major components, a cross-linking polymer between the lignin is incorporated into montmorillonite. Multilayer-assembled structure is formed due to stacking nature of high aspect montmorillonite, resulting in thermal durability up to 573 K, low thermal expansion, and oxygen barrier property below measurable limit. Preannealing for montmorillonite and the cross-linking formation enhance moisture barrier property superior to that of industrial engineering plastics, polyimide. As a result, the film has advantages for electronic film substrate. Furthermore, these properties can be achieved at the drying temperature up to 503 K, while the polyimide films are difficult to fabricate by this temperature. In order to examine its applicability for substrate film, flexible electrodes are finely printed on it and touch sensor device can be constructed with rigid elements on the electrode. In consequence, this nanocomposite film is expected to contribute to production of functional materials, progresses in expansion of biomass usage with low energy consumption, and construction of environmental friendly flexible electronic devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of Nanocomposite Modified Asphalt Mixtures Fatigue Life using Response Surface Methodology

NASA Astrophysics Data System (ADS)

Bala, N.; Napiah, M.; Kamaruddin, I.; Danlami, N.

2018-04-01

In this study, modelling and optimization of materials polyethylene, polypropylene and nanosilica for nanocomposite modified asphalt mixtures has been examined to obtain optimum quantities for higher fatique life. Response Surface Methodology (RSM) was applied for the optimization based on Box Behnken design (BBD). Interaction effects of independent variables polymers and nanosilica on fatique life were evaluated. The result indicates that the individual effects of polymers and nanosilica content are both important. However, the content of nanosilica used has more significant effect on fatique life resistance. Also, the mean error obtained from optimization results is less than 5% for all the responses, this indicates that predicted values are in agreement with experimental results. Furthermore, it was concluded that asphalt mixture design with high performance properties, optimization using RSM is a very effective approach.

Multifunctional PLA-PHB/cellulose nanocrystal films: processing, structural and thermal properties.

PubMed

Arrieta, M P; Fortunati, E; Dominici, F; Rayón, E; López, J; Kenny, J M

2014-07-17

Cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose by acid hydrolysis were added into poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends to improve the final properties of the multifunctional systems. CNC were also modified with a surfactant (CNCs) to increase the interfacial adhesion in the systems maintaining the thermal stability. Firstly, masterbatch pellets were obtained for each formulation to improve the dispersion of the cellulose structures in the PLA-PHB and then nanocomposite films were processed. The thermal stability as well as the morphological and structural properties of nanocomposites was investigated. While PHB increased the PLA crystallinity due to its nucleation effect, well dispersed CNC and CNCs not only increased the crystallinity but also improved the processability, the thermal stability and the interaction between both polymers especially in the case of the modified CNCs based PLA-PHB formulation. Likewise, CNCs were better dispersed in PLA-CNCs and PLA-PHB-CNCs, than CNC. Copyright © 2014 Elsevier Ltd. All rights reserved.

ESEM analysis of polymeric film in EVA-modified cement paste

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, D.A.; Monteiro, P.J.M.

2005-10-01

Portland cement pastes modified by 20% weight (polymer/cement ratio) of poly(ethylene-co-vinyl acetate) (EVA) were prepared, cured, and immersed in water for 11 days. The effects of water saturation and drying on the EVA polymeric film formed in cement pastes were observed using environmental scanning electron microscopy (ESEM). This technique allowed the imaging of the EVA film even in saturated samples. The decrease of the relative humidity inside the ESEM chamber did not cause any visual modification of the polymeric film during its drying.

Nanocomposites of polyimide and mixed oxide nanoparticles for high performance nanohybrid gate dielectrics in flexible thin film transistors

NASA Astrophysics Data System (ADS)

Kim, Ju Hyun; Hwang, Byeong-Ung; Kim, Do-Il; Kim, Jin Soo; Seol, Young Gug; Kim, Tae Woong; Lee, Nae-Eung

2017-05-01

Organic gate dielectrics in thin film transistors (TFTs) for flexible display have advantages of high flexibility yet have the disadvantage of low dielectric constant (low- k). To supplement low- k characteristics of organic gate dielectrics, an organic/inorganic nanocomposite insulator loaded with high- k inorganic oxide nanoparticles (NPs) has been investigated but high loading of high- k NPs in polymer matrix is essential. Herein, compositing of over-coated polyimide (PI) on self-assembled (SA) layer of mixed HfO2 and ZrO2 NPs as inorganic fillers was used to make dielectric constant higher and leakage characteristics lower. A flexible TFT with lower the threshold voltage and high current on/off ratio could be fabricated by using the hybrid gate dielectric structure of the nanocomposite with SA layer of mixed NPs on ultrathin atomic-layer deposited Al2O3. [Figure not available: see fulltext.

Preparation, characterization and antimicrobial efficiency of Ag/PDDA-diatomite nanocomposite.

PubMed

Panáček, Aleš; Balzerová, Anna; Prucek, Robert; Ranc, Václav; Večeřová, Renata; Husičková, Vendula; Pechoušek, Jiří; Filip, Jan; Zbořil, Radek; Kvítek, Libor

2013-10-01

Nanocomposites consisting of diatomaceous earth particles and silver nanoparticles (silver NPs) with high antimicrobial activity were prepared and characterized. For the purpose of nanocomposite preparation, silver NPs with an average size of 28nm prepared by modified Tollens process were used. Nanocomposites were prepared using poly(diallyldimethylammonium) chloride (PDDA) as an interlayer substance between diatomite and silver NPs which enables to change diatomite original negative surface charge to positive one. Due to strong electrostatic interactions between negatively charged silver NPs and positively charged PDDA-modified diatomite, Ag/PDDA-diatomite nanocomposites with a high content of silver (as high as 46.6mgAg/1g of diatomite) were prepared. Because of minimal release of silver NPs from prepared nanocomposites to aqueous media (<0.3mg Ag/1g of nanocomposite), the developed nanocomposites are regarded as a potential useful antimicrobial material with a long-term efficiency showing no risk to human health or environment. All the prepared nanocomposites exhibit a high bactericidal activity against Gram-negative and Gram-positive bacteria and fungicidal activity against yeasts at very low concentrations as low as 0.11g/L, corresponding to silver concentration of 5mg/L. Hence, the prepared nanocomposites constitute a promising candidate suitable for the microbial water treatment in environmental applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Preparation, characterization and properties of polymer-layered silicate nanocomposites

NASA Astrophysics Data System (ADS)

Fonseca, Claudia Alencar

Nanocomposites are a relatively new class of composites, that in the polymer area typically consist of particle-filled polymers where at least one dimension of the dispersed particles is in the nanometer range. Amongst all potential nanocomposite precursors, those based on clay and layered silicates have been more widely investigated. These nanocomposites exhibit markedly improved mechanical, thermal, optical and physico-chemical properties when compared to conventional (microscale) composites. In the present work, properties of nanocomposites of Ethylene Methacrylic Acid copolymers and organically modified Montmorillonite formed from the melt was investigated. Nanocomposites of Poly(vinyl alcohol) and Montmorillonite formed from solution was also studied.

Performance properties, lactic acid specific migration and swelling by simulant of biodegradable poly(lactic acid)/nanoclay multilayer films for food packaging.

PubMed

Scarfato, Paola; Di Maio, Luciano; Milana, Maria Rosaria; Giamberardini, Silvia; Denaro, Massimo; Incarnato, Loredana

2017-10-01

The aim of the study was the development of a multifunctional, high-performance, fully biodegradable multilayer polylactic acid (PLA) film for food packaging applications. In particular, sealable multilayer PLA-clay nanocomposite systems with different layouts in terms of composition and relative thickness of the layers, all consisting of a PLA-clay nanocomposite layer between two pure PLA layers for direct food contact, were designed and produced by blown film co-extrusion. The films obtained were analysed for their morphology, functional properties and lactic acid (LA)-specific migration in 50% ethanol. The results showed that, with respect to the unfilled multilayer system, taken as a reference, the nanocomposite films had significant improvements, up to about 40%, in their barriers to oxygen and tensile strengths, and resulted in being more easily sealable over a wide heat-sealing temperature range (80-100°C) with higher seal strength. Moreover, all films had LA migrations always well below the former generic overall migration limit of 60 mg kg -1 food (10 mg dm - 2 ) of European Union Regulation No. 10/2011 (deleted by the amending Regulation No. 2016/1416), even if their morphology was strongly modified during the migration tests due to the strong swelling action of the used simulant (simulant D1 = 50% ethanol (aq.) (v/v)) towards PLA.

Synthesis of Transparent Aqueous ZrO2 Nanodispersion with a Controllable Crystalline Phase without Modification for a High-Refractive-Index Nanocomposite Film.

PubMed

Xia, Yi; Zhang, Cong; Wang, Jie-Xin; Wang, Dan; Zeng, Xiao-Fei; Chen, Jian-Feng

2018-05-30

The controllable synthesis of metal oxide nanoparticles is of fundamental and technological interest. In this article, highly transparent aqueous nanodispersion of ZrO 2 with controllable crystalline phase, high concentration, and long-term stability was facilely prepared without any modification via the reaction of inexpensive inorganic zirconium salt and sodium hydroxide in water under an acid surrounding, combined with hydrothermal treatment. The as-prepared transparent nanodispersion had an average particle size of 7 nm, a high stability of 18 months, and a high solid content of 35 wt %. ZrO 2 nanocrystals could be readily dispersed in many solvents with high polarity including ethanol, dimethyl sulfoxide, acetic acid, ethylene glycol, and N, N-dimethylformamide, forming stable transparent nanodispersions. Furthermore, highly transparent polyvinyl alcohol/ZrO 2 nanocomposite films with high refractive index were successfully prepared with a simple solution mixing route. The refractive index could be tuned from 1.528 to 1.754 (@ 589 nm) by changing the mass fraction (0-80 wt %) of ZrO 2 in transparent nanocomposite films.

Development of a flexible nanocomposite TiO2 film as a protective coating for bioapplications of superelastic NiTi alloys

NASA Astrophysics Data System (ADS)

Aun, Diego Pinheiro; Houmard, Manuel; Mermoux, Michel; Latu-Romain, Laurence; Joud, Jean-Charles; Berthomé, Gregory; Buono, Vicente Tadeu Lopes

2016-07-01

An experimental procedure to coat superelastic NiTi alloys with flexible TiO2 protective nanocomposite films using sol-gel technology was developed in this work to improve the metal biocompatibility without deteriorating its superelastic mechanical properties. The coatings were characterized by scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and glazing incidence X-ray diffraction. The elasticity of the film was tested in coated specimens submitted to three-point bending tests. A short densification by thermal treatment at 500 °C for 10 min yielded a bilayer film consisting of a 50 nm-thick crystallized TiO2 at the inner interface with another 50-nm-thick amorphous oxide film at the outer interface. This bilayer could sustain over 6.4% strain without cracking and could thus be used to coat biomedical instruments as well as other devices made with superelastic NiTi alloys.

Vortex pinning landscape in MOD-TFA YBCO nanostroctured films

NASA Astrophysics Data System (ADS)

Gutierrez, J.; Puig, T.; Pomar, A.; Obradors, X.

2008-03-01

A methodology of general validity to study vortex pinning in YBCO based on Jc transport measurements is described. It permits to identify, separate and quantify three basic vortex pinning contributions associated to anisotropic-strong, isotropic-strong and isotropic-weak pinning centers. Thereof, the corresponding vortex pinning phase diagrams are built up. This methodology is applied to the new solution-derived YBCO nanostructured films, including controlled interfacial pinning by the growth of nanostructured templates by means of self-assembled processes [1] and YBCO-BaZrO3 nanocomposites prepared by modified solution precursors. The application of the methodology and comparison with a standard solution-derived YBCO film [2], enables us to identify the nature and the effect of the additional pinning centers induced. The nanostructured templates films show c-axis pinning strongly increased, controlling most of the pinning phase diagram. On the other hand, the nanocomposites have achieved so far, the highest pinning properties in HTc-superconductors [3], being the isotropic-strong defects contribution the origin of their unique properties. [1] M. Gibert et al, Adv. Mat. vol 19, p. 3937 (2007) [2] Puig.T et al, SuST EUCAS 2007 (to be published) [3] J. Gutierrez et al, Nat. Mat. vol. 6, p. 367 (2007) * Work supported by HIPERCHEM, NANOARTIS and MAT2005-02047

Carbon nanotube epoxy nanocomposites: the effects of interfacial modifications on the dynamic mechanical properties of the nanocomposites.

PubMed

Yoonessi, Mitra; Lebrón-Colón, Marisabel; Scheiman, Daniel; Meador, Michael A

2014-10-08

Surface functionalization of pretreated carbon nanotubes (CNT) using aromatic, aliphatic, and aliphatic ether diamines was performed. The pretreatment of the CNT consisted of either acid- or photo-oxidation. The acid treated CNT had a higher initial oxygen content compared to the photo-oxidized CNT and this resulted in a higher density of functionalization. X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) were used to verify the presence of the oxygenated and amine moieties on the CNT surfaces. Epoxy/0.1 wt % CNT nanocomposites were prepared using the functionalized CNT and the bulk properties of the nanocomposites were examined. Macroscale correlations between the interfacial modification and bulk dynamic mechanical and thermal properties were observed. The amine modified epoxy/CNT nanocomposites exhibited up to a 1.9-fold improvement in storage modulus (G') below the glass transition (Tg) and up to an almost 4-fold increase above the Tg. They also exhibited a 3-10 °C increase in the glass transition temperature. The aromatic diamine surface modified epoxy/CNT nanocomposites resulted in the largest increase in shear moduli below and above the Tg and the largest increase in the Tg. Surface examination of the nanocomposites with scanning electron microscopy (SEM) revealed indications of a greater adhesion of the epoxy resin matrix to the CNT, most likely due to the covalent bonding.

Incorporation of layered double nanomaterials in thin film nanocomposite nanofiltration membrane for magnesium sulphate removal

NASA Astrophysics Data System (ADS)

Hanis Tajuddin, Muhammad; Yusof, Norhaniza; Salleh, Wan Norharyati Wan; Fauzi Ismail, Ahmad; Hanis Hayati Hairom, Nur; Misdan, Nurasyikin

2018-03-01

Thin film nanocomposite (TFN) membrane with copper-aluminium layered double hydroxides (LDH) incorporated into polyamide (PA) selective layer has been prepared for magnesium sulphate salt removal. 0, 0.05, 0.1, 0.15, 0.2 wt% of LDH were dispersed in the trimesoyl chloride (TMC) in n-hexane as organic solution and embedded into PA layer during interfacial polymerization with piperazine. The fabricated membranes were further characterized to evaluate its morphological structure and membrane surface hydrophilicity. The TFN membranes performance were evaluated with divalent salt magnesium sulphate (MgSO4) removal and compared with thin film composite (TFC). The morphological structures of TFN membranes were altered and the surface hydrophilicity were enhanced with addition of LDH. Incorporation of LDH has improved the permeate water flux by 82.5% compared to that of TFC membrane with satisfactory rejection of MgSO4. This study has experimentally validated the potential of LDH to improve the divalent salt separation performance for TFN membranes.

Polyaniline-Modified Oriented Graphene Hydrogel Film as the Free-Standing Electrode for Flexible Solid-State Supercapacitors.

PubMed

Du, Pengcheng; Liu, Huckleberry C; Yi, Chao; Wang, Kai; Gong, Xiong

2015-11-04

In this study, we report polyaniline (PANI)-modified oriented graphene hydrogel (OGH) films as the free-standing electrode for flexible solid-state supercapacitors (SCs). The OGH films are prepared by a facile filtration method using chemically converted graphene sheets and then introduced to PANI on the surface of OGH films by in situ chemical polymerization. The PANI-modified OGH films possess high flexibility, high electrical conductivity, and mechanical robustness. The flexible solid-state SCs based on the PANI-modified OGH films exhibit a specific capacitance of 530 F/g, keeping 80% of its original value up to 10 000 charge-discharge cycles at the current density of 10 A/g. Remarkably, the flexible solid-state SCs maintain ∼100% capacitance retention bent at 180° for 250 cycles. Moreover, the flexible solid-state SCs are further demonstrated to be able to light up a red-light-emitting diode. These results indicate that the flexible solid-state SCs based on PANI-modified OGH films as the free-standing electrode have potential applications as energy-storage devices.

Glucose Biosensor Based on Immobilization of Glucose Oxidase in Platinum Nanoparticles/Graphene/Chitosan Nanocomposite Film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Hong; Wang, Jun; Kang, Xinhuang

2009-09-01

The bionanocomposite film consisting of glucose oxidase/Pt/functional graphene sheets/chitosan (GOD/Pt/FGS/chitosan) for glucose sensing was described. With the electrocatalytic synergy of FGS and Pt nanoparticles to hydrogen peroxide, a sensitive biosensor with detection limit of 0.6 µM glucose was achieved. The biosensor also had good reproducibility, long term stability and negligible interfering signals from ascorbic acid and uric acid comparing to the response to glucose. The large surface area and good conductivity of graphene suggests that graphene is a potential candidate for sensor material. The hybrid nanocomposite glucose sensor provides new opportunity for clinical diagnosis and point-of-care applications.

Anisotropic silver nanoparticles as filler for the formation of hybrid nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vodnik, Vesna V., E-mail: vodves@vinca.rs; Šaponjić, Zoran, E-mail: saponjic@vinca.rs; Džunuzović, Jasna V., E-mail: jasnav2002@googlemail.com

2013-01-15

Graphical abstract: Display Omitted Highlights: ► Prismatic and plate-like Ag nanoparticles were used as a precursors for preparation Ag/poly(vinyl alcohol) nanocomposite films. ► Results showed that the degree of crystallinity of the polymer decreases with Ag nanoparticles content. ► The presence of Ag nanoparticles in PVA induces higher thermo-oxidative stability with respect to PVA. -- Abstract: Prismatic and plate-like silver nanoparticles (Ag NPs) were synthesized according to the seed-mediated method. These particles were used as precursors for preparation of homogenous, transparent and colored Ag/poly(vinyl alcohol) (PVA) nanocomposite films with different concentrations of Ag by solution-casting technique. Optical and structural characterizationmore » of these nanocomposites includes UV–visible spectroscopy, X-ray diffraction (XRD), FTIR spectroscopy and SEM measurements. Further, the effect of embedded nanoparticles on the thermal properties of the PVA matrix was studied. The value of the glass transition temperature of polymer is found to increase after embedding Ag NPs. Comparison of thermal properties of pure PVA and nanocomposite films showed that the thermo-oxidative stability of polymer slightly increased in the presence of Ag NPs. Furthermore, the effect of the Ag NPs on the crystallinity of polymer was also observed.« less