Considerations of the Effects of Naphthalene Moieties on the Design of Proton-Conductive Poly(arylene ether ketone) Membranes for Direct Methanol Fuel Cells.

PubMed

Wang, Baolong; Hong, Lihua; Li, Yunfeng; Zhao, Liang; Wei, Yuxue; Zhao, Chengji; Na, Hui

2016-09-14

Novel sulfonated poly(arylene ether ketones) (SDN-PAEK-x), consisting of dual naphthalene and flexible sulfoalkyl groups, were prepared via polycondensation, demethylation, and sulfobutylation grafting reaction. Among them, SDN-PAEK-1.94 membrane with the highest ion exchange capacity (IEC = 2.46 mequiv·g(-1)) exhibited the highest proton conductivity, which was 0.147 S· cm(-1) at 25 °C and 0.271 S·cm(-1) at 80 °C, respectively. The introduction of dual naphthalene moieties is expected to achieve much enhanced properties compared to those of sulfonated poly(arylene ether ketones) (SNPAEK-x), consisting of single naphthalene and flexible sulfoalkyl groups. Compared with SNPAEK-1.60 with a similar IEC, SDN-PAEK-1.74 membrane showed higher proton conductivity, higher IEC normalized conductivity, and higher effective proton mobility, although it had lower analytical acid concentration. The SDN-PAEK-x membranes with IECs higher than 1.96 mequiv·g(-1) also exhibited higher proton conductivity than that of recast Nafion membrane. Furthermore, SDN-PAEK-1.94 displayed a better single cell performance with a maximum power density of 60 mW·cm(-2) at 80 °C. Considering its high proton conductivity, excellent single cell performance, good mechanical stabilities, low membrane swelling, and methanol permeability, SDN-PAEK-x membranes are promising candidates as alternative polymer electrolyte membranes to Nafion for direct methanol fuel cell applications.

Preparation and characterization of novel zwitterionic poly(arylene ether sulfone) ultrafiltration membrane with good thermostability and excellent antifouling properties

NASA Astrophysics Data System (ADS)

Rong, Guolong; Zhou, Di; Han, Xiaocui; Pang, Jinhui

2018-01-01

Zwitterionic poly(arylene ether sulfone) (PAES-NS) was synthesized via copolymerization by using a bisphenol monomer with a pyridine group. The chemical structures of the copolymers were confirmed by using Fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (NMR) spectroscopy; the copolymers showed good thermal stability. A series of polyphenysulfone (PPSU)/PAES-NS blend ultrafiltration (UF) membranes was prepared via conventional immersion precipitation phase inversion methods The morphologies of the modified membranes were investigated by scanning electron microscopy (SEM). The surface hydrophilicity of the UF membranes was studied by water contact angle measurement, indicating that the zwitterionic group increased the membrane hydrophilicity. UF of solvated model pollutants using the membranes showed a significant reduction of the irreversible adsorption of the foulants, illustrating the excellent anti-fouling properties of the membrane. The water flux of the PAES-NS membrane was significantly enhanced, being almost three times higher than that of the pristine PPSU membrane, with retention of a high rejection level. After three UF cycles, the water flux recovery of the PAES-NS membrane was as high as 96%.

Pendant dual sulfonated poly(arylene ether ketone) proton exchange membranes for fuel cell application

NASA Astrophysics Data System (ADS)

Nguyen, Minh Dat Thinh; Yang, Sungwoo; Kim, Dukjoon

2016-10-01

Poly(arylene ether ketone) (PAEK) possessing carboxylic groups at the pendant position is synthesized, and the substitution degree of pendant carboxylic groups is controlled by adjusting the ratio of 4,4-bis(4-hydroxyphenyl)valeric acid and 2,2-bis(4-hydroxyphenyl)propane. Dual sulfonated 3,3-diphenylpropylamine (SDPA) is grafted onto PAEK as a proton-conducting moiety via the amidation reaction with carboxylic groups. The transparent and flexible membranes with different degrees of sulfonation are fabricated so that we can test and compare their structure and properties with a commercial Nafion® 115 membrane for PEMFC applications. All prepared PAEK-SDPA membranes exhibit good oxidative and hydrolytic stability from Fenton's and high temperature water immersion test. SAXS analysis illustrates an excellent phase separation between the hydrophobic backbone and hydrophilic pendant groups, resulting in big ionic clusters. The proton conductivity was measured at different relative humidity, and its behavior was analyzed by hydration number of the membrane. Among a series of membranes, some samples (including B20V80-SDPA) show not only higher proton conductivity, but also higher integrated cell performance than those of Nafion® 115 at 100% relative humidity, and thus we expect these to be good candidate membranes for proton exchange membrane fuel cells (PEMFCs).

Durability and degradation analysis of hydrocarbon ionomer membranes in polymer electrolyte fuel cells accelerated stress evaluation

NASA Astrophysics Data System (ADS)

Shimizu, Ryo; Tsuji, Junichi; Sato, Nobuyuki; Takano, Jun; Itami, Shunsuke; Kusakabe, Masato; Miyatake, Kenji; Iiyama, Akihiro; Uchida, Makoto

2017-11-01

The chemical durabilities of two proton-conducting hydrocarbon polymer electrolyte membranes, sulfonated benzophenone poly(arylene ether ketone) (SPK) semiblock copolymer and sulfonated phenylene poly(arylene ether ketone) (SPP) semiblock copolymer are evaluated under accelerated open circuit voltage (OCV) conditions in a polymer electrolyte fuel cell (PEFC). Post-test characterization of the membrane electrodes assemblies (MEAs) is carried out via gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy. These results are compared with those of the initial MEAs. The SPP cell shows the highest OCV at 1000 h, and, in the post-test analysis, the SPP membrane retains up to 80% of the original molecular weight, based on the GPC results, and 90% of the hydrophilic structure, based on the NMR results. The hydrophilic structure of the SPP membrane is more stable after the durability evaluation than that of the SPK. From these results, the SPP membrane, with its simple hydrophilic structure, which does not include ketone groups, is seen to be significantly more resistant to radical attack. This structure leads to high chemical durability and thus impedes the chemical decomposition of the membrane.

Poly(arylene ether)s containing pendent ethynyl groups

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M. (Inventor); Jensen, Brian J. (Inventor)

1996-01-01

Poly(arylene ether)s containing pendent ethynyl and substituted ethynyl groups and poly(arylene ether) copolymers containing pendent ethynyl and substituted ethynyl groups are readily prepared from bisphenols containing ethynyl and substituted ethynyl groups. The resulting polymers are cured up to 350.degree. C. to provide crosslinked poly(arylene ether)s with good solvent resistance, high strength and modulus.

Poly(arylene ether)s containing pendent ethynyl groups

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M. (Inventor); Jensen, Brian J. (Inventor)

1994-01-01

Poly(arylene ether)s containing pendent ethynyl and substituted ethynyl groups and poly(arylene ether) copolymers containing pendent ethynyl and substituted ethynyl groups are readily prepared from bisphenols containing ethynyl and substituted ethynyl groups. The resulting polymers are cured up to 350 C to provide crosslinked poly(arylene ether)s with good solvent resistance, high strength and modulus.

Effects of Block Length and Membrane Processing Conditions on the Morphology and Properties of Perfluorosulfonated Poly(arylene ether sulfone) Multiblock Copolymer Membranes for PEMFC.

PubMed

Assumma, Luca; Nguyen, Huu-Dat; Iojoiu, Cristina; Lyonnard, Sandrine; Mercier, Régis; Espuche, Eliane

2015-07-01

Perfluorosulfonated poly(arylene ether sulfone) multiblock copolymers have been shown to be promising as proton exchange membranes. The commonly used approach for preparation of the membrane is solvent casting; the properties of the resulting membranes are very dependent on the membrane processing conditions. In this paper, we study the effects of block length, selectivity of the solvent, and thermal treatment on the membrane properties such as morphology, water uptake, and ionic conductivity. DiMethylSulfOxide (DMSO), and DiMethylAcetamide (DMAc) were selected as casting solvents based on the Flory-Huggins parameter calculated by inversion gas chromatography (IGC). It was found that the solvent selectivity has a mild impact on the mean size of the ionic domains and the expansion upon swelling, while it dramatically affects the supramolecular ordering of the blocks. The membranes cast from DMSO exhibit more interconnected ionic clusters yielding higher conductivities and water uptake as compared to membranes cast from DMAc. A 10-fold increase in proton conductivity was achieved after thermal annealing of membranes at 150 °C, and the ionomers with longer block lengths show conductivities similar to Nafion at 80 °C and low relative humidity (30%).

Sulfonated Copper Phthalocyanine/Sulfonated Polysulfone Composite Membrane for Ionic Polymer Actuators with High Power Density and Fast Response Time.

PubMed

Kwon, Taehoon; Cho, Hyeongrae; Lee, Jang-Woo; Henkensmeier, Dirk; Kang, Youngjong; Koo, Chong Min

2017-08-30

Ionic polymer composite membranes based on sulfonated poly(arylene ether sulfone) (SPAES) and copper(II) phthalocyanine tetrasulfonic acid (CuPCSA) are assembled into bending ionic polymer actuators. CuPCSA is an organic filler with very high sulfonation degree (IEC = 4.5 mmol H + /g) that can be homogeneously dispersed on the molecular scale into the SPAES membrane, probably due to its good dispersibility in SPAES-containing solutions. SPAES/CuPCSA actuators exhibit larger ion conductivity (102 mS cm -1 ), tensile modulus (208 MPa), strength (101 MPa), and strain (1.21%), exceptionally faster response to electrical stimuli, and larger mechanical power density (3028 W m -3 ) than ever reported for ion-conducting polymer actuators. This outstanding actuation performance of SPAES/CuPCSA composite membrane actuators makes them attractive for next-generation transducers with high power density, which are currently developed, e.g., for underwater propulsion and endoscopic surgery.

Tough poly(arylene ether) thermoplastics as modifiers for bismaleimides

NASA Technical Reports Server (NTRS)

Stenzenberger, H. D.; Roemer, W.; Hergenrother, P. M.; Jensen, B. J.

1989-01-01

Several aspects of research on thermoplastics as toughness modifiers are discussed, including the contribution of the backbone chemistry and the concentration of the poly(arylene ether) thermoplastic to fracture toughness, influence of the molecular weight of the poly(arylene ether) thermoplastic on neat resin fracture toughness, and the morphology of the thermoplastic modified networks. The results show that fracture toughness of brittle bismaleimide resins can be improved significantly with poly(arylene ether) thermoplastic levels of 20 percent by weight, and that high molecular weight poly(arylene ether) based on bisphenol A provides the highest degree of toughening. Preliminary composite evaluation shows that improvements in neat resin toughness translate into carbon fabric composite.

New aromatic activated dihalides and bisphenol monomers for the preparation of novel poly(arylene ethers)

NASA Technical Reports Server (NTRS)

Wolfe, James F.

1993-01-01

The goal of this research program was to synthesize a series of unique monomers of type I to be utilized at NASA-Langley in the preparation of new poly(arylene ether ketones), poly(arylene ether ketosulfones), and poly(arylene ether ketophosphine oxides). These A-A and A-B monomer systems, which possess activated aryl halide and/or phenolic end groups, are accessible via condensation reactions of appropriately substituted aryl acetonitrile carbanions with activated aryl dihalides followed by oxidative decyanation.

Functionalized poly(arylene ethers) as toughness modifiers for bismaleimides

NASA Technical Reports Server (NTRS)

Stenzenberger, H. D.; Roemer, W.; Hergenrother, P. M.; Jensen, B.; Breitigam, W.

1990-01-01

A family of novel, low molecular weight functionalized poly(arylene ether) resins has been investigated to ascertain its members' toughness-imparting contribution to neat bismaleimide (BMI) resin and BMI-matrix laminate composite properties. Attention is given to the contribution of the reactive poly(arylene ether)'s backbone chemistry to fracture toughness, as well as to the comparative influence of high and low molecular weight reactive poly(arylene ether) types on the modified BMI resin systems. The modified BMIs possess a polyphase morphology, with good adhesion between the thermoplastic nodules and the host thermoset systems.

Polyaryl ethers and related polysiloxane copolymer molecular coatings preparation and radiation degrdation

NASA Technical Reports Server (NTRS)

Mcgrath, J. E.; Hedrick, J. L.; Webster, D. C.; Johnson, B. C.; Mohanty, D. K.; Yilgor, I.

1983-01-01

Poly(arylene ether sulfones) comprise a class of materials known as engineering thermoplastics which have a variety of important applications. These polymers are tough, rigid materials with good mechanical properties over a wide temperature range, and they are processed by conventional methods into products typically having excellent hydrolytic, thermal, oxidative and dimensional stability. Wholly aromatic random copolymers of hydroquinone and biphenol with 4.4 prime dichlorodiphenyl sulfone were synthesized via mechanical nucleophilic displacement. Their structures were characterized and mechanical behavior studied. These tough, ductile copolymers show excellent radiation resistance to electron beam treatment and retain much of the mechanical properties up to at least 700 Mrads under argon.

Poly(aryl ethers) and related polysiloxane copolymer molecular coatings: Preparation and radiation degradation

NASA Technical Reports Server (NTRS)

Mcgrath, J. E.

1982-01-01

The radiation degradation of poly(arylene ether sulfones) and related materials is studied. These basic studies are important both as a means to developing stronger, more stable matrix resins for composite materials, as well as to improve the data base in regard to chemical structure-physical property relationships. Thirty homo and copolymers were synthesized, at least partially characterized and, in several cases suitable film casting techniques were developed. Four samples were chosen for initial radiation degradation. Poly(dimethyl siloxane) soft bocks/segments can preferentially migrate to the surface of copolymer films. Since siloxanes are utilized as thermal control coatings, this form of 'molecular' coating is of interest. The chemistry for preparing such copolymers with any of the polymers described was demonstrated.

Ketimine modifications as a route to novel amorphous and derived semicrystalline poly(arylene ether ketone) homo- and copolymers

NASA Technical Reports Server (NTRS)

Mohanty, D. K.; Lowery, R. C.; Lyle, G. D.; Mcgrath, J. E.

1987-01-01

A series of amine terminal amorphous poly(arylene ether ketone) oligomers of controlled molecular weights (2-15 K) were synthesized. These oligomers have been found to undergo 'self-crosslinking' reactions upon heating above 220 C, via the reaction of the terminal amine groups with the in-chain keto carbonyl functionalities. The resulting networks are ductile, chemically resistant, and nonporous. The networks obtained via generated ketimine functionality were characterized by solid state NMR. They have also been found to be remarkably stable toward hydrolysis. Ketimine functional bishalide monomers have also been synthesized. Such monomers have been utilized to synthesize a wide variety of amorphous poly(arylene ether) ketimine polymers. A high molecular weight hydroquinone functional poly(arylene ether) ketimine has been acid treated to regenerate a poly(arylene ether ketone) backbone in solution. This novel procedure thus allows for the synthesis of important matrix resins under relatively mild conditions.

Phenylethynl-terminated poly(arylene ethers)

NASA Technical Reports Server (NTRS)

Jensen, Brian J. (Inventor); Bryant, Robert G. (Inventor); Hergenrother, Paul M. (Inventor)

1993-01-01

Phenylethynyl-terminated poly(arylene ethers) are prepared in a wide range of molecular weights by adjusting monomer ratio and adding an appropriate amount of 4-fluoro- 4'-phenylethynyl benzophenone during polymer synthesis. The resulting phenylethynyl-terminated poly(arylene ethers) react and crosslink upon curing for one hour at 350 C to provide materials with improved solvent resistance, higher modulus, and better high temperature properties than the linear, uncrosslinked polymers.

Imide/arylene ether copolymers

NASA Technical Reports Server (NTRS)

Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor); Bass, Robert G. (Inventor)

1992-01-01

Imide/arylene ether block copolymers are prepared by reacting anhydride terminated poly(amic acids) with amine terminated poly(arylene ethers) in polar aprotic solvents and by chemically or thermally cyclodehydrating the resulting intermediate poly(amic acids). The resulting block copolymers have one glass transition temperature or two, depending upon the particular structure and/or the compatibility of the block units. Most of these block copolymers form tough, solvent resistant films with high tensile properties.

Property Enhancement Effects of Side-Chain-Type Naphthalene-Based Sulfonated Poly(arylene ether ketone) on Nafion Composite Membranes for Direct Methanol Fuel Cells.

PubMed

Wang, Baolong; Hong, Lihua; Li, Yunfeng; Zhao, Liang; Zhao, Chengji; Na, Hui

2017-09-20

Nafion/SNPAEK-x composite membranes were prepared by blending raw Nafion and synthesized side-chain-type naphthalene-based sulfonated poly(arylene ether ketone) with a sulfonation degree of 1.35 (SNPAEK-1.35). The incorporation of SNPAEK-1.35 polymer with ion exchange capacity (IEC) of 2.01 mequiv·g -1 into a Nafion matrix has the property enhancement effects, such as increasing IECs, improving proton conductivity, enhancing mechanical properties, reducing methanol crossover, and improving single cell performance of Nafion. Morphology studies show that Nafion/SNPAEK-x composite membranes exhibit a well-defined microphase separation structure depending on the contents of SNPAEK-1.35 polymer. Among them, Nafion/SNPAEK-7.5% with a bicontinuous morphology exhibits the best comprehensive properties. For example, it shows the highest proton conductivities of 0.092 S cm -1 at 25 °C and 0.163 S cm -1 at 80 °C, which are higher than those of recast Nafion with 0.073 S cm -1 at 25 °C and 0.133 S cm -1 at 80 °C, respectively. Nafion/SNPAEK-5.0% and Nafion/SNPAEK-7.5% membranes display an open circuit voltage of 0.77 V and a maximum power density of 47 mW cm -2 at 80 °C, which are much higher than those of recast Nafion of 0.63 V and 24 mW cm -2 under the same conditions. Nafion/SNPAEK-5.0% membrane also has comparable tensile strength (12.7 MPa) to recast Nafion (13.7 MPa), and higher Young's modulus (330 MPa) than that of recast Nafion (240 MPa). By combining their high proton conductivities, comparable mechanical properties, and good single cell performance, Nafion/SNPAEK-x composite membranes have the potential to be polymer electrolyte materials for direct methanol fuel cell applications.

Poly(arylene)-based anion exchange polymer electrolytes

DOEpatents

Kim, Yu Seung; Bae, Chulsung

2015-06-09

Poly(arylene) electrolytes including copolymers lacking ether groups in the polymer may be used as membranes and binders for electrocatalysts in preparation of anodes for electrochemical cells such as solid alkaline fuel cells.

Chemistry and properties of poly(arylene ether 1,3,4-oxadiazole)s and poly(arylene ether 1,2,4-triazole)s

NASA Technical Reports Server (NTRS)

Connell, J. W.; Hergenrother, P. M.; Wolf, P.

1992-01-01

Poly(arylene ether)s containing l,3,4-oxadiazole and 1,2,4-triazole units were prepared by the aromatic nucleophilic displacement reaction of bisphenol oxadiazole and bisphenol triazole compounds with activated aromatic dihalides. The polymers exhibited glass transition temperatures (Tg) ranging from 182 to 242 C, and several polymers exhibited melting transitions (Tm) ranging from 265 to 390 C. Inherent viscosities ranged from 1.02 to 3.40 dl/g, indicating relatively high molecular weights. Thin films exhibited tensile strengths, moduli, and elongations at 23 C of 90-110 MPa, 2.7-3.6 GPa, and 4-7 percent, respectively. Titanium-to-titanium tensile shear specimens of a poly(arylene ether 1,3,4-oxadiazole) exhibited tensile shear strengths at 23 and 150 C of 22.1 and 17.9 MPa, respectively.

Enhanced Proton Conductivity of Sulfonated Hybrid Poly(arylene ether ketone) Membranes by Incorporating an Amino-Sulfo Bifunctionalized Metal-Organic Framework for Direct Methanol Fuel Cells.

PubMed

Ru, Chunyu; Li, Zhenhua; Zhao, Chengji; Duan, Yuting; Zhuang, Zhuang; Bu, Fanzhe; Na, Hui

2018-03-07

Novel side-chain-type sulfonated poly(arylene ether ketone) (SNF-PAEK) containing naphthalene and fluorine moieties on the main chain was prepared in this work, and a new amino-sulfo-bifunctionalized metal-organic framework (MNS, short for MIL-101-NH 2 -SO 3 H) was synthesized via a hydrothermal technology and postmodification. Then, MNS was incorporated into a SNF-PAEK matrix as an inorganic nanofiller to prepare a series of organic-inorganic hybrid membranes (MNS@SNF-PAEK-XX). The mechanical property, methanol resistance, electrochemistry, and other properties of MNS@SNF-PAEK-XX hybrid membranes were characterized in detail. We found that the mechanical strength and methanol resistances of these hybrid membranes were improved by the formation of an ionic cross-linking structure between -NH 2 of MNS and -SO 3 H on the side chain of SNF-PAEK. Particularly, the proton conductivity of these hybrid membranes increased obviously after the addition of MNS. MNS@SNF-PAEK-3% exhibited the proton conductivity of 0.192 S·cm -1 , which was much higher than those of the pristine membrane (0.145 S·cm -1 ) and recast Nafion (0.134 S·cm -1 ) at 80 °C. This result indicated that bifunctionalized MNS rearranged the microstructure of hybrid membranes, which could accelerate the transfer of protons. The hybrid membrane (MNS@SNF-PAEK-3%) showed a better direct methanol fuel cell performance with a higher peak power density of 125.7 mW/cm 2 at 80 °C and a higher open-circuit voltage (0.839 V) than the pristine membrane.

Crystalline imide/arylene ether copolymers

NASA Technical Reports Server (NTRS)

Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor); Bass, Robert G. (Inventor)

1995-01-01

Crystalline imide/arylene ether block copolymers are prepared by reacting anhydride terminated poly(amic acids) with amine terminated poly)arylene ethers) in polar aprotic solvents and chemically or thermally cyclodehydrating the resulting intermediate poly(amic acids). The block copolymers of the invention have one glass transition temperature or two, depending on the particular structure and/or the compatibility of the block units. Most of these crystalline block copolymers for tough, solvent resistant films with high tensile properties. While all of the copolymers produced by the present invention are crystalline, testing reveals that copolymers with longer imide blocks or higher imide content have increased crystallinity.

Preparation, Fabrication, and Evaluation of Advanced Polymeric and Composite Materials

NASA Technical Reports Server (NTRS)

Orwoll, Robert A.

1997-01-01

The thesis titles are given below: physical and mechanical behavior of amorphous poly(arylene ether-co-imidasole)s and poly(arylene ether-co-imidasole) modification epoxies; the requirements of patentability as applied to the chemical arts; fabrication of thermoplastic polymer composite ribbon; blend of reactive diluents with phenylethynyl-terminated arylene ether oligomers; the synthesis, characterization, and application of ether-containing polyimides; the synthesis of reflective and electrically conductive polyimide films via an in-situ self-metalization procedure using silver (I) complexes; the thermal cure of phenylethynyl terminated polyimides and selected model compounds; and the synthesis, characterization, and molecular modeling of cyclic arylene ether oligomers.

Rhodium-Coordinated Poly(arylene-ethynylene)-alt-Poly(arylene-vinylene) Copolymer Acting as Photocatalyst for Visible-Light-Powered NAD+/NADH Reduction

PubMed Central

2014-01-01

A 2,2′-bipyridyl-containing poly(arylene-ethynylene)-alt-poly(arylene-vinylene) polymer, acting as a light-harvesting ligand system, was synthesized and coupled to an organometallic rhodium complex designed for photocatalytic NAD+/NADH reduction. The material, which absorbs over a wide spectral range, was characterized by using various analytical techniques, confirming its chemical structure and properties. The dielectric function of the material was determined from spectroscopic ellipsometry measurements. Photocatalytic reduction of nucleotide redox cofactors under visible light irradiation (390–650 nm) was performed and is discussed in detail. The new metal-containing polymer can be used to cover large surface areas (e.g. glass beads) and, due to this immobilization step, can be easily separated from the reaction solution after photolysis. Because of its high stability, the polymer-based catalyst system can be repeatedly used under different reaction conditions for (photo)chemical reduction of NAD+. With this concept, enzymatic, photo-biocatalytic systems for solar energy conversion can be facilitated, and the precious metal catalyst can be recycled. PMID:25130570

Preparation and characterization of poly (arylene ether isoxazole)s by fluoride ion-mediated aromatic nucleophilic displacement reactions

NASA Technical Reports Server (NTRS)

Herbert, C. G.; Bass, R. G.

1994-01-01

As part of a continuing effort to prepare novel thermally stable high-performance polymers, poly(arylene ether isoxazole)s have been prepared by fluoride ion-catalyzed aromatic nucleophilic substitution reactions with bis(trimethylsiloxyphenyl) isoxazoles and activated bisarylhalides in diphenyl sulfone. Initial investigation involving the preparation of these materials with isoxazole bisphenols and activated bisarylhalides in the presence of potassium carbonate indicated that, under reaction conditions necessary to prepare high-molecular-weight materials, the isoxazole monomer was converted to an enamino ketone. This side reaction was avoided by using fluoride as a base. However, trimethylsilyl ether derivatives of the isoxazole bisphenols were required in these polymerizations for the preparation of high-molecular-weight materials. Moderate to high inherent viscosity eta(sub inh): 0.43-0.87 dl/g) materials with good thermal stability (air: 409-477 C, helium: 435-512 C) can be prepared by the silyl ether method. Glass transition temperatures ranged from 182 to 225 C for polymers with phenyl pendants and from 170 to 214 C for those without. Molecular weight control by 2% endcapping and the incorporation of a phenyl pendant at the 4 position of the isoxazole is necessary to yield polymers soluble in polar aprotic solvents at room temperature. There is evidence, however, indicating the existence of crosslinks between the polymer chains when the silyl ether approach is utilized.

Poly(arylene ether)s That Resist Atomic Oxygen

NASA Technical Reports Server (NTRS)

Connell, John W.; Hergenrother, Paul; Smith, Joseph G., Jr.

1994-01-01

Novel poly(arylene ether)s containing phosphine oxide (PAEPO's) made via aromatic nucleophilic displacement reactions of activated aromatic dihalides (or, in some cases, activated aromatic dinitro compounds) with new bisphenol monomers containing phosphine oxide. Exhibited favorable combination of physical and mechanical properties and resistance to monatomic oxygen in oxygen plasma environment. Useful as adhesives, coatings, films, membranes, moldings, and composite matrices.

Effect of "bridge" on the performance of organic-inorganic crosslinked hybrid proton exchange membranes via KH550

NASA Astrophysics Data System (ADS)

Han, Hailan; Li, Hai Qiang; Liu, Meiyu; Xu, Lishuang; Xu, Jingmei; Wang, Shuang; Ni, Hongzhe; Wang, Zhe

2017-02-01

A series of novel organic-inorganic crosslinked hybrid proton exchange membranes were prepared using sulfonated poly(arylene ether ketone sulfone) polymers containing carboxyl groups (C-SPAEKS), (3-aminopropyl)-triethoxysilane (KH550), and tetraethoxysilane (TEOS). KH550 acted as a "bridge" after reacting with carboxyl and sulfonic groups of C-SPAEKS to form covalent and ionic crosslinked structure between the C-SPAEKS and SiO2 phase. The crosslinked hybrid membranes (C-SPAEKS/K-SiO2) were characterized by FT-IR spectroscopy, TGA, and electrochemistry, etc. The thermal stability, mechanical properties and proton conductivity of the crosslinked hybrid membranes were improved by the presence of both crosslinked structure and inorganic phase. The proton conductivity of C-SPAEKS/K-SiO2-8 was recorded as 0.110 S cm-1, higher than that of Nafion® (0.028 S cm-1) at 120 °C. Moreover, the methanol permeability of the C-SPAEKS/K-SiO2-8 was measured as 3.86 × 10-7 cm2 s-1, much lower than that of Nafion® 117 membranes (29.4 × 10-7 cm2 s-1) at 25 °C.

Analysis of cerium-composite polymer-electrolyte membranes during and after accelerated oxidative-stability test

NASA Astrophysics Data System (ADS)

Shin, Dongwon; Han, Myungseong; Shul, Yong-Gun; Lee, Hyejin; Bae, Byungchan

2018-02-01

The oxidative stability of membranes constructed from a composite of pristine sulfonated poly(arylene ether sulfone) and cerium was investigated by conducting an accelerated oxidative-stability test at the open-circuit voltage (OCV). The membranes were analyzed in situ through OCV and impedance measurements, cyclic voltammetry, and linear-sweep voltammetry to monitor the electrochemical properties during the stability test. Although the high-frequency resistance of a composite membrane was slightly higher than that of a pristine membrane because of the exchange of protons from the sulfonic acid with cerium ions, the composite membrane maintained its potential for much longer than the pristine membrane. The effect of the cerium ions as radical scavengers was confirmed by analyzing the drain water and chemical structure after operation. These post-operation analyses confirmed that cerium ions improved the oxidative stability of the hydrocarbon-based polymer during fuel-cell operation. It is clear that the cerium-based radical scavengers prevented chemical degradation of the polymer membrane as well as the electrode in terms of hydrogen cross-over, polymer-chain scission, and the electrochemical surface area, while they rarely diffused outward from the membrane.

Chemistry and adhesive properties of poly(arylene ether)s containing heterocyclic units

NASA Technical Reports Server (NTRS)

Connell, John W.

1991-01-01

Novel poly(arylene ether)s containing heterocyclic units were prepared, characterized, and evaluated as adhesives and composite matrices. The polymers were prepared by reacting a heterocyclic bisphenol with an activated aromatic dihalide in a polar aprotic solvent, using potassium carbonate. The polymerizations were generally carried out in N,N-dimethylacetamide at 155 C. In some cases, where the polymers were semicrystalline, higher temperatures and thus higher boiling solvents were necessary to keep the polymers in solution. Heterocyclic rings incorporated into the poly(arylene ether) backbone include phenylquinoxaline, phenylimidazole, benzimidazole, benzoxazole, 1,3,4-oxadiazole, and 1,2,4-triazole. The polymers were characterized by differential scanning calorimetry, solution viscosity, X-ray diffraction, thin film, and adhesive and (in some cases) composite properties. The glass transition temperatures, crystalline melt temperature, solubility, and mechanical properties varied depending upon the heterocyclic ring. The chemistry and properties of these materials are discussed.

Electroactive compositions with poly(arylene oxide) and stabilized lithium metal particles

DOEpatents

Zhang, Zhengcheng; Yuan, Shengwen; Amine, Khalil

2015-05-12

An electroactive composition includes an anodic material; a poly(arylene oxide); and stabilized lithium metal particles; where the stabilized lithium metal particles have a size less than about 200 .mu.m in diameter, are coated with a lithium salt, are present in an amount of about 0.1 wt % to about 5 wt %, and are dispersed throughout the composition. Lithium secondary batteries including the electroactive composition along with methods of making the electroactive composition are also discussed.

Poly[(arylene ethynylene)-alt-(arylene vinylene)]s Based on Anthanthrone and Its Derivatives: Synthesis and Photophysical, Electrochemical, Electroluminescent, and Photovoltaic Properties

PubMed Central

2017-01-01

Anthanthrone and its derivatives are large polycyclic aromatic compounds (PACs) that pose a number of challenges for incorporation into the structure of soluble conjugated polymers. For the first time, this group of PACs was employed as the building blocks for the synthesis of copolymers (P1–P5) based on poly[(arylene ethynylene)-alt-(arylene vinylene)]s backbone (−Ph–C≡C–Anth–C≡C–Ph–CH=CH–Ph–CH=CH−)n. During the synthesis of P1–P5, different alkyloxy side chains were incorporated in order to tune the properties of the polymers. Of the copolymer series only P1 (containing anthanthrone and branched 2-ethylhexyloxy side chains on phenylenes), P2 and P3 (for which the anthanthrones containing carbonyl groups were converted to anthanthrene containing alkyloxy substituents) were soluble. The photophysical, electrochemical, electroluminescent and photovoltaic properties of P1–P3 are reported, compared and discussed with respect to the effects of side chains. PMID:29151617

Chemistry and properties of new poly(arylene ether imidazoles)

NASA Technical Reports Server (NTRS)

Connell, J. W.; Hergenrother, P. M.

1990-01-01

As part of a program to develop high-temperature high-performance structural resins for aerospace applications, the chemistry and properties of new poly(arylene ether imidazoles) were investigated. The polymers were prepared by the nucleophilic displacement reaction of aromatic bis(imidazolephenols) with activated aromatic difluoro compounds. The amorphous thermoplastic polymers exhibited glass transition temperatures from 230 to 301 C, inherent viscosities from 0.46 to 1.46 dL/g, and number-average molecular weights as high as 59,300 g/mole. The polymers exhibit good toughness, adhesive, composite, and film properties. The chemical, physical, and mechanical properties of these materials are discussed.

Chemistry and properties of poly(arylene ether benzoxazole)s

NASA Technical Reports Server (NTRS)

Smith, J. G., Jr.; Connell, J. W.; Hergenrother, P. M.

1992-01-01

Several new poly(arylene ether benzoxazole)s (PAEBs) were prepared by the nucleophilic displacement reaction of activated aromatic difluorides with two novel bis(hydroxyphenyl benzoxazole), using potassium carbonate. The 6F-containing PAEBs exhibited better solubility and higher Tgs than did the 6,6'-bis-(2-(4-hydroxyphenyl)benzoxazole)-derived polymers. Several of the 6,6'bis(2-(4-hydroxyphenyl)benzoxazole)-derived polymers exhibited crystallinity by DSC and wide-angle X-ray diffraction. Unorientated thin film properties of the 6F-containing PAEBs were comparable to those of other 6F-containing PAEBS that were previously reported. The chemistry and the physical and mechanical properties of the above polymers are discussed.

Pore-Size-Tuned Graphene Oxide Frameworks as Ion-Selective and Protective Layers on Hydrocarbon Membranes for Vanadium Redox-Flow Batteries.

PubMed

Kim, Soohyun; Choi, Junghoon; Choi, Chanyong; Heo, Jiyun; Kim, Dae Woo; Lee, Jang Yong; Hong, Young Taik; Jung, Hee-Tae; Kim, Hee-Tak

2018-05-07

The laminated structure of graphene oxide (GO) membranes provides exceptional ion-separation properties due to the regular interlayer spacing ( d) between laminate layers. However, a larger effective pore size of the laminate immersed in water (∼11.1 Å) than the hydrated diameter of vanadium ions (>6.0 Å) prevents its use in vanadium redox-flow batteries (VRFB). In this work, we report an ion-selective graphene oxide framework (GOF) with a d tuned by cross-linking the GO nanosheets. Its effective pore size (∼5.9 Å) excludes vanadium ions by size but allows proton conduction. The GOF membrane is employed as a protective layer to address the poor chemical stability of sulfonated poly(arylene ether sulfone) (SPAES) membranes against VO 2 + in VRFB. By effectively blocking vanadium ions, the GOF/SPAES membrane exhibits vanadium-ion permeability 4.2 times lower and a durability 5 times longer than that of the pristine SPAES membrane. Moreover, the VRFB with the GOF/SPAES membrane achieves an energy efficiency of 89% at 80 mA cm -2 and a capacity retention of 88% even after 400 cycles, far exceeding results for Nafion 115 and demonstrating its practical applicability for VRFB.

Electro-Osmosis and Water Uptake in Polymer Electrolytes in Equilibrium with Water Vapor at Low Temperatures

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

Gallagher, K. G.; Pivovar, B. S.; Fuller, T. F.

2009-01-01

Water uptake and electro-osmosis are investigated to improve the understanding and aid the modeling of water transport in proton-exchange membrane fuel cells (PEMFCs) below 0 C. Measurements of water sorption isotherms show a significant reduction in the water capacity of polymer electrolytes below 0 C. This reduced water content is attributed to the lower vapor pressure of ice compared to supercooled liquid water. At -25 C, 1100 equivalent weight Nafion in equilibrium with vapor over ice has 8 moles of water per sulfonic acid group. Measurements of the electro-osmotic drag coefficient for Nafion and both random and multiblock copolymer sulfonatedmore » poly(arylene ether sulfone) (BPSH) chemistries are reported for vapor equilibrated samples below 0 C. The electro-osmotic drag coefficient of BPSH chemistries is found to be {approx}0.4, and that of Nafion is {approx}1. No significant temperature effect on the drag coefficient is found. The implication of an electro-osmotic drag coefficient less than unity is discussed in terms of proton conduction mechanisms. Simulations of the ohmically limited current below 0 C show that a reduced water uptake below 0 C results in a significant decrease in PEMFC performance.« less

Poly(N-arylenbenzimidazoles) via aromatic nucleophilic displacement

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

1995-01-01

Novel poly(N-arylenebenzimidazole)s (PNABIs) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl N-arylenebenzimidazole) monomers are synthesized by reacting phenyl 4-hydroxybenzoate with bis(2-aminoanilino) arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyl N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

Poly(N-arylenebenzimidazole)s via aromatic nucleophilic displacement

NASA Technical Reports Server (NTRS)

Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Jr., Joseph G. (Inventor)

1996-01-01

Novel poly(N-arylenebenzimidazole)s (PNABls) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl-N-arylenebenzimidazole) monomers are synthesized by reacting phenyl-4-hydroxybenzoate with bis(2-aminoanilino)arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyI-N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

Summary of GPC/DV results for space exposed poly(arylene ether phosphine oxide)s

NASA Technical Reports Server (NTRS)

Siochi, Emilie

1995-01-01

Gel Permeation Chromatography (GPC) was used to analyze poly(arylene ether phosphine oxide)s whose backbones were identical except for the ketone content and placement. These samples were exposed to low Earth orbit environment (predominantly atomic oxygen) on space shuttle flights. The materials and their unexposed controls were then characterized by GPC to investigate the effect of atomic oxygen on the molecular weight distributions. Analysis of the soluble portion of the samples revealed that there was significant loss of high molecular weight species. The presence of insoluble material also suggested that crosslinking was induced by the atomic oxygen exposure and that this very likely occurred at the high molecular weight portion of the molecular weight distribution.

Oxygen plasma resistant phosphine oxide containing imide/arylene copolymers

NASA Technical Reports Server (NTRS)

Jensen, Brian J.

1993-01-01

A series of oxygen plasma resistant imide/arylene ether copolymers were prepared by reacting anhydride-terminated poly(amide acids) and amine-terminated polyarylene ethers containing phosphine oxide units. Inherent viscosities for these copolymers ranged from 0.42 to 0.80 dL/g. After curing, the resulting copolymers had glass transition temperatures ranging from 224 C to 228 C. Solution cast films of the block copolymers were tough and flexible with tensile strength, tensile moduli, and elongation at break up to 16.1 ksi, 439 ksi, and 23 percent, respectively at 25 C and 9.1 ksi, 308 ksi and 97 percent, respectively at 150 C. The copolymers show a significant improvement in resistance to oxygen plasma when compared to the commercial polyimide Kapton. The imide/arylene ether copolymers containing phosphine oxide units are suitable as coatings, films, adhesives, and composite matrices.

Crystal structure and charge transport properties of poly(arylene-ethynylene) derivatives: A DFT approach

NASA Astrophysics Data System (ADS)

Garzón, Andrés; Granadino-Roldán, José M.; García, Gregorio; Moral, Mónica; Fernández-Gómez, Manuel

2013-04-01

In the present study, a series of crystalline poly(arylene-ethynylene) copolymers containing phenylethynylene and 2,5-dialkoxy-phenylethynylene units together with 1,3,4-thiadiazole rings has been modeled by means of periodic calculations. Optimized three-dimensional polymeric structures show interchain distances that are consistent with the experimental values reported for a related polymer. It has also been observed that the presence of pendant alkoxy chains brings on both a further flattening and a separation of the coplanar chains. This fact is linked to a decrease of the interchain cofacial distance. The electron transport character of the polymer crystal structures was assessed through Marcus theory. Electronic coupling between neighboring polymer chains is most influenced by the presence of alkoxy chains giving rise to an expectable enhancement of the electron hopping mobility.

New developments in thermally stable polymers

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M.

1991-01-01

Advances in high-temperature polymers since 1985 are discussed with the emphasis on the chemistry. High-temperature polymers refer to materials that exhibit glass-transition temperatures greater than 200 C and have the chemical structure expected to provide high thermooxidative stability. Specific polymers or series of polymers were selected to show how the chemical structure influences certain properties. Poly(arylene ethers) and polyimides are the two principal families of polymers discussed. Recent work on poly(arylene ethers) has concentrated on incorporating heterocyclic units within the polymer backbone. Recent polyimide work has centered on the synthesis of new polymers from novel monomers, several containing the trifluoromethyl group strategically located on the molecule. Various members in each of these polymer families display a unique combination of properties, heretofore unattainable. Other families of polymers are also briefly discussed with a polymer from an AB maleimidobenzocyclobutene exhibiting an especially attractive combination of properties.

Synthesis and Characterization of Poly (Arylene Ether Benzimidazole) Oligomers

NASA Technical Reports Server (NTRS)

Leonard, Michael J.

1995-01-01

Several poly(arylene ether benzimidazole) oligomers were prepared by the nucleophilic aromatic substitution reaction of a bisphenol benzimidazole and various alkyl-substituted aromatic bisphenols with an activated aromatic dihalide in N, N-dimethylacetarnide. Moderate to high molecular weight terpolymers were obtained in all cases, as shown by their inherent viscosities, which ranged from 0.50 to 0.87 dL g(sup -1). Glass transition temperatures (T(sub g)s) of polymer powders ranged from 267-280 C. Air-dried unoriented thin film T(sub g)s were markedly lower than those of the powders, whereas T(sub g)s of films dried in a nitrogen atmosphere were identical to those of the corresponding powders. In addition, air-dried films were dark amber and brittle, whereas nitrogen-dried films were yellow and creasable. Nitrogen-dried films showed slightly higher thin-film tensile properties than the air-dried films, as well.

A facile synthesis of highly stable multiblock poly(arylene ether)s based alkaline membranes for fuel cells

NASA Astrophysics Data System (ADS)

Jasti, Amaranadh; Shahi, Vinod K.

2014-12-01

Herein, we are disclosing simple route for the preparation of alkaline membranes (AMs) based on aminated multiblock poly(arylene ether)s (AMPEs) synthesized by nucleophilic substitution-poly condensation followed by quaternization and alkalization reactions. In this procedure, four quaternary ammonium groups are successfully introduced without use of carcinogenic reagents such as chloromethylmethyl ether (CMME). Hydrophilic/hydrophobic phase separation is responsible for their high hydroxide conductivity (∼150 mS cm-1 at 80 °C) due to development of interconnected ion transport pathway. AMs are exhibiting good alkaline stability due to the presence of two vicinal quaternary ammonium groups and avoid degradation such as Sommelet-Hauser rearrangement and Hofmann elimination. Vicinal quaternary ammonium groups also resist nucleophilic (OH-) attack and suppress the Stevens rearrangement as well as SN2 substitution reaction due to stearic hindrance. Optimized AM (AMPE-M20N15 (55% DCM)) exhibits about 0.95 V open circuit voltage (OCV) and 48.8 mW cm-2 power density at 65 °C in alkaline direct methanol fuel cell (ADMFC) operation. These results suggest promising begin for the preparation of stable and conductive AMs for ADMFC applications and useful for developing hydroxide conductive materials.

Sulfonated poly(ether sulfone)s containing pyridine moiety for PEMFC.

PubMed

Jang, Hohyoun; Islam, Md Monirul; Lim, Youngdon; Hossain, Md Awlad; Cho, Younggil; Joo, Hyunho; Kim, Whangi; Jeon, Heung-Seok

2014-10-01

Sulfonated poly(ether sulfone)s with varied degree of sulfonation (DS) were prepared via post-sulfonation of synthesized pyridine based poly(ether sulfone) (PPES) using concentrated sulfuric acid as sulfonating agent. The DS was varied with different mole ratio of 4,4'-(2,2-diphenylethenylidene)diphenol, DHTPE in the polymer unit. PPES copolymers were synthesized by direct polycondensation of pyridine unit with bis-(4-fluorophenyl)-sulfone, 4, 4'-sulfonyldiphenol and DHTPE. The structure of the resulting PPES copolymer membranes with different sulfonated units were studied by 1H NMR spectroscopy and thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of sulfonated polymer with water. The ion exchange capacity (IEC) and proton conductivity were evaluated according to the increase of DS. The water uptake (WU) of the resulting membranes was in the range of 17-58%, compared to that of Nafion 211 28%. The membranes provided proton conductivities of 65-95 mS/cm in contrast to 103 mS/cm of Nafion 211.

Synthesis and characterization of ionomers as polymer electrolytes for energy conversion devices

NASA Astrophysics Data System (ADS)

Oh, Hyukkeun

Single-ion conducting electrolytes present a unique alternative to traditional binary salt conductors used in lithium-ion batteries. Secondary lithium batteries are considered as one of the leading candidates to replace the combustible engines in automotive technology, however several roadblocks are present which prevent their widespread commercialization. Power density, energy density and safety properties must be improved in order to enable the current secondary lithium battery technology to compete with existing energy technologies. It has been shown theoretically that single-ion electrolytes can eliminate the salt concentration gradient and polarization loss in the cell that develops in a binary salt system, resulting in substantial improvements in materials utilization for high power and energy densities. While attempts to utilize single-ion conducting electrolytes in lithium-ion battery systems have been made, the low ionic conductivities prevented the successful operation of the battery cells in ambient conditions. This work focuses on designing single-ion conducting electrolytes with high ionic conductivities and electrochemical and mechanical stability which enables the stable charge-discharge performance of battery cells. Perfluorosulfonate ionomers are known to possess exceptionally high ionic conductivities due to the electron-withdrawing effect caused by the C-F bonds which stabilizes the negative charge of the anion, leading to a large number of free mobile cations. The effect of perfluorinated sulfonic acid side chains on transport properties of proton exchange membrane polymers was examinated via a comparison of three ionomers, having different side chain structures and a similar polymer backbone. The three different side chain structures were aryl-, pefluoro alkyl-, and alkyl-sulfonic acid groups, respectively. All ionomers were synthesized and characterized by 1H and 19F NMR. A novel ionomer synthesized with a pendant perfluorinated sulfonic acid group and a poly(ether ether ketone) backbone showed the highest proton conductivity and proton diffusion coefficient among the three ionomers, demonstrating the effect of the perfluorinated side chains. The proton conductivity of the novel ionomer was comparable to that of Nafion over a wide humidity range and temperature. A lithium perfluorosulfonate ionomer based on aromatic poly(arylene ether)s with pendant lithium perfluoroethyl sulfonates was prepared by ion exchange of the perlfuorosulfonic acid ionomer, and subsequently incoroporated into a lithium-ion battery cell as a single-ion conducting electrolyte. The microporous polymer film saturated with organic carbonates exhibited a nearly unity Li + transfer number, high ionic conductivity (e.g. > 10-3 S m-1 at room temperature) over a wide range of temperatures, high electrochemical stability, and excellent mechanical properties. Excellent cyclability with almost identical charge and discharge capacities have been demonstrated at ambient temperature in the batteries assembled from the prepared single-ion conductors. The mechanical stability of the polymer film was attributed to the rigid polymer backbone which was largely unaffected by the presence of plasticizing organic solvents, while the porous channels with high concentration of the perfluorinated side chains resulted in high ionic conductivity. The expected high charge-rate performance was not achieved, however, due to the high interfacial impedance present between the polymer electrolyte and the electrodes. Several procedural modifications were employed in order to decrease the interfacial impedance of the battery cell. The poly(arylene ether) based ionomer was saturated with an ionic liquid mixture, in order to explore the possibility of its application as a safe, inflammable electrolyte. A low-viscosity ionic liquid with high ionic conductivity, 1-butyl-3-methylimidazolium thiocyanate which has never been successfully utilized as an electrolyte for lithium-ion batteries was incorporated into a battery cell as a solvent mixture with propylene carbonate and lithium bis(trifluoromethane)sulfonimide impregnated in a free-standing hybrid electrolyte film. Outstanding ionic conductivity was achieved and the lithium half cell comprising a LTO cathode and a lithium metal anode separated by the solid polymer electrolyte showed good cyclability at room temperature and even at 0°C. The presence of a sufficient amount of propylene carbonate, which resulted in flammability of the polymer electrolyte, was discovered to be critical in the electrochemical stability of the polymer electrolyte.

Nitrile functionalized halloysite nanotubes/poly(arylene ether nitrile) nanocomposites: Interface control, characterization, and improved properties

NASA Astrophysics Data System (ADS)

Wan, Xinyi; Zhan, Yingqing; Zeng, Guangyong; He, Yi

2017-01-01

To develop high-performance halloysite nanotube (HNT)-based nanocomposites, the two key issues need to be considered: precise interface control and the dispersal of HNTs. This study presents an efficient way to functionalize halloysite nanotubes with 3-aminophenoxy-phthalonitrile, followed by compounding with poly(arylene ether nitrile) (PEN), to prepare functional nanocomposite films. The surface functionalization of HNTs was characterized and confirmed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Compared with neat PEN, the tensile strength and modulus of the resulting PEN nanocomposites with 3 wt% functionalized HNTs were found to increase by 25.7% and 20.7%, respectively. The good dispersion and high capacitance of the dielectric layer resulted in PEN/HNTs nancomposites with enhanced dielectric permittivity and relatively low dielectric loss. Moreover, the addition of functional HNTs greatly improved the thermal stability of PEN, which could be further enhanced through the chemical cross-linking reaction between the functional HNTs and the PEN matrix. This work provides a new path toward obtaining advanced polymer-based nanocomposites with functional properties.

Survey of inorganic polymers. [for composite matrix resins

NASA Technical Reports Server (NTRS)

Gerber, A. H.; Mcinerney, E. F.

1979-01-01

A literature search was carried out in order to identify inorganic, metallo-organic, and hybrid inorganic-organic polymers that could serve as potential matrix resins for advanced composites. The five most promising candidates were critically reviewed and recommendations were made for the achievement of their potential in terms of performance and cost. These generic polymer classes comprise: (1) Poly(arylsil sesquioxanes); (2) Poly(silyl arylene siloxanes); (3) Poly(silarylenes); (4) Poly(silicon-linked ferrocenes); and (5) Poly(organo phosphazenes). No single candidate currently possesses the necessary combination of physicomechanical properties, thermal stability, processability, and favorable economics. The first three classes exhibit the best thermal performance. On the other hand, poly (organo phosphazenes), the most extensively studied polymer class, exhibit the best combination of structure-property control, processability, and favorable economics.

Liquid-liquid phase separation in dilute solutions of poly(styrene sulfonate) with multivalent cations: Phase diagrams, chain morphology, and impact of temperature

NASA Astrophysics Data System (ADS)

Hansch, Markus; Hämisch, Benjamin; Schweins, Ralf; Prévost, Sylvain; Huber, Klaus

2018-01-01

The dilute solution behavior of sodium poly(styrene sulfonate) is studied in the presence of trivalent Al3+ and bivalent Ba2+ cations at various levels of excess NaCl. The study evaluates the phase behavior and the morphology of the polyelectrolyte chains with increasing extent of decoration with the Al3+ and Ba2+ cations and analyses the effect of temperature on these decorated chains. The phase behavior is presented in the form of the cation concentration versus the respective poly(styrene sulfonate) concentration, recorded at the onset of precipitation. Whereas poly(styrene sulfonate) with Al3+ exhibits a linear phase boundary, denoted as the "threshold line," which increases with increasing poly(styrene sulfonate) concentration, Ba2+ cations show a threshold line which is independent of the poly(styrene sulfonate) concentration. An additional re-entrant phase, at considerably higher cation content than those of the threshold lines, is observed with Al3+ cations but not with Ba2+ cations. The threshold line and the re-entrant phase boundary form parts of the liquid-liquid phase boundary observed at the limit of low polymer concentration. The dimensions of the polyelectrolyte chains shrink considerably while approaching the respective threshold lines on increase of the Al3+ and Ba2+ cation content. However, subtle differences occur between the morphological transformation induced by Al3+ and Ba2+. Most strikingly, coils decorated with Al3+ respond very differently to temperature variations than coils decorated with Ba2+ do. As the temperature increases, the poly(styrene sulfonate) chains decrease their size in the presence of Al3+ cations but increase in size in the presence of Ba2+ cations.

High performance anode based on a partially fluorinated sulfonated polyether for direct methanol fuel cells operating at 130 °C

NASA Astrophysics Data System (ADS)

Mack, Florian; Gogel, Viktor; Jörissen, Ludwig; Kerres, Jochen

2014-06-01

Due to the disadvantages of the Nafion polymer for the application in the direct methanol fuel cell (DMFC) especial at temperatures above 100 °C several polymers of the hydrocarbon type have already been investigated as membranes and ionomers in the DMFC. Among them were nonfluorinated and partially fluorinated arylene main-chain hydrocarbon polymers. In previous work, sulfonated polysulfone (sPSU) has been applied as the proton-conductive binder in the anode of a DMFC, ending up in good and stable performance. In continuation of this work, in the study presented here a polymer was prepared by polycondensation of decafluorobiphenyl and bisphenol AF. The formed polymer was sulfonated after polycondensation by oleum and the obtained partially fluorinated sulfonated polyether (SFS) was used as the binder and proton conductor in a DMFC anode operating at a temperature of 130 °C. The SFS based anode with 5% as ionomer showed comparable performance for the methanol oxidation to Nafion based anodes and significant reduced performance degradation versus Nafion and sPSU based anodes on the Nafion 115 membrane. Membrane electrode assemblies (MEAs) with the SFS based anode showed drastically improved performance compared to MEAs with Nafion based anodes during operation with lower air pressure at the cathode.

Correlation between polymer architecture, mesoscale structure and photovoltaic performance in side-chain-modified PAE-PAV:fullerene bulk-heterojunction solar cells

NASA Astrophysics Data System (ADS)

Rathgeber, S.; Kuehnlenz, F.; Hoppe, H.; Egbe, D. A. M.; Tuerk, S.; Perlich, J.; Gehrke, R.

2012-02-01

A poly(arylene-ethynylene)-alt-poly(arylene-vinylene) statistical copolymer carrying linear and branched alkoxy side chains along the conjugated backbone in a random manner, yields, compared to its regular substituted counterparts, an improved performance in polymer:fullerene bulk-heterojunction solar cells. Results obtained from GiWAXS experiments show that the improved performance of the statistical copolymer may be attributed to the following structural characteristics: 1) Well, ordered stacked domains that promote backbone planarization and thus improve the ππ-overlap. 2) Partly face-on alignment of domains relative to the electrodes for an improved active layer electrode charge transfer. Branched side chains seem to promote face-on domain orientation. Most likely they can minimize their unfavorable contact with the interface by just bringing the CH3 groups of the branches into direct contact with the surface so that favorable phenylene-substrate interaction can promote face-on orientation. 3) A more isotropic domain orientation throughout the active layer to ensure that the backbone alignment direction has components perpendicular and parallel to the electrodes in order to compromise between light absorption and efficient intra-chain charge transport.

High Dielectric Constants of Composites of Fiber-Like Copper Phthalocyanine-Coated Graphene Oxide Embedded in Poly(arylene Ether Nitriles)

NASA Astrophysics Data System (ADS)

Li, Jingwei; Pu, Zejun; Wang, Zicheng; Long, Ya; Jia, Kun; Liu, Xiaobo

2015-07-01

The surfaces of graphene oxide (GO) sheets were coated with fiber-like copper phthalocyanine (CuPc) by use of a solvothermal process. The product, GO@ CuPc, was used as a filler in high-performance poly(arylene ether nitrile) (PEN) composites. Films of the composites had high thermal stability, and glass-transition temperatures in the range 170-182°C. Thermogravimetric analysis revealed their initial decomposition temperatures were in the range 470-483°C. Scanning electron microscopy showed that dispersion of GO@ CuPc in PEN was much better than that of unmodified GO; this can be attributed to relatively strong interaction between GO@CuPc and the PEN matrix. All the composite films were highly flexible and had enhanced mechanical properties. Tensile strengths of the composites were as high as 89 MPa in the presence of 1 wt.% GO@CuPc, an increase of 20% compared with pure PEN film. Dielectric constants of the composite films were as high as 52 at 100 Hz when the GO@CuPc content was 5%. Because of these excellent mechanical and dielectric properties, PEN/GO@CuPc composites have much potential for use as film capacitors.

Dismantlable Thermosetting Adhesives Composed of a Cross-Linkable Poly(olefin sulfone) with a Photobase Generator.

PubMed

Sasaki, Takeo; Hashimoto, Shouta; Nogami, Nana; Sugiyama, Yuichi; Mori, Madoka; Naka, Yumiko; Le, Khoa V

2016-03-02

A novel photodetachable adhesive was prepared using a photodepolymerizable cross-linked poly(olefin sulfone). A mixture of a cross-linkable poly(olefin sulfone), a cross-linking reagent, and a photobase generator functioned as a thermosetting adhesive and exhibited high adhesive strength on quartz plates comparable to that obtained for commercially available epoxy adhesives. The cured resin was stable in the absence of UV light irradiation but completely lost its adhesive strength upon exposure of glued quartz plates to UV light in conjunction with heating to 100 °C.

Sulfonated amphiphilic block copolymers : synthesis, self-assembly in water, and application as stabilizer in emulsion polymerization

Treesearch

Jiguang Zhang; Matthew R. Dubay; Carl J. Houtman; Steven J. Severtson

2009-01-01

Described is the synthesis of diblock copolymers generated via sequential atom transfer radical polymerization (ATRP) of poly(n-butyl acrylate) (PnBA) followed by chain augmentation with either sulfonated poly(2-hydroxyethyl methacrylate) (PHEMA) or poly(2-hydroxyethyl acrylate) (PHEA) blocks. ATRP of PHEMA or PHEA from PnBA macroinitiator was conducted in acetone/...

Enhanced antifouling and antibacterial properties of poly (ether sulfone) membrane modified through blending with sulfonated poly (aryl ether sulfone) and copper nanoparticles

NASA Astrophysics Data System (ADS)

Zhang, Jingjing; Xu, Ya'nan; Chen, Shouwen; Li, Jiansheng; Han, Weiqing; Sun, Xiuyun; Wu, Dihua; Hu, Zhaoxia; Wang, Lianjun

2018-03-01

A series of novel blend ultrafiltration (UF) membranes have been successfully prepared from commercial poly (ether sulfone), lab-synthesized sulfonated poly (aryl ether sulfone) (SPAES, 1 wt%) and copper nanoparticles (0 ∼ 0.4 wt%) via immersion precipitation phase conversion. The micro-structure and separation performance of the membranes were characterized by field emission scanning electron microscopy (SEM) and cross-flow filtration experiments, respectively. Sodium alginate, bovine serum albumin and humic acid were chosen as model organic foulants to investigate the antifouling properties, while E. coil was used to evaluate the antibacterial property of the fabricated membranes. By the incorporation with SPAES and copper nanoparticles, the hydrophilicity, antifouling and antibacterial properties of the modified UF membranes have been profoundly improved. At a copper nanoparticles content of 0.4 wt%, the PES/SPAES/nCu(0.4) membrane exhibited a high pure water flux of 193.0 kg/m2 h, reaching the smallest contact angle of 52°, highest flux recovery ratio of 79% and largest antibacterial rate of 78.9%. Furthermore, the stability of copper nanoparticles inside the membrane matrix was also considerably enhanced, the copper nanoparticles were less than 0.08 mg/L in the effluent during the whole operation.

Synthesis and characterization of sulfonated poly ether ether ketone (sPEEK) membranes for low temperature fuel cells

NASA Astrophysics Data System (ADS)

Ali, Mawlood Maajal; Rizvi, S. J. A.; Azam, Ameer

2018-05-01

Poly ether ether ketone (PEEK) was sulfonated with 1.0 M sulphuric acid for varying durations to have various degrees of sulfonation (DS) from 43 to 55%. The FT-IR spectra confirmed the successful sulfonation of PEEK. The sulfonated PEEK (sPEEK) membranes were prepared by a solvent casting method using dimethylacetamide (DMAc) as solvent and upon drying the membranes were characterized. The DS% and ion exchange capacity (IEC) were determined by a back titration method. The IEC and DS of sPEEK was found to increase with the increment of sulfonation reaction time. Water uptake also increased with increase in the DS. The Thermogravimetric (TGA) curves revealed poor thermal stability of sPEEK. The proton conductivity of sPEEK membrane was found to considerably better with degree of sulfonation for fuel cell application.

Novel crosslinked membranes based on sulfonated poly(ether ether ketone) for direct methanol fuel cells.

PubMed

Zhu, Yuanqin; Zieren, Shelley; Manthiram, Arumugam

2011-07-14

Novel covalently crosslinked membranes based on sulfonated poly(ether ether ketone) and carboxylated polysulfone exhibit much lower methanol crossover and better performance in direct methanol fuel cells at 65 °C in 1 and 2 M methanol solutions compared to Nafion 115 membranes.

40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.

Code of Federal Regulations, 2010 CFR

2010-07-01

... derivatives, sulfonated, po-tas-sium salts. 721.1225 Section 721.1225 Protection of Environment ENVIRONMENTAL... derivatives, sulfonated, po-tas-sium salts. (a) Chemical substances and significant new uses subject to..., sulfonated, potassium salts (PMN P-89-711) is subject to reporting under this section for the significant new...

40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.

Code of Federal Regulations, 2011 CFR

2011-07-01

... derivatives, sulfonated, po-tas-sium salts. 721.1225 Section 721.1225 Protection of Environment ENVIRONMENTAL... derivatives, sulfonated, po-tas-sium salts. (a) Chemical substances and significant new uses subject to..., sulfonated, potassium salts (PMN P-89-711) is subject to reporting under this section for the significant new...

Multi-block sulfonated poly(phenylene) copolymer proton exchange membranes

DOEpatents

Fujimoto, Cy H [Albuquerque, NM; Hibbs, Michael [Albuquerque, NM; Ambrosini, Andrea [Albuquerque, NM

2012-02-07

Improved multi-block sulfonated poly(phenylene) copolymer compositions, methods of making the same, and their use as proton exchange membranes (PEM) in hydrogen fuel cells, direct methanol fuel cells, in electrode casting solutions and electrodes. The multi-block architecture has defined, controllable hydrophobic and hydrophilic segments. These improved membranes have better ion transport (proton conductivity) and water swelling properties.

Epoxy-crosslinked sulfonated poly (phenylene) copolymer proton exchange membranes

DOEpatents

Hibbs, Michael; Fujimoto, Cy H.; Norman, Kirsten; Hickner, Michael A.

2010-10-19

An epoxy-crosslinked sulfonated poly(phenylene) copolymer composition used as proton exchange membranes, methods of making the same, and their use as proton exchange membranes (PEM) in hydrogen fuel cells, direct methanol fuel cell, in electrode casting solutions and electrodes, and in sulfur dioxide electrolyzers. These improved membranes are tougher, have higher temperature capability, and lower SO.sub.2 crossover rates.

Self-assembled multilayers and photoluminescence properties of a new water-soluble poly(para-phenylene)

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

Shi, X.; Li, D.; Luett, M.

1998-07-01

This paper reports the synthesis and characterizations of a new water-soluble poly(paraphenylene) (PPP) and its applications in preparing self-assembled multi-layer films. This new water-soluble conducting polymer was prepared through the sulfonation reaction of poly(p-quarterphenylene-2,2{prime}-dicarboxylic acid). The incorporation of sulfonate groups has dramatically improved PPP's solubility in water at a wide pH range, whereas previous PPP is only slightly soluble in basic solutions. Dilute aqueous solutions of this polymer with acidic, neutral or basic pH emit brilliant blue light while irradiated with UV light. The sulfonated PPP emits from 350 nm to 455 nm with a maximum intensity at 380 nm.more » Self-assembled multilayers of this sulfonated PPP were constructed with a positively charged polymer poly(diallyl dimethyl ammonium chloride) and characterized with various surface analyses. Conductive (RuO{sub 2} and ITO), semiconductive (Si wafer), and non-conductive (SiO{sub 2}) substrates were used in the preparation of self-assembled multilayers. Electrical, optical and structural properties of these novel self-assembled thin films will be discussed.« less

Self-assembled multilayers and photoluminescence properties of a new water-soluble poly(para-phenylene)

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

Shi, X.; Li, D.Q.; Luett, M.

1998-03-01

This paper reports the synthesis and characterizations of a new water-soluble poly(para-phenylene) (PPP) and its applications in preparing self-assembled multilayer films. This new water-soluble conducting polymer was prepared through the sulfonation reaction of poly(p-quarterphenylene-2,2{prime}-dicarboxylic acid). The incorporation of sulfonate groups has dramatically improved PPP`s solubility in water at a wide pH range, whereas previous PPP is only slightly soluble in basic solutions. Dilute aqueous solutions of this polymer with acidic, neutral or basic pH emit brilliant blue light while irradiated with UV light. The sulfonated PPP emits from 350 nm to 455 nm with a maximum intensity at 380 nm.more » Self-assembled multilayers of this sulfonated PPP were constructed with a positively charged polymer poly(diallyl dimethyl ammonium chloride) and characterized with various surface analyses. Conductive (RuO{sub 2} and ITO), semiconductive (Si wafer), and non-conductive (SiO{sub 2}) substrates were used in the preparation of self-assembled multilayers. Electrical, optical and structural properties of these novel self-assembled thin films will be discussed.« less

Computational and experimental investigations of one-step conversion of poly(carbonate)s into value-added poly(aryl ether sulfone)s

PubMed Central

Yuen, Alexander; Wojtecki, Rudy J.; Hedrick, James L.; García, Jeannette M.

2016-01-01

It is estimated that ∼2.7 million tons poly(carbonate)s (PCs) are produced annually worldwide. In 2008, retailers pulled products from store shelves after reports of bisphenol A (BPA) leaching from baby bottles, reusable drink bottles, and other retail products. Since PCs are not typically recycled, a need for the repurposing of the PC waste has arisen. We report the one-step synthesis of poly(aryl ether sulfone)s (PSUs) from the depolymerization of PCs and in situ polycondensation with bis(aryl fluorides) in the presence of carbonate salts. PSUs are high-performance engineering thermoplastics that are commonly used for reverse osmosis and water purification membranes, medical equipment, as well as high temperature applications. PSUs generated through this cascade approach were isolated in high purity and yield with the expected thermal properties and represent a procedure for direct conversion of one class of polymer to another in a single step. Computational investigations performed with density functional theory predict that the carbonate salt plays two important catalytic roles in this reaction: it decomposes the PCs by nucleophilic attack, and in the subsequent polyether formation process, it promotes the reaction of phenolate dimers formed in situ with the aryl fluorides present. We envision repurposing poly(BPA carbonate) for the production of value-added polymers. PMID:27354514

Computational and experimental investigations of one-step conversion of poly(carbonate)s into value-added poly(aryl ether sulfone)s.

PubMed

Jones, Gavin O; Yuen, Alexander; Wojtecki, Rudy J; Hedrick, James L; García, Jeannette M

2016-07-12

It is estimated that ∼2.7 million tons poly(carbonate)s (PCs) are produced annually worldwide. In 2008, retailers pulled products from store shelves after reports of bisphenol A (BPA) leaching from baby bottles, reusable drink bottles, and other retail products. Since PCs are not typically recycled, a need for the repurposing of the PC waste has arisen. We report the one-step synthesis of poly(aryl ether sulfone)s (PSUs) from the depolymerization of PCs and in situ polycondensation with bis(aryl fluorides) in the presence of carbonate salts. PSUs are high-performance engineering thermoplastics that are commonly used for reverse osmosis and water purification membranes, medical equipment, as well as high temperature applications. PSUs generated through this cascade approach were isolated in high purity and yield with the expected thermal properties and represent a procedure for direct conversion of one class of polymer to another in a single step. Computational investigations performed with density functional theory predict that the carbonate salt plays two important catalytic roles in this reaction: it decomposes the PCs by nucleophilic attack, and in the subsequent polyether formation process, it promotes the reaction of phenolate dimers formed in situ with the aryl fluorides present. We envision repurposing poly(BPA carbonate) for the production of value-added polymers.

Immobilization of Acidithiobacillus ferrooxidans on sulfonated microporous poly(styrene-divinylbenzene) copolymer with granulated activated carbon and its use in bio-oxidation of ferrous iron.

PubMed

Koseoglu-Imer, Derya Yuksel; Keskinler, Bulent

2013-01-01

The immobilization efficiencies of Acidithiobacillus ferrooxidans cells on different immobilization matrices were investigated for biooxidation of ferrous iron (Fe(2+)) to ferric iron (Fe(3+)). Six different matrices were used such as the polyurethane foam (PUF), granular activated carbon (GAC), raw poly(styrene-divinylbenzene) copolymer (rawSDVB), raw poly(styrene-divinylbenzene) copolymer with granular activated carbon (rawSDVB-GAC), sulfonated poly(styrene-divinylbenzene) copolymer (sulfSDVB) and sulfonated poly(styrene-divinylbenzene) copolymer with granular activated carbon (sulfSDVB-GAC). The sulfSDVB-GAC polymer showed the best performance for Fe(2+) biooxidation. It was used at packed-bed bioreactor and the kinetic parameters were obtained. The highest Fe(2+) biooxidation rate (R) was found to be 4.02 g/L h at the true dilution rate (Dt) of 2.47 1/h and hydraulic retention time (τ) of 0.4 h. The sulfSDVB-GAC polymer was used for the first time as immobilization material for A. ferrooxidans for Fe(2+) biooxidation. Copyright © 2012 Elsevier B.V. All rights reserved.

Solvent resistant thermoplastic aromatic poly(imidesulfone) and process for preparing same

NASA Technical Reports Server (NTRS)

St.clair, T. L.; Yamaki, D. A. (Inventor)

1983-01-01

A process for preparing a thermoplastic poly(imidesulfone) is disclosed. This resulting material has thermoplastic properties which are generally associated with polysulfones but not polyimides, and solvent resistance which is generally associated with polyimides but not polysulfones. This system is processable in the 250 to 350 C range for molding, adhesive and laminating applications. This unique thermoplastic poly(imidesulfone) is obtained by incorporating an aromatic sulfone moiety into the backbone of an aromatic linear polyimide by dissolving a quantity of a 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) in a solution of 3,3'-diaminodiphenylsulfone and bis(2-methoxyethyl)ether, precipitating the reactant product in water, filtering and drying the recovered poly(amide-acid sulfone) and converting it to the poly(imidesulfone) by heating.

Process for preparing solvent resistant, thermoplastic aromatic poly(imidesulfone)

NASA Technical Reports Server (NTRS)

St.clair, T. L.; Yamaki, D. A. (Inventor)

1984-01-01

A process for preparing a thermoplastic poly(midesulfone) is disclosed. This resulting material has thermoplastic properties which are generally associated with polysulfones but not polyimides, and solvent resistant which is generally associated with polyimides but not polysulfones. This system is processable in the 250 to 350 C range for molding, adhesive and laminating applications. This unique thermoplastic poly(imidesulfone) is obtained by incorporating an aromatic sulfone moiety into the backbone of an aromatic linear polyimide by dissolving a quantity of a 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) in a solution of 3,3'-diaminodiphenylsulfone and bis(2-methoxyethyl)ether, precipitating the reactant product in water, filtering and drying the recovered poly(amide-acid sulfone) and converting it to the poly(imidesulfone) by heating.

Urea photosynthesis inside polyelectrolyte capsules: effect of confined media.

PubMed

Shchukin, Dmitry G; Möhwald, Helmuth

2005-06-07

The influence of the restricted volume of poly(styrene sulfonate)/poly(allylamine hydrochloride) capsules of different size (2.2, 4.2, and 8.1 microm) on the TiO2-assisted photosynthesis of urea from inorganic precursors (CO2 and NO(3-)) in aqueous solution was demonstrated. Poly(vinyl alcohol) was employed as electron donor to facilitate the photosynthetic process. Decreasing the size of the confined microvolume of polyelectrolyte capsules accelerates the NO(3-) photoreduction, which is a limiting stage of the urea photosynthesis and, correspondingly, increases the efficiency of urea production. The highest yield of urea photosynthesis (37%) was achieved for Cu-modified TiO2 nanoparticles encapsulated inside 2.2 microm poly(styrene sulfonate)/poly(allylamine hydrochloride) capsules.

Synthesis and Properties of Poly(ether sulfone)s with Clustered Sulfonic Groups for PEMFC Applications under Various Relative Humidity.

PubMed

Lee, Shih-Wei; Chen, Jyh-Chien; Wu, Jin-An; Chen, Kuei-Hsien

2017-03-22

Novel sulfonated poly(ether sulfone) copolymers (S4PH-x-PSs) based on a new aromatic diol containing four phenyl substituents at the 2, 2', 6, and 6' positions of 4,4'-diphenyl ether were synthesized. Sulfonation was found to occur exclusively on the 4 position of phenyl substituents by NMR spectroscopy. The ion exchange capacity (IEC) values can be controlled by adjusting the mole percent (x in S4PH-x-PS) of the new diol. The fully hydrated sulfonated poly(ether sulfone) copolymers had good proton conductivity in the range 0.004-0.110 S/cm at room temperature. The surface morphology of S4PH-x-PSs and Nafion 212 was investigated by atomic force microscopy (tapping-mode) and related to the percolation limit and proton conductivity. Single H 2 /O 2 fuel cell based on S4PH-40-PS loaded with 0.25 mg/cm 2 catalyst (Pt/C) exhibited a peak power density of 462.6 mW/cm 2 , which was close to that of Nafion 212 (533.5 mW/cm 2 ) at 80 °C with 80% RH. Furthermore, fuel cell performance of S4PH-35-PS with various relative humidity was investigated. It was confirmed from polarization curves that the fuel cell performance of S4PH-35-PS was not as high as that of Nafion 212 under fully hydrated state due to higher interfacial resistance between S4PH-35-PS and electrodes. While under low relative humidity (53% RH) at 80 °C, fuel cells based on S4PH-35-PS showed higher peak power density (234.9 mW/cm 2 ) than that (214.0 mW/cm 2 ) of Nafion 212.

Monitoring processing properties of high performance thermoplastics using frequency dependent electromagnetic sensing

NASA Technical Reports Server (NTRS)

Kranbuehl, D. E.; Delos, S. E.; Hoff, M. S.; Weller, L. W.; Haverty, P. D.

1987-01-01

An in situ NDE dielectric impedance measurement method has been developed for ascertaining the cure processing properties of high temperature advanced thermoplastic and thermosetting resins, using continuous frequency-dependent measurements and analyses of complex permittivity over 9 orders of magnitude and 6 decades of frequency at temperatures up to 400 C. Both ionic and Debye-like dipolar relaxation processes are monitored. Attention is given to LARC-TPI, PEEK, and poly(arylene ether) resins' viscosity, glass transition temperature, recrystallization, and residual solvent content and evolution properties.

Sequence-defined oligo(ortho-arylene) foldamers derived from the benzannulation of ortho(arylene ethynylene)s† †Electronic supplementary information (ESI) available. CCDC 1483959–1483967. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc02520j Click here for additional data file. Click here for additional data file.

PubMed Central

Lehnherr, Dan; Chen, Chen; Pedramrazi, Zahra; DeBlase, Catherine R.; Alzola, Joaquin M.; Keresztes, Ivan; Lobkovsky, Emil B.

2016-01-01

A Cu-catalyzed benzannulation reaction transforms ortho(arylene ethynylene) oligomers into ortho-arylenes. This approach circumvents iterative Suzuki cross-coupling reactions previously used to assemble hindered ortho-arylene backbones. These derivatives form helical folded structures in the solid-state and in solution, as demonstrated by X-ray crystallography and solution-state NMR analysis. DFT calculations of misfolded conformations are correlated with variable-temperature 1H and EXSY NMR to reveal that folding is cooperative and more favorable in halide-substituted naphthalenes. Helical ortho-arylene foldamers with specific aromatic sequences organize functional π-electron systems into arrangements ideal for ambipolar charge transport and show preliminary promise for the surface-mediated synthesis of structurally defined graphene nanoribbons. PMID:28567248

The influence of chain rigidity and the degree of sulfonation on the morphology of block copolymers as nano reactor

NASA Astrophysics Data System (ADS)

Hong, K.; Zhang, X.

2005-03-01

Polyelectrolyte block copolymer was used to form an ordered domain of ionic block as a ``nanoreactor'' due to its ability to bind oppositely charged metal ion, Zn^2+, Fe^2+ etc. The purpose of our research is to investigate the controllability of the size and morphology of domains (inorganic nano particles) by changing backbone stiffness, the charge density and the volume fraction of ionic block. Poly(styrene sulfonate) (PSS), which backbone is flexible, and poly(cyclohexadiene sulfonate) (PCHDS), which backbone is ``semiflexible'', were used as ionic blocks. We synthesized PtBS-PSS and PS-PCHDS with various degree of sulfonation and the volume fraction. Zinc oxide (ZnO) nano particles successfully formed in the ionic domain of microphase separated block copolymers. We used SANS to characterize the morphology of block copolymers and TEM for block copolymer containing ZnO nano particles. Our experimental results show that the chemistry of ``sulfonation'' of block copolymers can be successfully used to synthesize nano composite materials.

Molecular and morphological characterization of midblock-sulfonated styrenic triblock copolymers

DOE PAGES

Mineart, Kenneth P.; Ryan, Justin J.; Lee, Byeongdu; ...

2017-01-11

Midblock-sulfonated triblock copolymers afford a desirable opportunity to generate network-forming amphiphilic materials that are suitable for use in a wide range of emerging technologies as fuel-cell, water-desalination, ion-exchange, photovoltaic, or electroactive membranes. Employing a previously reported synthetic strategy wherein poly( p- tert-butylstyrene) remains unreactive, we have selectively sulfonated the styrenic midblock of a poly( p- tert-butylstyrene- b-styrene- b- p- tert- butylstyrene) (TST) triblock copolymer to different extents. Comparison of the resulting sulfonated copolymers with results from our prior study provides favorable quantitative agreement and suggests that a shortened reaction time is advantageous. An ongoing challenge regarding the morphological development ofmore » charged block copolymers is the competition between microphase separation of the incompatible blocks and physical cross-linking of ionic clusters, with the latter often hindering the former. Here, we expose the sulfonated TST copolymers to solvent-vapor annealing to promote nanostructural refinement. Furthermore, the effect of such annealing on morphological characteristics, as well as on molecular free volume, is explored.« less

Imide/arylene ether block copolymers

NASA Technical Reports Server (NTRS)

Jensen, B. J.; Hergenrother, P. M.; Bass, R. G.

1991-01-01

Two series of imide/arylene either block copolymers were prepared using an arylene ether block and either an amorphous or semi-crystalline imide block. The resulting copolymers were characterized and selected physical and mechanical properties were determined. These results, as well as comparisons to the homopolymer properties, are discussed.

Imide/arylene ether copolymers with pendent trifluoromethyl groups

NASA Technical Reports Server (NTRS)

Jensen, Brian J.; Havens, Stephen J.

1992-01-01

A series of imide/arylene ether block copolymers were prepared using an arylene ether block containing a hexafluoroisopropylidene group and an imide block containing a hexafluoroisopropylidene and a trifluoromethyl group in the polymer backbone. The copolymers were characterized and mechanical properties were determined and compared to the homopolymers.

Cellulose nanofiber-embedded sulfonated poly (ether sulfone) membranes for proton exchange membrane fuel cells.

PubMed

Xu, Xianlin; Li, Rui; Tang, Chenxiao; Wang, Hang; Zhuang, Xupin; Liu, Ya; Kang, Weimin; Shi, Lei

2018-03-15

Cellulose nanofibers were embedded into sulfonated poly (ether sulfone) matrix to heighten the water retention and proton conductivity of proton exchange membranes (PEMs). Cellulose nanofibers were obtained by hydrolyzing cellulose acetate nanofibers, which were prepared via electrostatic-induction-assisted solution blow spinning. Morphology, thermal stability, and mechanical properties of the PEMs were investigated. The results showed that proton conductivity, water uptake, and methanol permeability of the composite membranes were improved. Hydrophilicity of the composite membranes was gradually improved with the addition of nanofibers. When the content of nanofibers was 5 wt%, the highest proton conductivity was 0.13 S/cm (80 °C, 100% RH). Therefore, the cellulose nanofiber could be used as support materials to enhance the performance of proton exchange membranes, the composite membranes have potential application in Direct methanol fuel cells (DMFCs). Copyright © 2017 Elsevier Ltd. All rights reserved.

Chitin nanowhisker-supported sulfonated poly(ether sulfone) proton exchange for fuel cell applications.

PubMed

Zhang, Chan; Zhuang, Xupin; Li, Xiaojie; Wang, Wei; Cheng, Bowen; Kang, Weimin; Cai, Zhanjun; Li, Mengqin

2016-04-20

To balance the relationship among proton conductivity and mechanic strength of sulfonated poly(ether sulfone) (SPES) membrane, chitin nanowhisker-supported nanocomposite membranes were prepared by incorporating whiskers into SPES. The as-prepared chitin whiskers were prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) mediated oxidation of α-chitin from crab shells. The structure and properties of the composite membranes were examined as proton exchange membrane (PEM). Results showed that chitin nanowhiskers were dispersed incompactly in the SPES matrix. Thermal stability, mechanical properties, water uptake and proton conductivity of the nanocomposite films were improved from those of the pure SPES film with increasing whisker content, which ascribed to strong interactions between whiskers and between SPES molecules and chitin whiskers via hydrogen bonding. These indicated that composition of filler and matrix got good properties and whisker-supported membranes are promising materials for PEM. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preparation of graphene oxide/poly (3,4-ethylenedioxytriophene): Poly (styrene sulfonate) (PEDOT:PSS) electrospun nanofibers

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

Efelina, Vita; Widianto, Eri; Rusdiana, Dadi

2016-04-19

Graphene oxide (GO)/Poly (3,4-Ethylenedioxytriophene):Poly (styrene Sulfonate) (PEDOT:PSS) nanofibers have been successfully fabricated by a simple electrospinning technique to develop conductive nanofibers with polyvinyl alcohol (PVA) act as a carrier solution. Graphene oxide has been synthesized by Hummer’s method and has been confirmed by Raman Spectroscopy, FTIR and UV-Vis Spectroscopy. GO/PEDOT:PSS composite nanofibers. The structural and morphological properties were characterized by Scanning Electron Microscopy (SEM). The result of SEM show that GO/PEDOT:PSS nanofibers has a relatively uniform morphology nanofiber with diameter between 180 nm - 340 nm with smooth nanofiber surface. The produced nanofibers from this study can be utilized for various applicationsmore » such as flexible, conductive and transparent electrode.« less

A highly conductive poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) film with the solvent bath treatment by dimethyl sulfoxide as cathode for polymer tantalum capacitor

NASA Astrophysics Data System (ADS)

Ma, Xiaopin; Wang, Xiuyu; Li, Mingxiu; Chen, Tongning; Zhang, Hao; Chen, Qiang; Ding, Bonan; Liu, Yanpeng

2016-06-01

The highly conductive poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films were prepared on porous tantalum pentoxide surface as cathode for polymer tantalum capacitors (PTC). The electrical performances of PTC with PEDOT:PSS films as cathode were optimized by dimethyl sulfoxide (DMSO) bath treatment. With the DMSO-bath treatment of PTC, the equivalent series resistance (ESR) of PTC decreased from 25 mΩ to 9 mΩ. The ultralow ESR led to better capacitance-frequency performance. The device reliability investigation revealed the enhanced environmental stability of PTC. The enhanced performances were attributed to the conductivity improvement of PEDOT:PSS cathode films and the removal of excess PSS from PEDOT:PSS films.

Investigation of the adsorption of polymer chains on amine-functionalized double-walled carbon nanotubes.

PubMed

Ansari, R; Ajori, S; Rouhi, S

2015-12-01

Molecular dynamics (MD) simulations were used to study the adsorption of different polymer chains on functionalized double-walled carbon nanotubes (DWCNTs). The nanotubes were functionalized with two different amines: NH2 (a small amine) and CH2-NH2 (a large amine). Considering three different polymer chains, all with the same number of atoms, the effect of polymer type on the polymer-nanotube interaction was studied. In general, it was found that covalent functionalization considerably improved the polymer-DWCNT interaction. By comparing the results obtained with different polymer chains, it was observed that, unlike polyethylene and polyketone, poly(styrene sulfonate) only weakly interacts with the functionalized DWCNTs. Accordingly, the smallest radius of gyration was obtained with adsorbed poly(styrene sulfonate). It was also observed that the DWCNTs functionalized with the large amine presented more stable interactions with polyketone and poly(styrene sulfonate) than with polyethylene, whereas the DWCNTs functionalized with the small amine showed better interfacial noncovalent bonding with polyethylene.

Novel structure design of composite proton exchange membranes with continuous and through-membrane proton-conducting channels

NASA Astrophysics Data System (ADS)

Wang, Hang; Tang, Chenxiao; Zhuang, Xupin; Cheng, Bowen; Wang, Wei; Kang, Weimin; Li, Hongjun

2017-10-01

The primary goal of this study is to develop a high-performanced proton exchange membrane with the characteristics of through-membrane and continuous solution blown nanofibers as proton-conducting channels. The curled sulfonated phenolphthalein poly (ether sulfone) and poly (vinylidene fluoride) nanofibers were separately fabricated through the solution blowing process which is a new nanofiber fabricating method with high productivity, then they were fabricated into a sandwich-structured mat. Then this sandwich-structured mat was hot-pressed to form the designed structure using different melting temperatures of the two polymers by melting and making poly (vinylidene fluoride) flow into the phenolphthalein poly (ether sulfone) nanofiber mat. The characteristics of the composite membrane, such as morphology and performance of the membrane, were investigated. The characterization results proved the successful preparation of the membrane structure. Performance results showed that the novel structured membrane with through-membrane nanofibers significantly improved water swelling and methanol permeability, though its conductivity is lower than that of Nafion, the cell performance showed comparable results. Therefore, the novel structure design can be considered as a promising method for preparing of proton exchange membranes.

Sulfonated poly(styrene-divinylbenzene) modified with amines and the application for pipette-tip solid-phase extraction of carbendazim in apples.

PubMed

Ma, Yuxin; Liu, Lingling; Tang, Weiyang; Zhu, Tao

2017-10-01

Sulfonated poly(styrene-divinylbenzene) modified with five kinds of amine functional groups was applied to the determination of carbendazim in apple samples with a pipette-tip solid-phase extraction method. The structures of the polymers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Five different modifications of the solid-phase extraction sorbent based on sulfonated poly(styrene-divinylbenzene) were tested under static and pipette-tip solid-phase extraction conditions. The polymer modified with p-methoxyaniline showed the best recognition capacity and adsorption amount for carbendazim. Under the optimum conditions, 3.00 mg of the adsorbent, 1.00 mL of ethyl acetate as washing solvent, and 1.00 mL of ammonia/acetonitrile (5:95, v/v) as elution solvent were used in the pretreatment procedure of apple samples. The calibration graphs of carbendazim in methanol were linear over 5.00-200.00 μg/mL, and the limits of detection and quantification were 0.01 and 0.03 μg/mL, respectively. The method recoveries of carbendazim were in the range of 91.31-98.13% with associated intraday relative standard deviations of 0.76-2.13% and interday relative standard deviations of 1.10-1.85%. Sulfonated poly(styrene-divinylbenzene) modified with p-methoxyaniline showed satisfactory results (recovery: 97.96%) and potential for the rapid purification of carbendazim in apple samples combined with the pipette-tip solid-phase extraction. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role of sulfonation in the stability, reactivity, and selectivity of poly(ether imide) used to develop ion exchange membranes: DFT study with application to fuel cells.

PubMed

López-Chávez, Ernesto; Peña-Castañeda, Yésica A; de la Portilla-Maldonado, L César; Guzmán-Pantoja, Javier; Martínez-Magadán, José Manuel; Oviedo-Roa, Raúl; de Landa Castillo-Alvarado, Fray; Cruz-Torres, Armando

2014-07-01

The design of polymer electrolyte membranes for fuel cells must satisfy two equally important fundamental principles: optimization of the reactivity and the selectivity in order to improve the ion transport properties of the membrane as well as its long-term stability in the hydrated state at high temperature (above 100 °C). A study utilizing density functional theory (DFT) to elucidate the effect of the degree of sulfonation on the chemical stability, reactivity, and selectivity of poly(ether imide) (PEI), which allows the ionic transport properties of the membrane to be predicted, is reported here. Sulfonated poly(ether imide) (SPEI) structures with (-SO3H) n (n = 1-6) groups were built and optimized in order to calculate the above properties as functions of the number of sulfonyl groups. A comparative study demonstrated that the SPEI with four sulfonyl groups in its backbone is the polymer with the properties best suited for use in fuel cells.

40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzene, 1,2-dimethyl-, poly-propene... Significant New Uses for Specific Chemical Substances § 721.1225 Benzene, 1,2-dimethyl-, poly-propene... reporting. (1) The chemical substance identified as benzene, 1,2-dimethyl-, polypropene derivatives...

40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzene, 1,2-dimethyl-, poly-propene... Significant New Uses for Specific Chemical Substances § 721.1225 Benzene, 1,2-dimethyl-, poly-propene... reporting. (1) The chemical substance identified as benzene, 1,2-dimethyl-, polypropene derivatives...

40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzene, 1,2-dimethyl-, poly-propene... Significant New Uses for Specific Chemical Substances § 721.1225 Benzene, 1,2-dimethyl-, poly-propene... reporting. (1) The chemical substance identified as benzene, 1,2-dimethyl-, polypropene derivatives...

Intermolecular ionic cross-linked sulfonated poly(ether ether ketone) membranes containing diazafluorene for direct methanol fuel cell applications

NASA Astrophysics Data System (ADS)

Liang, Yu; Gong, Chenliang; Qi, Zhigang; Li, Hui; Wu, Zhongying; Zhang, Yakui; Zhang, Shujiang; Li, Yanfeng

2015-06-01

A series of novel ionic cross-linking sulfonated poly(ether ether ketone) (SPEEK) membranes containing the diazafluorene functional group are synthesized to reduce the swelling ratio and methanol permeability for direct methanol fuel cell (DMFC) applications. The ionic cross-linking is realized by the interaction between sulfonic acid groups and pyridyl in diazafluorene. The prepared membranes exhibit good mechanical properties, adequate thermal stability, good oxidative stability, appropriate water uptake and low swelling ratio. Moreover, the ionic cross-linked membranes exhibit lower methanol permeability in the range between 0.56 × 10-7 cm2 s-1 and 1.8 × 10-7 cm2 s-1, which is lower than Nafion 117, and they exhibit higher selectivity than Nafion 117 at 30 °C on the basis of applicable proton conductivity.

Preparation, Characterization and Utilization of Electrodes Coated with Polymeric Networks Formed by Gamma Radiation Crosslinking.

DTIC Science & Technology

1987-04-01

polymers such as poly[ diallyl dimethyl ammonium chloride] , poly [vinylbenzyl trimethyl ammonium chloride], poly[styrene sulfonic acid , sodium salt] and...poly[acrylic acid ], which would ordinarily dissolve from the electrode surface in aqueous solution unless crosslinked into a network, and several...Irradiation on a Water-Soluble Polymer: DDAC 8 E. Electrochemistry of DDAC Networks on Platinum and Graphite 10 F. Poly [acrylic acid ] Films on Graphite

An Extraordinary Sulfonated-Graphenal-Polymer-Based Electrolyte Separator for All-Solid-State Supercapacitors.

PubMed

Liu, Xubo; Men, Chuanling; Zhang, Xiaohua; Li, Qingwen

2016-09-01

Sulfonated graphenal polymers can be assembled up by poly(vinyl alcohol) adhesion. The porous assembly structure results in a remarkably improved ionic conductivity and thus enhances electrochemical performances such as specific capacitance, capacitance retention, and cycling stability. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of degree of sulfonation and casting solvent on sulfonated poly(ether ether ketone) membrane for vanadium redox flow battery

NASA Astrophysics Data System (ADS)

Xi, Jingyu; Li, Zhaohua; Yu, Lihong; Yin, Bibo; Wang, Lei; Liu, Le; Qiu, Xinping; Chen, Liquan

2015-07-01

The properties of sulfonated poly(ether ether ketone) (SPEEK) membranes with various degree of sulfonation (DS) and casting solvent are investigated for vanadium redox flow battery (VRFB). The optimum DS of SPEEK membrane is firstly confirmed by various characterizations such as physicochemical properties, ion selectivity, and VRFB single-cell performance. Subsequently the optimum casting solvent is selected for the optimum DS SPEEK membrane within N,N‧-dimethylformamide (DMF), N,N‧-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and dimethylsulfoxide (DMSO). The different performance of SPEEK membranes prepared with various casting solvents can be attributed to the different interaction between solvent and -SO3H group of SPEEK. In the VRFB single-cell test, the optimum SPEEK membrane with DS of 67% and casting solvent of DMF (S67-DMF membrane) exhibits higher VRFB efficiencies and better cycle-life performance at 80 mA cm-2. The investigation of various DS and casting solvent will be effective guidance on the selection and modification of SPEEK membrane towards VRFB application.

Dynamics of water in sulfonated poly(phenylene) membranes

NASA Astrophysics Data System (ADS)

Osti, Naresh; Etampawala, Thusitha; Shrestha, Umesh; Perahia, Dvora; Cornelius, Christopher

2011-03-01

The dynamics of water in networks formed by highly rigid ionic polymers, sulfonated poly(phenylene) as observed by quasi elastic neutron scattering (QENS) is presented. These rigid ionic polymers have potential as effective ion exchange membranes with impact on a large number of applications from water purification to clean energy, where its rigidity distinguishes it from other ionic polymers. Its transport characteristics are affected by its rigidness as well as by direct interactions with the solvent. Our QENS studies as a function of sulfonation levels, temperature and solvent content have shown that on the time scale of the measurement, the polymers are rigid. While macroscopically all samples swell, and transport water, the water molecules appear locally rather confined. Water however remind non-frozen to subzero temperatures. The results will be discussed in view of theoretical models including continues diffusion and hopping of solvent molecules.

A screen-printed carbon electrode modified with gold nanoparticles, poly(3,4-ethylenedioxythiophene), poly(styrene sulfonate) and a molecular imprint for voltammetric determination of nitrofurantoin.

PubMed

Dechtrirat, Decha; Yingyuad, Peerada; Prajongtat, Pongthep; Chuenchom, Laemthong; Sriprachuabwong, Chakrit; Tuantranont, Adisorn; Tang, I-Ming

2018-04-23

A molecularly imprinted polymer (MIP) and a nanocomposite prepared from gold nanoparticles (AuNP) and poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT:PSS) were deposited on a screen-printed carbon electrode (SPCE). The nanocomposite was prepared by one-pot simultaneous in-situ formation of AuNPs and PEDOT:PSS and was then inkjet-coated onto the SPCE. The MIP film was subsequently placed on the modified SPCE by co-electrodeposition of o-phenylenediamine and resorcinol in the presence of the antibiotic nitrofurantoin (NFT). Using differential pulse voltammetry (DPV), response at the potential of ~ 0.1 V (vs. Ag/AgCl) is linear in 1 nM to 1000 nM NFT concentration range, with a remarkably low detection limit (at S/N = 3) of 0.1 nM. This is two orders of magnitude lower than that of the control MIP sensor without the nanocomposite interlayer, thus showing the beneficial effect of AuNP-PEDOT:PSS. The electrode is highly reproducible (relative standard deviation 3.1% for n = 6) and selective over structurally related molecules. It can be re-used for at least ten times and was found to be stable for at least 45 days. It was successfully applied to the determination of NFT in (spiked) feed matrices and gave good recoveries. Graphical abstract Schematic representation of a voltammetric sensor for the determination of nitrofurantoin. The sensor is based on a screen-printed carbon electrode (SPCE) modified with an inkjet-printed gold nanoparticles-poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) nanocomposite and a molecularly imprinted polymer.

Membranes with well-defined ions transport channels fabricated via solvent-responsive layer-by-layer assembly method for vanadium flow battery.

PubMed

Xu, Wanxing; Li, Xianfeng; Cao, Jingyu; Zhang, Hongzhang; Zhang, Huamin

2014-02-06

In this work we presented a general strategy for the fabrication of membranes with well-defined ions transport channels through solvent-responsive layer-by-layer assembly (SR-LBL). Multilayered poly (diallyldimethylammonium chloride) (PDDA) and poly (acrylic acid) (PAA) complexes were first introduced on the inner pore wall and the surface of sulfonated poly (ether ether ketone)/poly (ether sulfone) (PES/SPEEK) nanofiltration membranes to form ions transport channels with tuned radius. This type of membranes are highly efficient for the separators of batteries especially vanadium flow batteries (VFBs): the VFBs assembled with prepared membranes exhibit an outstanding performance in a wide current density range, which is much higher than that assembled with commercial Nafion 115 membranes. This idea could inspire the development of membranes for other flow battery systems, as well as create further progress in similar areas such as fuel cells, electro-dialysis, chlor-alkali cells, water electrolysis and so on.

Membranes with well-defined ions transport channels fabricated via solvent-responsive layer-by-layer assembly method for vanadium flow battery

PubMed Central

Xu, Wanxing; Li, Xianfeng; Cao, Jingyu; Zhang, Hongzhang; Zhang, Huamin

2014-01-01

In this work we presented a general strategy for the fabrication of membranes with well-defined ions transport channels through solvent-responsive layer-by-layer assembly (SR-LBL). Multilayered poly (diallyldimethylammonium chloride) (PDDA) and poly (acrylic acid) (PAA) complexes were first introduced on the inner pore wall and the surface of sulfonated poly (ether ether ketone)/poly (ether sulfone) (PES/SPEEK) nanofiltration membranes to form ions transport channels with tuned radius. This type of membranes are highly efficient for the separators of batteries especially vanadium flow batteries (VFBs): the VFBs assembled with prepared membranes exhibit an outstanding performance in a wide current density range, which is much higher than that assembled with commercial Nafion 115 membranes. This idea could inspire the development of membranes for other flow battery systems, as well as create further progress in similar areas such as fuel cells, electro-dialysis, chlor-alkali cells, water electrolysis and so on. PMID:24500376

Coarse-grained simulations of polyelectrolyte complexes: MARTINI models for poly(styrene sulfonate) and poly(diallyldimethylammonium)

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

Vögele, Martin; Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt a. M.; Holm, Christian

2015-12-28

We present simulations of aqueous polyelectrolyte complexes with new MARTINI models for the charged polymers poly(styrene sulfonate) and poly(diallyldimethylammonium). Our coarse-grained polyelectrolyte models allow us to study large length and long time scales with regard to chemical details and thermodynamic properties. The results are compared to the outcomes of previous atomistic molecular dynamics simulations and verify that electrostatic properties are reproduced by our MARTINI coarse-grained approach with reasonable accuracy. Structural similarity between the atomistic and the coarse-grained results is indicated by a comparison between the pair radial distribution functions and the cumulative number of surrounding particles. Our coarse-grained models aremore » able to quantitatively reproduce previous findings like the correct charge compensation mechanism and a reduced dielectric constant of water. These results can be interpreted as the underlying reason for the stability of polyelectrolyte multilayers and complexes and validate the robustness of the proposed models.« less

Transparent Wood Smart Windows: Polymer Electrochromic Devices Based on Poly(3,4-Ethylenedioxythiophene):Poly(Styrene Sulfonate) Electrodes.

PubMed

Lang, Augustus W; Li, Yuanyuan; De Keersmaecker, Michel; Shen, D Eric; Österholm, Anna M; Berglund, Lars; Reynolds, John R

2018-03-09

Transparent wood composites, with their high strength and toughness, thermal insulation, and excellent transmissivity, offer a route to replace glass for diffusely transmitting windows. Here, conjugated-polymer-based electrochromic devices (ECDs) that switch on-demand are demonstrated using transparent wood coated with poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as a transparent conducting electrode. These ECDs exhibit a vibrant magenta-to-clear color change that results from a remarkably colorless bleached state. Furthermore, they require low energy and power inputs of 3 mWh m -2 at 2 W m -2 to switch due to a high coloration efficiency (590 cm 2  C -1 ) and low driving voltage (0.8 V). Each device component is processed with high-throughput methods, which highlights the opportunity to apply this approach to fabricate mechanically robust, energy-efficient smart windows on a large scale. © 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Sulfonated Holey Graphene Oxide (SHGO) Filled Sulfonated Poly(ether ether ketone) Membrane: The Role of Holes in the SHGO in Improving Its Performance as Proton Exchange Membrane for Direct Methanol Fuel Cells.

PubMed

Jiang, Zhong-Jie; Jiang, Zhongqing; Tian, Xiaoning; Luo, Lijuan; Liu, Meilin

2017-06-14

Sulfonated holey graphene oxides (SHGOs) have been synthesized by the etching of sulfonated graphene oxides with concentrated HNO 3 under the assistance of ultrasonication. These SHGOs could be used as fillers for the sulfonated aromatic poly(ether ether ketone) (SPEEK) membrane. The obtained SHGO-incorporated SPEEK membrane has a uniform and dense structure, exhibiting higher performance as proton exchange membranes (PEMs), for instance, higher proton conductivity, lower activation energy for proton conduction, and comparable methanol permeability, as compared to Nafion 112. The sulfonated graphitic structure of the SHGOs is believed to be one of the crucial factors resulting in the higher performance of the SPEEK/SHGO membrane, since it could increase the local density of the -SO 3 H groups in the membrane and induce a strong interfacial interaction between SHGO and the SPEEK matrix, which improve the proton conductivity and lower the swelling ratio of the membrane, respectively. Additionally, the proton conductivity of the membrane could be further enhanced by the presence of the holes in the graphitic planes of the SHGOs, since it provides an additional channel for transport of the protons. When used, direct methanol fuel cell with the SPEEK/SHGO membrane is found to exhibit much higher performance than that with Nafion 112, suggesting potential use of the SPEEK/SHGO membrane as the PEMs.

Dynamics and lithium binding energies of polyelectrolytes based on functionalized poly(para-phenylene terephthalamide).

PubMed

Grozema, F C; Best, A S; van Eijck, L; Stride, J; Kearley, G J; de Leeuw, S W; Picken, S J

2005-04-28

Polyelectrolyte materials are an interesting class of electrolytes for use in fuel cell and battery applications. Poly(para-phenylene terephthalamide) (PPTA, Kevlar) is a liquid crystalline polymer that, when sulfonated, is a polyelectrolyte that exhibits moderate ion conductivity at elevated temperatures. In this work, quasi-elastic neutron scattering (QENS) experiments were performed to gain insight into the effect of the presence of lithium counterions on the chain dynamics in the material. It was found that the addition of lithium ions decreases the dynamics of the chains. Additionally, the binding of lithium ions to the sulfonic acids groups was investigated by density functional theory (DFT) calculations. It was found that the local surroundings of the sulfonic acid group have very little effect on the lithium-ion binding energy. Binding energies for a variety of different systems were all calculated to be around 150 kcal/mol. The DFT calculations also show the existence of a structure in which a single lithium ion interacts with two sulfonic acid moieties on different chains. The formation of such "electrostatic cross-links" is believed to be the source of the increased tendency to aggregate and the reduced dynamics in the presence of lithium ions.

Fabrication of low-methanol-permeability sulfonated poly(phenylene oxide) membranes with hollow glass microspheres for direct methanol fuel cells

NASA Astrophysics Data System (ADS)

Ahn, Kisang; Kim, Myeongjin; Kim, Kiho; Ju, Hyun; Oh, Ilgeun; Kim, Jooheon

2015-02-01

Organic/inorganic composite membranes, based on sulfonated poly(phenylene oxide) (SPPO) and hollow glass microspheres (HGMs), with various compositions are prepared for use as proton exchange membranes in direct methanol fuel cells (DMFCs). Reaction time between chlorosulfonic acid solution and PPO is controlled to improve proton conductivity of the SPPO membrane. As a result, SPPO at 38.2% sulfonation is selected as the optimum degree of sulfonation. Afterwards, SPPO is successfully introduced onto the surfaces of HGMs to increase their dispersion in the SPPO matrix. The ion exchange capacities (IEC) and proton conductivities of the membranes decrease with increasing amounts of the SPPO-HGMs, because of the decrease of ionic sites with increasing HGM content. The SPPO-HGM composite membranes exhibit proton conductivities ranging from 0.0350 to 0.0212 S cm-1 and low methanol permeability ranging from 1.02 × 10-6 to 3.41 × 10-7 cm2 s-1 at 20 °C. Furthermore, the SPPO-HGM 9 wt%/SPPO membrane presents a maximum power density of 81.5 mW cm-2 and open circuit voltage of 0.70 V.

Influence of grafting solvents on the properties of polymer electrolyte membranes prepared by γ-ray preirradiation method

NASA Astrophysics Data System (ADS)

Kimura, Yosuke; Asano, Masaharu; Chen, Jinhua; Maekawa, Yasunari; Katakai, Ryoichi; Yoshida, Masaru

2008-07-01

The effect of grafting solvents, such as isopropanol (iPrOH), tetrachloroethane (TCE), tetrahydrofuran (THF), and toluene, on the preparation of poly(ethylene- co-tetrafluoroethylene)-graft-poly(styrene sulfonic acid) (ETFE-g-PSSA) electrolyte membranes by the γ-ray preirradiation grafting method was investigated. It was found that the iPrOH can drastically accelerate the grafting, resulting in a higher degree of grafting. However, for an appropriate degree of grafting of about 50%, the sulfonic acid groups in the ETFE-g-PSSA membrane prepared with the iPrOH were mainly distributed near the membrane surface, as shown by low proton conductivity in the membrane thickness direction. In contrast to this result, the ETFE-g-PSSA membranes prepared with the THF, toluene and TCE exhibited uniform distribution of the sulfonic acid groups in the membrane. Especially, in the case of the TCE grafting solvent, the chemical stability of the resultant electrolyte membrane was clearly higher than those prepared with the other grafting solvents.

The diffusion and conduction of lithium in poly(ethylene oxide)-based sulfonate ionomers

NASA Astrophysics Data System (ADS)

LaFemina, Nikki H.; Chen, Quan; Colby, Ralph H.; Mueller, Karl T.

2016-09-01

Pulsed field gradient nuclear magnetic resonance spectroscopy and dielectric relaxation spectroscopy have been utilized to investigate lithium dynamics within poly(ethylene oxide) (PEO)-based lithium sulfonate ionomers of varying ion content. The ion content is set by the fraction of sulfonated phthalates and the molecular weight of the PEO spacer, both of which can be varied independently. The molecular level dynamics of the ionomers are dominated by either Vogel-Fulcher-Tammann or Arrhenius behavior depending on ion content, spacer length, temperature, and degree of ionic aggregation. In these ionomers the main determinants of the self-diffusion of lithium and the observed conductivities are the ion content and ionic states of the lithium ion, which are profoundly affected by the interactions of the lithium ions with the ether oxygens of the polymer. Since many lithium ions move by segmental polymer motion in the ion pair state, their diffusion is significantly larger than that estimated from conductivity using the Nernst-Einstein equation.

Cross-linked sulfonated poly(ether ether ketone) by using diamino-organosilicon for proton exchange fuel cells.

PubMed

Kayser, Marie J; Reinholdt, Marc X; Kaliaguine, Serge

2011-03-31

Fuel cells are at the battlefront to find alternate sources of energy to the highly polluting, economically and environmentally constraining fossil fuels. This work uses an organosilicon molecule presenting two amine functions, bis(3-aminopropyl)-tetramethyldisiloxane (APTMDS) with the aim of preparing cross-linked sulfonated poly(ether ether ketone) (SPEEK) based membranes. The hybrid membranes obtained at varying APTMDS loadings are characterized for their acid, proton conductivity, water uptake, and swelling properties. APTMDS may be considered as an extreme case of silica nanoparticle and is therefore most advantageously distributed within the polymeric matrix. The two amine groups can interact, via electrostatic interactions, with the sulfonic acid groups of SPEEK, resulting in a double anchoring of the molecule. The addition of a small amount of APTMDS is enhancing the mechanical and hydrolytic properties of the membranes and allows some unfolding of the polymer chains, rendering some acid sites accessible to water molecules and thus available for proton transport.

A Study of influence on sulfonated TiO2-Poly (Vinylidene fluoride-co-hexafluoropropylene) nano composite membranes for PEM Fuel cell application

NASA Astrophysics Data System (ADS)

kumar, K. Selva; Rajendran, S.; Prabhu, M. Ramesh

2017-10-01

The present work describes the sulfonated Titania directly blended with Poly (Vinylidene fluoride-co-hexafluoropropylene) as a host polymer by solvent casting technique for PEM fuel cell application. Characterization studies such as FT-IR, SEM, EDX, AFM, Proton conductivity, contact angle measurement, IEC, TG, water uptake, tensile strength were performed by for synthesized proton conducting polymer electrolytes. The maximum proton conductivity value was found to be 3.6 × 10-3S/cm for 25 wt% sulfonated Titania based system at 80 °C. The temperature dependent proton conductivity of the polymer electrolyte follows an Arrhenius relationship. Surface morphology of the composite membranes was investigated by tapping mode. Thermal stability of the system was studied by TG analysis. The fabricated composite membranes with high proton conductivity, good water uptake and IEC parameters exhibited a maximum fuel cell power density of 85 Mw/cm2for PEM fuel cell application.

In vitro and in vivo evaluation of poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate)/dopamine-coated electrodes for dopamine delivery.

PubMed

Sui, L; Song, X J; Ren, J; Cai, W J; Ju, L H; Wang, Y; Wang, L Y; Chen, M

2014-06-01

Poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrene sulfonate) (PSS) has a variety of chemical and biomedical applications. The application of PEDOT/PSS polymers in drug delivery has attracted attention. However, whether conducting polymers of PEDOT/PSS could be used for dopamine delivery has not clear. In the present study, the PEDOT/PSS coatings incorporated with dopamine were fabricated on 0.5 mm diameter platinum electrodes, electrochemical properties, and dopamine delivery capacities of these electrodes were evaluated in vitro and in vivo through implanting these electrodes into brain striatum area. The findings demonstrated that the PEDOT/PSS/dopamine coatings on platinum electrodes could reduce electrodes impedances, increase charge storage capacities, and release significant levels of dopamine upon electrical stimulation of these electrodes. These results indicated that polymers of PEDOT/PSS/dopamine could be used for dopamine delivery, implicating potential application of PEDOT/PSS/dopamine-coated implantable electrodes in the treatment of some diseases associated with dopamine deficits, such as, electrodes for the treatment of Parkinson's disease during deep brain stimulation. Copyright © 2013 Wiley Periodicals, Inc.

Enhanced conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) film by acid treatment for indium tin oxide-free organic solar cells

NASA Astrophysics Data System (ADS)

Lin, Chun-Chiao; Huang, Chih-Kuo; Hung, Yu-Chieh; Chang, Mei-Ying

2016-08-01

An acid treatment is used in the enhancement of the conductivity of the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) thin film, which is often used as the anode in organic solar cells. There are three types of acid treatment for PEDOT:PSS thin film: hydrochloric, sulfuric, and phosphoric acid treatments. In this study, we examine and compare these three ways with each other for differences in conductivity. Hydrochloric acid results in the highest conductivity enhancement, from 0.3 to 1109 S/cm. We also discuss the optical transmittance, conductivity, surface roughness, surface morphology, and stability, as well as the factors that can influence device efficiency. The devices are fabricated using an acid-treated PEDOT:PSS thin film as the anode. The highest power conversion efficiency was 1.32%, which is a large improvement over that of the unmodified organic solar cell (0.21%). It is comparable to that obtained when using indium tin oxide (ITO) as an electrode, ca. 1.46%.

Alkyne Benzannulation Reactions for the Synthesis of Novel Aromatic Architectures.

PubMed

Hein, Samuel J; Lehnherr, Dan; Arslan, Hasan; J Uribe-Romo, Fernando; Dichtel, William R

2017-11-21

Aromatic compounds and polymers are integrated into organic field effect transistors, light-emitting diodes, photovoltaic devices, and redox-flow batteries. These compounds and materials feature increasingly complex designs, and substituents influence energy levels, bandgaps, solution conformation, and crystal packing, all of which impact performance. However, many polycyclic aromatic hydrocarbons of interest are difficult to prepare because their substitution patterns lie outside the scope of current synthetic methods, as strategies for functionalizing benzene are often unselective when applied to naphthalene or larger systems. For example, cross-coupling and nucleophilic aromatic substitution reactions rely on prefunctionalized arenes, and even directed metalation methods most often modify positions near Lewis basic sites. Similarly, electrophilic aromatic substitutions access single regioisomers under substrate control. Cycloadditions provide a convergent route to densely functionalized aromatic compounds that compliment the above methods. After surveying cycloaddition reactions that might be used to modify the conjugated backbone of poly(phenylene ethynylene)s, we discovered that the Asao-Yamamoto benzannulation reaction is notably efficient. Although this reaction had been reported a decade earlier, its scope and usefulness for synthesizing complex aromatic systems had been under-recognized. This benzannulation reaction combines substituted 2-(phenylethynyl)benzaldehydes and substituted alkynes to form 2,3-substituted naphthalenes. The reaction tolerates a variety of sterically congested alkynes, making it well-suited for accessing poly- and oligo(ortho-arylene)s and contorted hexabenzocoronenes. In many cases in which asymmetric benzaldehyde and alkyne cycloaddition partners are used, the reaction is regiospecific based on the electronic character of the alkyne substrate. Recognizing these desirable features, we broadened the substrate scope to include silyl- and halogen-substituted alkynes. Through a combined experimental and computational approach, we have elucidated mechanistic insight and key principles that govern the regioselectivity outcome of the benzannulation of structurally diverse alkynes. We have applied these methods to prepare sterically hindered, shape-persistent aromatic systems, heterocyclic aromatic compounds, functionalized 2-aryne precursors, polyheterohalogenated naphthalenes, ortho-arylene foldamers, and graphene nanoribbons. As a result of these new synthetic avenues, aromatic structures with interesting properties were uncovered such as ambipolar charge transport in field effect transistors based on our graphene nanoribbons, conformational aspects of ortho-arylene architectures resulting from intramolecular π-stacking, and modulation of frontier molecular orbitals via protonation of heteroatom containing aromatic systems. Given the availability of many substituted 2-(phenylethynyl)benzaldehydes and the regioselectivity of the benzannulation reaction, naphthalenes can be prepared with control of the substitution pattern at seven of the eight substitutable positions. Researchers in a range of fields are likely to benefit directly from newly accessible molecular and polymeric systems derived from polyfunctionalized naphthalenes.

Preparation of poly (arylene ether nitrile)/NzdFeB composite film with excellent thermal properties and tensile strength

NASA Astrophysics Data System (ADS)

Pan, Hai; Xu, Mingzhen; Liu, Xiaobo

2017-12-01

PEN/NdFeB composite films were prepared by the solution casting method. The thermal properties, fracture morphology and tensile strength of the composite films were tested by DSC, TGA, SEM and electromechanical universal testing machine, respectively. The results reveal that the composite film has good thermal properties and tensile strength. Glass-transition temperature and decomposition temperatures at weight loss of 5% ot the composite films retain at 166±1 C and 462±4 C, respectively. The composite film with 5 wt.% NdFeB has the best tensile strength value for 100.5 MPa. In addition, it was found that the NdFeB filler was well dispersed in PEN matrix by SEM analysis.

Characterization of vanadium ion uptake in sulfonated diels alder poly(phenylene) membranes

DOE PAGES

Lawton, Jamie; Jones, Amanda; Tang, Zhijiang; ...

2015-11-28

Sulfonated diels alder poly(phenylene) (SDAPP), alternative aromatic hydrocarbon membranes for vanadium redox flow batteries (VRFBs) are characterized using electron paramagnetic resonance (EPR). Membranes soaked in sulfuric acid and vanadyl sulfate are analyzed to determine the membrane environment in which the vanadyl ion (VO 2+) diffuses in the membranes. These results are compared to Nafion 117 membranes. In contrast to Nafion, the VO 2+ in SDAPP membranes exists in two different environments. The results of analysis of rotational diffusion determined from fits the EPR spectral lineshapes in comparison with previously reported permeation studies and measurements of partitioning functions reported here suggestmore » that the diffusion pathways in SDAPP are very different than in Nafion.« less

Ion distribution in quaternary-ammonium-functionalized aromatic polymers: effects on the ionic clustering and conductivity of anion-exchange membranes.

PubMed

Weiber, E Annika; Jannasch, Patric

2014-09-01

A series of copoly(arylene ether sulfone)s that have precisely two, three, or four quaternary ammonium (QA) groups clustered directly on single phenylene rings along the backbone are studied as anion-exchange membranes. The copolymers are synthesized by condensation polymerizations that involve either di-, tri-, or tetramethylhydroquinone followed by virtually complete benzylic bromination using N-bromosuccinimide and quaternization with trimethylamine. This synthetic strategy allows excellent control and systematic variation of the local density and distribution of QA groups along the backbone. Small-angle X-ray scattering of these copolymers shows extensive ionic clustering, promoted by an increasing density of QA on the single phenylene rings. At an ion-exchange capacity (IEC) of 2.1 meq g(-1), the water uptake decreases with the increasing local density of QA groups. Moreover, at moderate IECs at 20 °C, the Br(-) conductivity of the densely functionalized copolymers is higher than a corresponding randomly functionalized polymer, despite the significantly higher water uptake of the latter. Thus, the location of multiple cations on single aromatic rings in the polymers facilitates the formation of a distinct percolating hydrophilic phase domain with a high ionic concentration to promote efficient anion transport, despite probable limitations by reduced ion dissociation. These findings imply a viable strategy to improve the performance of alkaline membrane fuel cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Design, synthesis, and characterization of lightly sulfonated multigraft acrylate-based copolymer superelastomers

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

Misichronis, Konstantinos; Wang, Weiyu; Cheng, Shiwang

2018-01-29

Multigraft copolymer superelastomers consisting of a poly(n-butyl acrylate) backbone and polystyrene side chains were synthesized and the viscoelastic properties of the non-sulfonated and sulfonated final materials were investigated using extensional rheology (SER3). The non-linear viscoelastic experiments revealed significantly increased true stresses (up to 10 times higher) after sulfonating only 2–3% of the copolymer while the materials maintained high elongation (<700%). The linear viscoelastic experiments showed that the storage and loss modulus are increased by sulfonation and that the copolymers can be readily tuned and further improved by increasing the number of branching points and the molecular weight of the backbone.more » Here, in this way, we show that by tuning not only the molecular characteristics of the multigraft copolymers but also their architecture and chemical interaction, we can acquire thermoplastic superelastomer materials with desired viscoelastic properties.« less

SPEEK/PVDF/PES Composite as Alternative Proton Exchange Membrane for Vanadium Redox Flow Batteries

NASA Astrophysics Data System (ADS)

Fu, Zhimin; Liu, Jinying; Liu, Qifeng

2016-01-01

A membrane consisting of a blend of sulfonated poly(ether ether ketone) (SPEEK), poly(vinylidene fluoride) (PVDF), and poly(ether sulfone) (PES) has been fabricated and used as an ion exchange membrane for application in vanadium redox flow batteries (VRBs). The vanadium ion permeability of the SPEEK/PVDF/PES membrane was one order of magnitude lower than that of Nafion 117 membrane. The low-cost composite membrane exhibited better performance than Nafion 117 membrane at the same operating condition. A VRB single cell with SPEEK/PVDF/PES membrane showed significantly lower capacity loss, higher coulombic efficiency (>95%), and higher energy efficiency (>82%) compared with Nafion 117 membrane. In the self-discharge test, the duration of the cell with the SPEEK/PVDF/PES membrane was nearly two times longer than that with Nafion 117 membrane. Considering these good properties and its low cost, SPEEK/PVDF/PES membrane is expected to have excellent commercial prospects as an ion exchange membrane for VRB systems.

Poly(zwitterionic liquids) functionalized polypyrrole/graphene oxide nanosheets for electrochemically detecting dopamine at low concentration.

PubMed

Mao, Hui; Liang, Jiachen; Ji, Chunguang; Zhang, Haifeng; Pei, Qi; Zhang, Yuyang; Zhang, Yu; Hisaeda, Yoshio; Song, Xi-Ming

2016-08-01

Poly(3-(1-vinylimidazolium-3-yl)propane-1-sulfonate) (PVIPS), a novel kind of poly(zwitterionic liquids) (PZILs) containing both imidazolium cation and sulfonate anion, was successfully modified on the surface of polypyrrole/graphene oxide nanosheets (PPy/GO) by covalent bonding. The obtained novel PZILs functionalized PPy/GO nanosheets (PVIPS/PPy/GO) modified glassy carbon electrode (GCE) presented the excellent electrochemical catalytic activity towards dopamine (DA) with high stability, sensitivity, selectivity and wide linear range (40-1220nM), especially having a lower detection limit (17.3nM). The excellent analytical performance is attributed to the strongly negative charges on the surface of modified GCE in aqueous solution, which is different from conventional poly(ionic liquids) modified GCE. DA cations could be quickly enriched on the electrode surface by electrostatic interaction in solution due to the existence of SO3(-) groups with negative charge at the end of pendant groups in zwitterionic PVIPS, resulting in a change of the electrons transmission mode in the oxidation of DA, that is, from a typical diffusion-controlled process at conventional poly(1-vinyl-3-ethylimidazole bromide) (PVEIB)/PPy/GO modified GCE to a typical surface-controlled process. Copyright © 2016 Elsevier B.V. All rights reserved.

Solvent effect on post-irradiation grafting of styrene onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) films

NASA Astrophysics Data System (ADS)

Napoleão Geraldes, Adriana; Augusto Zen, Heloísa; Ribeiro, Geise; Fernandes Parra, Duclerc; Benévolo Lugão, Ademar

2013-03-01

Radiation-induced grafting of styrene onto ETFE films in different solvent was investigated after simultaneous irradiation (in post-irradiation condition) using a 60Co source. Grafting of styrene followed by sulfonation onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) are currently studied for synthesis of ion exchange membranes. The ETFE films were immersed in styrene/toluene, styrene/methanol and styrene/isopropyl alcohol and irradiated at 20 and 100 kGy doses at room temperature. The post-irradiation time was established at 14 day and the grafting degree was evaluated. The grafted films were sulfonated using chlorosulfonic acid and 1,2-dichloroethane 20:80 (v/v) at room temperature for 5 h. The degree of grafting (DOG) was determined gravimetrically and physical or chemical changes were evaluated by differential scanning calorimeter analysis (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The ion exchange capacity (IEC) values showed the best performance of sulfonation for ETFE membranes grafted in toluene solvent. Surface images of the grafted films by SEM technique have presented a strong effect of the solvents on the films morphology.

Electrical stimulation promotes nerve cell differentiation on polypyrrole/poly (2-methoxy-5 aniline sulfonic acid) composites.

PubMed

Liu, Xiao; Gilmore, Kerry J; Moulton, Simon E; Wallace, Gordon G

2009-12-01

The purpose of this work was to investigate for the first time the potential biomedical applications of novel polypyrrole (PPy) composites incorporating a large polyelectrolyte dopant, poly (2-methoxy-5 aniline sulfonic acid) (PMAS). The physical and electrochemical properties were characterized. The PPy/PMAS composites were found to be smooth and hydrophilic and have low electrical impedance. We demonstrate that PPy/PMAS supports nerve cell (PC12) differentiation, and that clinically relevant 250 Hz biphasic current pulses delivered via PPy/PMAS films significantly promote nerve cell differentiation in the presence of nerve growth factor (NGF). The capacity of PPy/PMAS composites to support and enhance nerve cell differentiation via electrical stimulation renders them valuable for medical implants for neurological applications.

Layer-by-Layer Self-Assembly of Plexcitonic Nanoparticles

DTIC Science & Technology

2013-08-12

nitrate , trisodium citrate tribasic dihydrate, sodium poly(styrene sulfonate) (PSS, MW ~70,000), poly(diallyldimethyl ammonium chloride ) (PDADMAC...Abstract: Colloidal suspensions of multilayer nanoparticles composed of a silver core, a polyelectrolyte spacer layer (inner shell), and a J-aggregate...multilayer architecture served as a framework for examining the coupling of the localized surface plasmon resonance exhibited by the silver core with

Materials comprising polydienes and hydrophilic polymers and related methods

DOEpatents

Mays, Jimmy W [Knoxville, TN; Deng, Suxiang [Knoxville, TN; Mauritz, Kenneth A [Hattiesburg, MS; Hassan, Mohammad K [Hattiesburg, MS; Gido, Samuel P [Hadley, MA

2011-11-22

Materials prepared from polydienes, such as poly(cyclohexadiene), and hydrophilic polymers, such as poly(alkylene oxide), are described. Methods of making the materials and their use in fuel cell membranes, batteries, breathable chemical-biological protective materials, and templates for sol-gel polymerization are also provided. The materials can be crosslinked and sulfonated, and can include copolymers and polymer blends.

Association of a multifunctional ionic block copolymer in a selective solvent

DOE PAGES

Etampawala, Thusitha N.; Aryal, Dipak; Osti, Naresh C.; ...

2016-11-14

The self-assembly of multiblock copolymers in solutions is controlled by a delicate balance between inherent phase segregation due to incompatibility of the blocks and the interaction of the individual blocks with the solvent. The current study elucidates the association of pentablock copolymers in a mixture of selective solvents which are good for the hydrophobic segments and poor for the hydrophilic blocks using small angle neutron scattering (SANS). The pentablock consists of a center block of randomly sulfonated polystyrene, designed for transport, tethered to poly-ethylene-r-propylene and end-capped by poly-t-butyl styrene, for mechanical stability. We find that the pentablock forms ellipsoidal core-shellmore » micelles with the sulfonated polystyrene in the core and Gaussian decaying chains of swollen poly-ethylene-r-propylene and poly-t-butyl styrene tertiary in the corona. With increasing solution concentration, the size of the micelle, the thickness of the corona, and the aggregation number increase, while the solvent fraction in the core decreases. As a result, in dilute solution the micelle increases in size as the temperature is increased, however, temperature effects dissipate with increasing solution concentration.« less

Development of graphene oxide/poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) thin film-based electrochemical surface plasmon resonance immunosensor for detection of human immunoglobulin G

NASA Astrophysics Data System (ADS)

Pothipor, Chammari; Lertvachirapaiboon, Chutiparn; Shinbo, Kazunari; Kato, Keizo; Kaneko, Futao; Ounnunkad, Kontad; Baba, Akira

2018-02-01

An electrochemically synthesized graphene oxide (GO)/poly(3,4-ethylenedioxythiophene) (PEDOT)/poly(styrene sulfonate) (PSS) thin film-based electrochemical surface plasmon resonance (EC-SPR) sensor chip was developed and employed for the detection of human immunoglobulin G (IgG). GO introduced the carboxylic group on the film surface, which also allowed electrochemical control, for the immobilization of the anti-IgG antibody via covalent bonding through amide coupling reaction. The SPR sensitivity of the detection was improved under the control by applying an electrochemical potential, by which the sensitivity was increased by the increment in applied potential. Among the open-circuit and different applied potentials in the range of -1.0 to 0.50 V, the EC-SPR immunosensor at an applied potential of 0.50 V exhibited the highest sensitivity of 6.08 × 10-3 mL µg-1 cm-2 and linearity in the human IgG concentration range of 1.0 to 10 µg mL-1 with a relatively low detection limit of 0.35 µg mL-1. The proposed sensor chip is promising for immunosensing at the physiological level.

High temperature proton exchange membranes with enhanced proton conductivities at low humidity and high temperature based on polymer blends and block copolymers of poly(1,3-cyclohexadiene) and poly(ethylene glycol)

DOE PAGES

Deng, Shawn; Hassan, Mohammad K.; Nalawade, Amol; ...

2015-09-16

Hot (at 120 °C) and dry (20% relative humidity) operating conditions benefit fuel cell designs based on proton exchange membranes (PEMs) and hydrogen due to simplified system design and increasing tolerance to fuel impurities. In this paper, presented are preparation, partial characterization, and multi-scale modeling of such PEMs based on cross-linked, sulfonated poly(1,3-cyclohexadiene) (xsPCHD) blends and block copolymers with poly(ethylene glycol) (PEG). These low cost materials have proton conductivities 18 times that of current industry standard Nafion at hot, dry operating conditions. Among the membranes studied, the blend xsPCHD-PEG PEM displayed the highest proton conductivity, which exhibits a morphology withmore » higher connectivity of the hydrophilic domain throughout the membrane. Simulation and modeling provide a molecular level understanding of distribution of PEG within this hydrophilic domain and its relation to proton conductivities. Finally, this study demonstrates enhancement of proton conductivity at high temperature and low relative humidity by incorporation of PEG and optimized sulfonation conditions.« less

Introducing multiple bio-functional groups on the poly(ether sulfone) membrane substrate to fabricate an effective antithrombotic bio-interface.

PubMed

Wang, Lingren; He, Min; Gong, Tao; Zhang, Xiang; Zhang, Lincai; Liu, Tao; Ye, Wei; Pan, Changjiang; Zhao, Changsheng

2017-11-21

It has been widely recognized that functional groups on biomaterial surfaces play important roles in blood compatibility. To construct an effective antithrombotic bio-interface onto the poly(ether sulfone) (PES) membrane surface, bio-functional groups of sodium carboxylic (-COONa), sodium sulfonic (-SO 3 Na) and amino (-NH 2 ) groups were introduced onto the PES membrane surface in three steps: the synthesis of PES with carboxylic (-COOH) groups (CPES) and water-soluble PES with sodium sulfonic (-SO 3 Na) groups and amino (-NH 2 ) groups (SNPES); the introduction of carboxylic groups onto the PES membrane by blending CPES with PES; and the grafting of SNPES onto CPES/PES membranes via the coupling of amino groups and carboxyl groups. The physical/chemical properties and bioactivities were dependent on the proportions of the additives. After introducing bio-functional groups, the excellent hemocompatibility of the modified membranes was confirmed by the inhibited platelet adhesion and activation, prolonged clotting times, suppressed blood-related complement and leukocyte-related complement receptor activations. Furthermore, cell tests indicated that the modified membranes showed better cytocompatibility in endothelial cell proliferation than the pristine PES membrane due to the synergistic promotion of the functional groups. To sum up, these results suggested that modified membranes present great potential in fields using blood-contacting materials, such as hemodialysis and surface endothelialization.

Morphology and Proton Transport in Sulfonated Block Copolymer and Mesoporous Polymer Electrolyte Membranes

NASA Astrophysics Data System (ADS)

Chen, Chelsea; Wong, David; Beers, Keith; Balsara, Nitash

2013-03-01

In an effort to understand the fundamentals of proton transport in polymer electrolyte membranes (PEMs), we have developed a series of poly(styrene-b-ethylene-b-styrene) (SES) membranes. The SES membranes were subsequently sulfonated to yield proton conducting S-SES membranes. We examine the effects of sulfonation level, temperature and thermal history on the morphology of S-SES membranes in both dry and hydrated states. The effects of these parameters on water uptake and proton transport characteristics of the membranes are also examined. Furthermore, building upon the strategy we deployed in sulfonating the SES membranes, we fabricated mesoporous S-SES membranes, with pores lined up with the proton conducting channels. These membranes have three distinct phases: structural block, proton-conducting block, and void. We examine the effects of pore size, domain structure and sulfonation level on water uptake and proton conductivity of the mesoporous PEMs at different temperatures. This work is funded by Department of Energy.

A study of the effect of polystyrene sulfonation on the performance of terephthaloyl chloride-dihydroxydiphenyl sulfone copolymer/polystyrene system

NASA Astrophysics Data System (ADS)

Kahraman, R.; Kahn, K. A.; Ali, S. A.; Hamid, S. H.; Sahin, A. Z.

1998-12-01

Thermal, morphological, and mechanical properties of composites of a liquid crystalline copolymer (LCP) poly(terephthaloyl chloride)-co-(p,p’-dihydroxydiphenyl sulfone) with polystyrene (PS) and sulfonated polystyrene (SPS) are presented and discussed. Sulfonation of polystyrene was expected to improve the interfacial adhesion by introducing hydrogen bonding in the LCP/PS system. The degree of sulfonation was 11 %. The incompatibility (lack of proper interfacial adhesion) of the LCP/PS system resulted in sharp decrease in the composite tensile strength with LCP addition. The performance of the system did not change when processed at a higher temperature (270 °C instead of 225 °C). While a composite plate of 25% LCP/PS could not be fabricated, it was possible for LCP/SPS (processed at 215 °C), indicating some improvement in interfacial bonding by sulfonation. Sulfonation of PS resulted in fracture with some degree of plastic deformation for pure SPS matrix and also the LCP/SPS system with the lowest LCP content (1 wt%), whereas plastic deformation was not observed for PS used as received. The strength of the LCP/SPS system also decreased with increase in LCP content, indicating that 11% sulfonation is not sufficient to introduce significant compatibility, but it was not as dramatic as that for LCP/PS. The performance of the LCP/SPS system was not affected significantly by heat treatment at the process temperature.

The thermal stability of photoacid generators in phenolic matrices

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

Barclay, G.G.; Medeiros, D.R.; Sinta, R.F.

1993-12-31

The thermal stability of various photolabile sulfonate esters in phenolic matrices have been investigated by differential scanning calorimetry and thermogravimetric analysis. It was observed that the thermal stability of these photoacid generators is lowered in the presence of phenolic groups. As a result acid can be thermally generated, thereby reducing the selectivity of photoacid generation. The sulfonate esters investigated in phenolic matrices included nitrobenzyl tosylates, imino sulfonates, benzoin tosylate and 1,2,3-tris(methanesulfonyloxy)benzene. Also the effect of the thermal generation of acid from these photoacid generators on the temperature and rate of deprotection of partially t-butoxycarbonate blocked poly (vinylphenol) was studied bymore » thermogravimetric analysis and FTIR.« less

Proton-conducting membrane based on epoxy resin-poly(vinyl alcohol)-sulfosuccinic acid blend and its nanocomposite with sulfonated multiwall carbon nanotubes for fuel-cell application

NASA Astrophysics Data System (ADS)

Kakati, Nitul; Das, Gautam; Yoon, Young Soo

2016-01-01

A blend of poly(vinyl alcohol) (PVA) with diglycidyl ether of bisphenol-A (DGB) in the presence of sulfosuccinic acid (SSA) was investigated as hydrolytically-stable proton-conducting membrane. The PVA modification was carried out by varying the DGB:SSA ratio (20:20, 10:20, and 5:20). A nanocomposite of the blend (20:20) was prepared with sulfonated multiwall carbon nanotubes (viz., 1, 3 and 5 wt%). The water uptake behavior and the proton conductivity of the prepared membranes were evaluated. The ionic conductivity of the membranes and the water uptake behavior depended on the s-MWCNT and the DGB contents. The ionic conductivity showed an enhancement for the blend and for the nanocomposite membrane as compared to the pristine polymer.

Special Issue on Powering the Future Force: New Power & Energy Technologies for the Warfighter (AMMTIAC Quarterly, Volume 4, Number 1 / WSTIAC Quarterly, Volume 9, Number 1)

DTIC Science & Technology

2009-04-27

an aromatic acidic polymer such as SPEEK or SPSf. Figure 5 shows four basic polymers in which benzimidazole (BIm), amino- benzimidazole (ABIm...Z., A. Manthiram, and M. D. Guiver, “Blend Membranes Based on Sulfonated Polyetheretherketone and Polysulfone Bearing Benzimidazole Side Groups for...Sulfonated Poly(ether ether ketone) and Polysulfone Bearing Benzimidazole Side Groups for Direct Methanol Fuel Cells,” Electrochemical and Solid State Letters

Simultaneous determination of caffeine and paracetamol by square wave voltammetry at poly(4-amino-3-hydroxynaphthalene sulfonic acid)-modified glassy carbon electrode.

PubMed

Tefera, Molla; Geto, Alemnew; Tessema, Merid; Admassie, Shimelis

2016-11-01

Poly(4-amino-3-hydroxynaphthalene sulfonic acid)-modified glassy carbon electrode (poly(AHNSA)/GCE) was prepared for simultaneous determination of caffeine and paracetamol using square-wave voltammetry. The method was used to study the effects of pH and scan rate on the voltammetric response of caffeine and paracetamol. Linear calibration curves in the range of 10-125μM were obtained for both caffeine and paracetamol in acetate buffer solution of pH 4.5 with a correlation coefficient of 0.9989 and 0.9986, respectively. The calculated detection limits (S/N=3) were 0.79μM for caffeine and 0.45μM for paracetamol. The effects of some interfering substances in the determination of caffeine and paracetamol were also studied and their interferences were found to be negligible which proved the selectivity of the modified electrode. The method was successfully applied for the quantitative determination of caffeine and paracetamol in Coca-Cola, Pepsi-Cola and tea samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ion-exchange composite membranes pore-filled with sulfonated poly(ether ether ketone) and Engelhard titanosilicate-10 for improved performance of vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Kim, Jihoon; Lee, Yongkyu; Jeon, Jae-Deok; Kwak, Seung-Yeop

2018-04-01

A series of ion-exchange membranes for vanadium redox flow batteries (VRBs) are prepared by filling the pores of a poly(tetrafluoroethylene) (PTFE) substrate with sulfonated poly(ether ether ketone) (SPEEK) and microporous Engelhard titanosilicate-10 (ETS-10). The effects of ETS-10 incorporation and PTFE reinforcement on membrane properties and VRB single-cell performance are investigated using various characterization tools. The results show that these composite membranes exhibit improved mechanical properties and reduced vanadium-ion permeabilities owing to the interactions between ETS-10 and SPEEK, the suppressed swelling of PTFE, and the unique ETS-10 framework. The composite membrane with 3 wt% ETS-10 (referred to as "SE3/P") exhibits the best membrane properties and highest ion selectivity. The VRB system with the SE3/P membrane exhibits higher cell capacity, higher cell efficiency, and lower capacity decay than that with a Nafion membrane. These results indicate that this composite membrane has potential as an alternative to Nafion in VRB systems.

Passivation-free solid state battery

DOEpatents

Abraham, Kuzhikalail M.; Peramunage, Dharmasena

1998-01-01

This invention pertains to passivation-free solid-state rechargeable batteries composed of Li.sub.4 Ti.sub.5 O.sub.12 anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMn.sub.2 O.sub.4, LiCoO.sub.2, LiNiO.sub.2 and LiV.sub.2 O.sub.5 and their derivatives.

Preparation and characterization of polymer blend based on sulfonated poly (ether ether ketone) and polyetherimide (SPEEK/PEI) as proton exchange membranes for fuel cells

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

Hashim, Nordiana; Ali, Ab Malik Marwan; Lepit, Ajis

2015-08-28

Blends of sulfonated poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared in five different weight ratios using N-methyl-2-pyrrolidone (NMP) as solvent by the solution cast technique. The degree of sulfonation (DS) of the sulfonated PEEK was determined from deuterated dimethyl sulfoxide (DMSO-d{sub 6}) solution of the purified polymer using {sup 1}H NMR method. The properties studied in the present investigation includes conductivity, water uptake, thermal stability and structure analysis of pure SPEEK as well as SPEEK-PEI polymer blend membranes. The experimental results show that the conductivity of the membranes increased with increase in temperature from 30 to 80°C,more » except for that of pure SPEEK membrane which increased with temperature from 30 to 60°C while its conductivity decreased with increasing temperature from 60 to 80°C. The conductivity of 70wt.%SPEEK-30wt.%PEI blend membrane at 80% relative humidity (RH) is found to be 1.361 × 10{sup −3} Scm{sup −1} at 30°C and 3.383 × 10{sup −3} Scm{sup −1} at 80°C respectively. It was also found that water uptake and thermal stability of the membranes slightly improved upon blending with PEI. Structure analysis was carried out using Fourier Transform Infrared (FTIR) spectroscopy which revealed considerable interactions between sulfonic acid group of SPEEK and imide groups of PEI. Modification of SPEEK by blending with PEI shows good potential for improving the electrical and physical properties of proton exchange membranes.« less

Fluorinated poly(ether sulfone) ionomers with disulfonated naphthyl pendants for proton exchange membrane applications

NASA Astrophysics Data System (ADS)

Hu, Zhaoxia; Lu, Yao; Zhang, Xulve; Yan, Xiaobo; Li, Na; Chen, Shouwen

2018-06-01

Proton exchange membranes based on fluorinated poly(ether sulfone)s with disulfonated naphthyl pendants (sSPFES) have been successfully prepared by post functionalization through polymeric SNAr reaction. Copolymer structure was confirmed by H-nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy, the physico-chemical properties of the sSPFES membranes were evaluated by thermogravimetric analysis, gel permeation chromatography, electro-chemical impedance spectroscopy, atomic force microscopy, Fenton, water-swelling and fuel cell test. The pendant grafting degree was controlled by varying the feeding amount of the disulfonaphthols, resulting in the ion exchange capacity about 1.28-1.73 mmol/g. The obtained sSPFES membranes were thermal stable, mechanical ductile, and exhibited dimensional change less than 17%, water uptake below 70%, and proton conductivity as high as 0.17-0.28 S/cm at 90°C in water. In a single H2/O2 fuel cell test at 80°C, the sSPFES-B-3.2 membrane (1.61 mmol/g) showed the maximum power output of 593-658 mW/cm2 at 60%-80% relative humidity, indicating their rather promising potential for fuel cell applications.

Fluorinated poly(ether sulfone) ionomers with disulfonated naphthyl pendants for proton exchange membrane applications

NASA Astrophysics Data System (ADS)

Hu, Zhaoxia; Lu, Yao; Zhang, Xulve; Yan, Xiaobo; Li, Na; Chen, Shouwen

2018-05-01

Proton exchange membranes based on fluorinated poly(ether sulfone)s with disulfonated naphthyl pendants (sSPFES) have been successfully prepared by post functionalization through polymeric SNAr reaction. Copolymer structure was confirmed by H-nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy, the physico-chemical properties of the sSPFES membranes were evaluated by thermogravimetric analysis, gel permeation chromatography, electro-chemical impedance spectroscopy, atomic force microscopy, Fenton, water-swelling and fuel cell test. The pendant grafting degree was controlled by varying the feeding amount of the disulfonaphthols, resulting in the ion exchange capacity about 1.28-1.73 mmol/g. The obtained sSPFES membranes were thermal stable, mechanical ductile, and exhibited dimensional change less than 17%, water uptake below 70%, and proton conductivity as high as 0.17-0.28 S/cm at 90°C in water. In a single H2/O2 fuel cell test at 80°C, the sSPFES-B-3.2 membrane (1.61 mmol/g) showed the maximum power output of 593-658 mW/cm2 at 60%-80% relative humidity, indicating their rather promising potential for fuel cell applications.

Organic Inorganic Hybrid Solar Cell Efficiency Improvement By Employing Au Nanocluster

DTIC Science & Technology

2015-06-14

ABSTRACT 16. SECURITY CLASSIFICATION OF: Poly( 3,4-ethyllenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS), a P-type organic polymer is frequently...Addition of small volume percentage of organic additives such as dimethyl sulfoxide (DMSO) has a positive effect on the conductivity of this polymer . In...Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 hybrid solar cell, tunable conductivity, organic polymer , heterojunction, nanocluster

Sulfonated poly(ether ether ketone)/poly(vinyl alcohol) sensitizing system for solution photogeneration of small Ag, Au, and Cu crystallites.

PubMed

Korchev, A S; Shulyak, T S; Slaten, B L; Gale, W F; Mills, G

2005-04-28

Illumination of air-free aqueous solutions containing sulfonated poly(ether ether ketone) and poly(vinyl alcohol) with 350 nm light results in benzophenone ketyl radicals of the polyketone. The polymer radicals form with a quantum yield 0.02 and decay with a second-order rate constant 6 orders of magnitude lower than that of typical alpha-hydroxy radicals. Evidence is presented that the polymeric benzophenone ketyl radicals reduce Ag+, Cu2+, and AuCl4- to metal particles of nanometer dimensions. Decreases in the reduction rates with increasing Ag(I), Cu(II), and Au(III) concentrations are explained using a kinetic model in which the metal ions quench the excited state of the polymeric benzophenone groups, which forms the macromolecular radicals. Quenching is fastest for Ag+, whereas Cu2+ and AuCl4- exhibit similar rate constants. Particle formation becomes more complex as the number of equivalents needed to reduce the metal ions increases; the Au(III) system is an extreme case where the radical reactions operate in parallel with secondary light-initiated and thermal reduction channels. For each metal ion, the polymer-initiated photoreactions produce crystallites possessing distinct properties, such as a very strong plasmon in the Ag case or the narrow size distribution exhibited by Au particles.

Highly stable multi-wall carbon nanotubes@poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) core-shell composites with three-dimensional porous nano-network for electrochemical capacitors

NASA Astrophysics Data System (ADS)

Zhou, Haihan; Han, Gaoyi; Chang, Yunzhen; Fu, Dongying; Xiao, Yaoming

2015-01-01

A facile and feasible electrochemical polymerization method has been used to construct the multi-wall carbon nanotubes@poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (MWCNTs@PEDOT/PSS) core-shell composites with three-dimensional (3D) porous nano-network microstructure. The composites are characterized with Fourier transform infrared spectroscopy, scanning electron microscope, and transmission electron microscopy. This special core-shell nanostructure can significantly reduce the ions diffusion distance and the 3D porous nano-network microstructure effectively enlarges the electrode/electrolyte interface. The electrochemical tests including cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy tests are performed, the results manifest the MWCNTs@PEDOT/PSS core-shell composites have superior capacitive behaviors and excellent cyclic stability, and a high areal capacitance of 98.1 mF cm-2 is achieved at 5 mV s-1 cyclic voltammetry scan. Furthermore, the MWCNTs@PEDOT/PSS composites exhibit obviously superior capacitive performance than that of PEDOT/PSS and PEDOT/Cl electrodes, indicating the effective composite of MWCNTs and PEDOT noticeably boosts the capacitive performance of PEDOT-based electrodes for electrochemical energy storage. Such a highly stable core-shell 3D network structural composite is very promising to be used as electrode materials for the high-performance electrochemical capacitors.

Poly(3,4-ethylenedioxythiophene):GlycosAminoGlycan Aqueous Dispersions: Toward Electrically Conductive Bioactive Materials for Neural Interfaces.

PubMed

Mantione, Daniele; Del Agua, Isabel; Schaafsma, Wandert; Diez-Garcia, Javier; Castro, Begona; Sardon, Haritz; Mecerreyes, David

2016-08-01

There is an actual need of advanced materials for the emerging field of bioelectronics. One commonly used material is the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) ( PSS) due to its general use in organic electronics. However, depending on the application in bioelectronics, PSS is not fully biocompatible due to the high acidity of the residual sulfonate protons of PSS. In this paper, the synthesis and biocompatibility properties of new poly(3,4-ethylenedioxythiophene):GlycosAminoGlycan ( GAG) aqueous dispersions and its resulting films are shown. Thus, negatively charged GAGs as an alternative to PSS are presented. Three different commercially available GAGs, hyaluronic acid, heparin, and chondroitin sulfate are used. Indeed, GAGs dispersions are prepared through an oxidative chemical polymerization in water. Biocompatibility assays of the GAGs coatings are performed using SH-SY5Y and CCF-STTG1 cell lines and with ATP and Ca(2+) . Results show full biocompatibility and a pronounced anti-inflammatory effect. This last characteristic becomes crucial if implanted in the body. These materials can be used for in vivo applications, as transistor or electrode for electrical recording and for all the possible situations when there is contact between electronic circuits and living tissues. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Storey, Robson, F.; Mauritz, Kenneth, A.; Patton, Derek, L.

The overall objective of this project was the development and evaluation of novel hydrocarbon fuel cell (FC) membranes that possess high temperature performance and long term chemical/mechanical durability in proton exchange membrane (PEM) fuel cells (FC). The major research theme was synthesis of aromatic hydrocarbon polymers of the poly(arylene ether sulfone) (PAES) type containing sulfonic acid groups tethered to the backbone via perfluorinated alkylene linkages and in some cases also directly attached to the phenylene groups along the backbone. Other research themes were the use of nitrogen-based heterocyclics instead of acid groups for proton conduction, which provides high temperature, lowmore » relative humidity membranes with high mechanical/thermal/chemical stability and pendant moieties that exhibit high proton conductivities in the absence of water, and synthesis of block copolymers consisting of a proton conducting block coupled to poly(perfluorinated propylene oxide) (PFPO) blocks. Accomplishments of the project were as follows: 1) establishment of a vertically integrated program of synthesis, characterization, and evaluation of FC membranes, 2) establishment of benchmark membrane performance data based on Nafion for comparison to experimental membrane performance, 3) development of a new perfluoroalkyl sulfonate monomer, N,N-diisopropylethylammonium 2,2-bis(p-hydroxyphenyl) pentafluoropropanesulfonate (HPPS), 4) synthesis of random and block copolymer membranes from HPPS, 5) synthesis of block copolymer membranes containing high-acid-concentration hydrophilic blocks consisting of HPPS and 3,3'-disulfonate-4,4'-dichlorodiphenylsulfone (sDCDPS), 6) development of synthetic routes to aromatic polymer backbones containing pendent 1H-1,2,3-triazole moieties, 7) development of coupling strategies to create phase-separated block copolymers between hydrophilic sulfonated prepolymers and commodity polymers such as PFPO, 8) establishment of basic performance properties of experimental membranes, 9) fabrication and FC performance testing of membrane electrode assemblies (MEA) from experimental membranes, and 10) measurement of ex situ and in situ membrane durability of experimental membranes. Although none of the experimental hydrocarbon membranes that issued from the project displayed proton conductivities that met DOE requirements, the project contributed to our basic understanding of membrane structure-property relationships in a number of key respects. An important finding of the benchmark studies is that physical degradation associated with humidity and temperature variations in the FC tend to open new fuel crossover pathways and act synergistically with chemical degradation to accelerate overall membrane degradation. Thus, for long term membrane survival and efficient fuel utilization, membranes must withstand internal stresses due to humidity and temperature changes. In this respect, rigid aromatic hydrocarbon fuel cell membranes, e.g. PAES, offer an advantage over un-modified Nafion membranes. The benchmark studies also showed that broadband dielectric spectroscopy is a potentially powerful tool in assessing shifts in the fundamental macromolecular dynamics caused by Nafion chemical degradation, and thus, this technique is of relevance in interrogating proton exchange membrane durability in fuel cells and macromolecular dynamics as coupled to proton migration, which is of fundamental relevance in proton exchange membranes in fuel cells. A key finding from the hydrocarbon membrane synthesis effort was that rigid aromatic polymers containing isolated ion exchange groups tethered tightly to the backbone (short tether), such as HPPS, provide excellent mechanical and durability properties but do not provide sufficient conductivity, in either random or block configuration, when used as the sole ion exchange monomer. However, we continue to hypothesize that longer tethers, and tethered groups spaced more closely within the hydrophilic chain elements of the polymer, will yield highly conductive materials with excellent mechanical properties. Another key finding is the superior performance of PAES membranes upon being subjected to open circuit voltage (OCV) testing. Throughout the course of the experiment, OCV for the PAES not only stayed higher but also decayed at a much lower rate, which is attributed to better dimensional stability and improved mechanical and gas barrier properties. The rigid backbone reinforcement of PAES adds gas diffusion tortuosity that restricts membrane degradation and OCV loss due to reduced fuel crossover. The overall results of creep, contractile stress and mechanical tensile tests confirm the conclusion that degraded MEAs of PAES membrane can handle stress and are more likely to be more durable in a fuel cell, even after subjected to 62h of OCV degradation.« less

Study of sulfonated polyether ether ketone with pendant lithiated fluorinated sulfonic groups as ion conductive binder in lithium-ion batteries

NASA Astrophysics Data System (ADS)

Wei, Zengbin; Xue, Lixin; Nie, Feng; Sheng, Jianfang; Shi, Qianru; Zhao, Xiulan

2014-06-01

In an attempt to reduce the Li+ concentration polarization and electrolyte depletion from the electrode porous space, sulfonated polyether ether ketone with pendant lithiated fluorinated sulfonic groups (SPEEK-FSA-Li) is prepared and attempted as ionic conductivity binder. Sulfonated aromatic poly(ether ether ketone) exhibits strong adhesion and chemical stability, and lithiated fluorinated sulfonic side chains help to enhance the ionic conductivity and Li+ ion diffusion due to the charge delocalization over the sulfonic chain. The performances are evaluated by cyclic voltammetry, electrochemical impedance spectroscopy, charge-discharge cycle testing, 180° peel testing, and compared with the cathode prepared with polyvinylidene fluoride binder. The electrode prepared with SPEEK-FSA-Li binder forms the relatively smaller resistances of both the SEI and the charge transfer of lithium ion transport. This is beneficial to lithium ion intercalation and de-intercalation of the cathode during discharging-charging, therefore the cell prepared with SPEEK-FSA-Li shows lower charge plateau potential and higher discharge plateau potential. Compared with PVDF, the electrode with ionic binder shows smaller decrease in capacity with the increasing of cycle rate. Meanwhile, adhesion strength of electrode prepared with SPEEK-FSA-Li is more than five times greater than that with PVDF.

High performance polymer development

NASA Technical Reports Server (NTRS)

Hergenrother, Paul M.

1991-01-01

The term high performance as applied to polymers is generally associated with polymers that operate at high temperatures. High performance is used to describe polymers that perform at temperatures of 177 C or higher. In addition to temperature, other factors obviously influence the performance of polymers such as thermal cycling, stress level, and environmental effects. Some recent developments at NASA Langley in polyimides, poly(arylene ethers), and acetylenic terminated materials are discussed. The high performance/high temperature polymers discussed are representative of the type of work underway at NASA Langley Research Center. Further improvement in these materials as well as the development of new polymers will provide technology to help meet NASA future needs in high performance/high temperature applications. In addition, because of the combination of properties offered by many of these polymers, they should find use in many other applications.

Flexible resistive switching device based on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/poly(4-vinylphenol) (PVP) composite and methyl red heterojunction

NASA Astrophysics Data System (ADS)

Hassan, Gul; Ali, Shawkat; Bae, Jinho; Lee, Chong Hyun

2017-04-01

To obtain a desired performance of non-volatile memory applications, heterojunction-based resistive switching devices have tremendous attractions. In this paper, we demonstrate resistive switching characteristics for heterojunction of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/poly(4-vinylphenol) (PVP) composite and methyl red sandwiched in between bottom and top silver (Ag) electrodes. The proposed heterojunction layers are fabricated through spin coater at 3000 rpm for 60 s each, and the Ag electrodes are deposited through a commercialized inkjet printer DMP-3000 on polyethyleneterephthalate (PET) substrate. To verify the proposed device, the resistive switching on dual polarity voltage of ±10.2 V is measured over more than 500 endurance cycles. The paper also presents an R off/ R on ratio which can adjust through an active layer's area and a blending ratio of the PEDOT:PSS and PVP. By applying the area of 100 μm2 and the blending ratio of 3:1, we achieve the higher R off/ R on ratio of 121, and its high resistance state (HRS) and low resistance state (LRS) are observed as 3000 kΩ and 24.7 kΩ, respectively. To maintain a long retention time, the device is encapsulated with PDMS, which changes a little variations of 52 Ω for HRS 498 Ω for LRS over 60 days. For the flexible realization to be utilized in wearable applications, it can be easily applied on a plastic substrate using printed technologies.

Hierarchical porous poly (ether sulfone) membranes with excellent capacity retention for vanadium flow battery application

NASA Astrophysics Data System (ADS)

Chen, Dongju; Li, Dandan; Li, Xianfeng

2017-06-01

A hierarchical poly (ether sulfone) (PES) porous membrane is facilely fabricated via a hard template method for vanadium flow battery (VFB) application. The construction of this hierarchical porous membrane is prepared via removing templates (phenolphthalein). The pore size can be well controlled by optimizing the template content in the cast solution, ensuring the membrane conductivity and selectively. The prepared hierarchical porous membrane can combine high ion selectivity with high proton conductivity, which renders a good electrochemical performance in a VFB. The optimized hierarchical porous membrane shows a columbic efficiency of 94.52% and energy efficiency of 81.66% along with a superior ability to maintain stable capacity over extended cycling at a current density of 80 mA cm-2. The characteristics of low cost, proven chemical stability and high electrochemical performance afford the hierarchical PES porous membrane great prospect in VFB application.

Particle-based Nano-Antennas at the Vis-NIR regime

DTIC Science & Technology

2013-11-01

PSS (poly(3,4-ethylenedioxythiophene) :poly(styrene sulfonate) is then spin coated and dried at 110oC to form a 50nm buffer layer partially covering...dominant effect is that during the spin coating of the 50nm PEDOT buffer a residual very thin layer coated also the top 50nm part of the Au disks...antennas, capacitive versus conductive coupling, on-demand design (termed ‘popcorn’ antennas), broadband plasmonic metamaterials, and light

Passivation-free solid state battery

DOEpatents

Abraham, K.M.; Peramunage, D.

1998-06-16

This invention pertains to passivation-free solid-state rechargeable batteries composed of Li{sub 4}Ti{sub 5}O{sub 12} anode, a solid polymer electrolyte and a high voltage cathode. The solid polymer electrolyte comprises a polymer host, such as polyacrylonitrile, poly(vinyl chloride), poly(vinyl sulfone), and poly(vinylidene fluoride), plasticized by a solution of a Li salt in an organic solvent. The high voltage cathode includes LiMn{sub 2}O{sub 4}, LiCoO{sub 2}, LiNiO{sub 2} and LiV{sub 2}O{sub 5} and their derivatives. 5 figs.

Positively charged and bipolar layered poly(ether imide) nanofiltration membranes for water softening applications

NASA Astrophysics Data System (ADS)

Gassara, S.; Abdelkafi, A.; Quémener, D.; Amar, R. Ben; Deratani, A.

2015-07-01

Poly(ether imide) (PEI) ultrafiltration membranes were chemically modified with branched poly(ethyleneimine) to obtain nanofiltration (NF) membrane Cat PEI with a positive charge in the pH range below 9. An oppositely charged polyelectrolyte layer was deposited on the resulting membrane surface by using sodium polystyrene sulfonate (PSSNa) and sodium polyvinyl sulfonate (PVSNa) to prepare a bipolar layered membrane NF Cat PEI_PSS and Cat PEI_PVS having a negatively charged surface and positively charged pores. Cat PEI exhibited good performance to remove multivalent cations (more than 90% of Ca2+) from single salt solutions except in presence of sulfate ions. Adding an anionic polyelectrolyte layer onto the positively charged surface resulted in a significant enhancement of rejection performance even in presence of sulfate anions. Application of the prepared membranes in water softening of natural complex mixtures was successful for the different studied membranes and a large decrease of hardness was obtained. Moreover, Cat PEI_PSS showed a good selectivity for nitrate removal. Fouling experiments were carried out with bovine serum albumin, as model protein foulant. Cat PEI_PSS showed much better fouling resistance than Cat PEI with a quantitative flux recovery ratio.

Optical-Electrical-Chemical Engineering of PEDOT:PSS by Incorporation of Hydrophobic Nafion for Efficient and Stable Perovskite Solar Cells.

PubMed

Ma, Shuang; Qiao, Wenyuan; Cheng, Tai; Zhang, Bing; Yao, Jianxi; Alsaedi, Ahmed; Hayat, Tasawar; Ding, Yong; Tan, Zhan'ao; Dai, Songyuan

2018-01-31

In PIN-type perovskite solar cells (PSCs), the hydroscopicity and acidity of the poly(3,4-ethylenedioxythiophene)-poly(styrene-sulfonate) (PEDOT:PSS) hole transport layer (HTL) have critical influences on the device stability. To eliminate these problems, Nafion, the hydrophobic perfluorosulfonic copolymer, is incorporated into PEDOT:PSS by a simple spin-coating process. For the modified film, Nafion/PSSH (poly(styrene sulfonate) acid) acts as an electron-blocking layer on the surface and the PEDOT-rich domain tends to gather into larger particles with better interchain charge transfer inside the film. Consequently, the modified PEDOT:PSS HTL shows enhanced conductivity and light transmittance as well as more favorable work function, ending up with the increased short-circuit current density (J sc ) and open-circuit voltage (V oc ) of the device. Finally, PSCs with Nafion-modified HTLs achieve the best power conversion efficiency of 16.72%, with 23.76% improvement compared with PEDOT:PSS-only devices (13.51%). Most importantly, the device stability is obviously enhanced because of the hydrophobicity and chemical and mechanical stability of the Nafion polymer that is enriched on the surface of the PEDOT:PSS film.

Nuclear magnetic resonance investigation of dynamics in poly(ethylene oxide)-based lithium polyether-ester-sulfonate ionomers

DOE PAGES

Roach, David J.; Dou, Shichen; Colby, Ralph H.; ...

2012-01-06

Nuclear magnetic resonance (NMR) spectroscopy has been utilized to investigate the dynamics of poly(ethylene oxide)-based lithium sulfonate ionomer samples that have low glass transition temperatures. 1H and 7Li spin-lattice relaxation times (T 1) of the bulk polymer and lithium ions, respectively, were measured and analyzed in samples with a range of ion contents. The temperature dependence of T 1 values along with the presence of minima in T 1 as a function of temperature enabled correlation times and activation energies to be obtained for both the segmental motion of the polymer backbone and the hopping motion of lithium cations. Similarmore » activation energies for motion of both the polymer and lithium ions in the samples with lower ion content indicate that the polymer segmental motion and lithium ion hopping motion are correlated in these samples, even though their respective correlation times differ significantly. A divergent trend is observed for correlation times and activation energies of the highest ion content sample with 100% lithium sulfonation due to the presence of ionic aggregation. Details of the polymer and cation dynamics on the nanosecond timescale are discussed and complement the findings of X-ray scattering and Quasi Elastic Neutron Scattering experiments.« less

High-performance free-standing capacitor electrodes of multilayered Co9S8 plates wrapped by carbonized poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/reduced graphene oxide

NASA Astrophysics Data System (ADS)

Yao, Tinghui; Li, Yali; Liu, Dequan; Gu, Yipeng; Qin, Shengchun; Guo, Xin; Guo, Hui; Ding, Yongqiang; Liu, Qiming; Chen, Qiang; Li, Junshuai; He, Deyan

2018-03-01

In this paper, a free-standing electrode structure composed of multilayered Co9S8 plates wrapped by carbonized poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)/reduced graphene oxide (PEDOT:PSS/rGO) layers is introduced. Excellent supercapacitive behaviors, especially long cycling stability at high current densities are delivered owing to the synergetic effects of stable electrical contact between the active material and carbonized PEDOT:PSS/rGO due to the wrapped configuration, efficient charge exchange between the multilayered Co9S8 plates and electrolyte, improved electrical conductance by rGO, and plenty of voids for accommodating volume changes. For the optimized electrode (starting materials: 0.5 mL PEDOT:PSS, 1.0 mL GO (6.0 mg mL-1) and 10.0 mg Co(OH)2), a specific capacitance of about 788.9 F g-1 at 1.0 A g-1 and good cycling stability of over 100% of the initial capacitance (∼488.6 F g-1) after 10000 cycles at a current density of 15.0 A g-1 can be achieved. The assembled asymmetric supercapacitor based on the optimized electrode//active carbon exhibits an energy density of ∼19.6 Wh kg-1 at a power density of 400.9 W kg-1.

Enhanced proton conductivity of proton exchange membranes by incorporating sulfonated metal-organic frameworks

NASA Astrophysics Data System (ADS)

Li, Zhen; He, Guangwei; Zhao, Yuning; Cao, Ying; Wu, Hong; Li, Yifan; Jiang, Zhongyi

2014-09-01

In this study, octahedral crystal MIL101(Cr) with a uniform size of ∼400 nm is synthesized via hydrothermal reaction. It is then functionalized with sulfonic acid groups by concentrated sulfuric acid and trifluoromethanesulfonic anhydride in nitromethane. The sulfonated MIL101(Cr) are homogeneously incorporated into sulfonated poly(ether ether ketone) (SPEEK) matrix to prepare hybrid membranes. The performances of hybrid membranes are evaluated by proton conductivity, methanol permeability, water uptake and swelling property, and thermal stability. The methanol permeability increased slightly from 6.12 × 10-7 to 7.39 × 10-7 cm2 s-1 with the filler contents increasing from 0 to 10 wt. %. However, the proton conductivity of the hybrid membranes increased significantly. The proton conductivity is increased up to 0.306 S cm-1 at 75 °C and 100% RH, which is 96.2% higher than that of pristine membranes (0.156 S cm-1). The increment of proton conductivity is attributed to the following multiple functionalities of the sulfonated MIL101(Cr) in hybrid membranes: i) providing sulfonic acid groups as facile proton hopping sites; ii) forming additional proton-transport pathways at the interfaces of polymer and MOFs; iii) constructing hydrogen-bonded networks for proton conduction via -OH provided by the hydrolysis of coordinatively unsaturated metal sites.

π-Electron-system-layered polymer: through-space conjugation and properties as a single molecular wire.

PubMed

Morisaki, Yasuhiro; Ueno, Shizue; Saeki, Akinori; Asano, Atsushi; Seki, Shu; Chujo, Yoshiki

2012-04-02

[2.2]Paracyclophane-based through-space conjugated oligomers and polymers were prepared, in which poly(p-arylene-ethynylene) (PAE) units were partially π-stacked and layered, and their properties in the ground state and excited state were investigated in detail. Electronic interactions among PAE units were effective through at least ten units in the ground state. Photoexcited energy transfer occurred from the stacked PAE units to the end-capping PAE moieties. The electrical conductivity of the polymers was estimated using the flash-photolysis time-resolved microwave conductivity (FP-TRMC) method and investigated together with time-dependent density functional theory (TD-DFT) calculations, showing that intramolecular charge carrier mobility through the stacked PAE units was a few tens of percentage larger than through the twisted PAE units. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performances of biological aerated filter employing hollow fiber membrane segments of surface-improved poly (sulfone) as biofilm carriers.

PubMed

Shen, Ying-Jie; Wu, Guang-Xia; Fan, Yao-Bo; Zhong, Hui; Wu, Lin-Lin; Zhang, Shao-Lai; Zhao, Xian-Hong; Zhang, Wei-Jun

2007-01-01

Using the surface of poly (sulfone) hollow fiber membrane segments as grafted layer, the hydrophilic acrylamide chain was grafted on by UV-photoinduced grafting polymerization. The gained improvement of surface wettability for the modified membrane was tested by measuring the contact-angle as well as FTIR spectra. Then correlation between the hydrophilic ability of support material and the biofilm adherence ability was demonstrated by comparing the pollutant removal rates from urban wastewater via two identical lab-scale up-flow biological aerated filters, one employed the surface wettability modified poly (sulfone) hollow fiber membrane segment as biofilm carrier and the other employed unmodified membrane segment as biofilm carrier. The experimental results showed that under the conditions of influent flux 5 L/h, hydraulic retention time 9 h and gas to liquid ratio (G/L) 10:1, the removal rates of chemical oxygen demand (COD) and ammonium nitrogen (NH4(+)-N) for the modified packing filter and the unmodified packing filter was averaged at 83.64% and 96.25%, respectively, with the former filter being 5%-20% more than the latter. The effluent concentration of COD, NH4(+)-N and turbidity for the modified packing filter was 25.25 mg/L, 2 mg/L and 8 NTU, respectively. Moreover, the ammonium nitrogen removal performance of the filter packing the modified PSF was compared with the other bioreactor packing of an efficient floating medium. The biomass test indicated that the modified membrane matrixes provided better specific adhesion (3310-5653 mg TSS/L support), which gave a mean of 1000 mg TSS/L more than the unmodified membrane did. In addition, the phenomenon of simultaneous denitrification on the inner surface of the support and nitrification on the outer surface was found in this work.

Fabrication of composite membranes using copper metal organic framework for energy application

NASA Astrophysics Data System (ADS)

Gahlot, Swati; Rajput, Abhishek; Kulshrestha, Vaibhav

2018-04-01

Present manuscript deals with the synthesis of nanocomposite polymer electrolyte membrane (PEM) based on copper based metal organic framework (Cu-MOF) and sulfonated poly ether sulfone (SPES) for fuel cell application. Prepared material and composite membrane has been analyzed through various techniques. Structural and thermal characterization of prepared material has been carried out through XRD, FTIR and TGA technique. Measurement shows the successful synthesis of MOF and also confirms the thermal stability. Prepared membranes shows good physicochemical properties and good ionic conductivity which can be utilized as PEM for fuel cell application.

Novel Polyanions Inhibiting Replication of Influenza Viruses

PubMed Central

Ciejka, Justyna; Milewska, Aleksandra; Wytrwal, Magdalena; Wojarski, Jacek; Golda, Anna; Ochman, Marek; Nowakowska, Maria

2016-01-01

Novel sulfonated derivatives of poly(allylamine hydrochloride) (NSPAHs) and N-sulfonated chitosan (NSCH) have been synthesized, and their activity against influenza A and B viruses has been studied and compared with that of a series of carrageenans, marine polysaccharides of well-documented anti-influenza activity. NSPAHs were found to be nontoxic and very soluble in water, in contrast to gel-forming and thus generally poorly soluble carrageenans. In vitro and ex vivo studies using susceptible cells (Madin-Darby canine kidney epithelial cells and fully differentiated human airway epithelial cultures) demonstrated the antiviral effectiveness of NSPAHs. The activity of NSPAHs was proportional to the molecular mass of the chain and the degree of substitution of amino groups with sulfonate groups. Mechanistic studies showed that the NSPAHs and carrageenans inhibit influenza A and B virus assembly in the cell. PMID:26729490

Electricity generation and removal performance of a microbial fuel cell using sulfonated poly (ether ether ketone) as proton exchange membrane to treat phenol/acetone wastewater.

PubMed

Wu, Hao; Fu, Yu; Guo, Chunyu; Li, Yanbo; Jiang, Nanzhe; Yin, Chengri

2018-07-01

The microbial fuel cell (MFC) has emerged as a promising technology for wastewater treatment and energy recovery, but the expensive cost of proton exchange membranes (PEMs) is a problem that need to be solved. In this study, a two-chamber MFC based on our self-made PEM sulfonated poly (ether ether ketone) membrane was set up to treat phenol/acetone wastewater and synchronously generate power. The maximum output voltage was 240-250 mV. Using phenol and acetone as substrates, the power generation time in an operation cycle was 289 h. The MFC exhibited good removal performance, with no phenol or acetone detected, respectively, when the phenol concentration was lower than 50 mg/L and the acetone concentration was lower than 100 mg/L. This study provides a cheap and eco-friendly way to treat phenol/acetone wastewater and generate useful energy by MFC technology. Copyright © 2018 Elsevier Ltd. All rights reserved.

Optimised mounting conditions for poly (ether sulfone) in radiation detection.

PubMed

Nakamura, Hidehito; Shirakawa, Yoshiyuki; Sato, Nobuhiro; Yamada, Tatsuya; Kitamura, Hisashi; Takahashi, Sentaro

2014-09-01

Poly (ether sulfone) (PES) is a candidate for use as a scintillation material in radiation detection. Its characteristics, such as its emission spectrum and its effective refractive index (based on the emission spectrum), directly affect the propagation of light generated to external photodetectors. It is also important to examine the presence of background radiation sources in manufactured PES. Here, we optimise the optical coupling and surface treatment of the PES, and characterise its background. Optical grease was used to enhance the optical coupling between the PES and the photodetector; absorption by the grease of short-wavelength light emitted from PES was negligible. Diffuse reflection induced by surface roughening increased the light yield for PES, despite the high effective refractive index. Background radiation derived from the PES sample and its impurities was negligible above the ambient, natural level. Overall, these results serve to optimise the mounting conditions for PES in radiation detection. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effect of ionic membrane properties on the performance of ionic polymer-metal composite (IPMC) actuator

NASA Astrophysics Data System (ADS)

Jho, Jae Y.; Han, Man J.; Park, Jong H.; Lee, Jang Y.; Wang, Hyuck S.

2005-05-01

On purpose to overcome the limit of conventional ionic polymer-metal composites (IPMC) using the commercial ionic membranes, novel IPMCs with radiation-grafted ion-exchange membranes were prepared. Poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-co-HFP) and poly(ethylene-co-tetrafluoroethylene) (ETFE) were radiation-grafted with styrene, and then sulfonated. The properties of the membranes were modulated by controlling the amount of polystyrene sulfonic acid (PSSA) groups in the membranes. The amount of PSSA groups were tuned by controlling the total absorbed dose of γ-ray. The membranes were characterized by measuring the water-uptake, the ion-exchange capacity, and the ion conductivity. The performance of the IPMCs using these membranes were analyzed with laser displacement meter. They exhibited much larger bending displacement in comparison with Nafion-based IPMC. With increasing the amount of PSSA groups, the maximum displacement and the bending speed were remarkably increased. The results made sure that the property of ion-exchange membrane was the key element affecting the actuation performance of IPMC.

Molecular deformation and stress-strain behavior of poly(bisphenol-A-diphenyl sulfone)

NASA Technical Reports Server (NTRS)

Hong, S.-D.; Chung, S. Y.; Fedors, R. F.

1983-01-01

The strain-birefringence response of poly(bisphenol-A-diphenyl sulfone) is found to be independent of temperature at temperatures below -100 C; at higher temperatures, the response becomes slightly dependent on temperature, with lower birefringence seen at higher temperatures. The stress-strain behavior and the stress-birefringence response both depend on temperature over the entire testing temperature range (-179 C to 150 C) studied; this dependence, however, is not pronounced. The evidence is seen as suggesting that the polymer molecules respond to deformation by undergoing conformational rearrangements; the mode of the molecular deformation remains unchanged for temperatures of -100 C or lower. At higher temperatures, the average length of the chain segments involved in the rearrangement increases. The stress-strain response is attributed mainly to chain orientation. The entropic contribution deriving from chain orientation at temperatures below -100 C is still substantial. The modest temperature dependence of the stress-strain response suggests that the energy barriers for the chain segments involved in the rearrangement are relatively low.

Phase Behavior of a Single Structured Ionomer Chain in Solution

DOE PAGES

Aryal, Dipak; Etampawala, Thusitha; Perahia, Dvora; ...

2014-08-14

Structured polymers offer a means to tailor transport pathways within mechanically stable manifolds. Here we examine the building block of such a membrane, namely a single large pentablock co-polymer that consist of a center block of a randomly sulfonated polystyrene, designed for transport, tethered to poly-ethylene-r-propylene and end-capped by poly-t-butyl styrene, for mechanical stability,using molecular dynamics simulations. The polymer structure in a cyclohexane-heptane mixture, a technologically viable solvent, and in water, a poor solvent for all segments and a ubiquitous substance is extracted. In all solvents the pentablock collapsed into nearly spherical aggregates where the ionic block is segregated. Inmore » hydrophobic solvents, the ionic block resides in the center, surrounded by swollen intermix of flexible and end blocks. In water all blocks are collapsed with the sulfonated block residing on the surface. Our results demonstrate that solvents drive different local nano-segregation, providing a gateway to assemble membranes with controlled topology.« less

Highly stable ionic-covalent cross-linked sulfonated poly(ether ether ketone) for direct methanol fuel cells

NASA Astrophysics Data System (ADS)

Lei, Linfeng; Zhu, Xingye; Xu, Jianfeng; Qian, Huidong; Zou, Zhiqing; Yang, Hui

2017-05-01

A novel ionic cross-linked sulfonated poly(ether ether ketone) containing equal content of sulfonic acid and pendant tertiary amine groups (TA-SPEEK) has been initially synthesized for the application in direct methanol fuel cells (DMFCs). By adjusting the ratio of p-xylene dibromide to tertiary amine groups of TA-SPEEK, a series of ionic-covalent cross-linked membranes (C-SPEEK-x) with tunable degree of cross-linking are prepared. Compared with the pristine membrane, the ionic and ionic-covalent cross-linked proton exchange membranes (PEMs) exhibit reduced methanol permeability and improved mechanical properties, dimensional and oxidative stability. The proton conductivity and methanol selectivity of protonated TA-SPEEK and C-SPEEK-x at 25 °C is up to 0.109 S cm-1 and 3.88 × 105 S s cm-3, respectively, which are higher than that of Nafion 115. The DMFC incorporating C-SPEEK-25 exhibits a maximum power density as high as 35.3 mW cm-2 with 4 M MeOH at 25 °C (31.8 mW cm-2 for Nafion 115). Due to the highly oxidative stability of the membrane, no obvious performance degradation of the DMFC is observed after more than 400 h operation, indicating such cost-effective ionic-covalent cross-linked membranes have substantial potential as alternative PEMs for DMFC applications.

Processable dodecylbenzene sulfonic acid (DBSA) doped poly(N-vinyl carbazole)-poly(pyrrole) for optoelectronic applications

PubMed Central

Hammed, W. A.; Rahman, M. S.; Mahmud, H. N. M. E.; Yahya, R.; Sulaiman, K.

2017-01-01

Abstract A soluble poly (n-vinyl carbazole)–polypyrrole (PNVC–Ppy) copolymer was prepared through oxidative chemical polymerization wherein dodecyl benzene sulfonic acid (DBSA) was used as a dopant to facilitate polymer-organic solvent interaction and ammonium persulfate (APS) was used as an oxidant. Compared with undoped PNVC–Ppy, the DBSA-doped PNVC–Ppy copolymer showed higher solubility in some selected organic solvents. The composition and structural characteristics of the DBSA-doped PNVC–Ppy were determined by Fourier transform infrared, ultraviolet–visible, and X-ray diffraction spectroscopic methods. Field emission scanning electron microscopic method was employed to observe the morphology of the DBSA-doped PNVC–Ppy copolymer. The electrical conductivity of the DBSA-doped PNVC–Ppy copolymer was measured at room temperature. The conductivity increased with increasing concentration of APS oxidant, and the highest conductivity was recorded at 0.004 mol/dm3 APS at a polymerization temperature of −5 °C. The increased conductivity can be explained by the extended half-life of pyrrole free radical at a lower temperature and a gradual increase in chain length over a prolonged time due to the slow addition of APS. Furthermore, the obtained soluble copolymer exhibits unique optical and thermal properties different from those of PNVC and Ppy. PMID:29491808

Conjugated polymer zwitterions and solar cells comprising conjugated polymer zwitterions

DOEpatents

Emrick, Todd; Russell, Thomas; Page, Zachariah; Liu, Yao

2018-06-05

A conjugated polymer zwitterion includes repeating units having structure (I), (II), or a combination thereof ##STR00001## wherein Ar is independently at each occurrence a divalent substituted or unsubstituted C_3-30 arylene or heteroarylene group; L is independently at each occurrence a divalent C_1-16 alkylene group, C_6-30arylene or heteroarylene group, or alkylene oxide group; and R¹ is independently at each occurrence a zwitterion. A polymer solar cell including the conjugated polymer zwitterion is also disclosed.

Silylene-diethynyl-arylene polymers having liquid crystalline properties

DOEpatents

Barton, Thomas J.; Ding, Yiwei

1993-09-07

The present invention provides linear organosilicon polymers including diethynyl-(substituted)arylene units, and a process for their preparation. These novel polymers possess useful properties including electrical conductivity, liquid crystallinity, and/or photoluminescence. These polymers possess good solubility in organic solvents. A preferred example is produced according to the following reaction scheme. ##STR1## These polymers can be solvent-cast to yield excellent films and can also be pulled into fibers from concentrated solutions. All possess substantial crystallinity as revealed by DSC analysis and observation through a polarizing microscope, and possess liquid crystalline properties.

Structure and Dynamics Ionic Block co-Polymer Melts: Computational Study

NASA Astrophysics Data System (ADS)

Aryal, Dipak; Perahia, Dvora; Grest, Gary S.

Tethering ionomer blocks into co-polymers enables engineering of polymeric systems designed to encompass transport while controlling structure. Here the structure and dynamics of symmetric pentablock copolymers melts are probed by fully atomistic molecular dynamics simulations. The center block consists of randomly sulfonated polystyrene with sulfonation fractions f = 0 to 0.55 tethered to a hydrogenated polyisoprene (PI), end caped with poly(t-butyl styrene). We find that melts with f = 0.15 and 0.30 consist of isolated ionic clusters whereas melts with f = 0.55 exhibit a long-range percolating ionic network. Similar to polystyrene sulfonate, a small number of ionic clusters slow the mobility of the center of mass of the co-polymer, however, formation of the ionic clusters is slower and they are often intertwined with PI segments. Surprisingly, the segmental dynamics of the other blocks are also affected. NSF DMR-1611136; NERSC; Palmetto Cluster Clemson University; Kraton Polymers US, LLC.

All printed touchless human-machine interface based on only five functional materials

NASA Astrophysics Data System (ADS)

Scheipl, G.; Zirkl, M.; Sawatdee, A.; Helbig, U.; Krause, M.; Kraker, E.; Andersson Ersman, P.; Nilsson, D.; Platt, D.; Bodö, P.; Bauer, S.; Domann, G.; Mogessie, A.; Hartmann, Paul; Stadlober, B.

2012-02-01

We demonstrate the printing of a complex smart integrated system using only five functional inks: the fluoropolymer P(VDF:TrFE) (Poly(vinylidene fluoride trifluoroethylene) sensor ink, the conductive polymer PEDOT:PSS (poly(3,4 ethylenedioxythiophene):poly(styrene sulfonic acid) ink, a conductive carbon paste, a polymeric electrolyte and SU8 for separation. The result is a touchless human-machine interface, including piezo- and pyroelectric sensor pixels (sensitive to pressure changes and impinging infrared light), transistors for impedance matching and signal conditioning, and an electrochromic display. Applications may not only emerge in human-machine interfaces, but also in transient temperature or pressure sensing used in safety technology, in artificial skins and in disposable sensor labels.

High-Speed Coating Method for Photovoltaic Textiles with Closed-Type Die Coater

NASA Astrophysics Data System (ADS)

Imai, Takahiko; Shibayama, Norihisa; Takamatsu, Seiichi; Shiraishi, Kenji; Marumoto, Kazuhiro; Itoh, Toshihiro

2013-06-01

We developed a closed-type die-coating method to fabricate thin films for electronic devices. We succeeded in the die-coating of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) water dispersions and regioregular poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) solution to fabricate thin films of these organic materials with extremely high speeds of 5 and 20 m/min, respectively. The film thicknesses were evaluated by cross-sectional scanning electron microscopy (SEM). The deviations of the film thicknesses from our target values were less than 5%. We fabricated Al/P3HT:PCBM/PEDOT:PSS/indium tin oxide (ITO)/poly(ethylene terephthalate) (PET) textiles as an example of an application of the method, and the photovoltaic characteristic of the devices was confirmed.

Growth and behavior of chondrocytes on nano engineered surfaces and construction of micropatterned co-culture platforms using layer-by-layer platforms using layer-by-layer assembly lift-off method

NASA Astrophysics Data System (ADS)

Shaik, Jameel

Several approaches such as self-assembled monolayers and layer-by-layer assembled multilayer films are being used as tools to study the interactions of cells with biomaterials in vitro. In this study, the layer-by-layer assembly approach was used to create monolayer, bilayer, trilayer, five, ten and twenty-bilayer beds of eleven different biomaterials. The various biomaterials used were poly(styrene-sulfonate), fibronectin, poly-L-lysine, poly-D-lysine, laminin, bovine serum albumin, chondroitin sulfate, poly(ethyleneimine), polyethylene glycol amine, collagen and poly(dimethyldiallyl-ammonium chloride) with unmodified tissue-culture polystyrene as standard control. Three different cell lines---primary bovine articular chondrocytes, and two secondary cell lines, human chondrosarcoma cells and canine chondrocytes were used in these studies. Chondrocyte morphology and attachment, viability, proliferation, and functionality were determined using bright field microscopy, the Live/Dead viability assay, MTT assay, and immunocytochemistry, respectively. Atomic force microscopy of the nanofilms indicated an increase in surface roughness with increasing number of layers. The most important observations from the studies on primary bovine articular chondrocytes were that these cells exhibited increasing viability and cell metabolic activity with increasing number of bilayers. The increase in viability was more pronounced than the increase in cell metabolic activity. Also, bovine chondrocytes on bilayers of poly(dimethyldiallyl-ammonium chloride, poly-L-lysine, poly(styrene-sulfonate), and bovine serum albumin were substantially bigger in size and well-attached when compared to the cells grown on monolayer and trilayers. Lactate dehydrogenase assay performed on chondrosarcoma cells grown on 5- and 10-bilayer multilayer beds indicated that the 10-bilayer beds had reduced cytotoxicity compared to the 5-bilayer beds. MTT assay performed on canine chondrocytes grown on 5-, 10-, and 20-bilayer nanofilm beds revealed increasing cell metabolic activity for BSA with increasing bilayers. Micropatterned multilayer beds having poly-L-lysine, poly-D-lysine, laminin poly(dimethyldiallyl-ammonium chloride) and poly(ethyleneimine) as the terminating layers were fabricated using the Layer-by-layer Lift-off (LbL-LO) method that combines photolithography and LbL self-assembly. Most importantly, micropatterned co-culture platforms consisting of anti-CD 44 rat monoclonal and anti-rat osteopontin (MPIIIB101) antibodies were constructed using the LbL-LO method for the first time. These co-culture platforms have several applications especially for studies of stem and progenitor cells. Co-culture platforms exhibiting spatiotempora-based differentiation can be built with LbL-LO for the differentiation of stem cells into the desired cell lineage.

Influence of Hydrophobicity on Polyelectrolyte Complexation

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

Sadman, Kazi; Wang, Qifeng; Chen, Yaoyao

Polyelectrolyte complexes are a fascinating class of soft materials that can span the full spectrum of mechanical properties from low viscosity fluids to glassy solids. This spectrum can be accessed by modulating the extent of electrostatic association in these complexes. However, to realize the full potential of polyelectrolyte complexes as functional materials their molecular level details need to be clearly correlated with their mechanical response. The present work demonstrates that by making simple amendments to the chain architecture it is possible to affect the salt responsiveness of polyelectrolyte complexes in a systematic manner. This is achieved by quaternizing poly(4-vinylpyridine) (QVP)more » with methyl, ethyl and propyl substituents– thereby increasing the hydrophobicity with increasing side chain length– and complexing them with a common anionic polyelectrolyte, poly(styrene sulfonate). The mechanical 1 ACS Paragon Plus Environment behavior of these complexes is compared to the more hydrophilic system of poly(styrene sulfonate) and poly(diallyldimethylammonium) by quantifying the swelling behavior in response to salt stimuli. More hydrophobic complexes are found to be more resistant to doping by salt, yet the mechanical properties of the complex remain contingent on the overall swelling ratio of the complex itself, following near universal swelling-modulus master curves that are quantified in this work. The rheological behavior of QVP complex coacervates are found to be approximately the same, only requiring higher salt concentrations to overcome strong hydrophobic interactions, demonstrating that hydrophobicity can be used as an important parameter for tuning the stability of polyelectrolyte complexes in general, while still preserving the ability to be processed “saloplastically”.« less

Investigating the chemical mist deposition technique for poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) on textured crystalline-silicon for organic/crystalline-silicon heterojunction solar cells

NASA Astrophysics Data System (ADS)

Hossain, Jaker; Ohki, Tatsuya; Ichikawa, Koki; Fujiyama, Kazuhiko; Ueno, Keiji; Fujii, Yasuhiko; Hanajiri, Tatsuro; Shirai, Hajime

2016-03-01

Chemical mist deposition (CMD) of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was investigated in terms of cavitation frequency f, solvent, flow rate of nitrogen, substrate temperature Ts, and substrate dc bias Vs as variables for efficient PEDOT:PSS/crystalline silicon (c-Si) heterojunction solar cells. The high-speed-camera and differential mobility analysis characterizations revealed that the average size and flux of PEDOT:PSS mist depend on f, type of solvent, and Vs. Film deposition occurred when positive Vs was applied to the c-Si substrate at Ts of 30-40 °C, whereas no deposition of films occurred with negative Vs, implying that the film is deposited mainly from negatively charged mist. The uniform deposition of PEDOT:PSS films occurred on textured c-Si(100) substrates by adjusting Ts and Vs. The adhesion of CMD PEDOT:PSS film to c-Si was greatly enhanced by applying substrate dc bias Vs compared with that of spin-coated film. The CMD PEDOT:PSS/c-Si heterojunction solar cell devices on textured c-Si(100) in 2 × 2 cm2 exhibited a power conversion efficiency η of 11.0% with better uniformity of the solar cell parameters. Furthermore, η was increased to 12.5% by adding an AR coating layer of molybdenum oxide MoOx formed by CMD. These findings suggest that CMD with negatively charged mist has great potential for the uniform deposition of organic and inorganic materials on textured c-Si substrates by suitably adjusting Ts and Vs.

Structure and Dynamics of Ionic Block Copolymer Melts: Computational Study

DOE PAGES

Aryal, Dipak; Agrawal, Anupriya; Perahia, Dvora; ...

2017-09-06

Structure and dynamics of melts of copolymers with an ABCBA topology, where C is an ionizable block, have been studied by fully atomistic molecular dynamics (MD) simulations. Introducing an ionizable block for functionality adds a significant element to the coupled set of interactions that determine the structure and dynamics of the macromolecule. The polymer consists of a randomly sulfonated polystyrene C block tethered to a flexible poly(ethylene-r-propylene) bridge B and end-capped with poly(tert-butylstyrene) A. The chemical structure and topology of these polymers constitute a model for incorporation of ionic blocks within a framework that provides tactility and mechanical stability. Heremore » in this paper we resolve the structure and dynamics of a structured polymer on the nanoscale constrained by ionic clusters. We find that the melts form intertwined networks of the A and C blocks independent of the degree of sulfonation of the C block with no long-range order. The cluster cohesiveness and morphology affect both macroscopic translational motion and segmental dynamics of all the blocks.« less

Structure and Dynamics of Ionic Block Copolymer Melts: Computational Study

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

Aryal, Dipak; Agrawal, Anupriya; Perahia, Dvora

Structure and dynamics of melts of copolymers with an ABCBA topology, where C is an ionizable block, have been studied by fully atomistic molecular dynamics (MD) simulations. Introducing an ionizable block for functionality adds a significant element to the coupled set of interactions that determine the structure and dynamics of the macromolecule. The polymer consists of a randomly sulfonated polystyrene C block tethered to a flexible poly(ethylene-r-propylene) bridge B and end-capped with poly(tert-butylstyrene) A. The chemical structure and topology of these polymers constitute a model for incorporation of ionic blocks within a framework that provides tactility and mechanical stability. Heremore » in this paper we resolve the structure and dynamics of a structured polymer on the nanoscale constrained by ionic clusters. We find that the melts form intertwined networks of the A and C blocks independent of the degree of sulfonation of the C block with no long-range order. The cluster cohesiveness and morphology affect both macroscopic translational motion and segmental dynamics of all the blocks.« less

Resistive and Capacitive γ-Ray Dosimeters Based On Triggered Depolymerization in Carbon Nanotube Composites.

PubMed

Zeininger, Lukas; He, Maggie; Hobson, Stephen T; Swager, Timothy M

2018-05-25

We report γ-ray dosimeters using carbon nanotubes wrapped with metastable poly(olefin sulfone)s (POSs) that readily depolymerize when exposed to ionizing radiation. New POSs, designed for wrapping single-walled carbon nanotubes (SWCNTs), are synthesized and characterized. The resulting POS-SWCNT composites serve as the active transducer in a novel class of γ-ray dosimeters. In our devices, polymer degradation results in immediate changes in the electronic potential of the POS-SWCNT active layers by decreasing the electron tunneling barriers between individualized tubes and by creating enhanced cofacial π-π electron contacts. By incorporating the SWCNT-POS composites into small resistive device platforms, we establish a rare example of real-time detection and dosimetry of radioactive ionizing radiation using organic-based materials. We show that the sensitivity of our platform closely depends on the intrinsic stability of the polymer matrix, the opacity toward γ-rays, and the dispersion efficiency (i.e., the individualization and isolation of the individual SWCNT charge carriers). Resistance decreases up to 65% after irradiation with a 40 krad dose demonstrates the high sensitivity of this novel class of γ-ray sensors. In addition, the detection mechanism was evaluated using a commercial capacitive device platform. The ease of fabrication and low power consumption of these small and inexpensive sensor platforms combined with appealing sensitivity parameters establishes the potential of the poly(olefin sulfone)-SWCNT composites to serve as a new transduction material in γ-ray sensor applications.

Multilayer poly(3,4-ethylenedioxythiophene)-dexamethasone and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate-carbon nanotubes coatings on glassy carbon microelectrode arrays for controlled drug release.

PubMed

Castagnola, Elisa; Carli, Stefano; Vomero, Maria; Scarpellini, Alice; Prato, Mirko; Goshi, Noah; Fadiga, Luciano; Kassegne, Sam; Ricci, Davide

2017-07-13

The authors present an electrochemically controlled, drug releasing neural interface composed of a glassy carbon (GC) microelectrode array combined with a multilayer poly(3,4-ethylenedioxythiophene) (PEDOT) coating. The system integrates the high stability of the GC electrode substrate, ideal for electrical stimulation and electrochemical detection of neurotransmitters, with the on-demand drug-releasing capabilities of PEDOT-dexamethasone compound, through a mechanically stable interlayer of PEDOT-polystyrene sulfonate (PSS)-carbon nanotubes (CNT). The authors demonstrate that such interlayer improves both the mechanical and electrochemical properties of the neural interface, when compared with a single PEDOT-dexamethasone coating. Moreover, the multilayer coating is able to withstand 10 × 10 6 biphasic pulses and delamination test with negligible change to the impedance spectra. Cross-section scanning electron microscopy images support that the PEDOT-PSS-CNT interlayer significantly improves the adhesion between the GC substrate and PEDOT-dexamethasone coating, showing no discontinuities between the three well-interconnected layers. Furthermore, the multilayer coating has superior electrochemical properties, in terms of impedance and charge transfer capabilities as compared to a single layer of either PEDOT coating or the GC substrate alone. The authors verified the drug releasing capabilities of the PEDOT-dexamethasone layer when integrated into the multilayer interface through repeated stimulation protocols in vitro, and found a pharmacologically relevant release of dexamethasone.

Microbial desalination cell with sulfonated sodium poly(ether ether ketone) as cation exchange membranes for enhancing power generation and salt reduction.

PubMed

Moruno, Francisco Lopez; Rubio, Juan E; Atanassov, Plamen; Cerrato, José M; Arges, Christopher G; Santoro, Carlo

2018-06-01

Microbial desalination cell (MDC) is a bioelectrochemical system capable of oxidizing organics, generating electricity, while reducing the salinity content of brine streams. As it is designed, anion and cation exchange membranes play an important role on the selective removal of ions from the desalination chamber. In this work, sulfonated sodium (Na + ) poly(ether ether ketone) (SPEEK) cation exchange membranes (CEM) were tested in combination with quaternary ammonium chloride poly(2,6-dimethyl 1,4-phenylene oxide) (QAPPO) anion exchange membrane (AEM). Non-patterned and patterned (varying topographical features) CEMs were investigated and assessed in this work. The results were contrasted against a commercially available CEM. This work used real seawater from the Pacific Ocean in the desalination chamber. The results displayed a high desalination rate and power generation for all the membranes, with a maximum of 78.6±2.0% in salinity reduction and 235±7mWm -2 in power generation for the MDCs with the SPEEK CEM. Desalination rate and power generation achieved are higher with synthesized SPEEK membranes when compared with an available commercial CEM. An optimized combination of these types of membranes substantially improves the performances of MDC, making the system more suitable for real applications. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Inverted polymer solar cell based on MEH-PPV/PC61BM coupled with ZnO nanoparticles as electron transport layer

NASA Astrophysics Data System (ADS)

Salem, A. M. S.; El-Sheikh, S. M.; Harraz, Farid A.; Ebrahim, S.; Soliman, M.; Hafez, H. S.; Ibrahim, I. A.; Abdel-Mottaleb, M. S. A.

2017-12-01

In this work, we demonstrate the use of annealed sol-gel derived ZnO nanoparticles acting as electron transport layer (ETL) in inverted bulk heterojunction (BHJ) polymer solar cells (PSCs). We have examined the photovoltaic performance of devices based on poly(2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene) (MEH-PPV):(6,6)-phenyl-C61-butyric acid methyl ester (PC61BM) blend system employing the ZnO nanoparticles as an ETL with CuI as hole transport layer (HTL) in comparison to the case of using the conventional HTL of poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) sulfonic acid (PEDOT:PSS). The effect of the presence of another layer of ZnO macrospheres attached to the ZnO nanoparticles is also investigated. The highest power conversion efficiency (PCE) value of 1.35% was achieved for device: ITO/ZnO nanoparticles/MEH-PPV:PC61BM/CuI/Ag, which is 275% more the value obtained when CuI was replaced by PEDOT:PSS. The comprehensive analyses on structural and optical characteristics including SEM, XRD, FTIR, PL and UV-vis spectroscopy indicated that the use of the ZnO nanoparticles alone as ETL, together with the CuI as HTL could effectively reduce trap-assisted recombination and charge accumulation at the interface, which is beneficial for the enhanced device performance.

Effect of LEO Exposure on Aromatic Polymers Containing Phenylphosphine Oxide Groups

NASA Technical Reports Server (NTRS)

Watson, K. A.; Ghose, S.; Lillehei, P. T.; Smith, J. G., Jr.; Connell, J. W.

2007-01-01

As part of the Materials on The International Space Station Experiment (MISSE), aromatic polymers containing phenylphosphine oxide groups were exposed to low Earth orbit (LEO) for approximately 4 years. All of the aromatic polymers containing phenylphosphine oxide groups survived the exposure despite the high fluence of atomic oxygen that completely eroded other polymer films such as Kapton and Mylar of comparable or greater thickness. The samples consisted of a colorless polyimide film and a poly(arylene ether benzimidazole) film and thread. The samples were characterized for changes in physical properties, thermal/optical properties (i.e. solar absorptivity and thermal emissivity), surface chemistry (X-ray photoelectron spectroscopy), and surface topography (atomic force microscopy). The data from the polymer samples on MISSE were compared to samples from the same batch of material stored under ambient conditions on Earth. In addition, comparisons were made between the MISSE samples and those subjected to shorter term space flight exposures. The results of these analyses will be presented.

Novel organic LED structures based on a highly conductive polymeric photonic crystal electrode.

PubMed

Petti, Lucia; Rippa, Massimo; Capasso, Rossella; Nenna, Giuseppe; Del Mauro, Anna De Girolamo; Maglione, Maria Grazia; Minarini, Carla

2013-08-09

In this work we demonstrate the possibility to realize a novel unconventional ITO-free organic light emitting diode (OLED) utilizing a photonic polymeric electrode. Combining electron beam lithography and a plasma etching process to partially structure the highly conductive poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) it is possible to realize an embedded photonic crystal (PC) structure. The realized PC-anode drastically reduces the light trapped in the OLED, demonstrating the possibility to eliminate further process stages and making it easier to use this technology even on rollable and flexible substrates.

Novel organic LED structures based on a highly conductive polymeric photonic crystal electrode

NASA Astrophysics Data System (ADS)

Petti, Lucia; Rippa, Massimo; Capasso, Rossella; Nenna, Giuseppe; De Girolamo Del Mauro, Anna; Grazia Maglione, Maria; Minarini, Carla

2013-08-01

In this work we demonstrate the possibility to realize a novel unconventional ITO-free organic light emitting diode (OLED) utilizing a photonic polymeric electrode. Combining electron beam lithography and a plasma etching process to partially structure the highly conductive poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) it is possible to realize an embedded photonic crystal (PC) structure. The realized PC-anode drastically reduces the light trapped in the OLED, demonstrating the possibility to eliminate further process stages and making it easier to use this technology even on rollable and flexible substrates.

High Performance of Supercapacitor from PEDOT:PSS Electrode and Redox Iodide Ion Electrolyte

PubMed Central

Gao, Xing; Zu, Lei; Cai, Xiaomin; Li, Ce; Lian, Huiqin; Liu, Yang; Wang, Xiaodong; Cui, Xiuguo

2018-01-01

Insufficient energy density and poor cyclic stability is still challenge for conductive polymer-based supercapacitor. Herein, high performance electrochemical system has been assembled by combining poly (3,4-ethylenedioxythiophene) (PEDOT):poly (styrene sulfonate) (PSS) redox electrode and potassium iodide redox electrolyte, which provide the maximum specific capacity of 51.3 mAh/g and the retention of specific capacity of 87.6% after 3000 cycles due to the synergic effect through a simultaneous redox reaction both in electrode and electrolyte, as well as the catalytic activity for reduction of triiodide of the PEDOT:PSS. PMID:29772662

Covalent conjugation of graphene oxide with methotrexate and its antitumor activity

NASA Astrophysics Data System (ADS)

Wojtoniszak, M.; Urbas, K.; Perużyńska, M.; Kurzawski, M.; Droździk, M.; Mijowska, E.

2013-05-01

Here, we have functionalized graphene oxide with anticancer drug methotrexate through amide bonding. A kinetics of the drug release from graphene oxide in physiological solution - phosphate buffered saline (PBS) containing different biocompatible polymers have been investigated. Dispersion of MTX-GO in poly sodium-4-styrene sulfonate and poly ethylene glycol resulted in increase of the release time. The material was characterized with transmission electron microscopy, atomic force microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and UV-vis spectroscopy. Furthermore, antineoplastic action against human breast adenocarcinoma cell line MCF7 of MTX-GO and empty graphene oxide was explored.

Radiation-grafted proton exchange membranes based on co-grafting from binary monomer mixtures into poly(ethylene-co-tetrafluoroethylene) (ETFE) film

NASA Astrophysics Data System (ADS)

Sohn, Joon-Yong; Sung, Hae-Jun; Song, Joo-Myung; Shin, Junhwa; Nho, Young-Chang

2012-08-01

In this study, proton exchange membranes (PEMs) based on a poly(ethylene-co-tetrafluoroethylene) (ETFE) film were synthesized through the graft copolymerization of styrene and VTMS (vinyltrimethoxysilane), or styrene and TMSPM (3-(trimethoxysilyl) propyl methacrylate) binary monomer systems using a simultaneous irradiation method. The prepared membranes with the similar degrees of grafting were investigated by measuring ion exchange capacity, proton conductivity, water uptake, chemical stability, and dimensional stability. The results indicate that the silane-crosslinked proton exchange membrane (PEM) has not only lower water uptake and dimensional change but also high proton conductivity at low humidity condition compared to non-crosslinked poly(ethylene-co-tetrafluoroethylene)-g-poly(styrene sulfonic acid) (ETFE-g-PSSA). Also, the chemical stability of silane-crosslinked fuel cell membranes was more improved than that of non-crosslinked fuel cell membrane.

Solid polymer electrolytes

DOEpatents

Abraham, Kuzhikalail M.; Alamgir, Mohamed; Choe, Hyoun S.

1995-01-01

This invention relates to Li ion (Li.sup.+) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF.sub.3 SO.sub.2).sub.2, LiAsF.sub.6, and LiClO.sub.4.

40 CFR 721.9582 - Certain perfluoroalkyl sulfonates.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-0319306979-40-8 Poly(oxy-1,2-ethanediyl), .alpha.-[2-(methylamino)ethyl]-.omega.-[(1,1,3,3-tetramethylbutyl...]amino]ethyl]-.omega.-hydroxy- 38850-52-1 1-Propanaminium, 3-[(carboxymethyl)[(1,1,2,2,3,3,4,4,5,5,6,6,6...-heptadecafluorooctyl)sulfonyl]methylamino]carbonyl]-.omega.-butoxy- 52166-82-2 1-Propanaminium, N,N,N-trimethyl-3-[[(1...

40 CFR 721.9582 - Certain perfluoroalkyl sulfonates.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-0319306979-40-8 Poly(oxy-1,2-ethanediyl), .alpha.-[2-(methylamino)ethyl]-.omega.-[(1,1,3,3-tetramethylbutyl...]amino]ethyl]-.omega.-hydroxy- 38850-52-1 1-Propanaminium, 3-[(carboxymethyl)[(1,1,2,2,3,3,4,4,5,5,6,6,6...-heptadecafluorooctyl)sulfonyl]methylamino]carbonyl]-.omega.-butoxy- 52166-82-2 1-Propanaminium, N,N,N-trimethyl-3-[[(1...

40 CFR 721.9582 - Certain perfluoroalkyl sulfonates.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-0319306979-40-8 Poly(oxy-1,2-ethanediyl), .alpha.-[2-(methylamino)ethyl]-.omega.-[(1,1,3,3-tetramethylbutyl...]amino]ethyl]-.omega.-hydroxy- 38850-52-1 1-Propanaminium, 3-[(carboxymethyl)[(1,1,2,2,3,3,4,4,5,5,6,6,6...-heptadecafluorooctyl)sulfonyl]methylamino]carbonyl]-.omega.-butoxy- 52166-82-2 1-Propanaminium, N,N,N-trimethyl-3-[[(1...

40 CFR 721.9582 - Certain perfluoroalkyl sulfonates.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-0319306979-40-8 Poly(oxy-1,2-ethanediyl), .alpha.-[2-(methylamino)ethyl]-.omega.-[(1,1,3,3-tetramethylbutyl...]amino]ethyl]-.omega.-hydroxy- 38850-52-1 1-Propanaminium, 3-[(carboxymethyl)[(1,1,2,2,3,3,4,4,5,5,6,6,6...-heptadecafluorooctyl)sulfonyl]methylamino]carbonyl]-.omega.-butoxy- 52166-82-2 1-Propanaminium, N,N,N-trimethyl-3-[[(1...

Treatment of poly- and perfluoroalkyl substances in U.S. full-scale water treatment systems.

PubMed

Appleman, Timothy D; Higgins, Christopher P; Quiñones, Oscar; Vanderford, Brett J; Kolstad, Chad; Zeigler-Holady, Janie C; Dickenson, Eric R V

2014-03-15

The near ubiquitous presence of poly- and perfluoroalkyl substances (PFASs) in humans has raised concerns about potential human health effects from these chemicals, some of which are both extremely persistent and bioaccumulative. Because some of these chemicals are highly water soluble, one major pathway for human exposure is the consumption of contaminated drinking water. This study measured concentrations of PFASs in 18 raw drinking water sources and 2 treated wastewater effluents and evaluated 15 full-scale treatment systems for the attenuation of PFASs in water treatment utilities throughout the U.S. A liquid-chromatography tandem mass-spectrometry method was used to enable measurement of a suite of 23 PFASs, including perfluorocarboxylic acids (PFCAs) and perfluorosulfonic acids (PFSAs). Despite the differences in reporting levels, the PFASs that were detected in >70% of the source water samples (n = 39) included PFSAs, perfluorobutane sulfonic acid (74%), perfluorohexane sulfonic acid (79%), and perfluorooctane sulfonic acid (84%), and PFCAs, perfluoropentanoic acid (74%), perfluorohexanoic acid (79%), perfluoroheptanoic acid (74%), and perfluorooctanoic acid (74%). More importantly, water treatment techniques such as ferric or alum coagulation, granular/micro-/ultra- filtration, aeration, oxidation (i.e., permanganate, ultraviolet/hydrogen peroxide), and disinfection (i.e., ozonation, chlorine dioxide, chlorination, and chloramination) were mostly ineffective in removing PFASs. However, anion exchange and granular activated carbon treatment preferably removed longer-chain PFASs and the PFSAs compared to the PFCAs, and reverse osmosis demonstrated significant removal for all the PFASs, including the smallest PFAS, perfluorobutanoic acid. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synthesis and evaluation of poly(Sodium 2-Acrylamido-2-Methylpropane Sulfonate-co-Styrene)/magnetite nanoparticle composites as corrosion inhibitors for steel.

PubMed

El-Mahdy, Gamal A; Atta, Ayman M; Al-Lohedan, Hamad A

2014-01-30

Self-stabilized magnetic polymeric composite nanoparticles of coated poly-(sodium 2-acrylamido-2-methylpropane sulfonate-co-styrene)/magnetite (PAMPS-Na-co-St/Fe3O4) were prepared by emulsifier-free miniemulsion polymerization using styrene (St) as a monomer, 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na) as an ionic comonomer, N,N-methylenebisacrylamide (MBA) as crosslinker, hexadecane (HD) as a hydrophobic solvent, and 2,2-azodiisobutyronitrile (AIBN) as an initiator in the presence of hydrophobic oleic acid coated magnetite particles. Hydrophobic oleic acid coated magnetite particles with an average size of about 7-10 nm were prepared with the new modified water-based magnetite ferrofluid, synthesized by a chemical modified coprecipitation method. The morphology and the particle size distributions of the crosslinked PAMPS-Na-co-St/Fe3O4 composite were observed and analyzed by transmission electron microscopy (TEM). The average Fe3O4 content of PAMPS-Na-co-St/Fe3O4 was determined by thermogravimetric analysis (TGA). The inhibitory action of PAMPS-Na-co-St/Fe3O4 towards steel corrosion in 1 M HCl solutions has been investigated by polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements indicate that PAMPS-Na-co-St/Fe3O4 acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.

Determination of the Si-conducting polymer interfacial properties using A-C impedance techniques

NASA Technical Reports Server (NTRS)

Nagasubramanian, G.; Di Stefano, Salvador; Moacanin, Jovan

1985-01-01

A study was made of the interfacial properties of poly(pyrrole) (PP) deposited electrochemically onto single crystal p-Si surfaces. The interfacial properties are dependent upon the counterions. The formation of 'quasi-ohmic' and 'nonohmic' contacts, respectively, of PP(ClO4) and PP films doped with other counterions (BF4 and para-toluene sulfonate) with p-Si, are explained in terms of the conductivity of these films and the flat band potential, V(fb), of PP relative to that of p-Si. The PP film seems to passivate or block intrinsic surface states present on the p-Si surface. The differences in the impedance behavior of para-toluene sulfonate doped and ClO4 doped PP are compared.

Functional solid additive modified PEDOT:PSS as an anode buffer layer for enhanced photovoltaic performance and stability in polymer solar cells

PubMed Central

Xu, Binrui; Gopalan, Sai-Anand; Gopalan, Anantha-Iyengar; Muthuchamy, Nallal; Lee, Kwang-Pill; Lee, Jae-Sung; Jiang, Yu; Lee, Sang-Won; Kim, Sae-Wan; Kim, Ju-Seong; Jeong, Hyun-Min; Kwon, Jin-Beon; Bae, Jin-Hyuk; Kang, Shin-Won

2017-01-01

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is most commonly used as an anode buffer layer in bulk-heterojunction (BHJ) polymer solar cells (PSCs). However, its hygroscopic and acidic nature contributes to the insufficient electrical conductivity, air stability and restricted photovoltaic (PV) performance for the fabricated PSCs. In this study, a new multifunctional additive, 2,3-dihydroxypyridine (DOH), has been used in the PEDOT: PSS buffer layer to obtain modified properties for PEDOT: PSS@DOH and achieve high PV performances. The electrical conductivity of PEDOT:PSS@DOH films was markedly improved compared with that of PEDOT:PSS. The PEDOT:PSS@DOH film exhibited excellent optical characteristics, appropriate work function alignment, and good surface properties in BHJ-PSCs. When a poly(3-hexylthiohpene):[6,6]-phenyl C61-butyric acid methyl ester blend system was applied as the photoactive layer, the power conversion efficiency of the resulting PSCs with PEDOT:PSS@DOH(1.0%) reached 3.49%, outperforming pristine PEDOT:PSS, exhibiting a power conversion enhancement of 20%. The device fabricated using PEDOT:PSS@DOH (1.0 wt%) also exhibited improved thermal and air stability. Our results also confirm that DOH, a basic pyridine derivative, facilitates adequate hydrogen bonding interactions with the sulfonic acid groups of PSS, induces the conformational transformation of PEDOT chains and contributes to the phase separation between PEDOT and PSS chains. PMID:28338088

Functional solid additive modified PEDOT:PSS as an anode buffer layer for enhanced photovoltaic performance and stability in polymer solar cells

NASA Astrophysics Data System (ADS)

Xu, Binrui; Gopalan, Sai-Anand; Gopalan, Anantha-Iyengar; Muthuchamy, Nallal; Lee, Kwang-Pill; Lee, Jae-Sung; Jiang, Yu; Lee, Sang-Won; Kim, Sae-Wan; Kim, Ju-Seong; Jeong, Hyun-Min; Kwon, Jin-Beon; Bae, Jin-Hyuk; Kang, Shin-Won

2017-03-01

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is most commonly used as an anode buffer layer in bulk-heterojunction (BHJ) polymer solar cells (PSCs). However, its hygroscopic and acidic nature contributes to the insufficient electrical conductivity, air stability and restricted photovoltaic (PV) performance for the fabricated PSCs. In this study, a new multifunctional additive, 2,3-dihydroxypyridine (DOH), has been used in the PEDOT: PSS buffer layer to obtain modified properties for PEDOT: PSS@DOH and achieve high PV performances. The electrical conductivity of PEDOT:PSS@DOH films was markedly improved compared with that of PEDOT:PSS. The PEDOT:PSS@DOH film exhibited excellent optical characteristics, appropriate work function alignment, and good surface properties in BHJ-PSCs. When a poly(3-hexylthiohpene):[6,6]-phenyl C61-butyric acid methyl ester blend system was applied as the photoactive layer, the power conversion efficiency of the resulting PSCs with PEDOT:PSS@DOH(1.0%) reached 3.49%, outperforming pristine PEDOT:PSS, exhibiting a power conversion enhancement of 20%. The device fabricated using PEDOT:PSS@DOH (1.0 wt%) also exhibited improved thermal and air stability. Our results also confirm that DOH, a basic pyridine derivative, facilitates adequate hydrogen bonding interactions with the sulfonic acid groups of PSS, induces the conformational transformation of PEDOT chains and contributes to the phase separation between PEDOT and PSS chains.

Solid polymer electrolytes

DOEpatents

Abraham, K.M.; Alamgir, M.; Choe, H.S.

1995-12-12

This invention relates to Li ion (Li{sup +}) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF{sub 3}SO{sub 2}){sub 2}, LiAsF{sub 6}, and LiClO{sub 4}. 2 figs.

21 CFR 73.3121 - Poly(hydroxyethyl methacrylate)-dye copolymers.

Code of Federal Regulations, 2011 CFR

2011-04-01

...-naphthalenedisulfonic acid, 4-amino-5-hydroxy-3,6-bis((4-((2-(sulfooxy)ethyl)sulfonyl)phenyl)azo)-tetrasodium salt] (CAS...)-] (CAS Reg. No. 60958-41-0); (5) Reactive Blue No. 19 [2-anthracene-sulfonic acid, 1-amino-9,10-dihydro-9...); (6) Reactive Blue No. 4 [2-anthracenesulfonic acid, 1-amino-4-(3-((4,6-dichloro-s-triazin-2-yl)amino...

21 CFR 73.3121 - Poly(hydroxyethyl methacrylate)-dye copolymers.

Code of Federal Regulations, 2010 CFR

2010-04-01

...-naphthalenedisulfonic acid, 4-amino-5-hydroxy-3,6-bis((4-((2-(sulfooxy)ethyl)sulfonyl)phenyl)azo)-tetrasodium salt] (CAS...)-] (CAS Reg. No. 60958-41-0); (5) Reactive Blue No. 19 [2-anthracene-sulfonic acid, 1-amino-9,10-dihydro-9...); (6) Reactive Blue No. 4 [2-anthracenesulfonic acid, 1-amino-4-(3-((4,6-dichloro-s-triazin-2-yl)amino...

Relative size selection of a conjugated polyelectrolyte in virus-like protein structures.

PubMed

Brasch, Melanie; Cornelissen, Jeroen J L M

2012-02-01

A conjugated polyelectrolyte poly[(2-methoxy-5-propyloxy sulfonate)-phenyl-ene vinylene] (MPS-PPV) drives the assembly of virus capsid proteins to form single virus-like particles (VLPs) and aggregates with more than two VLPs, with a relative selection of high molecular weight polymer in the latter. This journal is © The Royal Society of Chemistry 2012

Properties investigation of sulfonated poly(ether ether ketone)/polyacrylonitrile acid-base blend membrane for vanadium redox flow battery application.

PubMed

Li, Zhaohua; Dai, Wenjing; Yu, Lihong; Liu, Le; Xi, Jingyu; Qiu, Xinping; Chen, Liquan

2014-11-12

Acid-base blend membrane prepared from sulfonated poly(ether ether ketone) (SPEEK) and polyacrylonitrile (PAN) was detailedly evaluated for vanadium redox flow battery (VRFB) application. SPEEK/PAN blend membrane exhibited dense and homogeneous cross-section morphology as scanning electron microscopy and energy-dispersive X-ray spectroscopy images show. The acid-base interaction of ionic cross-linking and hydrogen bonding between SPEEK and PAN could effectively reduce water uptake, swelling ratio, and vanadium ion permeability, and improve the performance and stability of blend membrane. Because of the good balance of proton conductivity and vanadium ion permeability, blend membrane with 20 wt % PAN (S/PAN-20%) showed higher Coulombic efficiency (96.2% vs 91.1%) and energy efficiency (83.5% vs 78.4%) than Nafion 117 membrane at current density of 80 mA cm(-2) when they were used in VRFB single cell. Besides, S/PAN-20% membrane kept a stable performance during 150 cycles at current density of 80 mA cm(-2) in the cycle life test. Hence the SPEEK/PAN acid-base blend membrane could be used as promising candidate for VRFB application.

Low vanadium ion permeabilities of sulfonated poly(phthalazinone ether ketone)s provide high efficiency and stability for vanadium redox flow batteries

NASA Astrophysics Data System (ADS)

Chen, Liyun; Zhang, Shouhai; Chen, Yuning; Jian, Xigao

2017-07-01

A series of novel sulfonated poly(phthalazinone ether ketone)s containing pendant phenyl moieties (SPPEK-Ps) are synthesized and thoroughly characterized. The chemical structures of the polymers are confirmed by 1H NMR and FTIR analysis. The physicochemical properties and single cell performance of SPPEK-P membranes are systematically evaluated, revealing that the membranes are thermally, chemically and mechanically stable. The area resistances of SPPEK-P-90 and SPPEK-P-100 are 0.75 Ω cm2 and 0.34 Ω cm2, respectively. SPPEK-P membranes are impermeable to the bulky hydrated VO2+ ion and exhibited low V3+ ion permeability (SPPEK-P-90, 2.53 × 10-5 cm min-1) (Nafion 115 membrane: 9.0 × 10-4 cm min-1). Tests of SPPEK-P-90 in vanadium redox flow batteries (VRFBs) demonstrate a comparable columbic efficiency (CE) and energy efficiency (EE) to that of Nafion 115, where the CE is 98% and the EE is 83% at 60 mA cm-2. Moreover, the SPPEK-P-90 membrane exhibits stable performance in cell over 100 charge-discharge cycles (∼450 h).

Synthesis and characterization of poly(3-sulfopropylmethacrylate) brushes for potential antibacterial applications.

PubMed

Ramstedt, Madeleine; Cheng, Nan; Azzaroni, Omar; Mossialos, Dimitris; Mathieu, Hans Jörg; Huck, Wilhelm T S

2007-03-13

This article describes the aqueous atom transfer radical polymerization synthesis of poly(3-sulfopropylmethacrylate) brushes onto gold and Si/SiO2 surfaces in a controlled manner. The effect of Cu(I)/Cu(II) ratio was examined, and a quartz crystal microbalance was used to study the kinetics of the brush synthesis. The synthesized brushes displayed a thickness from a few nanometers to several hundred nanometers and were characterized using atomic force microscopy, ellipsometry, Fourier transform infrared spectroscopy (FTIR), contact angle measurements, and X-ray photoelectron spectroscopy (XPS). The as-synthesized sulfonate brushes had very good ion-exchange properties for the ions tested in this study, i.e., Na+, K+, Cu2+, and Ag+. FTIR and XPS show that the metal ions are coordinating to sulfonate moieties inside the brushes. The brushes were easily loaded with silver ions, and the effect of silver ion concentration on silver loading of the brush was examined. The silver-loaded brushes were shown to be antibacterial toward both gram negative and gram positive bacteria. The silver leaching was studied through leaching experiments into water, NaNO3, and NaCl (physiological medium). The results from these leaching experiments are compared and discussed in the article.

Thermoelectric Properties of Highly Conductive Poly(3,4-ethylenedioxythiophene) Polystyrene Sulfonate Printed Thin Films.

PubMed

Beretta, Davide; Barker, Alex J; Maqueira-Albo, Isis; Calloni, Alberto; Bussetti, Gianlorenzo; Dell'Erba, Giorgio; Luzio, Alessandro; Duò, Lamberto; Petrozza, Annamaria; Lanzani, Guglielmo; Caironi, Mario

2017-05-31

Organic conductors are being evaluated for potential use in waste heat recovery through lightweight and flexible thermoelectric generators manufactured using cost-effective printing processes. Assessment of the potentiality of organic materials in real devices still requires a deeper understanding of the physics behind their thermoelectric properties, which can pave the way toward further development of the field. This article reports a detailed thermoelectric study of a set of highly conducting inkjet-printed films of commercially available poly(3,4-ethylenedioxythiophene) polystyrene sulfonate formulations characterized by in-plane electrical conductivity, spanning the interval 10-500 S/cm. The power factor is maximized for the formulation showing an intermediate electrical conductivity. The Seebeck coefficient is studied in the framework of Mott's relation, assuming a (semi-)classical definition of the transport function. Ultraviolet photoelectron spectroscopy at the Fermi level clearly indicates that the shape of the density of states alone is not sufficient to explain the observed Seebeck coefficient, suggesting that carrier mobility is important in determining both the electrical conductivity and thermopower. Finally, the cross-plane thermal conductivity is reliably extracted thanks to a scaling approach that can be easily performed using typical pump-probe spectroscopy.

Fabrication and properties of light-emitting diodes based on self-assembled multilayers of poly(phenylene vinylene)

NASA Astrophysics Data System (ADS)

Fou, A. C.; Onitsuka, O.; Ferreira, M.; Rubner, M. F.; Hsieh, B. R.

1996-05-01

Light-emitting diodes have been fabricated from self-assembled multilayers of poly(p-phenylene vinylene) (PPV) and two different polyanions; polystyrene sulfonic acid (SPS) and polymethacrylic acid (PMA). The type of polyanion used to assemble the multilayer thin films was found to dramatically influence the behavior and performance of devices fabricated with indium tin oxide and aluminum electrodes. Light-emitting devices fabricated from PMA/PPV multilayers were found to exhibit luminance levels in the range of 20-60 cd/m2, a thickness dependent turn-on voltage and classical rectifying behavior with rectification ratios greater than 105. In sharp contrast, the devices based on SPS/PPV exhibited near symmetric current-voltage curves, thickness independent turn-on voltages and much lower luminance levels. The significant difference in device behavior observed between these two systems is primarily due to a doping effect induced either chemically or electrochemically by the sulfonic acid groups of SPS. It was also found that the performance of these devices depends on the type of layer that is in contact with the Al top electrode thereby making it possible to manipulate device efficiency at the molecular level.

(Photo)physical Properties of New Molecular Glasses End-Capped with Thiophene Rings Composed of Diimide and Imine Units

PubMed Central

2014-01-01

New symmetrical arylene bisimide derivatives formed by using electron-donating–electron-accepting systems were synthesized. They consist of a phthalic diimide or naphthalenediimide core and imine linkages and are end-capped with thiophene, bithiophene, and (ethylenedioxy)thiophene units. Moreover, polymers were obtained from a new diamine, N,N′-bis(5-aminonaphthalenyl)naphthalene-1,4,5,8-dicarboximide and 2,5-thiophenedicarboxaldehyde or 2,2′-bithiophene-5,5′-dicarboxaldehyde. The prepared azomethine diimides exhibited glass-forming properties. The obtained compounds emitted blue light with the emission maximum at 470 nm. The value of the absorption coefficient was determined as a function of the photon energy using spectroscopic ellipsometry. All compounds are electrochemically active and undergo reversible electrochemical reduction and irreversible oxidation processes as was found in cyclic voltammetry and differential pulse voltammetry (DPV) studies. They exhibited a low electrochemically (DPV) calculated energy band gap (Eg) from 1.14 to 1.70 eV. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels and Eg were additionally calculated theoretically by density functional theory at the B3LYP/6-31G(d,p) level. The photovoltaic properties of two model compounds as the active layer in organic solar cells in the configuration indium tin oxide/poly(3,4-(ethylenedioxy)thiophene):poly(styrenesulfonate)/active layer/Al under an illumination of 1.3 mW/cm2 were studied. The device comprising poly(3-hexylthiophene) with the compound end-capped with bithiophene rings showed the highest value of Voc (above 1 V). The conversion efficiency of the fabricated solar cell was in the range of 0.69–0.90%. PMID:24966893

Preparation of sulfonic-functionalized graphene oxide as ion-exchange material and its application into electrochemiluminescence analysis.

PubMed

Chen, Guifen; Zhai, Shengyong; Zhai, Yanling; Zhang, Ke; Yue, Qiaoli; Wang, Lei; Zhao, Jinsheng; Wang, Huaisheng; Liu, Jifeng; Jia, Jianbo

2011-03-15

Graphene oxide (GO) obtained from chemical oxidation of flake graphite was derivatized with sulfonic groups to form sulfonic-functionalized GO (GO-SO(3)(-)) through four sulfonation routes: through amide formation between the carboxylic group of GO and amine of sulfanilic acid (AA-GO-SO(3)(-)), aryl diazonium reaction of sulfanilic acid (AD-GO-SO(3)(-)), amide formation between the carboxylic group of GO and amine of cysteamine and oxidation by H(2)O(2) (CA-GO-SO(3)(-)), and alkyl diazonium reaction of cysteamine and oxidation by H(2)O(2) (CD-GO-SO(3)(-)). Results of Fourier transform infrared spectroscopy and X-ray photoelectrospectrocopy showed that -SO(3)(-) groups were attached onto GO. Thermo gravimetric analysis showed that derivatization with sulfonic groups improved thermo stability of GO. X-ray diffraction results indicated that GO-SO(3)(-) had more ordered π-π stacking structure than the original GO. GO-SO(3)(-) and cationic polyelectrote, poly (diallyldimethylammoniumchloride) (PDDA) were adsorbed at indium tin oxide (ITO) glass surface through layer-by-layer assembling to form (GO-SO(3)(-)/PDDA)(n)/ITO multilayers. After tris-(2,2'-bipyridyl) ruthenium (II) dichloride (Ru(bpy)(3)(2+)) was incorporated into the multilayers, the obtained Ru(bpy)(3)(2+)/(GO-SO(3)(-)/PDDA)(n)/ITO electrodes can be used as electrochemiluminescence sensors for detection of organic amine with high sensitivity (limit of detection of 1 nM) and stability. Copyright © 2010 Elsevier B.V. All rights reserved.

Effect of counterions on the formation of ohmic contact between p-Si and poly(pyrrole) film - An ac impedance analysis

NASA Technical Reports Server (NTRS)

Nagsubramanian, G.; Distefano, S.; Moacanin, J.

1986-01-01

Conditions under which poly(pyrrole) (PP) films form ohmic contact with single-crystal p-Si are described. Counterions affect both the conductivity and flatband potential, V(FB), values of poly(pyrrole). While paratoluene-sulfonate-doped PP acts like a switch, the impedance behavior of PP films doped with ClO4(-), BF4(-), or PF6(-) allows evaluation of the V(FB) of these films. The formation of 'quasi-ohmic' and 'nonohmic' contacts, respectively, of PP (ClO4) and PP films doped with other counterions, with p-Si, are explained in terms of conductivity of these films and V(FB) of PP films with respect to that of p-Si. PP film seems to passivate or block intrinsic surface states present on p-Si surface.

Cs[Tf 2N]: a second polymorph with a layered structure

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

Stritzinger, Jared Tyler; Droessler, Janelle E.; Scott, Brian Lindley

Here, the structural determination of the ionic liquid, caesium bis­[(tri­fluoro­meth­yl)sulfon­yl]imide or poly[[ μ4-bis­[(tri­fluoro­meth­yl)sulfon­yl]imido]caesium(I)], Cs[N(SO 2CF 3) 2] or Cs[Tf 2N], reveals a second polymorph that also crystallizes in a layer structure possessing monoclinic P2 1/c symmetry at 120 K instead of C2/c for the known polymorph. The caesium ions in the cationic layers are coordinated by the sulfonyl groups of the bis­triflimide mol­ecules from anion layers while the tri­fluoro­methyl groups are oriented in the opposite direction, forming a non-polar surface separating the layers.

Cs[Tf 2N]: a second polymorph with a layered structure

DOE PAGES

Stritzinger, Jared Tyler; Droessler, Janelle E.; Scott, Brian Lindley; ...

2018-03-23

Here, the structural determination of the ionic liquid, caesium bis­[(tri­fluoro­meth­yl)sulfon­yl]imide or poly[[ μ4-bis­[(tri­fluoro­meth­yl)sulfon­yl]imido]caesium(I)], Cs[N(SO 2CF 3) 2] or Cs[Tf 2N], reveals a second polymorph that also crystallizes in a layer structure possessing monoclinic P2 1/c symmetry at 120 K instead of C2/c for the known polymorph. The caesium ions in the cationic layers are coordinated by the sulfonyl groups of the bis­triflimide mol­ecules from anion layers while the tri­fluoro­methyl groups are oriented in the opposite direction, forming a non-polar surface separating the layers.

Friedel-Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery.

PubMed

Merle, Géraldine; Ioana, Filipoi Carmen; Demco, Dan Eugen; Saakes, Michel; Hosseiny, Seyed Schwan

2013-12-30

Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel-Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol) showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO2+ crossover compared to Nafion.

Determinations of molecular weight and molecular weight distribution of high polymers by the rheological properties

NASA Technical Reports Server (NTRS)

Huang, J. Y.; Hou, T. H.; Tiwari, S. N.

1989-01-01

Several methods are reviewed by which the molecular weight (MW) and the molecular weight distribution (MWD) of polymeric material were determined from the rheological properties. A poly(arylene ether) polymer with six different molecular weights was used in this investigation. Experimentally measured MW and MWD were conducted by GPC/LALLS (gel permeation chromatography/low angle laser light scattering), and the rheological properties of the melts were measured by a Rheometric System Four rheometer. It was found that qualitative information of the MW and MWD of these polymers could be derived from the viscoelastic properties, with the methods proposed by Zeichner and Patel, and by Dormier et al., by shifting the master curves of the dynamic storage modulus, G', and the loss modulus, G'', along the frequency axis. Efforts were also made to calculate quantitative profiles of MW and MWD for these polymers from their rheological properties. The technique recently proposed by Wu was evaluated. It was found that satisfactory results could only be obtained for polymers with single modal distribution in the molecular weight.

Investigation of Polymer Liquid Crystals

NASA Technical Reports Server (NTRS)

Han, Kwang S.

1996-01-01

The positron annihilation lifetime spectroscopy (PALS) using a low energy flux generator may provide a reasonably accurate technique for measuring molecular weights of linear polymers and characterization of thin polyimide films in terms of their dielectric constants and hydrophobity etc. Among the tested samples are glassy poly arylene Ether Ketone films, epoxy and other polyimide films. One of the proposed techniques relates the free volume cell size (V(sub f)) with sample molecular weight (M) in a manner remarkably similar to that obtained by Mark Houwink (M-H) between the inherent viscosity (eta) and molecular wieght of polymer solution. The PALS has also demonstrated that free-volume cell size in thermoset is a versatile, useful parameter that relates directly to the polymer segmental molecular weight, the cross-link density, and the coefficient of thermal expansion. Thus, a determination of free volume cell size provides a viable basis for complete microstructural characterization of thermoset polyimides and also gives direct information about the cross-link density and coefficient of expansion of the test samples. Seven areas of the research conducted are reported here.

Flow curve analysis of a Pickering emulsion-polymerized PEDOT:PSS/PS-based electrorheological fluid

NASA Astrophysics Data System (ADS)

Kim, So Hee; Choi, Hyoung Jin; Leong, Yee-Kwong

2017-11-01

The steady shear electrorheological (ER) response of poly(3, 4-ethylenedioxythiophene): poly(styrene sulfonate)/polystyrene (PEDOT:PSS/PS) composite particles, which were initially fabricated from Pickering emulsion polymerization, was tested with a 10 vol% ER fluid dispersed in a silicone oil. The model independent shear rate and yield stress obtained from the raw torque-rotational speed data using a Couette type rotational rheometer under an applied electric field strength were then analyzed by Tikhonov regularization, which is the most suitable technique for solving an ill-posed inverse problem. The shear stress-shear rate data also fitted well with the data extracted from the Bingham fluid model.

Dwindling the resistance value of PEDOT:PSS – coated on fabric yarns

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

Amba Sankar, K.N., E-mail: amb@psgias.ac.in; Kallol, Mohanta

2016-05-23

Herein we describe by dip coating method to transform typical fabric yarn to conductive fiber. Different types of yarns have been used to coat from a known conductive polymer, Poly (3,4ethylenedioxythiophene) Poly (styrene sulfonic acid). We have optimized the method to have lesser resistance of the conductive yarns. The minimum resistance achieved has a value of 77 Ω/cm. This value is not high as metals but could be comparable to that of metal oxides or semiconducting materials. However, flexibility of yarns and feeling of fabric combining with the conductivity developed in this process is suitable for wearable electronics and alsomore » as gas sensors, electromagnetic shielding.« less

Orientation selectivity in a multi-gated organic electrochemical transistor

NASA Astrophysics Data System (ADS)

Gkoupidenis, Paschalis; Koutsouras, Dimitrios A.; Lonjaret, Thomas; Fairfield, Jessamyn A.; Malliaras, George G.

2016-06-01

Neuromorphic devices offer promising computational paradigms that transcend the limitations of conventional technologies. A prominent example, inspired by the workings of the brain, is spatiotemporal information processing. Here we demonstrate orientation selectivity, a spatiotemporal processing function of the visual cortex, using a poly(3,4ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) organic electrochemical transistor with multiple gates. Spatially distributed inputs on a gate electrode array are found to correlate with the output of the transistor, leading to the ability to discriminate between different stimuli orientations. The demonstration of spatiotemporal processing in an organic electronic device paves the way for neuromorphic devices with new form factors and a facile interface with biology.

Determination of caffeic acid in wine using PEDOT film modified electrode.

PubMed

Bianchini, C; Curulli, A; Pasquali, M; Zane, D

2014-08-01

A novel method using PEDOT (poly(3,4-ethylenedioxy) thiophene) modified electrode was developed for the determination of caffeic acid (CA) in wine. Cyclic voltammetry (CV) with the additions standard method was used to quantify the analyte at PEDOT modified electrodes. PEDOT films were electrodeposited on Platinum electrode (Pt) in aqueous medium by galvanostatic method using sodium poly(styrene-4-sulfonate) (PSS) as electrolyte and surfactant. CV allows detecting the analyte over a wide concentration range (10.0nmoll(-1)-6.5mmoll(-1)). The electrochemical method proposed showed good statistical and analytical parameters as linearity range, LOD, LOQ and sensitivity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Autoclave Sterilization of PEDOT:PSS Electrophysiology Devices.

PubMed

Uguz, Ilke; Ganji, Mehran; Hama, Adel; Tanaka, Atsunori; Inal, Sahika; Youssef, Ahmed; Owens, Roisin M; Quilichini, Pascale P; Ghestem, Antoine; Bernard, Christophe; Dayeh, Shadi A; Malliaras, George G

2016-12-01

Autoclaving, the most widely available sterilization method, is applied to poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) electrophysiology devices. The process does not harm morphology or electrical properties, while it effectively kills E. coli intentionally cultured on the devices. This finding paves the way to widespread introduction of PEDOT:PSS electrophysiology devices to the clinic. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Water-Soluble Polyaniline Complex for Ink-Jet Printing of Optoelectronic Devices

NASA Astrophysics Data System (ADS)

Gribkova, O. L.; Saf'yanova, L. V.; Tameev, A. R.; Lypenko, D. A.; Tverskoi, V. A.; Nekrasov, A. A.

2018-03-01

The influence of the ratio of components in polyaniline (PANI) complexes with poly(sulfonic acid) on the viscosity of their aqueous solutions and electric conductivity of layers formed thereof. The optical properties and morphology of PANI complex layers formed by ink-jet printing have been studied. The optimum ratio of components to be used in anodic buffer layers for organic solar cells is determined.

Pore size and concentration effect of mesoporous silica nanoparticles on the coefficient of thermal expansion and optical transparency of poly(ether sulfone) films.

PubMed

Vo, Nhat Tri; Patra, Astam K; Kim, Dukjoon

2017-01-18

Mesoporous silica nanoparticles (MSNs) with uniform size (<50 nm) yet with different pore diameters were synthesized, and used as fillers in poly(ether sulfone) (PES) films in order to decrease their coefficient of thermal expansion (CTE) without sacrificing optical transparency. Here, both CTE and optical transparency of the MSN/PES nanocomposite films gradually decreased with increasing MSN concentration. The PES films containing MSNs with larger pores showed the best performance in CTE and optical transparency. While the CTE decreased by 32.3% with increasing MSN content up to 0.5 wt%, the optical transparency decreased by only less than 6.9% because of the small and uniform particle size of less than 50 nm, which minimizes light scattering. This pore size effect is more clearly observed via an annealing process, which enables the polymer chains to slowly move and fill in the free volume in the pores of the MSN, and thus restricts the thermal motion. The effect of the silica nanoparticles was investigated not only on the thermal stability but also on the mechanical stability. We expect the MSNs synthesized in this study to be used as a promising filler to enhance the thermal and mechanical stability of the PES substrate without sacrificing its optical transparency.

TEMPO addition into pre-irradiated fluoropolymers and living-radical graft polymerization of styrene for preparation of polymer electrolyte membranes

NASA Astrophysics Data System (ADS)

Sawada, Shin-ichi; Suzuki, Akihiro; Terai, Takayuki; Maekawa, Yasunari

2010-04-01

We prepared proton exchange membranes (PEMs) by 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO)-mediated living-radical graft polymerization (LRGP) of styrene into fluoropolymer films and subsequent sulfonation. Poly(vinylidene fluoride) (PVDF) and poly(ethylene- co-tetrafluoroethylene) (ETFE) films were first irradiated and then treated with TEMPO solutions in various solvents. TEMPO addition was confirmed by the test of styrene grafting into TEMPO-treated films at 60 °C, at which the LRGP never proceeds. This test enabled us to differentiate the LRGP from the conventional graft polymerization. In order to gain a deep insight about TEMPO-addition reaction, the TEMPO-penetration behavior into the base polymer films was examined by a permeation experiment and computer simulation. Xylene and dioxane were appropriate solvents for the complete introduction of TEMPO into PVDF and ETFE films, respectively. Then, the LRGP of styrene was performed based on the fully TEMPO-capped films at 125 °C with various solvents. By using an alcoholic solvent, the degree of grafting was enhanced and it reached a maximum of 38%. This grafted film was sulfonated to prepare a PEM showing an ion exchange capacity of 2.2 meq/g and proton conductivity of 1.6×10 -1 S/cm.

Electrospun sulfonated poly(ether ketone) nanofibers as proton conductive reinforcement for durable Nafion composite membranes

NASA Astrophysics Data System (ADS)

Klose, Carolin; Breitwieser, Matthias; Vierrath, Severin; Klingele, Matthias; Cho, Hyeongrae; Büchler, Andreas; Kerres, Jochen; Thiele, Simon

2017-09-01

We show that the combination of direct membrane deposition with proton conductive nanofiber reinforcement yields highly durable and high power density fuel cells. Sulfonated poly(ether ketone) (SPEK) was directly electrospun onto gas diffusion electrodes and then filled with Nafion by inkjet-printing resulting in a 12 μm thin membrane. The ionic membrane resistance (30 mΩ*cm2) was well below that of a directly deposited membrane reinforced with chemically inert (PVDF-HFP) nanofibers (47 mΩ*cm2) of comparable thickness. The power density of the fuel cell with SPEK reinforced membrane (2.04 W/cm2) is 30% higher than that of the PVDF-HFP reinforced reference sample (1.57 W/cm2). During humidity cycling and open circuit voltage (OCV) hold, the SPEK reinforced Nafion membrane showed no measurable degradation in terms of H2 crossover current density, thus fulfilling the target of 2 mA/cm2 of the DOE after degradation. The chemical accelerated stress test (100 h OCV hold at 90 °C, 30% RH, H2/air, 50/50 kPa) revealed a degradation rate of about 0.8 mV/h for the fuel cell with SPEK reinforced membrane, compared to 1.0 mV/h for the PVDF-HFP reinforced membrane.

Post-irradiation time effects on the graft of poly(ethylene-alt-tetrafluoroethylene) (ETFE) films for ion exchange membrane application

NASA Astrophysics Data System (ADS)

Geraldes, Adriana N.; Zen, Heloísa A.; Ribeiro, Geise; Ferreira, Henrique P.; Souza, Camila P.; Parra, Duclerc F.; Santiago, Elisabete I.; Lugão, Ademar B.

2010-03-01

Grafting of styrene followed by sulfonation onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) was studied for synthesis of ion exchange membranes. Radiation-induced grafting of styrene onto ETFE films was investigated after simultaneous irradiation (in post-irradiation condition) using a 60Co source. The ETFE films were irradiated at 20 kGy dose at room temperature and chemical changes were monitored after contact with styrene for grafting. The post-irradiation time was established at 14 days when the films were remained in styrene/toluene 1:1 v/v. After this period the grafting degree was evaluated in the samples. The grafted films were sulfonated using chlorosulfonic acid and 1, 2-dichloroethane 20:80 (v/v) at room temperature for 5 h. The membranes were analyzed by infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermogravimetric measurements (TG) and degree of grafting (DOG). The ion exchange capacity (IEC) of membranes was determined by acid-base titration and the values for ETFE membranes were achieved higher than Nafion ® films. Preliminary single cell performance was made using pure H 2 and O 2 as reactants at a cell temperature of 80 °C and atmospheric gas pressure. The fuel cell performance of ETFE films was satisfactory when compared to state-of-art Nafion ® membranes.

A novel crosslinking strategy for preparing poly(vinyl alcohol)-based proton-conducting membranes with high sulfonation

NASA Astrophysics Data System (ADS)

Tsai, Chun-En; Lin, Chi-Wen; Hwang, Bing-Joe

This study synthesizes poly(vinyl alcohol) (PVA)-based polymer electrolyte membranes by a two-step crosslinking process involving esterization and acetal ring formation reactions. This work also uses sulfosuccinic acid (SSA) as the first crosslinking agent to form an inter-crosslinked structure and a promoting sulfonating agent. Glutaraldehyde (GA) as the second crosslinking agent, reacts with the spare OH group of PVA and forms, not only a dense structure at the outer membrane surface, but also a hydrophobic protective layer. Compared with membranes prepared by a traditional one-step crosslinking process, membranes prepared by the two-step crosslinking process exhibit excellent dissolution resistance in water. The membranes become water-insoluble even at a molar ratio of SO 3H/PVA-OH as high as 0.45. Moreover, the synthesized membranes also exhibit high proton conductivities and high methanol permeability resistance. The current study measures highest proton conductivity of 5.3 × 10 -2 S cm -1 at room temperature from one of the synthesized membranes, higher than that of the Nafion ® membrane. Methanol permeability of the synthesized membranes measures about 1 × 10 -7 cm 2 S -1, about one order of magnitude lower than that of the Nafion ® membrane.

Significant vertical phase separation in solvent-vapor-annealed poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) composite films leading to better conductivity and work function for high-performance indium tin oxide-free optoelectronics.

PubMed

Yeo, Jun-Seok; Yun, Jin-Mun; Kim, Dong-Yu; Park, Sungjun; Kim, Seok-Soon; Yoon, Myung-Han; Kim, Tae-Wook; Na, Seok-In

2012-05-01

In the present study, a novel polar-solvent vapor annealing (PSVA) was used to induce a significant structural rearrangement in poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films in order to improve their electrical conductivity and work function. The effects of polar-solvent vapor annealing on PEDOT:PSS were systematically compared with those of a conventional solvent additive method (SAM) and investigated in detail by analyzing the changes in conductivity, morphology, top and bottom surface composition, conformational PEDOT chains, and work function. The results confirmed that PSVA induces significant phase separation between excess PSS and PEDOT chains and a spontaneous formation of a highly enriched PSS layer on the top surface of the PEDOT:PSS polymer blend, which in turn leads to better 3-dimensional connections between the conducting PEDOT chains and higher work function. The resultant PSVA-treated PEDOT:PSS anode films exhibited a significantly enhanced conductivity of up to 1057 S cm(-1) and a tunable high work function of up to 5.35 eV. The PSVA-treated PEDOT:PSS films were employed as transparent anodes in polymer light-emitting diodes (PLEDs) and polymer solar cells (PSCs). The cell performances of organic optoelectronic devices with the PSVA-treated PEDOT:PSS anodes were further improved due to the significant vertical phase separation and the self-organized PSS top surface in PSVA-treated PEDOT:PSS films, which can increase the anode conductivity and work function and allow the direct formation of a functional buffer layer between the active layer and the polymeric electrode. The results of the present study will allow better use and understanding of polymeric-blend materials and will further advance the realization of high-performance indium tin oxide (ITO)-free organic electronics.

Thermochemical characterization of some thermally stable thermoplastic and thermoset polymers

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Gilwee, W. J., Jr.; Parker, J. A.

1979-01-01

The thermochemical and flammability properties of some thermally stable polymers considered for use in aircraft interiors are described. The properties studied include: (1) thermomechanical properties such as glass transition and melt temperature; (2) dynamic thermogravimetric analysis in anaerobic environment; (3) flammability properties such as oxygen index, flame spread, and smoke evolution; and (4) selected physical properties. The thermoplastic polymers evaluated include polyphenylene sulfide, polyaryl sulfone, 9,9-bis(4-hydroxyphenyl)-fluorene polycarbonate-poly(dimethylsiloxane) and polyether sulfone. The thermoset polymers evaluated include epoxy, bismaleimide, a modified phenolic, and polyaromatic melamine resin. These resins were primarily used in the fabrication of glass-reinforced prepregs for the construction of experimental panels. Test results and relative rankings of some of the flammability parameters are presented, and the relationship of the molecular structure, char yield, and flammability properties of these polymers are discussed.

All-solution-processed PbS quantum dot solar modules

NASA Astrophysics Data System (ADS)

Jang, Jihoon; Shim, Hyung Cheoul; Ju, Yeonkyeong; Song, Jung Hoon; An, Hyejin; Yu, Jong-Su; Kwak, Sun-Woo; Lee, Taik-Min; Kim, Inyoung; Jeong, Sohee

2015-05-01

A rapid increase in power conversion efficiencies in colloidal quantum dot (QD) solar cells has been achieved recently with lead sulphide (PbS) QDs by adapting a heterojunction architecture, which consists of small-area devices associated with a vacuum-deposited buffer layer with metal electrodes. The preparation of QD solar modules by low-cost solution processes is required to further increase the power-to-cost ratio. Herein we demonstrate all-solution-processed flexible PbS QD solar modules with a layer-by-layer architecture comprising polyethylene terephthalate (PET) substrate/indium tin oxide (ITO)/titanium oxide (TiO2)/PbS QD/poly(3-hexylthiophene) (P3HT)/poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS)/Ag, with an active area of up to 30 cm2, exhibiting a power conversion efficiency (PCE) of 1.3% under AM 1.5 conditions (PCE of 2.2% for a 1 cm2 unit cell). Our approach affords trade-offs between power and the active area of the photovoltaic devices, which results in a low-cost power source, and which is scalable to larger areas.A rapid increase in power conversion efficiencies in colloidal quantum dot (QD) solar cells has been achieved recently with lead sulphide (PbS) QDs by adapting a heterojunction architecture, which consists of small-area devices associated with a vacuum-deposited buffer layer with metal electrodes. The preparation of QD solar modules by low-cost solution processes is required to further increase the power-to-cost ratio. Herein we demonstrate all-solution-processed flexible PbS QD solar modules with a layer-by-layer architecture comprising polyethylene terephthalate (PET) substrate/indium tin oxide (ITO)/titanium oxide (TiO2)/PbS QD/poly(3-hexylthiophene) (P3HT)/poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS)/Ag, with an active area of up to 30 cm2, exhibiting a power conversion efficiency (PCE) of 1.3% under AM 1.5 conditions (PCE of 2.2% for a 1 cm2 unit cell). Our approach affords trade-offs between power and the active area of the photovoltaic devices, which results in a low-cost power source, and which is scalable to larger areas. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01508a

Persistence of perfluoroalkyl acid precursors in AFFF-impacted groundwater and soil.

PubMed

Houtz, Erika F; Higgins, Christopher P; Field, Jennifer A; Sedlak, David L

2013-08-06

Several classes of polyfluorinated chemicals that are potential precursors to the perfluorinated carboxylates and sulfonates are present in aqueous film-forming foams (AFFF). To assess the persistence of these AFFF-derived precursors, groundwater, soil, and aquifer solids were obtained in 2011 from an unlined firefighter training area at a U.S. Air Force Base where AFFF was regularly used between 1970 and 1990. To measure the total concentration of perfluorinated carboxylate and sulfonate precursors in archived AFFF formulations and AFFF-impacted environmental samples, a previously developed assay that uses hydroxyl radical to oxidize precursors to perfluorinated carboxylates was adapted for these media. This assay was employed along with direct measurement of 22 precursors found in AFFF and a suite of other poly- and perfluoroalkyl substances (PFASs). On a molar basis, precursors accounted for 41-100% of the total concentration of PFASs in archived AFFF formulations. In the training area, precursors measured by the oxidation assay accounted for an average of 23% and 28% of total PFASs (i.e., precursors and perfluorinated carboxylates and sulfonates) in groundwater and solids samples, respectively. One precursor in AFFF, perfluorohexane sulfonamide amine, was observed on several highly contaminated soil and aquifer solids samples, but no other precursors present in AFFF formulations were detected in any samples at this field site. Suspected intermediate transformation products of precursors in AFFF that were directly measured accounted for approximately half of the total precursor concentration in samples from the training site. The fraction of PFASs consisting of perfluorinated carboxylates and sulfonates was greater in groundwater and solid samples than in any archived AFFF formulations, suggesting that much of the mass of precursors released at the site was converted to perfluorinated carboxylates and sulfonates. The precursors that have persisted at this site may generate significant amounts of additional perfluorinated carboxylates and sulfonates upon remediation of contaminated groundwater or aquifer solids.

Switching characteristics for ferroelectric random access memory based on RC model in poly(vinylidene fluoride-trifluoroethylene) ultrathin films

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

Liu, ChangLi; Complex and Intelligent System Research Center, East China University of Science and Technology, Shanghai 200237; Wang, XueJun

2016-05-15

The switching characteristic of the poly(vinylidene fluoride-trifluoroethlene) (P(VDF-TrFE)) films have been studied at different ranges of applied electric field. It is suggest that the increase of the switching speed upon nucleation protocol and the deceleration of switching could be related to the presence of a non-ferroelectric layer. Remarkably, a capacitor and resistor (RC) links model plays significant roles in the polarization switching dynamics of the thin films. For P(VDF-TrFE) ultrathin films with electroactive interlayer, it is found that the switching dynamic characteristics are strongly affected by the contributions of resistor and non-ferroelectric (non-FE) interface factors. A corresponding experiment is designedmore » using poly(3,4-ethylene dioxythiophene):poly(styrene sulfonic) (PEDOT-PSSH) as interlayer with different proton concentrations, and the testing results show that the robust switching is determined by the proton concentration in interlayer and lower leakage current in circuit to reliable applications of such polymer films. These findings provide a new feasible method to enhance the polarization switching for the ferroelectric random access memory.« less

Thermal Annealing Effect on Poly(3-hexylthiophene): Fullerene:Copper-Phthalocyanine Ternary Photoactive Layer

PubMed Central

Derouiche, H.; Mohamed, A. B.

2013-01-01

We have fabricated poly(3-hexylthiophene) (P3HT)/copper phthalocyanine (CuPc)/fullerene (C60) ternary blend films. This photoactive layer is sandwiched between an indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT/PSS) photoanode and a bathocuproine (BCP)/aluminium photocathode. The thin films have been characterized by atomic force microscope (AFM) and ultraviolet/visible spectroscopy in order to study the influence of P3HT doping on the morphological and optical properties of the photoactive layer. We have also compared the I-V characteristics of three different organic solar cells: ITO/PEDOT:PSS/CuPc0.5:C600.5/BCP/Al and ITO/PEDOT:PSS/P3HT0.3:CuPc0.3:C600.4/BCP/Al with and without annealing. Both structures show good photovoltaic behaviour. Indeed, the incorporation of P3HT into CuPc:C60 thin film improves all the photovoltaic characteristics. We have also seen that thermal annealing significantly improves the optical absorption ability and stabilizes the organic solar cells making it more robust to chemical degradation. PMID:23766722

Tailored adhesion behavior of polyelectrolyte thin films deposited on plasma-treated poly(dimethylsiloxane) for functionalized membranes

NASA Astrophysics Data System (ADS)

Bassil, Joelle; Alem, Halima; Henrion, Gérard; Roizard, Denis

2016-04-01

Completely homogenous films formed via the layer-by-layer assembly of poly(diallyldimethylammonium chloride) (PDADMAC) and the poly(styrene sulfonate) were successfully obtained on plasma-treated poly(dimethylsiloxane) (PDMS) substrates. To modify the hydrophobicity of the PDMS surface, a cold plasma treatment was previously applied to the membrane, which led to the creation of hydrophilic groups on the surface of the membrane. PDMS wettability and surface morphology were successfully correlated with the plasma parameters. A combination of contact angle measurements, scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis was used to demonstrate that homogeneous and hydrophilic surfaces could be achieved on PDMS cold-plasma-treated membranes. The stability of the assembled PEL layer on the PDMS was evaluated using a combination of pull-off testing and X-ray photoelectron spectroscopy (XPS), which confirmed the relevance of a plasma pre-treatment as the adhesion of the polyelectrolyte multilayers was greatly enhanced when the deposition was completed on an activated PDMS surface at 80 W for 5 min.

Thermal annealing effect on poly(3-hexylthiophene): fullerene:copper-phthalocyanine ternary photoactive layer.

PubMed

Derouiche, H; Mohamed, A B

2013-01-01

We have fabricated poly(3-hexylthiophene) (P3HT)/copper phthalocyanine (CuPc)/fullerene (C60) ternary blend films. This photoactive layer is sandwiched between an indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT/PSS) photoanode and a bathocuproine (BCP)/aluminium photocathode. The thin films have been characterized by atomic force microscope (AFM) and ultraviolet/visible spectroscopy in order to study the influence of P3HT doping on the morphological and optical properties of the photoactive layer. We have also compared the I-V characteristics of three different organic solar cells: ITO/PEDOT:PSS/CuPc₀.₅:C60₀.₅/BCP/Al and ITO/PEDOT:PSS/P3HT₀.₃:CuPc₀.₃:C60₀.₄/BCP/Al with and without annealing. Both structures show good photovoltaic behaviour. Indeed, the incorporation of P3HT into CuPc:C60 thin film improves all the photovoltaic characteristics. We have also seen that thermal annealing significantly improves the optical absorption ability and stabilizes the organic solar cells making it more robust to chemical degradation.

Tunable hole injection of solution-processed polymeric carbon nitride towards efficient organic light-emitting diode

NASA Astrophysics Data System (ADS)

Zhang, Xiaowen; Zheng, Qinghong; Tang, Zhenyu; Li, Wanshu; Zhang, Yan; Xu, Kai; Xue, Xiaogang; Xu, Jiwen; Wang, Hua; Wei, Bin

2018-02-01

Polymeric carbon nitride (CNxHy) has been facilely synthesized from dicyandiamide and functions as a solution-processed hole injection layer in organic light-emitting diodes (OLEDs). The measurements using X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and impedance spectroscopy elucidate that CNxHy exhibits superior film morphology and extra electric properties such as tailored work function and tunable hole injection. The luminous efficiency of CNxHy-based OLED is found to improve by 76.6% in comparison to the counterpart using favorite solution-processed poly(ethylene dioxythiophene):poly(styrene sulfonate) as the hole injection layer. Our results also pave a way for broadening carbon nitride applications in organic electronics using the solution process.

Pressure Mapping Mat for Tele-Home Care Applications

PubMed Central

Saenz-Cogollo, Jose Francisco; Pau, Massimiliano; Fraboni, Beatrice; Bonfiglio, Annalisa

2016-01-01

In this paper we present the development of a mat-like pressure mapping system based on a single layer textile sensor and intended to be used in home environments for monitoring the physical condition of persons with limited mobility. The sensor is fabricated by embroidering silver-coated yarns on a light cotton fabric and creating pressure-sensitive resistive elements by stamping the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) at the crossing points of conductive stitches. A battery-operated mat prototype was developed and includes the scanning circuitry and a wireless communication module. A functional description of the system is presented together with a preliminary experimental evaluation of the mat prototype in the extraction of plantar pressure parameters. PMID:26978369

Ultrathin epidermal strain sensor based on an elastomer nanosheet with an inkjet-printed conductive polymer

NASA Astrophysics Data System (ADS)

Tetsu, Yuma; Yamagishi, Kento; Kato, Akira; Matsumoto, Yuya; Tsukune, Mariko; Kobayashi, Yo; Fujie, Masakatsu G.; Takeoka, Shinji; Fujie, Toshinori

2017-08-01

To minimize the interference that skin-contact strain sensors cause natural skin deformation, physical conformability to the epidermal structure is critical. Here, we developed an ultrathin strain sensor made from poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) inkjet-printed on a polystyrene-polybutadiene-polystyrene (SBS) nanosheet. The sensor, whose total thickness and gauge factor were ˜1 µm and 0.73 ± 0.10, respectively, deeply conformed to the epidermal structure and successfully detected the small skin strain (˜2%) while interfering minimally with the natural deformation of the skin. Such an epidermal strain sensor will open a new avenue for precisely detecting the motion of human skin and artificial soft-robotic skin.

Friedel–Crafts Crosslinked Highly Sulfonated Polyether Ether Ketone (SPEEK) Membranes for a Vanadium/Air Redox Flow Battery

PubMed Central

Merle, Géraldine; Ioana, Filipoi Carmen; Demco, Dan Eugen; Saakes, Michel; Hosseiny, Seyed Schwan

2014-01-01

Highly conductive and low vanadium permeable crosslinked sulfonated poly(ether ether ketone) (cSPEEK) membranes were prepared by electrophilic aromatic substitution for a Vanadium/Air Redox Flow Battery (Vanadium/Air-RFB) application. Membranes were synthesized from ethanol solution and crosslinked under different temperatures with 1,4-benzenedimethanol and ZnCl2 via the Friedel–Crafts crosslinking route. The crosslinking mechanism under different temperatures indicated two crosslinking pathways: (a) crosslinking on the sulfonic acid groups; and (b) crosslinking on the backbone. It was observed that membranes crosslinked at a temperature of 150 °C lead to low proton conductive membranes, whereas an increase in crosslinking temperature and time would lead to high proton conductive membranes. High temperature crosslinking also resulted in an increase in anisotropy and water diffusion. Furthermore, the membranes were investigated for a Vanadium/Air Redox Flow Battery application. Membranes crosslinked at 200 °C for 30 min with a molar ratio between 2:1 (mol repeat unit:mol benzenedimethanol) showed a proton conductivity of 27.9 mS/cm and a 100 times lower VO2+ crossover compared to Nafion. PMID:24957118

Phase Behavior and Conductivity of Phosphonated Block Copolymers Containing Ionic Liquids

NASA Astrophysics Data System (ADS)

Jung, Ha Young; Kim, Sung Yeon; Park, Moon Jeong

2015-03-01

As the focus on proton exchange fuel cells continues to escalate in the era of alternative energy systems, the rational design of sulfonated polymers has emerged as a key technique for enhancing device efficiency. While the sulfonic acid group guarantees high proton conductivity of membranes under humidified conditions, the growing need for high temperature operation has discouraged their practical uses in fuel cells. In this respect, phosphonated polymers have drawn intensive attention in recent years owing to their self-dissociation ability. In this study, we have synthesized a set of phosphonated block copolymers, poly(styrenephosphonate-methylbutylene) (PSP- b - PMB), by varying phosphonation level (PL). A wide variety of self-assembled morphologies, i.e., disordered, lamellar, hexagonally perforated lamellae and hexagonally packed cylindrical phases, were observed with PL. Remarkably, upon comparing the morphology of PSP- b-PMB and that of sulfonated analog, we found distinctly dissimilar domain sizes at the same molecular weight and composition. A range of ionic liquids (ILs) were incorporated into the PSP- b-PMB block copolymers and their ion transport properties were examined. It has been revealed that the degree of confinement of ionic phases (domain size) impacts the ion mobility and proton dissociation efficiency of IL-containing polymers.

Ion pair reinforced semi-interpenetrating polymer network for direct methanol fuel cell applications.

PubMed

Fang, Chunliu; Julius, David; Tay, Siok Wei; Hong, Liang; Lee, Jim Yang

2012-06-07

This paper describes the synthesis of ion-pair-reinforced semi-interpenetrating polymer networks (SIPNs) as proton exchange membranes (PEMs) for the direct methanol fuel cells (DMFCs). Specifically, sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO), a linear polymer proton source, was immobilized in a brominated PPO (BPPO) network covalently cross-linked by ethylenediamine (EDA). The immobilization of SPPO in the SIPN network was accomplished not only by the usual means of mechanical interlocking but also by ion pair formation between the sulfonic acid groups of SPPO and the amine moieties formed during the cross-linking reaction of BPPO with EDA. Through the ion pair interactions, the immobilization of SPPO polymer in the BPPO network was made more effective, resulting in a greater uniformity of sulfonic acid cluster distribution in the membrane. The hydrophilic amine-containing cross-links also compensated for some of the decrease in proton conductivity caused by ion pair formation. The SIPN membranes prepared as such showed good proton conductivity, low methanol permeability, good mechanical properties, and dimensional stability. Consequently, the PPO based SIPN membranes were able to deliver a higher maximum power density than Nafion, demonstrating the potential of the SIPN structure for PEM designs.

Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid)/poly(L-lactic acid) and self-assembly of polyelectrolytes.

PubMed

Dellacasa, Elena; Zhao, Li; Yang, Gesheng; Pastorino, Laura; Sukhorukov, Gleb B

2016-01-01

The enantiomers poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) were alternately adsorbed directly on calcium carbonate (CaCO3) templates and on poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) multilayer precursors in order to fabricate a novel layer-by-layer (LBL) assembly. A single layer of poly(L-lysine) (PLL) was used as a linker between the (PDLA/PLLA) n stereocomplex and the cores with and without the polymeric (PSS/PAH) n /PLL multilayer precursor (PEM). Nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) were used to characterize the chemical composition and molecular weight of poly(lactic acid) polymers. Both multilayer structures, with and without polymeric precursor, were firstly fabricated and characterized on planar supports. A quartz crystal microbalance (QCM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and ellipsometry were used to evaluate the thickness and mass of the multilayers. Then, hollow, spherical microcapsules were obtained by the removal of the CaCO3 sacrificial template. The chemical composition of the obtained microcapsules was confirmed by differential scanning calorimetry (DSC) and wide X-ray diffraction (WXRD) analyses. The microcapsule morphology was evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements. The experimental results confirm the successful fabrication of this innovative system, and its full biocompatibility makes it worthy of further characterization as a promising drug carrier for sustained release.

Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid)/poly(L-lactic acid) and self-assembly of polyelectrolytes

PubMed Central

Yang, Gesheng; Pastorino, Laura

2016-01-01

Summary The enantiomers poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) were alternately adsorbed directly on calcium carbonate (CaCO3) templates and on poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) multilayer precursors in order to fabricate a novel layer-by-layer (LBL) assembly. A single layer of poly(L-lysine) (PLL) was used as a linker between the (PDLA/PLLA)n stereocomplex and the cores with and without the polymeric (PSS/PAH)n/PLL multilayer precursor (PEM). Nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) were used to characterize the chemical composition and molecular weight of poly(lactic acid) polymers. Both multilayer structures, with and without polymeric precursor, were firstly fabricated and characterized on planar supports. A quartz crystal microbalance (QCM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and ellipsometry were used to evaluate the thickness and mass of the multilayers. Then, hollow, spherical microcapsules were obtained by the removal of the CaCO3 sacrificial template. The chemical composition of the obtained microcapsules was confirmed by differential scanning calorimetry (DSC) and wide X-ray diffraction (WXRD) analyses. The microcapsule morphology was evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements. The experimental results confirm the successful fabrication of this innovative system, and its full biocompatibility makes it worthy of further characterization as a promising drug carrier for sustained release. PMID:26925356

Characterization of flammability properties of some thermoplastic and thermoset resins. [for aircraft interiors

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.

1978-01-01

The thermochemical and flammability properties of some thermally stable polymers considered for use in aircraft interiors are described. The properties studied include: (1) thermomechanical properties such as glass transition and melt temperature; (2) dynamic thermogravimetric analysis in anaerobic environment; (3) flammability properties such as oxygen index, flame spread, and smoke evolution; and (4) selected physical properties. The thermoplastic polymers evaluated included polyphenylene sulfide, polyaryl sulfone, 9,9-bis(4-hydroxyphenyl)-fluorene polycarbonate-poly(dimethylsiloxane) and polyether sulfone. The thermoset polymers evaluated included epoxy, bismaleimide, a modified phenolic and polyaromatic melamine resin. These resins were primarily used in the fabrication of glass reinforced prepregs for the construction of experimental panels. Test results and relative rankings of some of the flammability parameters are presented and the relationship of the molecular structure, char yield, and flammability properties of these polymers are discussed.

Tensile Properties of a Cellulose Ether Hydrogel

NASA Technical Reports Server (NTRS)

Hinkley, Jeffrey A.; Gehrke, Stevin H.

2003-01-01

Poly(hydroxycellulose) solutions were molded into dumbell-shaped specimens crosslinked with divinyl sulfone. The resulting hydrogels were tested in tension at room temperature and also at a temperature above the 40 C shrinkage transition. In contrast to behavior seen in some other responsive gels, apparent initial tangent moduli were lower in the shrunken state; breaking elongations were significantly higher. Possible molecular mechanisms are suggested, and implications for the design of temperature-responsive actuators ("artificial muscles") from this material are discussed.

Radical-induced generation of small silver particles in SPEEK/PVA polymer films and solutions: UV-Vis, EPR, and FT-IR studies.

PubMed

Korchev, A S; Konovalova, T; Cammarata, V; Kispert, L; Slaten, L; Mills, G

2006-01-03

The present study is centered on the processes involved in the photochemical generation of nanometer-sized Ag particles via illumination at 350 nm of aqueous solutions and cross linked films containing sulfonated poly(ether ether ketone) and poly(vinyl alcohol). Optical and electron paramagnetic resonance experiments, including electron nuclear double resonance data, proved conclusively that the photogenerated chromophore exhibiting a band with lambda(max) = 565 nm is an alpha-hydroxy aromatic (ketyl) radical of the polymeric ketone. This reducing species was produced by illumination of either solutions or films, but the radical lifetime extended from minutes in the fluid phase to hours in the solid. Direct evidence is presented that this long-lived chromophore reduces Ag(I), Cu(II), and Au(III) ions in solution. A rate constant of k = 1.4 x 10(3) M(-)(1) s(-)(1) was obtained for the reduction of Ag(+) by the ketyl radical from the post-irradiation formation of Ag crystallites. FTIR results confirmed that the photoprocess yielding polymeric ketyl radicals involves a reaction between the macromolecules. The photochemical oxidation of the polymeric alcohol, as well as the formation of light-absorbing macromolecular products and polyols, indicates that the sulfonated polyketone experienced transformations similar to those encountered during illumination of the benzophenone/2-propanol system.

L-Arginine modified multi-walled carbon nanotube/sulfonated poly(ether ether ketone) nanocomposite films for biomedical applications

NASA Astrophysics Data System (ADS)

Kaya, Hatice; Bulut, Osman; Kamali, Ali Reza; Ege, Duygu

2018-06-01

Favorable implant-tissue interactions are crucial to achieve successful osseointegration of the implants. Poly(ether ether ketone) (PEEK) is an interesting alternative to titanium in orthopedics because of its low cost, high biocompatibility and comparable mechanical properties with cancellous bone. Despite these advantages; however, the untreated surface of PEEK fails to osseointegrate due to its bioinert and hydrophobic behavior. This paper deals with the surface modification of PEEK with a novel method. For this, PEEK was first treated with concentrated sulfuric acid to prepare sulfonated PEEK (SPEEK) films using a solvent casting method. Then, 1 and 2 wt% multi-walled carbon nanotube was incorporated into SPEEK to form nanocomposite films. The samples were characterized with Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy. After successful preparation of the nanocomposite films, L-arginine was covalently conjugated on the nanocomposite films to further improve their surface properties. Subsequently, the samples were characterized using X-ray Photoemission Spectroscopy (XPS), water contact angle measurements and Atomic Force Microscopy (AFM) and Dynamic Mechanical Thermal Analysis (DMTA). Finally, cell culture studies were carried out by using Alamar Blue assay to evaluate the biocompatibility of the films. The results obtained indicate the successful preparation of L-arginine-conjugated MWCNT/SPEEK nanocomposite films. The modified surface shows potential to improve implants' mechanical and biological performances.

Sensitive and Selective NH₃ Monitoring at Room Temperature Using ZnO Ceramic Nanofibers Decorated with Poly(styrene sulfonate).

PubMed

Andre, Rafaela S; Kwak, Dongwook; Dong, Qiuchen; Zhong, Wei; Correa, Daniel S; Mattoso, Luiz H C; Lei, Yu

2018-04-01

Ammonia (NH₃) gas is a prominent air pollutant that is frequently found in industrial and livestock production environments. Due to the importance in controlling pollution and protecting public health, the development of new platforms for sensing NH₃ at room temperature has attracted great attention. In this study, a sensitive NH₃ gas device with enhanced selectivity is developed based on zinc oxide nanofibers (ZnO NFs) decorated with poly(styrene sulfonate) (PSS) and operated at room temperature. ZnO NFs were prepared by electrospinning followed by calcination at 500 °C for 3 h. The electrospun ZnO NFs are characterized to evaluate the properties of the as-prepared sensing materials. The loading of PSS to prepare ZnO NFs/PSS composite is also optimized based on the best sensing performance. Under the optimal composition, ZnO NFs/PSS displays rapid, reversible, and sensitive response upon NH₃ exposure at room temperature. The device shows a dynamic linear range up to 100 ppm and a limit of detection of 3.22 ppm and enhanced selectivity toward NH₃ in synthetic air, against NO₂ and CO, compared to pure ZnO NFs. Additionally, a sensing mechanism is proposed to illustrate the sensing performance using ZnO NFs/PSS composite. Therefore, this study provides a simple methodology to design a sensitive platform for NH₃ monitoring at room temperature.

High-k 3D-barium titanate foam/phenolphthalein poly(ether sulfone)/cyanate ester composites with frequency-stable dielectric properties and extremely low dielectric loss under reduced concentration of ceramics

NASA Astrophysics Data System (ADS)

Zheng, Longhui; Yuan, Li; Guan, Qingbao; Liang, Guozheng; Gu, Aijuan

2018-01-01

Higher dielectric constant, lower dielectric loss and better frequency stability have been the developing trends for high dielectric constant (high-k) materials. Herein, new composites have been developed through building unique structure by using hyperbranched polysiloxane modified 3D-barium titanate foam (BTF) (BTF@HSi) as the functional fillers and phenolphthalein poly(ether sulfone) (cPES)/cyanate ester (CE) blend as the resin matrix. For BTF@HSi/cPES/CE composite with 34.1 vol% BTF, its dielectric constant at 100 Hz is as high as 162 and dielectric loss is only 0.007; moreover, the dielectric properties of BTF@HSi/cPES/CE composites exhibit excellent frequency stability. To reveal the mechanism behind these attractive performances of BTF@HSi/cPES/CE composites, three kinds of composites (BTF/CE, BTF/cPES/CE, BTF@HSi/CE) were prepared, their structure and integrated performances were intensively investigated and compared with those of BTF@HSi/cPES/CE composites. Results show that the surface modification of BTF is good for preparing composites with improved thermal stability; while introducing flexible cPES to CE is beneficial to fabricate composites with good quality through effectively blocking cracks caused by the stress concentration, and then endowing the composites with good dielectric properties at reduced concentration of ceramics.

Source attribution of poly- and perfluoroalkyl substances (PFASs) in surface waters from Rhode Island and the New York Metropolitan Area

PubMed Central

Zhang, Xianming; Lohmann, Rainer; Dassuncao, Clifton; Hu, Xindi C.; Weber, Andrea K.; Vecitis, Chad D.; Sunderland, Elsie M.

2017-01-01

Exposure to poly and perfluoroalkyl substances (PFASs) has been associated with adverse health effects in humans and wildlife. Understanding pollution sources is essential for environmental regulation but source attribution for PFASs has been confounded by limited information on industrial releases and rapid changes in chemical production. Here we use principal component analysis (PCA), hierarchical clustering, and geospatial analysis to understand source contributions to 14 PFASs measured across 37 sites in the Northeastern United States in 2014. PFASs are significantly elevated in urban areas compared to rural sites except for perfluorobutane sulfonate (PFBS), N-methyl perfluorooctanesulfonamidoacetic acid (N-MeFOSAA), perfluoroundecanate (PFUnDA) and perfluorododecanate (PFDoDA). The highest PFAS concentrations across sites were for perfluorooctanate (PFOA, 56 ng L−1) and perfluorohexane sulfonate (PFOS, 43 ng L−1) and PFOS levels are lower than earlier measurements of U.S. surface waters. PCA and cluster analysis indicates three main statistical groupings of PFASs. Geospatial analysis of watersheds reveals the first component/cluster originates from a mixture of contemporary point sources such as airports and textile mills. Atmospheric sources from the waste sector are consistent with the second component, and the metal smelting industry plausibly explains the third component. We find this source-attribution technique is effective for better understanding PFAS sources in urban areas. PMID:28217711

Determination of fenitrothion in water using a voltammetric sensor based on a polymer-modified glassy carbon electrode.

PubMed

Amare, Meareg; Abicho, Samuel; Admassie, Shimelis

2014-01-01

A glassy carbon electrode (GCE) modified with poly(4-amino-3-hydroxynaphthalene sulfonic acid) (poly-AHNSA) was used for the selective and sensitive determination of fenitrothion (FT) organophosphorus pesticide in water. The electrochemical behavior of FT at the bare GCE and the poly-AHNSA/GCE were compared using cyclic voltammetry. Enhanced peak current response and shift to a lower potential at the polymer-modified electrode indicated the electrocatalytic activity of the polymer film towards FT. Under optimized solution and method parameters, the adsorptive stripping square wave voltammetric reductive peak current of FT was linear to FT concentration in the range of 0.001 to 6.6 x 10(-6) M, and the LOD obtained (3delta/m) was 7.95 x 10(-10) M. Recoveries in the range 96-98% of spiked FT in tap water and reproducible results with RSD of 2.6% (n = 5) were obtained, indicating the potential applicability of the method for the determination of trace levels of FT in environmental samples.

Hollow multilayer microcapsules for pH-/thermally responsive drug delivery using aliphatic poly(urethane-amine) as smart component.

PubMed

Shi, Jun; Du, Chao; Shi, Jin; Wang, Yaming; Cao, Shaokui

2013-04-01

Hollow multilayer microcapsules made of aliphatic poly(urethane-amine) (PUA) and sodium poly(styrene sulfonate) (PSS), templated on PSS-doped CaCO3 particles, are prepared for pH-/thermally responsive drug delivery. The electrostatic interaction and hydrogen bonding under weak-acid conditions between aliphatic PUA and PSS contribute to the formation of multilayer microcapsules. Scanning electron microscopy (SEM) results demonstrate an obvious variation of the hollow multilayer microcapsules in response to changes in temperature and pH value. Drug-release behaviors using DOX as a model drug demonstrate that the drug release increases on decreasing the pH value because of the interaction weakness between aliphatic PUA and PSS in acidic conditions. Moreover, the drug release is higher at 55 °C than that at 37 °C for the sake of the shrinkage of aliphatic PUA above its lower critical solution temperature (LCST). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure-property relationships in polymers for dielectric capacitors

NASA Astrophysics Data System (ADS)

Gupta, Sahil

Effective energy storage is a key challenge of the 21st century that has fueled research in the area of energy storage devices. In this dissertation, structure-property relationships have been evaluated for polymers that might be suitable for storing energy in high-energy density, high-temperature capacitors. Firstly, hydroxyl-modified polypropylenes (PPOH) were synthesized by copolymerization of the propylene and undecenyloxytrimethylsilane monomers. The presence of H-bonding in PPOH copolymers increased their glass-transition temperature. Steric hindrance by the comonomer reduced the PP crystal growth rate and crystal size, resulting in a melting point depression. The comonomer was restricted outside the crystalline domains leaving the alpha-monoclinic crystal structure of PP unaffected, but increasing the fold-surface free energy. Crystallization was slower for PPOH copolymers than PP, but exhibited a skewed bell curve as a function of hydroxyl concentration. H-bonding persisted even at melt temperatures up to 250°C resulting in a higher elasticity and viscosity for PPOH copolymers. Secondly, sulfonated poly(ether ether ketone) (HSPEEK) was synthesized by sulfonating PEEK with sulfuric acid, and further neutralized with Zn to obtain ZnSPEEK. The thermal and dielectric properties of SPEEK were compared with PEEK. The glass-transition increased and melting point were high enough to enable the use of polymer at 180°C. The incorporation of sulfonic groups in PEEK increased the dielectric constant. HSPEEK had a higher dielectric constant than ZnSPEEK due to higher dipolar mobility, but the dielectric loss was also higher for HSPEEK due to electrode polarization and DC conduction. These results were consistent with our observations from sulfonated polystyrene (HSPS), which was used as a >model&lang' polymer. Lastly, commercial poly(4-methyl-1-pentene) (P4MP) was characterized to check its viability as a high-temperature polymer dielectric. Thermal stability up to 200°C, high melting point (> 225°C) and melting onset at 160 - 190°C indicated that P4MP could be used at 180 - 200°C. Thin free-standing films (~10 mum) with controlled crystal structure and surface morphology were prepared using blade coating and their drying dynamics were measured using a custom-designed solvent-casting platform. These films were further stretched uniaxially or biaxially, and their effect on the dielectric properties of P4MP was studied.

Glucose Oxidase Adsorption on Sequential Adsorbed Polyelectrolyte Films Studied by Spectroscopic Techniques

NASA Astrophysics Data System (ADS)

Tristán, Ferdinando; Solís, Araceli; Palestino, Gabriela; Gergely, Csilla; Cuisinier, Frédéric; Pérez, Elías

2005-04-01

The adsorption of Glucose Oxidase (GOX) on layers of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) deposited on Sequentially Adsorbed Polyelectrolyte Films (SAPFs) were studied by three different spectroscopic techniques. These techniques are: Optical Wave Light Spectroscopy (OWLS) to measure surface density; Fluorescence Resonance Energy Transfer (FRET) to verify the adsorption of GOX on the surface; and Fourier Transform Infrared Spectroscopy in Attenuated Total Reflection mode (FTIR-HATR) to inspect local structure of polyelectrolytes and GOX. Two positive and two negative polyelectrolytes are used: Cationic poly(ethyleneimine) (PEI) and poly(allylamine hydrochloride) (PAH) and anionic poly(sodium 4-styrene sulfonate) (PSS) and poly(acrylic acid) (PAA). These spectroscopic techniques do not require any labeling for GOX or SAPFs, specifically GOX and PSS are naturally fluorescent and are used as a couple donor-acceptor for the FRET technique. The SAPFs are formed by a (PEI)-(PSS/PAH)2 film followed by (PAA/PAH)n bilayers. GOX is finally deposited on top of SAPFs at different values of n (n=1..5). Our results show that GOX is adsorbed on positive ended SAPFs forming a monolayer. Contrary, GOX adsorption is not observed on negative ended film polyelectrolyte. GOX stability was tested adding a positive and a negative polyelectrolyte after GOX adsorption. Protein is partially removed by PAH and PAA, with lesser force by PAA.

Tunable electroluminescent color for 2, 5-diphenyl -1, 4-distyrylbenzene with two trans-double bonds

NASA Astrophysics Data System (ADS)

Cheng, Gang; Zhang, Yingfang; Zhao, Yi; Liu, Shiyong; Xie, Zengqi; Xia, Hong; Hanif, Muddasir; Ma, Yuguang

2005-07-01

Exciplex emission is observed in electroluminescent (EL) spectrum of an organic light-emitting device (OLED), where 2, 5-diphenyl -1, 4-distyrylbenzene with two trans-double bonds (trans-DPDSB), (8-hydroxyquinoline) aluminum, and N,N'-diphenyl-N,N'-bis(1-naphthyl)-(1,1'-biphenyl)-4,4'-diamine (NPB) are used as light-emitting, electron-transporting, and hole-transporting layers, respectively. This emission can be dramatically weakened by inserting a hole-injecting layer of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) between the hole-transporting layer and the anode. Consequently, EL color of this OLED is tuned from white to blue. This phenomenon may result from the improvement of hole injection, which shifts the major recombination zone from the NPB/trans-DPDSB interface to the trans-DPDSB layer.

Mesoporous poly(ionic liquid) supported palladium(II) catalyst for oxidative coupling of benzene under atmospheric oxygen

NASA Astrophysics Data System (ADS)

Liu, Yangqing; Wang, Kai; Hou, Wei; Shan, Wanjian; Li, Jing; Zhou, Yu; Wang, Jun

2018-01-01

Multi-functional mesoporous poly(ionic liquid) (MPIL) containing pyridine-based ionic liquid (IL) moieties and adjacent double sbnd COOH groups was synthesized through the free radical copolymerization of IL monomer N-propane sulfonate-4-vinylpyridine, maleic anhydride and divinylbenzene. Palladium(II) species were anchored on this MPIL support, affording the first efficient heterogeneous catalyst for the oxidative coupling of benzene to biphenyl under atmospheric oxygen at low temperature. The biphenyl yield of 15.0% (selectivity: 98.5%, turnover number: 62) was even higher than the one over the homogeneous counterpart palladium acetate. The catalyst can be facilely separated and reused. The IL moiety in the polymeric framework endowed the formation of immobilized palladium(II) species with high electrophilicity, which responds to the high performance.

Preparation of poly(2-amino thiophenol) nanodiscs by a "combined hard-soft template" approach and characterization.

PubMed

Komathi, Shanmugasundaram; Palaniappan, Subramanian; Manisankar, Paramasivam; Gopalan, Anantha Iyengar; Lee, Kwang-Pill

2010-12-15

A seed induced chemical oxidative polymerization was used for the preparation of pure poly(2-amino thiophenol) nanodiscs (P2AT-NDs (P)). Two templates, (hard (MCM-41) and soft (β-napthalene sulfonic acid), were utilized for the preparation of the seed, P2AT nanostructures loaded MCM-41. The field emission scanning electron microscopy reveals nanodisc morphology for P2AT (P). X-ray diffraction, current-potential characteristics and electrochemical impedance spectroscopy were used to evaluate the physicochemical properties of P2AT-ND (P). The P2AT-ND (P) exhibits semicrystalline behaviour, good electron transport and lesser charge transfer resistance at the interface as compared to simple P2AT prepared by conventional chemical route. Copyright © 2010 Elsevier Inc. All rights reserved.

Transition-Metal-Free Synthesis of 1,3-Butadiene-Containing π-Conjugated Polymers.

PubMed

Cai, Xuediao; Liu, Yating; Lu, Tian; Yang, Rui; Luo, Chuxin; Zhang, Qi; Chai, Yonghai

2016-12-01

This work describes the synthesis of π-conjugated polymers possessing arylene and 1,3-butadiene alternating units in the main chain by the reaction of α,β-unsaturated ester/nitrile containing γ-H with aromatic/heteroaromatic aldehyde compound. By using 4-(4-formylphenyl)-2-butylene acid ethyl ester as a model monomer, the different polymerization conditions, including catalyst, catalyst amount, and solvent, are optimized. The polymerization of 4-(4-formylphenyl)-2-butylene acid ethyl ester is carried out by refluxing in ethanol for 72 h with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as a catalyst to give a 1,3-butadiene-containing π-conjugated polymer, poly(phenylene-1,3-butadiene), in 84.3% yield with M¯n and M¯w/M¯n (PDI) estimated as 6172 and 1.65, respectively. Based on this new methodology, a series of π-conjugated polymers containing 1,3-butadiene units with different substituents are obtained in high yields. A possible mechanism is proposed for the polymerization through a six-membered ring transition state and then a 1,5-H shift intermediate. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of SiO2 grafted MWCNTs on the mechanical and dielectric properties of PEN composite films

NASA Astrophysics Data System (ADS)

Jin, Fei; Feng, Mengna; Huang, Xu; Long, Cheng; Jia, Kun; Liu, Xiaobo

2015-12-01

In this study, the functional poly (arylene ether nitrile) (PEN)/multiwall carbon nanotubes (MWCNTs)/SiO2 nanocomposite with high mechanical and good electrical properties were fabricated through a simple and effective method. Specifically, the surface modification using highly ordered and porous SiO2 not only improves the dispersion of the MWCNTs in polymer matrix, but also combines the excellent properties of SiO2 and MWCNTs. Transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), and scanning electron microscope (SEM) were employed to confirm the surface functionalization of MWCNTs. As a result, all the composite films exhibited good dielectric properties with high dielectric constant of 7 as well as low dielectric loss of 0.04. Besides, the results of mechanical tests showed that the tensile strength and modulus reached their highest values at the 2 wt% MWCNTs-SiO2 loading content (125 MPa and 2950 MPa, respectively). The rheological results showed that MWCNTs-SiO2/PEN composites have a typical solid-like viscoelastic response as frequencies changes. Therefore, all the results revealed that surface functionalization has strong influence on the dispersion state of MWCNTs in PEN matrix.

Acquisition of a SAXS Facility for the Study of Novel Polymer Nanocomposite Membranes

DTIC Science & Technology

2015-02-19

at the 2015 MRS Spring National Meeting, San Francisco , CA, April, 2015. 2. A. Millet and D. Suleiman “Sulfonation and Characterization of Poly...the 2015 ACS PRISM Meeting San Juan , PR March, 2015. 3. D. Suleiman “Polymer Nanocomposites: Technology for the XXI Century.” Oral Key Note...have been using the equipment: 1. Rinaldo Díaz 2. Arnaldo López 3. Alexander Millet 4. Nataira Pagán 5. Luis Sotomayor 6. Vanessa Torres 7

Investigation of Proton Conductivity of Cation-Exchanged, Sulfonated Poly(b-Styrene-b-Isobutylene-b-Styrene) Membranes

DTIC Science & Technology

2009-09-01

solvents. Similar behavior was observed for Nafion -117 (also a polymer with ionic SO3H clusters) by other researchers (14). Results shown in this...pattern was only valid for ionic S-SIBS membranes exchanged with cations; neither acid form of SIBS-97-H nor Nafion -117 fell on this line. In order...10  vi INTENTIONALLY LEFT BLANK. 1 1. Introduction Research in ionic polymers has been gaining popularity in the scientific community

An electrochemically-driven dual-mode display device with both reflective and emissive modes using poly(p-phenylenevinylene) derivatives

NASA Astrophysics Data System (ADS)

Tsuneyasu, Shota; Jin, Lu; Nakamura, Kazuki; Kobayashi, Norihisa

2016-04-01

We demonstrate a novel electrochemical dual-mode displaying (DMD) device, which enables control of both coloration and light emission using an electrochemical reaction. The coloration control of the DMD device was based on an electrochromic (EC) reaction, whereas the light emission of the device was caused by an electrochemiluminescence (ECL) mechanism. This novel DMD device consisted of a pair of facing conductive polymer-modified electrodes: comb-shaped interdigitated Au electrodes modified with poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) layers and poly(2,3-dihydrothieno-1,4-dioxin)-poly(styrene sulfonate) (PEDOT/PSS) film-modified indium tin oxide (ITO) electrodes. When a bias voltage was applied between the PEDOT/PSS film-modified ITO electrode and the comb-shaped electrodes, a color change of the device was observed by the EC reaction of the MEH-PPV and PEDOT/PSS. On the other hand, an emission was obtained when the bias voltage was applied between two comb-shaped interdigitated electrodes. The orange emission was ascribed to the ECL reaction of the MEH-PPV layer, which resulted from the formation of a p-i-n junction in this layer.

Chemically grafted polymeric filters for chemical sensors: Hyperbranched poly(acrylic acid) films incorporating {Beta}-cyclodextrin receptors and amine-functionalized filter layers

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

Dermody, D.L.; Peez, R.F.; Bergbreiter, D.E.

1999-02-02

The authors report a new molecular-filter approach for enhancing the selectivity of chemical sensors. Specifically, they describe electrochemical sensors prepared from Au electrodes coated with {beta}-cyclodextrin-functionalized, hyperbranched poly(acrylic acid)(PAA) films capped with a chemically grafted, ultrathin polyamine layer. The hyperbranched PAA film is a highly functionalized framework for covalently binding the {beta}-cyclodextrin molecular receptors. The thin, grafted polyamine overlayer acts as a pH-sensitive molecular filter that selectively passes suitably charged analytes. Poly(amidoamine) dendrimers or poly-D-lysine is used as 10--15-nm-thick filter layers. The results show that at low pH, when the polyamines are fully protonated, positively charged redox probe molecules, suchmore » as benzyl viologen (BV), do not permeate the filter layer. However, at high pH, when the filter layer is uncharged, BV penetrates the filter layer and is reduced at the electrode. The opposite pH dependence is observed for negatively charged redox molecules such as anthraquinone-2-sulfonate (AQS). Both BV and AQS specifically interact with the {beta}-cyclodextrin receptors underlying the polyamine filter layers.« less

Application of Novel Anion-Exchange Blend Membranes (AEBMs) to Vanadium Redox Flow Batteries.

PubMed

Cho, Hyeongrae; Krieg, Henning M; Kerres, Jochen A

2018-06-19

Both cation-exchange membranes and anion-exchange membranes are used as ion conducting membranes in vanadium redox flow batteries (VRFBs). Anion-exchange membranes (AEMs) are applied in vanadium redox flow batteries due to the high blocking property of vanadium ions via the Donnan exclusion effect. In this study, novel anion-exchange blend membranes (AEBMs) were prepared, characterized, and applied in VRFBs. Bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide), poly[(1-(4,4′-diphenylether)-5-oxybenzimidazole)-benzimidazole] (PBI-OO) and sulfonated polyether sulfone polymer were combined to prepare 3-component AEBMs with 1,2,4,5-tetramethylimidazole (TMIm) for quaternization. 3-component AEBMs showed significantly enhanced chemical and mechanical properties compared with those of 2-component AEBMs, resulting in an improved performance in VRFBs. The compositions of the anion-exchange polymers in 3-component AEBMs were systematically varied to optimize the AEBMs for the redox-flow battery application. While the 3-component AEBMs showed comparable efficiencies with Nafion ® 212 membranes, they displayed improved vanadium ions cross-over as was confirmed by open circuit voltage tests and capacity fade tests conducted in VRFBs. In addition, one of the synthesized 3-component AEBM had a superior coulombic efficiency and capacity retention in a charging⁻discharging test over 300 cycles at a current density of 40 mA/cm². It can thus be concluded that 3-component AEBMs are promising candidates for long-term operation in VRFBs.

Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries

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

Tang, Zhijiang; Lawton, Jamie S.; Sun, Che-Nan

2014-09-03

Here, sulfonated Diels-Alder poly(phenylene) (SDAPP) membranes were synthesized and characterized as potential electrolyte separators for vanadium redox flow batteries. The SDAPP membranes studied had ion exchange capacities of 1.4, 1.8 and 2.3 meq/g. Transmission electron microscopy imaging shows that the ionic domains in SDAPP are roughly 0.5 nm in dimension, while Nafion has a hydrophilic phase width of around 5 nm. The sulfuric acid uptake by SDAPP was higher than that for Nafion, but the materials had similar water uptake from solutions of various sulfuric acid concentrations. In equilibration with sulfuric acid concentrations ranging from 0–17.4 mol·kg -1, SDAPP withmore » a IEC of 2.3 meq/g had the highest conductivity, ranging from 0.21 to 0.05 S·cm -1, while SDAPP with a IEC of 1.8 had conductivity close to Nafion 117, ranging from 0.11 to 0.02 S·cm -1. With varying sulfuric acid concentration and temperature, vanadium permeability in SDAPP is positively correlated to the membrane's IEC. The vanadium permeability of SDAPP 2.3 is similar to that of Nafion, but permeability values for SDAPP 1.8 and SDAPP 1.4 are substantially lower. The vanadium permeation decreases with increasing electrolyte sulfuric acid concentration. Lastly, vanadium diffusion activation energy is about 20 kJ·mol -1 in both SDAPP and Nafion.« less

3D conductive nanocomposite scaffold for bone tissue engineering

PubMed Central

Shahini, Aref; Yazdimamaghani, Mostafa; Walker, Kenneth J; Eastman, Margaret A; Hatami-Marbini, Hamed; Smith, Brenda J; Ricci, John L; Madihally, Sundar V; Vashaee, Daryoosh; Tayebi, Lobat

2014-01-01

Bone healing can be significantly expedited by applying electrical stimuli in the injured region. Therefore, a three-dimensional (3D) ceramic conductive tissue engineering scaffold for large bone defects that can locally deliver the electrical stimuli is highly desired. In the present study, 3D conductive scaffolds were prepared by employing a biocompatible conductive polymer, ie, poly(3,4-ethylenedioxythiophene) poly(4-styrene sulfonate) (PEDOT:PSS), in the optimized nanocomposite of gelatin and bioactive glass. For in vitro analysis, adult human mesenchymal stem cells were seeded in the scaffolds. Material characterizations using hydrogen-1 nuclear magnetic resonance, in vitro degradation, as well as thermal and mechanical analysis showed that incorporation of PEDOT:PSS increased the physiochemical stability of the composite, resulting in improved mechanical properties and biodegradation resistance. The outcomes indicate that PEDOT:PSS and polypeptide chains have close interaction, most likely by forming salt bridges between arginine side chains and sulfonate groups. The morphology of the scaffolds and cultured human mesenchymal stem cells were observed and analyzed via scanning electron microscope, micro-computed tomography, and confocal fluorescent microscope. Increasing the concentration of the conductive polymer in the scaffold enhanced the cell viability, indicating the improved microstructure of the scaffolds or boosted electrical signaling among cells. These results show that these conductive scaffolds are not only structurally more favorable for bone tissue engineering, but also can be a step forward in combining the tissue engineering techniques with the method of enhancing the bone healing by electrical stimuli. PMID:24399874

Fuel cell performance of pendent methylphenyl sulfonated poly(ether ether ketone ketone)s

NASA Astrophysics Data System (ADS)

Zhang, Hanyu; Stanis, Ronald J.; Song, Yang; Hu, Wei; Cornelius, Chris J.; Shi, Qiang; Liu, Baijun; Guiver, Michael D.

2017-11-01

Meta- and para-linked homopolymers bearing 3-methylphenyl (Me) pendent groups were postsulfonated to create sulfonated poly(ether ether ketone ketone) (SPEEKK) backbone isomers, which are referred to as Me-p-SPEEKK and Me-m-SPEEKK. Their thermal and oxidative stability, mechanical properties, dimensional stability, methanol permeability, and proton conductivity are characterized. Me-p-SPEEKK and Me-m-SPEEKK proton conductivities at 100 °C are 116 and 173 mS cm-1, respectively. Their methanol permeabilities are 3.3-3.9 × 10-7 cm2 s-1, and dimensional swelling at 100 °C is 16.4-17.5%. Me-p-SPEEKK and Me-m-SPEEKK were fabricated into membrane electrode assemblies (MEAs), and electrochemical properties were evaluated within a direct methanol fuel cell (DMFC) and proton-exchange membrane fuel cell (PEMFC). When O2 is used as the oxidant at 80 °C and 100% RH, the maximum power density of Me-m-SPEEKK reaches 657 mW cm-2, which is higher than those of Nafion 115 (552 mW cm-2). DMFC performance is 85 mW cm-2 at 80 °C with 2.0 M methanol using Me-p-SPEEKK due to its low MeOH crossover. In general, these electrochemical results are comparable to Nafion. These ionomer properties, combined with a potentially less expensive and scalable polymer manufacturing process, may broaden their potential for many practical applications.

Sensitization to radiation and alkylating agents by inhibitors of poly(ADP-ribose) polymerase is enhanced in cells deficient in DNA double-strand break repair.

PubMed

Löser, Dana A; Shibata, Atsushi; Shibata, Akiko K; Woodbine, Lisa J; Jeggo, Penny A; Chalmers, Anthony J

2010-06-01

As single agents, chemical inhibitors of poly(ADP-ribose) polymerase (PARP) are nontoxic and have clinical efficacy against BRCA1- and BRCA2-deficient tumors. PARP inhibitors also enhance the cytotoxicity of ionizing radiation and alkylating agents but will only improve clinical outcomes if tumor sensitization exceeds effects on normal tissues. It is unclear how tumor DNA repair proficiency affects the degree of sensitization. We have previously shown that the radiosensitizing effect of PARP inhibition requires DNA replication and will therefore affect rapidly proliferating tumors more than normal tissues. Because many tumors exhibit defective DNA repair, we investigated the impact of double-strand break (DSB) repair integrity on the sensitizing effects of the PARP inhibitor olaparib. Sensitization to ionizing radiation and the alkylating agent methylmethane sulfonate was enhanced in DSB repair-deficient cells. In Artemis(-/-) and ATM(-/-) mouse embryo fibroblasts, sensitization was replication dependent and associated with defective repair of replication-associated damage. Radiosensitization of Ligase IV(-/-) mouse embryo fibroblasts was independent of DNA replication and is explained by inhibition of "alternative" end joining. After methylmethane sulfonate treatment, PARP inhibition promoted replication-independent accumulation of DSB, repair of which required Ligase IV. Our findings predict that the sensitizing effects of PARP inhibitors will be more pronounced in rapidly dividing and/or DNA repair defective tumors than normal tissues and show their potential to enhance the therapeutic ratio achieved by conventional DNA-damaging agents.

3D conductive nanocomposite scaffold for bone tissue engineering.

PubMed

Shahini, Aref; Yazdimamaghani, Mostafa; Walker, Kenneth J; Eastman, Margaret A; Hatami-Marbini, Hamed; Smith, Brenda J; Ricci, John L; Madihally, Sundar V; Vashaee, Daryoosh; Tayebi, Lobat

2014-01-01

Bone healing can be significantly expedited by applying electrical stimuli in the injured region. Therefore, a three-dimensional (3D) ceramic conductive tissue engineering scaffold for large bone defects that can locally deliver the electrical stimuli is highly desired. In the present study, 3D conductive scaffolds were prepared by employing a biocompatible conductive polymer, ie, poly(3,4-ethylenedioxythiophene) poly(4-styrene sulfonate) (PEDOT:PSS), in the optimized nanocomposite of gelatin and bioactive glass. For in vitro analysis, adult human mesenchymal stem cells were seeded in the scaffolds. Material characterizations using hydrogen-1 nuclear magnetic resonance, in vitro degradation, as well as thermal and mechanical analysis showed that incorporation of PEDOT:PSS increased the physiochemical stability of the composite, resulting in improved mechanical properties and biodegradation resistance. The outcomes indicate that PEDOT:PSS and polypeptide chains have close interaction, most likely by forming salt bridges between arginine side chains and sulfonate groups. The morphology of the scaffolds and cultured human mesenchymal stem cells were observed and analyzed via scanning electron microscope, micro-computed tomography, and confocal fluorescent microscope. Increasing the concentration of the conductive polymer in the scaffold enhanced the cell viability, indicating the improved microstructure of the scaffolds or boosted electrical signaling among cells. These results show that these conductive scaffolds are not only structurally more favorable for bone tissue engineering, but also can be a step forward in combining the tissue engineering techniques with the method of enhancing the bone healing by electrical stimuli.

The effect of polystyrene sodium sulfonate grafting on polyethylene terephthalate artificial ligaments on in vitro mineralisation and in vivo bone tissue integration

PubMed Central

Vaquette, Cédryck; Viateau, Véronique; Guérard, Sandra; Anagnostou, Fani; Manassero, Mathieu; Castner, David G.; Migonney, Véronique

2013-01-01

This study investigates the impact of polystyrene sodium sulfonate (PolyNaSS) grafting onto the osseointegration of a polyethylene terephthalate artificial ligament (Ligament Advanced Reinforcement System, LARS™) used for Anterior Cruciate Ligament (ACL). The performance of grafted and non-grafted ligaments was assessed in vitro by culturing human osteoblasts under osteogenic induction and this demonstrated that the surface modification was capable of up-regulating the secretion of ALP and induced higher level of mineralisation as measured 6 weeks post-seeding by Micro-Computed Tomography. Grafted and non-grafted LARS™ were subsequently implanted in an ovine model for ACL reconstruction and the ligament-to-bone interface was evaluated by histology and biomechanical testing 3 and 12 months post-implantation. The grafted ligaments exhibited more frequent direct ligament-to-bone contact and bone formation in the core of the ligament at the later time point than the nongrafted specimens, the grafting also significantly reduced the fibrous encapsulation of the ligament 12 months post-implantation. However, this improved osseo-integration was not translated into a significant increase in the biomechanical pull-out loads. These results provide evidences that PolyNaSS grafting improved the osseo-integration of the artificial ligament within the bone tunnels. This might positively influence the outcome of the surgical reconstructions, as higher ligament stability is believed to limit micro-movement and therefore permits earlier and enhanced healing. PMID:23790438

Novel proton exchange membranes based on structure-optimized poly(ether ether ketone ketone)s and nanocrystalline cellulose

NASA Astrophysics Data System (ADS)

Ni, Chuangjiang; Wei, Yingcong; Zhao, Qi; Liu, Baijun; Sun, Zhaoyan; Gu, Yan; Zhang, Mingyao; Hu, Wei

2018-03-01

Two sulfonated fluorenyl-containing poly(ether ether ketone ketone)s (SFPEEKKs) were synthesized as the matrix of composite proton exchange membranes by directly sulfonating copolymer precursors comprising non-sulfonatable fluorinated segments and sulfonatable fluorenyl-containing segments. Surface-modified nanocrystalline cellulose (NCC) was produced as the "performance-enhancing" filler by treating the microcrystalline cellulose with acid. Two families of SFPEEKK/NCC nanocomposite membranes with various NCC contents were prepared via a solution-casting procedure. Results revealed that the insertion of NCC at a suitable ratio could greatly enhance the proton conductivity of the pristine membranes. For example, the proton conductivity of SFPEEKK-60/NCC-4 (SFPEEKK with 60% fluorenyl segments in the repeating unit, and inserted with 4% NCC) composite membrane was as high as 0.245 S cm-1 at 90 °C, which was 61.2% higher than that of the corresponding pure SFPEEKK-60 membrane. This effect could be attributed to the formation of hydrogen bond networks and proton conduction paths through the interaction between -SO3H/-OH groups on the surface of NCC particles and -SO3H groups on the SFPEEKK backbones. Furthermore, the chemically modified NCC filler and the optimized chemical structure of the SFPEEKK matrix also provided good dimensional stability and mechanical properties of the obtained nanocomposites. In conclusion, these novel nanocomposites can be promising proton exchange membranes for fuel cells at moderate temperatures.

Insertion of NiO electron blocking layer in fabrication of GaN-organic heterostructures

NASA Astrophysics Data System (ADS)

Li, Junmei; Guo, Wei; Jiang, Jie'an; Gao, Pingqi; Bo, Baoxue; Ye, Jichun

2018-03-01

We report the fabrication of a NiO thin film on top of an n-type GaN epitaxial layer. The electron-blocking capability of NiO in a hybrid organic/inorganic heterostructure consisting of n-GaN/NiO/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is discussed. Surface morphology, crystallography orientation, bandgap, and fermi level information of NiO films were investigated in detail. A rectifying property consistent with the proposed band diagram was observed in the current-voltage measurement. Theoretical analysis also demonstrated the effective electron blocking due to band alignment and a more balanced carrier distribution inside the GaN region with NiO inserted into the n-GaN/PEDOT:PSS heterostructure. This work provides a promising approach to the fabrication of high-efficiency hybrid optoelectronic devices.

MnO2-Graphene Oxide-PEDOT:PSS Nanocomposite for an Electrochemical Supercapacitor

NASA Astrophysics Data System (ADS)

Patil, Dipali S.; Pawar, Sachin A.; Shin, Jae Cheol; Kim, Hyo Jin

2018-04-01

A ternary nanocomposite with poly (3,4 ethylene dioxythiophene:poly(styrene sulfonate) (PEDOT:PSS)-MnO2 nanowires-graphene oxide (PMn-GO) was synthesized by using simple chemical route. The formation of the nanocomposite was analyzed by using X-ray diffraction and X-ray photoelectron spectroscopy. Field-emission scanning microscopy (FESEM) revealed the formation of MnO2 nanowires and graphene oxide nanosheets. The highest specific capacitance (areal capacitance) of 841 Fg -1 (177 mFcm -2) at 10 mVs -1 and energy density of 0.593 kWhkg -1 at 0.5 mA were observed for PMn-GO, indicating a constructive synergistic effect of PEDOT:PSS, MnO2 nanowires and graphene oxide. The achieved promising electrochemical characteristics showed that this ternary nanocomposite is a good alternative as an electrode material for supercapacitor.

[Analysis and identification of emulsifying viscosity reducer by FTIR and 1H NMR].

PubMed

Zhu, Hong; Guan, Run-ling; Shen, Jing-mei

2007-01-01

Separation and purification of viscosity reducer for crude oil were performed with distillation and dissolution-precipitation. The functional group of its main component was identified by FTIR It was deduced that the main component of the crude oil viscosity reducer is the tricopolymer of poly ethyl acrylate/methyl methacrylate/acrylic acid. The structure of the component was also ascertained and quantitively analysed with 1 H NMR and MS. The mol ratio of the three monomers is 37. 1 : 25. 8 : 37. 1, and the mass ratio is 41. 1 : 28. 8 : 29. 8. The structure of the part soluble in methanol was identified by FTIR. The result showed that the nonionic sufactant is poly ethylene oxide with the moleculear mass range of 800-1600, and the anionic surfactant is alkylbenzene sulfonate. The residue is accessory ingredient and water.

High flux nanofiltration membranes based on layer-by-layer assembly modified electrospun nanofibrous substrate

NASA Astrophysics Data System (ADS)

Xu, Guo-Rong; Liu, Xiao-Yu; Xu, Jian-Mei; Li, Lu; Su, Hui-Chao; Zhao, He-Li; Feng, Hou-Jun

2018-03-01

Herein, high flux nanofiltration (NF) membranes were fabricated by combined procedures of electrospinning, layer-by-layer (LBL) assembly, and phase inversion. The membranes displayed three-dual structure constituted polyether sulfone (PES) coating layer, LBL assembly modified electrospun polyester (PET) nanofibrous mats, and non-woven supports. High flux NF membranes thus prepared are characterized by ultrathin phase inversion layer (∼10 μm) while that of conventional membranes are 100-150 μm, implying that very high flux could be expected. Various factors including electrospinning conditions, chitosan (CHI)/alginate (ALG) concentration, PES concentration, exposed time, coagulating temperature, thermal treatment, and sulfonated poly ether ketone (SPEEK) content were systematically investigated. Structures of the membranes were characterized by field emission scanning electron microscopy (FESEM), mechanical properties test, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and static contact angle measurements. The separation experiments indicated that thus prepared membranes exhibited high flux of as high as ∼75 L m-2 h-1 with Mg SO4 rejection of ∼80%.

Thermochemical characterization of some thermoplastic materials. [flammability and toxicity properties for aircraft interiors

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.; Hilado, C. J.

1977-01-01

The thermochemical and flammability characteristics of some typical thermoplastic materials currently in use or being considered for use in aircraft interiors are described. The properties studied included thermomechanical properties such as glass-transition and melt temperature, changes in polymer enthalpy, thermogravimetric analysis in anerobic and oxidative environments, oxygen index, smoke evolution, relative toxicity of the volatile products of pyrolysis, and selected physical properties. The generic polymers evaluated included acrylonitrile butadiene styrene, bisphenol A polycarbonate, 9,9 bis (4-hydroxyphenyl) fluorene polycarbonate-poly (dimethylsiloxane) block polymer, phenolphthalein-bisphenol A polycarbonate, phenolphthalein polycarbonate, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, chlorinated polyvinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters, including molding characteristics of some of the advanced polymers, are described. Test results and relative rankings of some of the flammability, smoke, and toxicity properties are presented. Under these test conditions, some of the advanced polymers evaluated were significantly less flammable and toxic than or equivalent to polymers in current use.

Composite Electrolyte Membranes from Partially Fluorinated Polymer and Hyperbranched, Sulfonated Polysulfone

PubMed Central

Subianto, Surya; Roy Choudhury, Namita; Dutta, Naba

2013-01-01

Macromolecular modification of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF) was done with various proportions of sulfonic acid terminated, hyperbranched polysulfone (HPSU) with a view to prepare ion conducting membranes. The PVDF-co-HFP was first chemically modified by dehydrofluorination and chlorosulfonation in order to make the membrane more hydrophilic as well as to introduce unsaturation, which would allow crosslinking of the PVDF-co-HFP matrix to improve the stability of the membrane. The modified samples were characterized for ion exchange capacity, morphology, and performance. The HPSU modified S-PVDF membrane shows good stability and ionic conductivity of 5.1 mS cm−1 at 80 °C and 100% RH for blends containing 20% HPSU, which is higher than the literature values for equivalent blend membranes using Nafion. SEM analysis of the blend membranes containing 15% or more HPSU shows the presence of spherical domains with a size range of 300–800 nm within the membranes, which are believed to be the HPSU-rich area. PMID:28348282

Study of interface chemistry between the carrier-transporting layers and their influences on the stability and performance of organic solar cells

NASA Astrophysics Data System (ADS)

Hilal, Muhammad; Han, Jeong In

2018-06-01

This is the first study that described how the interface interactions of graphene oxide (GO) with poly(3-hexylthiophene): 3'H-cyclopropa [8,25] [5,6] fullerene-C60-D5h(6)-3'-butanoic acid 3'-phenyl methyl ester (PCBM) and with poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) are influencing the stability and performance of poly(3-hexylthiophene): poly(3-hexylthiophene) (P3HT) (P3HT:PCBM)-based organic solar cell. The interface functionalization of these carrier-transporting layers was confirmed by XRD pattern, XPS analysis, and Raman spectroscopy. These interfaces chemical bond formation helped to firmly attach the GO layer with PCBM and PEDOT:PSS layers, forming a strong barrier against water molecule absorption and also provided an easy pathway for fast transfer of free carriers between P3HT:PCBM layer and metal electrodes via the backbone of the conjugated GO sheets. Because of these interface interactions, the device fabricated with PCBM/GO composite as an electron transport layer and GO/PEDOT:PSS composite as hole transport layer demonstrated a remarkable improvement in the value of power conversion efficiency (5.34%) and reproducibility with a high degree of control over the environmental stability (600 h). This study is paving a way for a new technique to further improve the stability and PCE for the commercialization of OSCs.

All-solution-processed PbS quantum dot solar modules.

PubMed

Jang, Jihoon; Shim, Hyung Cheoul; Ju, Yeonkyeong; Song, Jung Hoon; An, Hyejin; Yu, Jong-Su; Kwak, Sun-Woo; Lee, Taik-Min; Kim, Inyoung; Jeong, Sohee

2015-05-21

A rapid increase in power conversion efficiencies in colloidal quantum dot (QD) solar cells has been achieved recently with lead sulphide (PbS) QDs by adapting a heterojunction architecture, which consists of small-area devices associated with a vacuum-deposited buffer layer with metal electrodes. The preparation of QD solar modules by low-cost solution processes is required to further increase the power-to-cost ratio. Herein we demonstrate all-solution-processed flexible PbS QD solar modules with a layer-by-layer architecture comprising polyethylene terephthalate (PET) substrate/indium tin oxide (ITO)/titanium oxide (TiO2)/PbS QD/poly(3-hexylthiophene) (P3HT)/poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS)/Ag, with an active area of up to 30 cm(2), exhibiting a power conversion efficiency (PCE) of 1.3% under AM 1.5 conditions (PCE of 2.2% for a 1 cm(2) unit cell). Our approach affords trade-offs between power and the active area of the photovoltaic devices, which results in a low-cost power source, and which is scalable to larger areas.

Development of electroactive nanofibers based on thermoplastic polyurethane and poly(o-ethoxyaniline) for biological applications.

PubMed

Cruz, Karina Ferreira Noronha; Formaggio, Daniela Maria Ducatti; Tada, Dayane Batista; Cristovan, Fernando Henrique; Guerrini, Lilia Müller

2017-02-01

Electroactive nanofibers based on thermoplastic polyurethane (TPU) and poly(alkoxy anilines) produced by electrospinning has been explored for biomaterials applications. The thermoplastic polyurethane is a biocompatible polymer with good mechanical properties. The production of TPU nanofibers requires the application of high voltage during electrospinning in order to prepare uniform mats due to its weak ability to elongate during the process. To overcome this limitation, a conductive polymer can be incorporated to the process, allowing generates mats without defects. In this study, poly(o-ethoxyaniline) POEA doped with dodecylbenzene sulfonic acid (DBSA) was blended with thermoplastic polyurethane (TPU) by solution method. Films were produced by casting and nanofibers were prepared by electrospinning. The effect of the POEA on morphology, distribution of diameter and cell viability of the nanofibers was evaluated. The results demonstrated that the incorporation of POEA in TPU provided to the mats a suitable morphology for cellular growth. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 601-607, 2017. © 2016 Wiley Periodicals, Inc.

Multiwall carbon nanotube and poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) composite films for transistor and inverter devices.

PubMed

Yun, Dong-Jin; Hong, KiPyo; Kim, Se hyun; Yun, Won-Min; Jang, Jae-young; Kwon, Woo-Sung; Park, Chan-Eon; Rhee, Shi-Woo

2011-01-01

Highly conductive multiwalled carbon nanotube (MWNT)/Poly(3,4-ethylenedioxythiophene) polymerized with poly(4-styrenesulfonate) (PEDOT:PSS) films were prepared by spin coating a mixture solution. The solution was prepared by dispersing MWNT in the PEDOT:PSS solution in water using ultrasonication without any oxidation process. The effect of the MWNT loading in the solution on the film properties such as surface roughness, work function, surface energy, optical transparency, and conductivity was studied. The conductivity of MWNT/PEDOT:PSS composite film was increased with higher MWNT loading and the high conductivity of MWNT/PEDOT:PSS films enabled them to be used as a source/drain electrode in organic thin film transistor (OTFT). The pentacene TFT with MWNT/PEDOT:PSS S/D electrode showed much higher performance with mobility about 0.2 cm²/(V s) and on/off ratio about 5 × 10⁵ compared to that with PEDOT:PSS S/D electrode (∼0.05 cm²/(V s), 1 × 10⁵). The complementary inverters exhibited excellent characteristics, including high gain value of about 30.

Ionically self-assembled monolayers (ISAMs)

NASA Astrophysics Data System (ADS)

Janik, John

2001-04-01

Ionically self-assembled monolayers (ISAMs), fabricated by alternate adsorption of cationic and anionic components, yield exceptionally homogeneous thin films with sub-nanometer control of the thickness and relative special location of the component materials. Using organic electrochromic materials such as polyaniline, we report studies of electrochromic responses in ISAM films. Reversible changes in the absorption spectrum are observed with the application of voltages on the order of 1.0 V. Measurements are made using both liquid electrolytes and in all-solid state devices incorporating solid polyelectrolytes such as poly(2-acylamido 2-methyl propane sulfonic acid) (PAMPS).

Low Permeable Hydrocarbon Polymer Electrolyte Membrane for Vanadium Redox Flow Battery.

PubMed

Jung, Ho-Young; Moon, Geon-O; Jung, Seunghun; Kim, Hee Tak; Kim, Sang-Chai; Roh, Sung-Hee

2017-04-01

Polymer electrolyte membrane (PEM) confirms the life span of vanadium redox flow battery (VRFB). Products from Dupont, Nafion membrane, is mainly used for PEM in VRFB. However, permeation of vanadium ion occurs because of Nafion’s high permeability. Therefore, the efficiency of VRFB decreases and the prices becomes higher, which hinders VRFB’s commercialization. In order to solve this problem, poly(phenylene oxide) (PPO) is sulfonated for the preparation of low-priced hydrocarbon polymer electrolyte membrane. sPPO membrane is characterized by fundamental properties and VRFB cell test.

Space radiation-induced effects in polymer photodetectors

NASA Astrophysics Data System (ADS)

Taylor, Edward W.; Le, Dang T.; Durstock, Michael F.; Taylor, Barney E.; Claus, Richard O.; Zeng, Tingying; Morath, Christian P.; Cardimona, David A.

2002-09-01

Self-assembled polymer photo-detectors (PPDs) composed of ruthenium complex N3 and PPDs based on thin films of poly(p-phenylene vinlyene) with sulfonated polystyrene are examined for their ability to function in a simulated space radiation environment. Examination of the PPD pre- and post- response data following gamma-ray irradiation ranging in total dose from 10 krad(Si) to 100 krad(Si) are examined. The output photovoltage was observed to decrease for all irradiated devices. The brief study was performed at room temperature and a discussion of the preliminary data and results are presented.

Assessment of polyelectrolyte coating stability under dynamic buffer conditions in CE.

PubMed

Swords, Kyleen E; Bartline, Peter B; Roguski, Katherine M; Bashaw, Sarah A; Frederick, Kimberley A

2011-09-01

Dynamic buffer conditions are present in many electrophoretically driven separations. Polyelectrolyte multilayer coatings have been employed in CE because of their chemical and physical stability as well as their ease of application. The goal of this study is to measure the effect of dynamic changes in buffer pH on flow using a real-time method for measuring EOF. Polyelectrolyte multilayers (PEMs) were composed of pairs of strong or completely ionized polyelectrolytes including poly(diallyldimethylammonium) chloride and poly(styrene sulfonate) and weak or ionizable polyelectrolytes including poly(allylamine) and poly(methacrylic acid). Polyelectrolyte multilayers of varying thicknesses (3, 4, 7, 8, 15, or 16 layers) were also studied. While the magnitude of the EOF was monitored every 2 s, the buffer pH was exchanged from a relatively basic pH (7.1) to increasingly acidic pHs (6.6, 6.1, 5.5, and 5.1). Strong polyelectrolytes responded minimally to changes in buffer pH (<1%), whereas substantial (>10%) and sometimes irreversible changes were measured with weak polyelectrolytes. Thicker coatings resulted in a similar magnitude of response but were more likely to degrade in response to buffer pH changes. The most stable coatings were formed from thinner layers of strong polyelectrolytes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reversible clustering of pH- and temperature-responsive Janus magnetic nanoparticles.

PubMed

Isojima, Tatsushi; Lattuada, Marco; Vander Sande, John B; Hatton, T Alan

2008-09-23

Janus nanoparticles have been synthesized consisting of approximately 5 nm magnetite nanoparticles coated on one side with a pH-dependent and temperature-independent polymer (poly(acrylic acid), PAA), and functionalized on the other side by a second (tail) polymer that is either a pH-independent polymer (polystyrene sodium sulfonate, PSSNa) or a temperature-dependent polymer (poly(N-isopropyl acrylamide), PNIPAM). These Janus nanoparticles are dispersed stably as individual particles at high pH values and low temperatures, but can self-assemble at low pH values (PSSNa) or at high temperatures (>31 degrees C) (PNIPAM) to form stable dispersions of clusters of approximately 80-100 nm in hydrodynamic diameter. The Janus nanoparticle compositions were verified using FTIR and XPS, and their structures observed directly by TEM. Their clustering behavior is analyzed by dynamic light scattering and zeta potential measurements.

Improving Fire Resistance of Cotton Fabric through Layer-by-Layer Assembled Graphene Multilayer Nanocoating

NASA Astrophysics Data System (ADS)

Jang, Wonjun; Chung, Il Jun; Kim, Junwoo; Seo, Seongmin; Park, Yong Tae; Choi, Kyungwho

2018-05-01

In this study, thin films containing poly(vinyl alcohol) (PVA) and graphene nanoplatelets (GNPs), stabilized with poly(4-styrene-sulfonic acid) (PSS), were assembled by a simple and cost-effective layer-by-layer (LbL) technique in order to introduce the anti-flammability to cotton. These antiflammable layers were characterized by using UV-vis spectrometry and quartz crystal microbalance as a function of the number of bilayers deposited. Scanning electron microscopy was used to visualize the morphology of the thin film coatings on the cotton fabric. The graphene-polymer thin films introduced anti-flammable properties through thermally stable carbonaceous layers at a high temperature. The thermal stability and flame retardant property of graphene-coated cotton was demonstrated by thermogravimetric analysis, cone calorimetry, and vertical flame test. The results indicate that LbL-assembled graphene-polymer thin films can be applied largely in the field of flame retardant.

Biomimetic synthesis of water-soluble conducting copolymers/homopolymers of pyrrole and 3,4-ethylenedioxythiophene.

PubMed

Bruno, Ferdinando F; Fossey, Stephen A; Nagarajan, Subhalakshmi; Nagarajan, Ramaswamy; Kumar, Jayant; Samuelson, Lynne A

2006-02-01

A novel biomimetic route for the synthesis of electrically conducting homopolymers/copolymers of pyrrole and 3,4-ethylenedioxythiophene (EDOT) in the presence of a polyelectrolyte, such as polystyrene sulfonate (SPS), is presented. A poly(ethylene glycol)-modified hematin (PEG-hematin) was used to catalyze the homopolymerization of pyrrole and EDOT as well as copolymerization of EDOT and pyrrole in the presence of SPS to yield homopolymers of polypyrrole/SPS and PEDOT/SPS as well as a polypyrrole-co-poly(3,4-ethylenedioxythiophene)/SPS complex. Spectroscopic characterization [UV-visible, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS)], thermal analysis, (TGA), and electrical conductivity studies for these complexes indicated the presence of a stable and electrically conductive form of these polymers. Furthermore, the presence of SPS that serves as a charge-compensating dopant in this complex provides a unique combination of properties such as processability and water solubility.

Redox-active charge carriers of conducting polymers as a tuner of conductivity and its potential window

PubMed Central

Park, Han-Saem; Ko, Seo-Jin; Park, Jeong-Seok; Kim, Jin Young; Song, Hyun-Kon

2013-01-01

Electric conductivity of conducting polymers has been steadily enhanced towards a level worthy of being called its alias, “synthetic metal”. PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate)), as a representative conducting polymer, recently reached around 3,000 S cm−1, the value to open the possibility to replace transparent conductive oxides. The leading strategy to drive the conductivity increase is solvent annealing in which aqueous solution of PEDOT:PSS is treated with an assistant solvent such as DMSO (dimethyl sulfoxide). In addition to the conductivity enhancement, we found that the potential range in which PEDOT:PSS is conductive is tuned wider into a negative potential direction by the DMSO-annealing. Also, the increase in a redox-active fraction of charge carriers is proposed to be responsible for the enhancement of conductivity in the solvent annealing process. PMID:23949091

Mercaptoheterocyclic ligands grafted on a poly(ethylene vinyl alcohol) membrane for the purification of immunoglobulin G in a salt independent thiophilic chromatography.

PubMed

Coffinier, Yannick; Vijayalakshmi, Mookambeswaran A

2004-08-25

In this study, we attempted a limited combinatorial approach for designing affinity ligands based on mercaptoheterocyclic components. The template, divinyl sulfone structure (DVS), which was grafted on poly(ethylene vinyl alcohol) (PEVA) hollow fiber membrane, has served for the tethering of different heterocyclic compounds as pyridine, imidazole, purine and pyrimidine rings. Their ability to adsorb specifically IgG in a salt independent manner out of pure IgG solution, mixture of IgG/albumin and human plasma was demonstrated. Mercapto methyl imidazole (MMI) has shown the best adsorption of IgG in terms of binding capacity. No subclass discrimination was observed on all tested ligands except for mercapto methyl pyrimidine where the major IgG subclass adsorbed was IgG3. MMI gave an IgG binding capacity of 100 microg/cm2 of hollow fiber membrane surface area.

PUA/PSS multilayer coated CaCO3 microparticles as smart drug delivery vehicles.

PubMed

Du, Chao; Shi, Jun; Shi, Jin; Zhang, Li; Cao, Shaokui

2013-10-01

Hybrid CaCO3 microparticles coated by sodium poly(styrene sulfonate) (PSS) and aliphatic poly(urethane-amine) (PUA) were developed as thermal-/pH-responsive drug delivery vehicles via LbL self-assembly technique. The DOX release from the CaCO3 microparticles was higher than 60% within 36 h, whereas the value of PUA/PSS-coated microparticles was only 20%. The results demonstrated that the PUA/PSS multilayer coating could reduce the drug release rate and significantly assuage the initial burst release of DOX. In addition, the drug release of the hybrid microparticles was found to be thermal-/pH-dual responsive. More interestingly, more than 90% of DOX was released in 36 h at pH2.1 and 55 °C owing to the combined action of the dissolution of the CaCO3 core and the shrinkage of aliphatic PUA. Copyright © 2013 Elsevier B.V. All rights reserved.

Electrical properties of multilayers from low- and high-molecular-weight polyelectrolytes.

PubMed

Radeva, Tsetska; Milkova, Viktoria; Petkanchin, Ivana

2004-11-15

The formation of stable multilayer films by using as constituents sodium poly(4-styrene sulfonate) (PSS) and poly(4-vinyl pyridine) (PVP) was studied by electrooptics. A strong increase in basicity of the pyridine rings in the electrical field of the oppositely charged PSS chains was suggested to be the driving force for multilayer film formation. A linear increase in the film thickness was registered after deposition of the first three layers, with no dependence on the polyelectrolyte molecular weight. The electrooptical effect was found to increase with increasing area of each next layer, but depended on the molecular weights of both polymers. Polarization of "condensed" counterions along the chains of the last-adsorbed layer was suggested to explain this dependence. Following the counterion dynamics, we come to the conclusion that the electrical properties of the top layer govern the electrooptical behavior of the PSS/PVP film.

Stretchable Light-Emitting Diodes with Organometal-Halide-Perovskite-Polymer Composite Emitters.

PubMed

Bade, Sri Ganesh R; Shan, Xin; Hoang, Phong Tran; Li, Junqiang; Geske, Thomas; Cai, Le; Pei, Qibing; Wang, Chuan; Yu, Zhibin

2017-06-01

Intrinsically stretchable light-emitting diodes (LEDs) are demonstrated using organometal-halide-perovskite/polymer composite emitters. The polymer matrix serves as a microscale elastic connector for the rigid and brittle perovskite and induces stretchability to the composite emissive layers. The stretchable LEDs consist of poly(ethylene oxide)-modified poly(3,4-ethylenedioxythiophene) polystyrene sulfonate as a transparent and stretchable anode, a perovskite/polymer composite emissive layer, and eutectic indium-gallium as the cathode. The devices exhibit a turn-on voltage of 2.4 V, and a maximum luminance intensity of 15 960 cd m -2 at 8.5 V. Such performance far exceeds all reported intrinsically stretchable LEDs based on electroluminescent polymers. The stretchable perovskite LEDs are mechanically robust and can be reversibly stretched up to 40% strain for 100 cycles without failure. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Full cell study of Diels Alder poly(phenylene) anion and cation exchange membranes in vanadium redox flow batteries

DOE PAGES

Pezeshki, Alan M.; Fujimoto, Cy; Sun, Che -Nan; ...

2015-11-14

In this paper, we report on the performance of Diels Alder poly(phenylene) membranes in vanadium redox flow batteries. The membranes were functionalized with quaternary ammonium groups to form an anion exchange membrane (QDAPP) and with sulfonic acid groups to form a cation exchange membrane (SDAPP). Both membrane classes showed similar conductivities in the battery environment, suggesting that the ion conduction mechanism in the material is not strongly affected by the moieties along the polymer backbone. The resistance to vanadium permeation in QDAPP was not improved relative to SDAPP, further suggesting that the polarity of the functional groups do not playmore » a significant role in the membrane materials tested. Both QDAPP and SDAPP outperformed Nafion membranes in cycling tests, with both achieving voltage efficiencies above 85% while maintaining 95% coulombic efficiency while at a current density of 200 mA/cm 2.« less

Improved electrical conductivity of poly(ethylene oxide) nanofibers using multi-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Lee, J. Y.; Kang, T.-H.; Choi, J. H.; Choi, I.-S.; Yu, W.-R.

2018-03-01

Highly conductive nanofibers with 1570 S/m were obtained from an electrospun solution of polymer containing multiwalled carbon nanotubes (MWCNTs). Homogeneous dispersion of high concentrations of MWCNTs was achieved by attaching poly(styrenesulfonic acid graft aniline) (PSS-g-ANI), an amphiphilic surfactant, to the MWCNT surface. The hydrophilic sulfonic acid group facilitated the dissolution of PSS-g-ANI-grafted MWCNTs in a polyethylene oxide (PEO) solution up to 6.7 wt% MWCNT. To our knowledge, this is the highest level of MWCNT doping attained in a solution designed for electrospinning. With the incorporation of PSS-g-ANI, the concentration of MWCNTs embedded in the electrospun nanofibers increased. More importantly, the alignment of MWCNTs along the nanofiber axis increased significantly, as confirmed by observed birefringence under crossed polarizers. The combination of higher doping levels and better alignment afforded highly conductive nanofibers suitable for electronic nanodevices.

Phase-separation induced extraordinary toughening of magnetic hydrogels

NASA Astrophysics Data System (ADS)

Tang, Jingda; Li, Chenghai; Li, Haomin; Lv, Zengyao; Sheng, Hao; Lu, Tongqing; Wang, T. J.

2018-05-01

Phase separation markedly influences the physical properties of hydrogels. Here, we find that poly (N, N-dimethylacrylamide) (PDMA) hydrogels suffer from phase separation in aqueous sodium hydroxide solutions when the concentration is higher than 2 M. The polymer volume fraction and mechanical properties show an abrupt change around the transition point. We utilize this phase separation mechanism to synthesize tough magnetic PDMA hydrogels with the in-situ precipitation method. For comparison, we also prepared magnetic poly (2-acrylamido-2-methyl-propane sulfonic acid sodium) (PNaAMPS) magnetic hydrogels, where no phase separation occurs. The phase-separated magnetic PDMA hydrogels exhibit an extraordinarily high toughness of ˜1000 J m-2; while non-phase-separated magnetic PNaAMPS hydrogels only show a toughness of ˜1 J m-2, three orders of magnitude lower than that of PDMA hydrogels. This phase separation mechanism may become a new approach to prepare tough magnetic hydrogels and inspire more applications.

Hydrogen-bonded aggregates in precise acid copolymers

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

Lueth, Christopher A.; Bolintineanu, Dan S.; Stevens, Mark J., E-mail: msteve@sandia.gov

2014-02-07

We perform atomistic molecular dynamics simulations of melts of four precise acid copolymers, two poly(ethylene-co-acrylic acid) (PEAA) copolymers, and two poly(ethylene-co-sulfonic acid) (PESA) copolymers. The acid groups are spaced by either 9 or 21 carbons along the polymer backbones. Hydrogen bonding causes the acid groups to form aggregates. These aggregates give rise to a low wavevector peak in the structure factors, in agreement with X-ray scattering data for the PEAA materials. The structure factors for the PESA copolymers are very similar to those for the PEAA copolymers, indicating a similar distance between aggregates which depends on the spacer length butmore » not on the nature of the acid group. The PEAA copolymers are found to form more dimers and other small aggregates than do the PESA copolymers, while the PESA copolymers have both more free acid groups and more large aggregates.« less

Photogeneration of H2O2 in Water-Swollen SPEEK/PVA Polymer Films.

PubMed

Lockhart, PaviElle; Little, Brian K; Slaten, B L; Mills, G

2016-06-09

Efficient reduction of O2 took place via illumination with 350 nm photons of cross-linked films containing a blend of sulfonated poly(ether etherketone) and poly(vinyl alcohol) in contact with air-saturated aqueous solutions. Swelling of the solid macromolecular matrices in H2O enabled O2 diffusion into the films and also continuous extraction of the photogenerated H2O2, which was the basis for a method that allowed quantification of the product. Peroxide formed with similar efficiencies in films containing sulfonated polyketones prepared from different precursors and the initial photochemical process was found to be the rate-determining step. Generation of H2O2 was most proficient in the range of 4.9 ≤ pH ≤ 8 with a quantum yield of 0.2, which was 10 times higher than the efficiencies determined for solutions of the polymer blend. Increases in temperature as well as [O2] in solution were factors that enhanced the H2O2 generation. H2O2 quantum yields as high as 0.6 were achieved in H2O/CH3CN mixtures with low water concentrations, but peroxide no longer formed when film swelling was suppressed. A mechanism involving reduction of O2 by photogenerated α-hydroxy radicals from the polyketone in competition with second-order radical decay processes explains the kinetic features. Higher yields result from the films because cross-links present in them hinder diffusion of the radicals, limiting their decay and enhancing the oxygen reduction pathway.

Spatial and temporal trends of poly- and perfluoroalkyl substances in fish fillets and water collected from pool 2 of the Upper Mississippi River.

PubMed

Newsted, John L; Holem, Ryan; Hohenstein, Gary; Lange, Cleston; Ellefson, Mark; Reagen, William; Wolf, Susan

2017-11-01

In 2011, poly- and perfluoroalkyl substances (PFASs) were analyzed in surface water and fish fillet samples taken from Pool 2 of the Upper Mississippi River, a 33-mile stretch inclusive of the Minneapolis/St. Paul, Minnesota (USA) metropolitan area. Approximately 100 each of bluegill, freshwater drum, smallmouth bass, and white bass were sampled within the study area. Surface water samples were also collected from each of the 10 sampling reaches established for the study. Water and fillet samples were analyzed for perfluorinated carboxylic acids (C4-C12), perfluorinated sulfonic acids (C4, C6, and C8), and perfluorooctane sulfonamide. Perfluorooctane sulfonate (PFOS) was observed with the greatest frequency in fish fillets and ranged from 3.0 to 760 ng/g wet weight. Mean (geometric) PFOS concentrations in bluegill, freshwater drum, smallmouth bass, and white bass were 20, 28, 29, and 58 ng/g wet weight, respectively. When compared with fish data collected in 2009, a significant reduction (p < 0.05) in PFOS concentrations was noted. This finding was confirmed based on data from studies conducted in 2012 and 2013. Overall, between 2009 and 2013, PFOS concentrations decreased by 65, 76, and 50% for bluegill, freshwater drum, and white bass, respectively (44% decrease for smallmouth bass from 2009 to 2012). These declines in fish PFOS concentrations are consistent with ongoing efforts to effectively control sources of PFASs to the Mississippi River. Environ Toxicol Chem 2017;36:3138-3147. © 2017 SETAC. © 2017 SETAC.

Direct AFM force measurements between air bubbles in aqueous polydisperse sodium poly(styrene sulfonate) solutions: effect of collision speed, polyelectrolyte concentration and molar mass.

PubMed

Browne, Christine; Tabor, Rico F; Grieser, Franz; Dagastine, Raymond R

2015-07-01

Interactions between colliding air bubbles in aqueous solutions of polydisperse sodium poly(styrene sulfonate) (NaPSS) using direct force measurements were studied. The forces measured with deformable interfaces were shown to be more sensitive to the presence of the polyelectrolytes when compared to similar measurements using rigid interfaces. The experimental factors that were examined were NaPSS concentration, bubble collision velocity and polyelectrolyte molar mass. These measurements were then compared with an analytical model based on polyelectrolyte scaling theory in order to explain the effects of concentration and bubble deformation on the interaction between bubbles. Typically structural forces from the presence of monodisperse polyelectrolyte between interacting surfaces may be expected, however, it was found that the polydispersity in molar mass resulted in the structural forces to be smoothed and only a depletion interaction was able to be measured between interacting bubbles. It was found that an increase in number density of NaPSS molecules resulted in an increase in the magnitude of the depletion interaction. Conversely this interaction was overwhelmed by an increase in the fluid flow in the system at higher bubble collision velocities. Polymer molar mass dispersity plays a significant role in the interactions present between the bubbles and has implications that also affect the polyelectrolyte overlap concentration of the solution. Further understanding of these implications can be expected to play a role in the improvement in operations in such fields as water treatment and mineral processing where polyelectrolytes are used extensively. Copyright © 2015 Elsevier Inc. All rights reserved.

Distribution profiles of per- and poly fluoroalkyl substances (PFASs) and their re-regulation by ocean currents in the East and South China Sea.

PubMed

Zheng, Hongyuan; Wang, Feng; Zhao, Zhen; Ma, Yuxin; Yang, Haizhen; Lu, Zhibo; Cai, Minggang; Cai, Minghong

2017-12-15

We investigated the distribution of 17 individual per- and polyfluoroalkyl substances (PFASs) in 42 surface water samples collected from the East and South China Seas (7.0-36.0°N, 110.0°N-123.0°E). Concentrations of 7 individual PFASs, including perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluoropentanoic acid (PFPA), perfluorohexanoate (PFHxA), perfluoroheptanoate (PFHpA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonamide (FOSA), were quantified in the East China Sea, but only concentrations of PFOA and FOSA were quantified in the South China Sea. The total concentrations of the 17 PFASs ranged from 181 to 2658pg/L in the East China Sea and from 62 to 494pg/L in the South China Sea. We also show that river fluxes and ocean currents had a strong influence on the distribution of PFASs in the East China Sea. Using ArcGIS 10.1, we show how ocean currents control the spatial distribution of PFOA in the central South China Sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dramatic improvement in water retention and proton conductivity in electrically aligned functionalized CNT/SPEEK nanohybrid PEM.

PubMed

Gahlot, Swati; Kulshrestha, Vaibhav

2015-01-14

Nanohybrid membranes of electrically aligned functionalized carbon nanotube f CNT with sulfonated poly ether ether ketone (SPEEK) have been successfully prepared by solution casting. Functionalization of CNTs was done through a carboxylation and sulfonation route. Further, a constant electric field (500 V·cm(-2)) has been applied to align CNTs in the same direction during the membrane drying process. All the membranes are characterized chemically, thermally, and mechanically by the means of FTIR, DSC, DMA, UTM, SEM, TEM, and AFM techniques. Intermolecular interactions between the components in hybrid membranes are established by FTIR. Physicochemical measurements were done to analyze membrane stability. Membranes are evaluated for proton conductivity (30-90 °C) and methanol crossover resistance to reveal their potential for direct methanol fuel cell application. Incorporation of f CNT reasonably increases the ion-exchange capacity, water retention, and proton conductivity while it reduces the methanol permeability. The maximum proton conductivity has been found in the S-sCNT-5 nanohybrid PEM with higher methanol crossover resistance. The prepared membranes can be also used for electrode material for fuel cells and batteries.

Effect of water on the changes in morphology and proton conductivity for the highly crystalline hydrocarbon polymer electrolyte membrane for fuel cells.

PubMed

Barique, Mohammad A; Wu, Libin; Takimoto, Naohiko; Kidena, Koh; Ohira, Akihiro

2009-12-10

The effects of water on the changes in morphology of sulfonated poly(phenylene sulfide) (SPPS) hydrocarbon polymer electrolyte membranes (PEM) with an ion exchange capacity (IEC) of 0-2.0 mequiv/g are investigated using small-angle X-ray scattering (SAXS) and atomic force microscopy (AFM). Wide-angle X-ray scattering (WAXS) was used to characterize the effect of direct sulfonation on the changes in membrane crystalline structure, and it was found that the crystallinity and crystallite domain size decrease and the volume of the amorphous region in the SPPS membranes increases with increasing IEC. The experimental data have been fitted to the Porod law for approaching the analysis of the sharpness of the polymer/water interface, development of the proton channel, or dispersion of water in the hydrated membranes. Porod plots showed positive deviation which revealed that the polymer/water interface in the hydrated SPPS membrane is not smooth but diffused and a well-developed proton channel does not form in the membrane.

Degradation of Perfluorooctanoic Acid and Perfluoroctane Sulfonate by Enzyme Catalyzed Oxidative Humification Reactions

NASA Astrophysics Data System (ADS)

Huang, Q.

2016-12-01

Poly- and perfluoroalkyl substances (PFASs) are alkyl based chemicals having multiple or all hydrogens replaced by fluorine atoms, and thus exhibit high thermal and chemical stability and other unusual characteristics. PFASs have been widely used in a wide variety of industrial and consumer products, and tend to be environmentally persistent. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are two representative PFASs that have drawn particular attention because of their ubiquitous presence in the environment, resistance to degradation and toxicity to animals. This study examined the decomposition of PFOA and PFOS in enzyme catalyzed oxidative humification reactions (ECOHR), a class of reactions that are ubiquitous in the environment involved in natural organic humification. Reaction rates and influential factors were examined, and high-resolution mass spectrometry was used to identify possible products. Fluorides and partially fluorinated compounds were identified as likely products from PFOA and PFOS degradation, which were possibly formed via a combination of free radical decomposition, rearrangements and coupling processes. The findings suggest that PFOA and PFOS may be transformed during humification, and ECOHR can potentially be used for the remediation of these chemicals.

Formation of nanotunnels inside a resist film in laser interference lithography.

PubMed

Wei, Qi; Hu, Fanhua; Wang, Liyuan

2015-05-19

A few kinds of 2-diazo-1-naphthoquinone-4-sulfonates of poly(4-hydroxylstyrene) were prepared to form one-component i-line photoresists. In the laser interference lithography experiments of some of the photoresists, nanotunnels were observed to be aligned in the interior of the resist film. The shape and size of the nanotunnels remain virtually unchanged even under an increased exposure dose, indicating that the exposure energy is confined within the tunnel space. The formation of the nanotunnels results from the effect of standing waves and the permeation of developer from the surface deep into the resist films.

Electrochromic Behavior of Ionically Self-Assembled Thin Films

NASA Astrophysics Data System (ADS)

Janik, J. A.; Heflin, J. R.; Marciu, D.; Miller, M. B.; Davis, R. M.

2001-03-01

Ionically self-assembled monolayers (ISAMs), fabricated by alternate adsorption of cationic and anionic components, yield exceptionally homogeneous thin films with sub-nanometer control of the thickness and relative special location of the component materials. Using organic electrochromic materials such as polyaniline, we report studies of electrochromic responses in ISAM films. Reversible changes in the absorption spectrum are observed with the application of voltages on the order of 1.0 V. Measurements are made using both liquid electrolytes and in all-solid state devices incorporating solid polyelectrolytes such as poly(2-acylamido 2-methyl propane sulfonic acid) (PAMPS).

Molecular Engineering of Liquid Crystalline Polymers by Living Polymerization. 10. Influence of Molecular Weight on the Phase Transitions of Poly(Omega-((4-Cyano-4’-Biphenyl)oxy)alkyl Vinyl Ethers)s with Nonyl and Decanyl Alkyl Groups

DTIC Science & Technology

1990-10-16

washed with concentrated sulfuric acid , then with water, dried over anhydrous magnesium sulfate, refluxed over calcium hydride and freshly distilled...oxide, filtered, and fractionally distilled under reduced pressure. Trifluoromethane sulfonic acid (triflic acid , 98%, Aldrich) w s distilled under...flask. Then the flask was filled with argon, cooled to 0°C and the methylene chloride, dimethyl sulfide and triflic acid were added via a syringe. The

Deprotonation of a Seemingly Hydridic Diborane(6) To Build a B-B Bond.

PubMed

Kaese, Thomas; Budy, Hendrik; Bolte, Michael; Lerner, Hans-Wolfram; Wagner, Matthias

2017-06-19

Deprotonation of the doubly arylene-bridged diborane(6) derivative 1H 2 with (Me 3 Si) 3 CLi or (Me 3 Si) 2 NK gives the B-B σ-bonded species M[1H] in essentially quantitative yields (THF, room temperature; M=Li, K, arylene=4,4'-di-tert-butyl-2,2'-biphenylylene). With nBuLi as the base, the yield of Li[1H] drops to 20 % and the 1,1-bis(9-borafluorenyl)butane Li[2H] is formed as a side product (30 %). In addition to the 1,1-butanediyl fragment, the two boron atoms of Li[2H] are linked by a μ-H bridge. In the closely related molecule Li[3H], the corresponding μ-H atom can be abstracted with (Me 3 Si) 3 CLi to afford the B-B-bonded conjugated base Li 2 [3] (THF, 150 °C; 15 %). Li[1H] and Li[2H] were characterized by NMR spectroscopy and X-ray crystallography. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Trypanocidal 1,3-arylene diketone bis(guanylhydrazone)s. Structure-activity relationships among substituted and heterocyclic analogues.

PubMed

Ulrich, P; Cerami, A

1984-01-01

Based on the antitrypanosomal activity of 1,3-diacetylbenzene bis(guanylhydrazone) (4) and 2,6-diacetylpyridine bis(guanylhydrazone) (17), a number of substituted and heterocyclic 1,3-arylene diketone bis(guanylhydrazone)s were prepared and tested against Trypanosoma brucei infections in mice. A wide range of ED50 values was observed among 5-substituted derivatives of 4. The 5-amino analogue 5 and 5-acetamido analogue 6 were about twice as active as 4. 1,3,5-Triacetylbenzene tris(guanylhydrazone) (12) was about 9 times as active as 4 and was approximately one-half as active as the currently used trypanocide diminazene aceturate in this test system. Other 5-derivatives had activity equivalent to or less than that of the parent compound 4. Three new heterocyclic analogues were all less active than 2,6-diacetylpyridine derivative 17 and benzene derivative 4. Ring substitution ortho to the guanylhydrazone side chains was invariably detrimental to activity. Side-chain homologues 1,3-dipentanoylbenzene bis(guanylhydrazone) and 1,3-diacetylbenzene bis(2-imidazolin-2-ylhydrazone) were essentially inactive.

Hydrogels with a Memory: Dual-Responsive, Organometallic Poly(ionic liquid)s with Hysteretic Volume-Phase Transition

PubMed Central

2017-01-01

We report on the synthesis and structure–property relations of a novel, dual-responsive organometallic poly(ionic liquid) (PIL), consisting of a poly(ferrocenylsilane) backbone of alternating redox-active, silane-bridged ferrocene units and tetraalkylphosphonium sulfonate moieties in the side groups. This PIL is redox responsive due to the presence of ferrocene in the backbone and also exhibits a lower critical solution temperature (LCST)-type thermal responsive behavior. The LCST phase transition originates from the interaction between water molecules and the ionic substituents and shows a concentration-dependent, tunable transition temperature in aqueous solution. The PIL’s LCST-type transition temperature can also be influenced by varying the redox state of ferrocene in the polymer main chain. As the polymer can be readily cross-linked and is easily converted into hydrogels, it represents a new dual-responsive materials platform. Interestingly, the as-formed hydrogels display an unusual, strongly hysteretic volume-phase transition indicating useful thermal memory properties. By employing the dispersing abilities of this cationic PIL, CNT-hydrogel composites were successfully prepared. These hybrid conductive composite hydrogels showed bi-stable states and tunable resistance in heating–cooling cycles. PMID:28654756

Composite films of oxidized multiwall carbon nanotube and poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) as a contact electrode for transistor and inverter devices.

PubMed

Yun, Dong-Jin; Rhee, Shi-Woo

2012-02-01

Composite films of multiwall carbon nanotube (MWNT)/poly(3,4-ethylenedioxythiophene) polymerized with poly(4-styrenesulfonate) (PEDOT:PSS) were prepared by spin-coating a mixture solution. The effect of the MWNT loading and the MWNT oxidation, with acid solution or ultraviolet (UV)-ozone treatment, on the film properties such as surface roughness, work function, surface energy, optical transparency and conductivity were studied. Also pentacene thin film transistors and inverters were made with these composite films as a contact metal and the device characteristics were measured. The oxidation of MWNT reduced the conductivity of MWNT/PEDOT:PSS composite film but increased the work function and transparency. UV-ozone treated MWNT/PEDOT:PSS composite film showed higher conductivity (14000 Ω/□) and work function (4.9 eV) than acid-oxidized MWNT/PEDOT:PSS composite film and showed better performance as a source/drain electrode in organic thin film transistor (OTFT) than other types of MWNT/PEDOT:PSS composite films. Hole injection barrier of the UV-ozone treated MWNT/PEDOT:PSS composite film with pentacene was significantly lower than any other films because of the higher work function.

Salt-responsive polyzwitterionic materials for surface regeneration between switchable fouling and antifouling properties.

PubMed

Chen, Hong; Yang, Jintao; Xiao, Shengwei; Hu, Rundong; Bhaway, Sarang M; Vogt, Bryan D; Zhang, Mingzhen; Chen, Qiang; Ma, Jie; Chang, Yung; Li, Lingyan; Zheng, Jie

2016-08-01

Development of smart regenerative surface is a highly challenging but important task for many scientific and industrial applications. Specifically, very limited research efforts were made for surface regeneration between bio-adhesion and antifouling properties, because bioadhesion and antifouling are the two highly desirable but completely opposite properties of materials. Herein, we developed salt-responsive polymer brushes of poly(3-(1-(4-vinylbenzyl)-1H-imidazol-3-ium-3-yl) propane-1-sulfonate) (polyVBIPS), which can be switched reversibly and repeatedly between protein capture/release and surface wettability in a controllable manner. PolyVBIPS brush has demonstrated its switching ability to resist both protein adsorption from 100% blood plasma/serum and bacterial attachment in multiple cycles. PolyVBIPS brush also exhibits reversible surface wettability from ∼40° to 25° between in PBS and in 1M NaCl solutions in multiple cycles. Overall, the salt-responsive behaviors of polyVBIPS brushes can be interpreted by the "anti-polyelectrolyte effect", i.e. polyVBIPS brushes adopt a collapsed chain conformation at low ionic strengths to achieve surface adhesive, but an extended chain conformation at high ionic strength to realize antifouling properties. We expect that polyVBIPS will provide a simple, robust, and promising system for the fabrication of smart surfaces with biocompatible, reliable, and regenerative properties. Unlike many materials with "one-time switching" capability for surface regeneration, we developed a new regenerative surface of zwitterionic polymer brush, which exhibits a reversible salt-induced switching property between a biomolecule-adhesive state and a biomolecule repellent state in complex media for multiple cycles. PolyVBIPS is easily synthesized and can be straightforward coated on the surface, which provides a simple, robust, and promising system for the fabrication of smart surfaces with biocompatible, reliable, regenerative properties. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Nitrogen and sulfur Co-doped microporous activated carbon macro-spheres for CO2 capture.

PubMed

Sun, Yahui; Li, Kaixi; Zhao, Jianghong; Wang, Jianlong; Tang, Nan; Zhang, Dongdong; Guan, Taotao; Jin, Zuer

2018-04-27

Millimeter-sized nitrogen and sulfur co-doped microporous activated carbon spheres (NSCSs) were first synthesized from poly(styrene-vinylimidazole-divinylbenzene) resin spheres through concentrated H 2 SO 4 sulfonation, carbonization and KOH activation. Styrene (ST) and N-vinylimidazole (VIM) were carbon and nitrogen sources, while the sulfonic acid functional groups introduced by the simple concentrated sulfuric acid sulfonation worked simultaneously as cross-linking agent and sulfur source during the following thermal treatments. It was found that the surface chemistries, textural structures, and CO 2 adsorption performances of the NSCSs were significantly affected by the addition of VIM. The NSCS-4-700 sample with a molar ratio of ST: VIM = 1: 0.75 showed the best CO 2 uptake at different temperatures and pressures. An exhaustive adsorption evaluation indicated that CO 2 sorption at low pressures originated from the synergistic effect of surface chemistry and micropores below 8.04 Å, while at the moderate pressure of 8.0 bar, CO 2 uptake was dominated by the volume of micropores. The thermodynamics suggested the exothermic and orderly nature of the adsorption process, which was dominated by a physisorption mechanism. The high CO 2 adsorption capacity, fast kinetic adsorption rate, and great regeneration stability of the nitrogen and sulfur co-doped activated carbon spheres indicated that the as-prepared carbon adsorbents were good candidates for large-scale CO 2 capture. Copyright © 2018 Elsevier Inc. All rights reserved.

Label-Free LSPR Detection of Trace Lead(II) Ions in Drinking Water by Synthetic Poly(mPD-co-ASA) Nanoparticles on Gold Nanoislands.

PubMed

Qiu, Guangyu; Ng, Siu Pang; Liang, Xiongyi; Ding, Ning; Chen, Xiangfeng; Wu, Chi-Man Lawrence

2017-02-07

Using self-assembly gold nanoislands (SAM-AuNIs) functionalized by poly(m-phenylenediamine-co-aniline-2-sulfonic acid) (poly(mPD-co-ASA)) copolymer nanoparticles as specific receptors, a highly sensitive localized surface plasmon resonance (LSPR) optochemical sensor is demonstrated for detection of trace lead cation (Pb(II)) in drinking water. The copolymer receptor is optimized in three aspects: (1) mole ratio of mPD:ASA monomers, (2) size of copolymer nanoparticles, and (3) surface density of the copolymer. It is shown that the 95:5 (mPD:ASA mole ratio) copolymer with size less than 100 nm exhibits the best Pb(II)-sensing performance, and the 200 times diluted standard copolymer solution contributes to the most effective functionalization protocol. The resulting poly(mPD-co-ASA)-functionalized LSPR sensor attains the detection limit to 0.011 ppb toward Pb(II) in drinking water, and the linear dynamic range covers 0.011 to 5000 ppb (i.e., 6 orders of magnitude). In addition, the sensing system exhibits robust selectivity to Pb(II) in the presence of other metallic cations as well as common anions. The proposed functional copolymer functionalized on AuNIs is found to provide excellent Pb(II)-sensing performance using simple LSPR instrumentation for rapid drinking-water inspection.

Structural and electrical properties of Ag grid/poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) coatings for diode application through advanced printing technology.

PubMed

Duraisamy, Navaneethan; Ponniah, Ganeshthangaraj; Jo, Jeongdai; Choi, Kyung-Hyun

2013-08-01

This paper is focused on printed techniques for the fabrication of hybrid structure of silver (Ag) grid/poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) (PEDOT:PSS) on polyethylene terepthalate (PET) as a flexible substrate. Ag grid has been printed on PET substrate by using gravure offset printing process, followed by PEDOT:PSS thin film deposition on Ag grid through electrohydrodynamic atomization (EHDA) technique. The important parameters for achieving uniform hybrid structure of Ag grid/PEDOT:PSS through printed techniques have been clearly discussed. Field emission scanning electron microscope studies revealed the uniformity of printed Ag grid with homogeneous deposition of PEDOT:PSS on Ag grid. The optical properties of Ag grid/PEDOT:PSS were measured by UV-visible spectroscopy, which showed nearly 80-82% of transparency in the visible region and it was nearly same as PEDOT:PSS thin film on PET substrate. Current-voltage (I-V) analysis of fabricated hybrid device by using printed Ag grid/PEDOT:PSS as a bottom electrode showed good rectifying behavior with possible interfacial mechanisms. Capacitance-voltage (C-V) analysis was carried over different frequencies. These results suggest that fabrication of hybrid structure through printed techniques will play a significant role in mass production of printed electronic devices for commercial application by using flexible substrate.

Influence of polymeric electron injection layers on the electrical properties of solution-processed multilayered polymer light-emitting diodes

NASA Astrophysics Data System (ADS)

Itoh, Eiji; Kurami, Kazuhiko

2016-02-01

In this study, we fabricated multilayered polymer-based light-emitting diodes (pLEDs) with various solution-processed electron-injection layers (EILs), and investigated the influence of the EILs on the electrical properties of pLEDs in indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid) (PEDOT:PSS)/poly[(9,9-dioctylfluorene-alt-(1,4-phenylene((4-sec-butylphenyl)amino)-1,4-phenylene))] (TFB) (HTL)/poly(9,9-dioctylfluorene-alt-1,4-benzothiadiazole) (F8BT) (EML)/EIL/Al structures. We have used the quaternized ammonium π-conjugated polyelectrolyte derivative (poly[(9,9-di(3,3‧-N,N‧-trimethylammonium)propylfluorenyl-2,7-diyl)-co-(1,4-phenylene)]diiodide salt) (PF-PDTA), a mixture of PF-PDTA and CS2CO3, and the aliphatic-amine-based polymer poly(ethylene imine) (PEI) as solution-processed EILs, and compared them with LiF as a solvent-free EIL. The EILs enhanced the electron injection and improve the pLED performance. High external quantum efficiencies of nearly 4% were obtained in the pLEDs with the combination of a multilayered structure fabricated by a transfer printing technique and EILs of a PF-PDTA:CS2CO3 mixture and PEI. On the other hand, the device with PF-PDTA exhibited lower efficiency, higher driving voltage, and larger leakage current at lower voltage. The migration of ionic charges was suggested from the abnormal dielectric behaviors, and serious damage on the electrode material occurred when both an acid hole-injection layer (PEDOT:PSS) and PF-PDTA were used. On the other hand, the pLEDs with ultrathin PEI showed high performance and stable device operation in terms of the influence of ionic charges.

Salt dependence of compression normal forces of quenched polyelectrolyte brushes

NASA Astrophysics Data System (ADS)

Hernandez-Zapata, Ernesto; Tamashiro, Mario N.; Pincus, Philip A.

2001-03-01

We obtained mean-field expressions for the compression normal forces between two identical opposing quenched polyelectrolyte brushes in the presence of monovalent salt. The brush elasticity is modeled using the entropy of ideal Gaussian chains, while the entropy of the microions and the electrostatic contribution to the grand potential is obtained by solving the non-linear Poisson-Boltzmann equation for the system in contact with a salt reservoir. For the polyelectrolyte brush we considered both a uniformly charged slab as well as an inhomogeneous charge profile obtained using a self-consistent field theory. Using the Derjaguin approximation, we related the planar-geometry results to the realistic two-crossed cylinders experimental set up. Theoretical predictions are compared to experimental measurements(Marc Balastre's abstract, APS March 2001 Meeting.) of the salt dependence of the compression normal forces between two quenched polyelectrolyte brushes formed by the adsorption of diblock copolymers poly(tert-butyl styrene)-sodium poly(styrene sulfonate) [PtBs/NaPSS] onto an octadecyltriethoxysilane (OTE) hydrophobically modified mica, as well as onto bare mica.

Differences between tethered polyelectrolyte chains adsorbed onto bare mica and hydrophobically modified mica, comparison with theory.

NASA Astrophysics Data System (ADS)

Balastre, Marc; Tamashiro, Mario N.; Hernandez, Ernesto; Pincus, Philip; Tirrell, Matthew

2001-03-01

End-grafted polymers generated from the adsorption of asymmetric diblock copolymers on solid surface play an important role in many areas of science and technology. While the small insoluble block acts as an anchor, the charged soluble block confers useful properties to the surface. This study looks at tethered layers of poly(styrene sulfonate)/poly(t-butyl styrene) (PtBS-PSS) adsorbed on both mica (hydrophilic) and octadecyltriethoxysilane (OTE) modified mica (hydrophobic). Normal compressing forces at two different constant grafting densities (bare and modified mica) were measured with the surface force apparatus and compared with theoretical prediction. The effect of salt concentration (Cs) upon the thickness of the self-assembled layers (Lo) was measured in each case. For adsorption of diblock copolymers onto OTE the resulting scaling relationship is much closer to the brush theory, Lo Cs-1/3. This result suggests that the adsorbed amount on mica is not high enough to form a brush.

Polymeric Flexible Immunosensor Based on Piezoresistive Micro-Cantilever with PEDOT/PSS Conductive Layer.

PubMed

Zhao, Rui; Sun, Ying

2018-02-03

In this paper, a fully polymeric micro-cantilever with the surface passivation layer of parylene-C and the strain resistor of poly(3,4-ethylenedioxythiophene)/poly (styrene sulfonate) (PEDOT/PSS) was proposed and demonstrated for immunoassays. By optimizing the design and fabrication of the polymeric micro-cantilever, a square resistance of 220 Ω/□ for PEDOT/PSS conductive layer have been obtained. The experimental spring constant and the deflection sensitivity were measured to be 0.017 N/m and 8.59 × 10 -7 nm -1 , respectively. The biological sensing performances of polymeric micro-cantilever were investigated by the immunoassay for human immunoglobulin G (IgG). The immunosensor was experimentally demonstrated to have a linear behavior for the detection of IgG within the concentrations of 10~100 ng/mL with a limit of detection (LOD) of 10 ng/mL. The experimental results indicate that the proposed polymeric flexible conductive layer-based sensors are capable of detecting trace biological substances.

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

Kumar, Pankaj, E-mail: pankaj@mail.nplindia.ernet.in; Centre for Organic Electronics, Physics, University of Newcastle, Callaghan NSW-2308; Bilen, Chhinder

The degradation and thermal regeneration of poly(3-hexylethiophene) (P3HT):[6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCBM) and P3HT:indene-C{sub 60} bisadduct (ICBA) polymer solar cells, with Ca/Al and Ca/Ag cathodes and indium tin oxide/poly(ethylene-dioxythiophene):polystyrene sulfonate anode have been investigated. Degradation occurs via a combination of three primary pathways: (1) cathodic oxidation, (2) active layer phase segregation, and (3) anodic diffusion. Fully degraded devices were subjected to thermal annealing under inert atmosphere. Degraded solar cells possessing Ca/Ag electrodes were observed to regenerate their performance, whereas solar cells having Ca/Al electrodes exhibited no significant regeneration of device characteristics after thermal annealing. Moreover, the solar cells withmore » a P3HT:ICBA active layer exhibited enhanced regeneration compared to P3HT:PCBM active layer devices as a result of reduced changes to the active layer morphology. Devices combining a Ca/Ag cathode and P3HT:ICBA active layer demonstrated ∼50% performance restoration over several degradation/regeneration cycles.« less

Continuous structural evolution of calcium carbonate particles: a unifying model of copolymer-mediated crystallization.

PubMed

Kulak, Alex N; Iddon, Peter; Li, Yuting; Armes, Steven P; Cölfen, Helmut; Paris, Oskar; Wilson, Rory M; Meldrum, Fiona C

2007-03-28

Two double-hydrophilic block copolymers, each comprising a nonionic block and an anionic block comprising pendent aromatic sulfonate groups, were used as additives to modify the crystallization of CaCO3. Marked morphological changes in the CaCO3 particles were observed depending on the reaction conditions used. A poly(ethylene oxide)-b-poly(sodium 4-styrenesulfonate) diblock copolymer was particularly versatile in effecting a morphological change in calcite particles, and a continuous structural transition in the product particles from polycrystalline to mesocrystal to single crystal was observed with variation in the calcium concentration. The existence of this structural sequence provides unique insight into the mechanism of polymer-mediated crystallization. We propose that it reflects continuity in the crystallization mechanism itself, spanning the limits from nonoriented aggregation of nanoparticles to classical ion-by-ion growth. The various pathways to polycrystalline, mesocrystal, and single-crystal particles, which had previously been considered to be distinct, therefore all form part of a unifying crystallization framework based on the aggregation of precursor subunits.

Organic-inorganic hybrid polyionic liquid based polyoxometalate as nano porous material for selective oxidation of sulfides

NASA Astrophysics Data System (ADS)

Rafiee, Ezzat; Shahebrahimi, Shabnam

2017-07-01

Organic-inorganic hybrid nano porous materials based on poly(ionic liquid)-polyoxometalate (PIL-POM) were reported. These hybrid materials were synthesized by the reaction of 4-vinyl pyridine with 1,3-propanesultone, followed by the polymerization and also sulfonate-functionalized cross-linked poly(4-vinylpyridine) and combining these polymers with H5PMo10V2O40 (PMo10V2). Activity of prepared PIL-PMo10V2 hybrids were investigated as catalysts for oxidation of sulfides with H2O2 as oxidant. For understanding catalytic activities of the PIL-PMo10V2 hybrids in oxidation of sulfides, effect of catalyst composition, substrate, and reaction conditions were studied. The results show that the PIL-PMo10V2 hybrids are active as selective heterogeneous catalysts for oxidation of sulfides and can be recovered and reused. The catalyst was characterized by FT-IR, TGA-DSC, XRD, SEM/EDX, BET, CV and zeta potential measurement. Also, average molecular weight of prepared catalysts were measured.

Fabrication of High-Sensitivity Skin-Attachable Temperature Sensors with Bioinspired Microstructured Adhesive.

PubMed

Oh, Ju Hyun; Hong, Soo Yeong; Park, Heun; Jin, Sang Woo; Jeong, Yu Ra; Oh, Seung Yun; Yun, Junyeong; Lee, Hanchan; Kim, Jung Wook; Ha, Jeong Sook

2018-02-28

In this study, we demonstrate the fabrication of a highly sensitive flexible temperature sensor with a bioinspired octopus-mimicking adhesive. A resistor-type temperature sensor consisting of a composite of poly(N-isopropylacrylamide) (pNIPAM)-temperature sensitive hydrogel, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, and carbon nanotubes exhibits a very high thermal sensitivity of 2.6%·°C -1 between 25 and 40 °C so that the change in skin temperature of 0.5 °C can be accurately detected. At the same time, the polydimethylsiloxane adhesive layer of octopus-mimicking rim structure coated with pNIPAM is fabricated through the formation of a single mold by utilizing undercut phenomenon in photolithography. The fabricated sensor shows stable and reproducible detection of skin temperature under repeated attachment/detachment cycles onto skin without any skin irritation for a long time. This work suggests a high potential application of our skin-attachable temperature sensor to wearable devices for medical and health-care monitoring.

Polymeric Flexible Immunosensor Based on Piezoresistive Micro-Cantilever with PEDOT/PSS Conductive Layer

PubMed Central

Sun, Ying

2018-01-01

In this paper, a fully polymeric micro-cantilever with the surface passivation layer of parylene-C and the strain resistor of poly(3,4-ethylenedioxythiophene)/poly (styrene sulfonate) (PEDOT/PSS) was proposed and demonstrated for immunoassays. By optimizing the design and fabrication of the polymeric micro-cantilever, a square resistance of 220 Ω/□ for PEDOT/PSS conductive layer have been obtained. The experimental spring constant and the deflection sensitivity were measured to be 0.017 N/m and 8.59 × 10−7 nm−1, respectively. The biological sensing performances of polymeric micro-cantilever were investigated by the immunoassay for human immunoglobulin G (IgG). The immunosensor was experimentally demonstrated to have a linear behavior for the detection of IgG within the concentrations of 10~100 ng/mL with a limit of detection (LOD) of 10 ng/mL. The experimental results indicate that the proposed polymeric flexible conductive layer-based sensors are capable of detecting trace biological substances. PMID:29401669

Target binding influences permeability in aptamer-polyelectrolyte microcapsules.

PubMed

Sultan, Yasir; DeRosa, Maria C

2011-05-09

Aptamer-polyelectrolyte microcapsules are prepared for potential use as triggered delivery vehicles and microreactors. The hollow microcapsules are prepared from the sulforhodamine B aptamer and the polyelectrolytes poly(allylamine hydrochloride) and poly(sodium 4-styrene-sulfonate), using layer-by-layer (LbL) film deposition templated on a sacrificial CaCO(3) spherical core. Scanning electron microscopy and confocal microscopy confirm the formation of spherical CaCO(3) cores and LbL-aptamer microcapsules. Colocalization studies with fluorescently-tagged aptamer and sulforhodamine B verify the ability of the aptamer to recognize its cognate target in the presence of the K(+) ions that are required for its characteristic G-quadruplex formation. Fluorescence recovery after photobleaching studies confirms a significant difference in the permeability of the aptamer-polyelectrolyte microcapsules for the sulforhodamine B dye target compared to control microcapsules prepared with a random oligonucleotide. These results suggest that aptamer-based 'smart' responsive films and microcapsules could be applied to problems of catalysis and controlled release. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Structure-Property Relationship of Poly(amide-imide)/Organoclay Nanocomposites

NASA Astrophysics Data System (ADS)

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

2011-06-01

Surface treated montmorillonite (MMT) was used to prepare nanocomposites with poly(amide-imide) (PAI) 5 by solution intercalation technique with various percent of organoclay (5-15 mass %). Surface modification of the MMT was performed with Cloisite 20A for ample compatibilization with the PAI matrix. The PAI 5 chains were produced through polycondensation of 4,4-diamino diphenyl sulfone 4 with N-trimellitylimido-L-alanine 3 in a medium consisting of triphenyl phosphite, N-methyl-2-pyrolidone (NMP), pyridine and calcium chloride. The PAI-Nanocomposites morphology and clay dispersion were investigated by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and PAI chains on the properties of PAI-Nanocomposites films were investigated by using UV-Vis spectroscopy, thermogravimetric analysis (TGA) and water uptake measurements. Thermal stability of nanocomposites increased relative to the neat polyamide with increasing organoclay content but water uptake of these materials decreased as compared to the neat polyamide indicating reduced permeability.

Short-wavelength ablation of polymers in the high-fluence regime

NASA Astrophysics Data System (ADS)

Liberatore, Chiara; Mann, Klaus; Müller, Matthias; Pina, Ladislav; Juha, Libor; Vyšín, Ludek; Rocca, Jorge J.; Endo, Akira; Mocek, Tomas

2014-05-01

Short-wavelength ablation of poly(1,4-phenylene ether-ether-sulfone) (PPEES) and poly(methyl methacrylate) (PMMA) was investigated using extreme ultraviolet (XUV) and soft x-ray (SXR) radiation from plasma-based sources. The initial experiment was performed with a 10 Hz desktop capillary-discharge XUV laser lasing at 46.9 nm. The XUV laser beam was focused onto the sample by a spherical mirror coated with a Si/Sc multilayer. The same materials were irradiated with 13.5 nm radiation emitted by plasmas produced by focusing an optical laser beam onto a xenon gas-puff target. A Schwarzschild focusing optics coated with a Mo/Si multilayer was installed at the source to achieve energy densities exceeding 0.1 J cm-2 in the tight focus. The existing experimental system at the Laser Laboratorium Göttingen was upgraded by implementing a 1.2 J driving laser. An increase of the SXR fluence was secured by improving the alignment technique.

Optical biosensor with poly[N-nonyl-3,6-bis(ethylenedioxythiophene)carbazole] matrix for monitoring of phenol derivatives

NASA Astrophysics Data System (ADS)

Jedrychowska, Agnieszka; Malecha, Karol; Cabaj, Joanna; Sołoducho, Jadwiga

2014-08-01

The aim of the research was to develop an enzymatic, optical biosensor which provides quick and convenient determination of phenolic compounds in aqueous solutions. The biosensing strategy concerns design, fabrication and testing of a miniature ceramic-based biosensor which is destined for in-situ substrate monitoring. The base of the measuring system was fabricated using low temperature co-fired ceramics (LTCC) technology. The biocatalyst - laccase- was immobilized on the thin film of poly[N-nonyl-3,6-bis(ethylenedioxythiophene)carbazole] which provided good binding of the enzyme to the substrate and positively affected on the catalytic activity of the protein. In order to evaluate properties of the designed biosensor, its response for various concentrations of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diamonnium sal (ABTS) was measured. The optical biosensor produced by presented method could find applications in many fields, i.e. for detection of phenolic compounds in food products and beverages, in industry for control of technological processes or for environmental monitoring

Antibacterial polymer coatings.

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

Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan

2009-09-01

A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores onmore » its surface.« less

Assessment of relative flammability and thermochemical properties of some thermoplastic materials

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Parker, J. A.

1977-01-01

Thermomechanical properties, flammability, oxygen index, relative toxicity of pyrolysis effluents, and char yields were studied for 12 advanced polymers which are candidates for use in aircraft interiors as decorative films, compression- and injection-molded parts and thermoplastic parts. Polymers sampled included polyphenylene sulfide, 9,9 bis (4-hydroxyphenol) fluorene polycarbonate-poly (dimethylsiloxane), polyether sulfone, polyvinyl fluoride and polyvinylidene fluoride. Availability of these samples, whether in commercial form or in test quantities, is specified. An estimate of relative fire resistance for the materials was obtained; the five polymers listed above were found to be the most fire resistant of the 12 sampled.

New monomers for high performance polymers

NASA Technical Reports Server (NTRS)

Gratz, Roy F.

1993-01-01

This laboratory has been concerned with the development of new polymeric materials with high thermo-oxidative stability for use in the aerospace and electronics industries. Currently, there is special emphasis on developing matrix resins and composites for the high speed civil transport (HSCT) program. This application requires polymers that have service lifetimes of 60,000 hr at 350 F (177 C) and that are readily processible into void-free composites, preferably by melt-flow or powder techniques that avoid the use of high boiling solvents. Recent work has focused on copolymers which have thermally stable imide groups separated by flexible arylene ether linkages, some with trifluoromethyl groups attached to the aromatic rings. The presence of trifluoromethyl groups in monomers and polymers often improves their solubility and processibility. The goal of this research was to synthesize several new monomers containing pendant trifluoromethyl groups and to incorporate these monomers into new imide/arylene ether copolymers. Initially, work was begun on the synthesis of three target compounds. The first two, 3,5-dihydroxybenzo trifluoride and 3-amino 5-hydroxybenzo trifluoride, are intermediates in the synthesis of more complex monomers. The third, 3,5-bis (3-amino-phenoxy) benzotrifluoride, is an interesting diamine that could be incorporated into a polyimide directly.

Photophysical and electrical properties of polyphenylquinolines containing carbazole or indolo[3,2-b]carbazole fragments as new optoelectronic materials

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

Svetlichnyi, V. M., E-mail: valsvet@hq.macro.ru; Aleksandrova, E. L.; Myagkova, L. A.

2011-10-15

Photophysical and electrical properties of new synthesized 2,6-polyphenylquinolines (PPQs) containing an oxygen or phenylamine bridging group between quinoline cycles and, as an arylene radical, alkylated derivatives of carbazole or indolo[3,2-b]carbazole are studied. It is shown that the photosensitivity for new PPQs is 10{sup 4}-10{sup 5} cm{sup 2}/J and the photogeneration quantum yield of free carriers is as high as 0.15. Photophysical parameters increase with the phenylamine bridging group in place of the oxygen one and when using indolocarbazole instead of carbazole. It is found that a film of polyphenylquinoline containing an oxygen bridging group and an alkylcarbazole fragment in themore » polymer repeat unit exhibits 'white' luminescence. Both electron and hole transport with a mobility of {approx}10{sup -6} cm{sup 2}/(V s) are detected in films of all studied polymers. The conductivity value and type can be controlled by varying the chemical structure of the (oxygen or phenylamine) bridging group between PPQ cycles and by choosing carbazole or indolo[3,2-b]carbazole derivatives as an arylene radical.« less

Polyelectrolyte brushes: a novel stable lubrication system in aqueous conditions.

PubMed

Kobayashi, Motoyasu; Terada, Masami; Takahara, Atsushi

2012-01-01

Surface-initiated controlled radical copolymerizations of 2-dimethylaminoethyl methacrylate (DMAEMA), 2-(methacryloyloxy)ethyl phosphorylcholine (MPC), 2-(methacryloyloxy)ethyltrimethylammonium chloride) (MTAC), and 3-sulfopropyl methacrylate potassium salt (SPMK) were carried out on a silicon wafer and glass ball to prepare polyelectrolyte brushes with excellent water wettability. The frictional coefficient of the polymer brushes was recorded on a ball-on-plate type tribometer by linear reciprocating motion of the brush specimen at a selected velocity of 1.5 x 10(-3) m s-1 under a normal load of 0.49 N applied to the stationary glass ball (d = 10 mm) at 298 K. The poly(DMAEMA-co-MPC) brush partially cross-linked by bis(2-iodoethoxy)ethane maintained a relatively low friction coefficient around 0.13 under humid air (RH > 75%) even after 200 friction cycles. The poly(SPMK) brush revealed an extremely low friction coefficient around 0.01 even after 450 friction cycles. We supposed that the abrasion of the brush was prevented owing to the good affinity of the poly(SPMK) brush for water forming a water lubrication layer, and electrostatic repulsive interactions among the brushes bearing sulfonic acid groups. Furthermore, the poly(SPMK-co-MTAC) brush with a chemically cross-linked structure showed a stable low friction coefficient in water even after 1400 friction cycles under a normal load of 139 MPa, indicating that the cross-linking structure improved the wear resistance of the brush layer.

Effect of Micellization on the Adsorption Kinetics of Polymeric Surfactants to the Solid/Water Interface

NASA Astrophysics Data System (ADS)

Toomey, Ryan; Tirrell, Matthew

2002-03-01

We have studied the adsorption kinetics of two classes of hydrophobic/ionic diblock copolymer surfactants in aqueous environments to understand the role that micellization plays in the adsorption process. The two systems studied were poly(t-butyl styrene)-block-poly(styrene sulfonate) (PtBS-b-PSS) and polystyrene-block-poly(acrylic acid) (PS-b-PAA). It is found that by changing the hydrophobicity of the adsorbing surface, micelle adsorption can be turned on or off. When micelle adsorption occurs, the initial adsorption rate is always slower than the supply rate of micelles to the surface, indicating “reaction-limited” adsorption. Since these micelles have essentially frozen cores, the adsorption cannot be explained by the release of unimers from the micelles. Rather, micelles directly adsorb, and they have to overcome the potential barrier imposed by their corona. Due to micellization, the adsorption rate can also be a complex function of ionic strength. A regime was found where the initial adsorption rate decreased with increasing ionic strength. This anomaly can be explained by the onset of micellization. As the salt concentration is increased, more micelles are formed. However micelles adsorb roughly an order of magnitude slower than free chains. Therefore, if increasing the ionic strength produces more micelles, the adsorption rate will simultaneously decrease.

Investigations on the effects of electrode materials on the device characteristics of ferroelectric memory thin film transistors fabricated on flexible substrates

NASA Astrophysics Data System (ADS)

Yang, Ji-Hee; Yun, Da-Jeong; Seo, Gi-Ho; Kim, Seong-Min; Yoon, Myung-Han; Yoon, Sung-Min

2018-03-01

For flexible memory device applications, we propose memory thin-film transistors using an organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] gate insulator and an amorphous In-Ga-Zn-O (a-IGZO) active channel. The effects of electrode materials and their deposition methods on the characteristics of memory devices exploiting the ferroelectric field effect were investigated for the proposed ferroelectric memory thin-film transistors (Fe-MTFTs) at flat and bending states. It was found that the plasma-induced sputtering deposition and mechanical brittleness of the indium-tin oxide (ITO) markedly degraded the ferroelectric-field-effect-driven memory window and bending characteristics of the Fe-MTFTs. The replacement of ITO electrodes with metal aluminum (Al) electrodes prepared by plasma-free thermal evaporation greatly enhanced the memory device characteristics even under bending conditions owing to their mechanical ductility. Furthermore, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) was introduced to achieve robust bending performance under extreme mechanical stress. The Fe-MTFTs using PEDOT:PSS source/drain electrodes were successfully fabricated and showed the potential for use as flexible memory devices. The suitable choice of electrode materials employed for the Fe-MTFTs is concluded to be one of the most important control parameters for highly functional flexible Fe-MTFTs.

Redox-controlled molecular permeability of composite-wall microcapsules

NASA Astrophysics Data System (ADS)

Ma, Yujie; Dong, Wen-Fei; Hempenius, Mark A.; Möhwald, Helmuth; Julius Vancso, G.

2006-09-01

Many smart materials in bioengineering, nanotechnology and medicine allow the storage and release of encapsulated drugs on demand at a specific location by an external stimulus. Owing to their versatility in material selection, polyelectrolyte multilayers are very promising systems in the development of microencapsulation technologies with permeation control governed by variations in the environmental conditions. Here, organometallic polyelectrolyte multilayer capsules, composed of polyanions and polycations of poly(ferrocenylsilane) (PFS), are introduced. Their preparation involved layer-by-layer self-assembly onto colloidal templates followed by core removal. PFS polyelectrolytes feature redox-active ferrocene units in the main chain. Incorporation of PFS into the capsule walls allowed us to explore the effects of a new stimulus, that is, changing the redox state, on capsule wall permeability. The permeability of these capsules could be sensitively tuned via chemical oxidation, resulting in a fast capsule expansion accompanied by a drastic permeability increase in response to a very small trigger. The substantial swelling could be suppressed by the application of an additional coating bearing common redox-inert species of poly(styrene sulfonate) (PSS-) and poly(allylamine hydrochloride) (PAH+) on the outer wall of the capsules. Hence, we obtained a unique capsule system with redox-controlled permeability and swellability with a high application potential in materials as well as in bioscience.

Bioinspired Transparent Laminated Composite Film for Flexible Green Optoelectronics.

PubMed

Lee, Daewon; Lim, Young-Woo; Im, Hyeon-Gyun; Jeong, Seonju; Ji, Sangyoon; Kim, Yong Ho; Choi, Gwang-Mun; Park, Jang-Ung; Lee, Jung-Yong; Jin, Jungho; Bae, Byeong-Soo

2017-07-19

Herein, we report a new version of a bioinspired chitin nanofiber (ChNF) transparent laminated composite film (HCLaminate) made of siloxane hybrid materials (hybrimers) reinforced with ChNFs, which mimics the nanofiber-matrix structure of hierarchical biocomposites. Our HCLaminate is produced via vacuum bag compressing and subsequent UV-curing of the matrix resin-impregnated ChNF transparent paper (ChNF paper). It is worthwhile to note that this new type of ChNF-based transparent substrate film retains the strengths of the original ChNF paper and compensates for ChNF paper's drawbacks as a flexible transparent substrate. As a result, compared with high-performance synthetic plastic films, such as poly(ethylene terephthalate), poly(ether sulfone), poly(ethylene naphthalate), and polyimide, our HCLaminate is characterized to exhibit extremely smooth surface topography, outstanding optical clarity, high elastic modulus, high dimensional stability, etc. To prove our HCLaminate as a substrate film, we use it to fabricate flexible perovskite solar cells and a touch-screen panel. As far as we know, this work is the first to demonstrate flexible optoelectronics, such as flexible perovskite solar cells and a touch-screen panel, actually fabricated on a composite film made of ChNF. Given its desirable macroscopic properties, we envision our HCLaminate being utilized as a transparent substrate film for flexible green optoelectronics.

Zwitterionic polymer functionalization of polysulfone membrane with improved antifouling property and blood compatibility by combination of ATRP and click chemistry.

PubMed

Xiang, Tao; Lu, Ting; Xie, Yi; Zhao, Wei-Feng; Sun, Shu-Dong; Zhao, Chang-Sheng

2016-08-01

The chemical compositions are very important for designing blood-contacting membranes with good antifouling property and blood compatibility. In this study, we propose a method combining ATRP and click chemistry to introduce zwitterionic polymer of poly(sulfobetaine methacrylate) (PSBMA), negatively charged polymers of poly(sodium methacrylate) (PNaMAA) and/or poly(sodium p-styrene sulfonate) (PNaSS), to improve the antifouling property and blood compatibility of polysulfone (PSf) membranes. Attenuated total reflectance-Fourier transform infrared spectra, X-ray photoelectron spectroscopy and water contact angle results confirmed the successful grafting of the functional polymers. The antifouling property and blood compatibility of the modified membranes were systematically investigated. The zwitterionic polymer (PSBMA) grafted membranes showed good resistance to protein adsorption and bacterial adhesion; the negatively charged polymer (PNaSS or PNaMAA) grafted membranes showed improved blood compatibility, especially the anticoagulant property. Moreover, the PSBMA/PNaMAA modified membrane showed both antifouling property and anticoagulant property, and exhibited a synergistic effect in inhibiting blood coagulation. The functionalization of membrane surfaces by a combination of ATRP and click chemistry is demonstrated as an effective route to improve the antifouling property and blood compatibility of membranes in blood-contact. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Layer-by-layer polyelectrolyte-polyester hybrid microcapsules for encapsulation and delivery of hydrophobic drugs.

PubMed

Luo, Rongcong; Venkatraman, Subbu S; Neu, Björn

2013-07-08

A two-step process is developed to form layer-by-layer (LbL) polyelectrolyte microcapsules, which are able to encapsulate and deliver hydrophobic drugs. Spherical porous calcium carbonate (CaCO3) microparticles were used as templates and coated with a poly(lactic acid-co-glycolic acid) (PLGA) layer containing hydrophobic compounds via an in situ precipitation gelling process. PLGA layers that precipitated from N-methyl-2-pyrrolidone (NMP) had a lower loading and smoother surface than those precipitated from acetone. The difference may be due to different viscosities and solvent exchange dynamics. In the second step, the successful coating of multilayer polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) onto the PLGA coated CaCO3 microparticles was confirmed with AFM and ζ-potential studies. The release of a model hydrophobic drug, ibuprofen, from these hybrid microcapsules with different numbers of PAH/PSS layers was investigated. It was found that the release of ibuprofen decreases with increasing layer numbers demonstrating the possibility to control the release of ibuprofen with these novel hybrid microcapsules. Besides loading of hydrophobic drugs, the interior of these microcapsules can also be loaded with hydrophilic compounds and functional nanoparticles as demonstrated by loading with Fe3O4 nanoparticles, forming magnetically responsive dual drug releasing carriers.

Characterization of modified PVDF membrane by gamma irradiation for non-potable water reuse.

PubMed

Lim, Seung Joo; Kim, Tak-Hyun; Shin, In Hwan

2015-01-01

Poly(vinylidene fluorine) (PVDF) membranes were grafted by gamma-ray irradiation and were sulfonated by sodium sulfite to modify the surface of the membranes. The characteristics of the modified PVDF membranes were evaluated by the data of Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscope (FE-SEM), the contact angle of the membrane surface and the water permeability. From the results of FT-IR, XPS and FE-SEM, it was shown that the modified membranes were successfully grafted by gamma-ray irradiation and were sulfonated. The content of oxygen and sulfur increased with the monomer concentration, while the content of fluorine sharply decreased. The pore size of the modified membranes decreased after gamma-ray irradiation. The contact angle and the water permeability showed that the hydrophilicity of the modified membranes played a role in determining the membrane performance. The feasibility study of the modified PVDF membranes for using non-potable water reuse were carried out using a laboratory-scale microfiltration system. Grey wastewater was used as the influent in the filtration unit, and permeate quality satisfied non-potable water reuse guidelines in the Republic of Korea.

Starch derivative-based superabsorbent with integration of water-retaining and controlled-release fertilizers.

PubMed

Zhong, Kang; Lin, Zuan-Tao; Zheng, Xi-Liang; Jiang, Gang-Biao; Fang, Yu-Sheng; Mao, Xiao-Yun; Liao, Zong-Wen

2013-02-15

Phosphate rock (PHR), a traditional fertilizer, is abundant, but is hard to be utilized by plants. To improve the utilization of PHR, and to integrate water-retaining and controlled-release fertilizers, an agricultural superabsorbent polymer based on sulfonated corn starch/poly (acrylic acid) embedding phosphate rock (SCS/PAA/PHR) was prepared. PHR can be suspended and well-dispersed in SCS/PAA by sulfonated corn starch (SCS). PHR and KOH were mixed in acrylic acid solution to provide phosphorus (P) and potassium (K) nutrients, respectively. Impacts on water absorption capacity of the superabsorbent were investigated. The maximum swelling capacity in distilled water or 0.9 wt.% (weight percent) NaCl solution reached 498 g g(-1) and 65 g g(-1) (water/prepared dry superabsorbent) respectively. Moreover, release behaviours of P and K in SCS/PAA/PHR were also investigated. The results showed that SCS/PAA/PHR possessed excellent sustained-release property of plant nutrient, and the SCS/PAA could improve the P release greatly. Besides, the XPS analysis was employed to study the relationship between PHR and superabsorbent polymer. Copyright © 2012 Elsevier Ltd. All rights reserved.

Chemical and radiation crosslinked polymer electrolyte membranes prepared from radiation-grafted ETFE films for DMFC applications

NASA Astrophysics Data System (ADS)

Chen, Jinhua; Asano, Masaharu; Yamaki, Tetsuya; Yoshida, Masaru

To develop a highly chemically stable polymer electrolyte membrane for application in a direct methanol fuel cell (DMFC), doubly crosslinked membranes were prepared by chemical crosslinking using bifunctional monomers, such as divinylbenzene (DVB) and bis(p, p-vinyl phenyl) ethane (BVPE), and by radiation crosslinking. The membranes were prepared by grafting of m, p-methylstyrene (MeSt) and p-tert-butylstyrene (tBuSt) into poly(ethylene- co-tetrafluoroethylene) (ETFE) films and subsequent sulfonation. The effects of the DVB and BVPE crosslinkers on the grafting kinetics and the properties of the prepared membranes, such as water uptake, proton conductivity and chemical stability were investigated. Radiation crosslinking was introduced by irradiation of the ETFE base film, the grafted film or the sulfonated membrane. The membrane crosslinked by DVB and BVPE crosslinkers and post-crosslinked by γ-ray irradiation of the corresponding grafted film possessed the highest chemical stability among the prepared membranes, a significantly lower methanol permeability compared to Nafion ® membranes, and a better DMFC performance for high methanol feed concentration. Therefore, this doubly crosslinked membrane was promising for application in a DMFC where relatively high methanol concentration could be fed.

Robust Multilayer Graphene-Organic Frameworks for Selective Separation of Monovalent Anions.

PubMed

Zhao, Yan; Zhu, Jiajie; Li, Jian; Zhao, Zhijuan; Charchalac Ochoa, Sebastian Ignacio; Shen, Jiangnan; Gao, Congjie; Van der Bruggen, Bart

2018-05-30

The chemical and mechanical stability of graphene nanosheets was used in this work to design a multilayer architecture of graphene, grafted with sulfonated 4,4'-diaminodiphenyl sulfone (SDDS). Quaternized poly(phenylene oxide) (QPPO) was synthesized and mixed with SDDS (rGO-SDDS-rGO@QPPO), yielding a multilayer graphene-organic framework (MGOF) with positive as well as negative functional groups that can be applied as a versatile electrodriven membrane in electrodialysis (ED). Multilayer graphene-organic frameworks are a new class of multilayer structures, with an architecture having a tunable interlayer spacing connected by cationic polymer material. MGOF membranes were demonstrated to allow for an excellent selective separation of monovalent anions in aqueous solution. Furthermore, different types of rGO-SDDS-rGO@QPPO membranes were found to have a good mechanical strength, with a tensile strength up to 66.43 MPa. The membrane (rGO-SDDS-rGO@QPPO-2) also has a low surface electric resistance (2.79 Ω·cm 2 ) and a low water content (14.5%) and swelling rate (4.7%). In addition, the selective separation between Cl - and SO 4 2- of the MGOF membranes could be as high as 36.6%.

Ion Exchange Polymeric Coatings for Selective Capacitive Deionization

NASA Astrophysics Data System (ADS)

Jain, Amit; Kim, Jun; Li, Qilin; Verduzco, Rafael

Capacitive deionization (CDI) is an energy-efficient technology for adsorbing and removing scalants and foulants from water by utilizing electric potential between porous carbon electrodes. Currently, industrial application of CDI is limited to low salinity waters due to the limited absorption capacities of carbon electrodes. However, CDI can potentially be used as a low-cost approach to selectively remove divalent ions from high salinity water. Divalent ions such as sulfonates and carbonates cause scaling and thus performance deterioration of membrane-based desalination systems. In this work, we investigated ion-exchange polymer coatings for use in a membrane capacitive deionization (MCDI) process for selective removal of divalent ions. Poly-Vinyl Alcohol (PVA) base polymer was crosslinked and charged using sulfo-succinic acid (SSA) to give a cation exchange layer. 50 um thick standalone polymer films had a permeability of 4.25*10-7 cm2/s for 10mM NaCl feed. Experiments on electrodes with as low as 10 υm thick coating of cation exchange polymer are under progress and will be evaluated on the basis of their selective salt removal efficiency and charge efficiency, and in future we will extend this work to sulfonated block copolymers and anion exchange polymers.

Morphological and physical characterization of poly(styrene-isobutylene-styrene) block copolymers and ionomers thereof

NASA Astrophysics Data System (ADS)

Baugh, Daniel Webster, III

Poly(styrene-isobutylene-styrene) block copolymers made by living cationic polymerization using a difunctional initiator and the sequential monomer addition technique were analyzed using curve-resolution software in conjunction with high-resolution GPC. Fractional precipitation and selective solvent extraction were applied to a representative sample in order to confirm the identity of contaminating species. The latter were found to be low molecular weight polystyrene homopolymer, diblock copolymer, and higher molecular weight segmented block copolymers formed by intermolecular electrophilic aromatic substitution linking reactions occurring late in the polymerization of the styrene outer blocks. Solvent-cast films of poly(styrene-isobutylene-styrene) (PS-PIB-PS) block copolymers and block ionomers were analyzed using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Four block copolymer samples with center block molecular weights of 52,000 g/mol and PS volume fractions (o sbPS) ranging from 0.17 to 0.31 were studied. All samples exhibited hexagonally packed cylinders of PS within the PIB matrix. Cylinder spacing was in the range 32 to 36 nm for most samples, while cylinder diameters varied from 14 to 21 nm. Porod analysis of the scattering data indicated the presence of isolated phase mixing and sharp phase boundaries. PS-PIB-PS block copolymers and ionomers therefrom were analyzed using dynamic mechanical analysis (DMA) and tensile testing. The study encompassed five block copolymer samples with similar PIB center blocks with molecular weights of approx52,000 g/mol and PS weight fractions ranging from 0.127 to 0.337. Ionomers were prepared from two of these materials by lightly sulfonating the PS outer blocks. Sulfonation levels varied from 1.7 to 4.7 mol % and the sodium and potassium neutralized forms were compared to the parent block copolymers. Dynamic mechanical analysis (DMA) of the block copolymer films indicated the existence of a third phase attributed to PIB chains near the PS domain interface which experience reduced mobility due to their firm attachment to the hard PS domain. The relative amount of this phase decreased in samples with larger PS blocks, while the temperature of the associated transition increased. Tensile testing showed increased tensile strength but decreased elongation at break with larger PS blocks. DMA of the ionomers indicated improved dynamic modulus at temperatures above 100spcirc$C. Tensile testing of the ionomers indicated slight improvements in tensile strength with little loss in elongation at break. PS-PIB-PS block copolymer ionomer (BCP01, center block molecular weight = 53,000 g/mole; 25.5 wt % polystyrene, 4.7% sulfonation of phenyl units, 100% neutralized with KOH) was compounded with various organic and inorganic acid salts of 2-ethylhexyl-p-dimethyl aminobenzoate (ODAB) to explore the efficacy of these compounds as ionic plasticizers. (Abstract shortened by UMI.)

Polymer electrolyte membrane assembly for fuel cells

NASA Technical Reports Server (NTRS)

Yen, Shiao-Ping S. (Inventor); Kindler, Andrew (Inventor); Yavrouian, Andre (Inventor); Halpert, Gerald (Inventor)

2002-01-01

An electrolyte membrane for use in a fuel cell can contain sulfonated polyphenylether sulfones. The membrane can contain a first sulfonated polyphenylether sulfone and a second sulfonated polyphenylether sulfone, wherein the first sulfonated polyphenylether and the second sulfonated polyphenylether sulfone have equivalent weights greater than about 560, and the first sulfonated polyphenylether and the second sulfonated polyphenylether sulfone also have different equivalent weights. Also, a membrane for use in a fuel cell can contain a sulfonated polyphenylether sulfone and an unsulfonated polyphenylether sulfone. Methods for manufacturing a membrane electrode assemblies for use in fuel cells can include roughening a membrane surface. Electrodes and methods for fabricating such electrodes for use in a chemical fuel cell can include sintering an electrode. Such membranes and electrodes can be assembled into chemical fuel cells.

Polymer electrolyte membrane assembly for fuel cells

NASA Technical Reports Server (NTRS)

Yen, Shiao-Ping S. (Inventor); Kindler, Andrew (Inventor); Yavrouian, Andre (Inventor); Halpert, Gerald (Inventor)

2000-01-01

An electrolyte membrane for use in a fuel cell can contain sulfonated polyphenylether sulfones. The membrane can contain a first sulfonated polyphenylether sulfone and a second sulfonated polyphenylether sulfone, wherein the first sulfonated polyphenylether and the second sulfonated polyphenylether sulfone have equivalent weights greater than about 560, and the first sulfonated polyphenylether and the second sulfonated polyphenylether sulfone also have different equivalent weights. Also, a membrane for use in a fuel cell can contain a sulfonated polyphenylether sulfone and an unsulfonated polyphenylether sulfone. Methods for manufacturing a membrane electrode assemblies for use in fuel cells can include roughening a membrane surface. Electrodes and methods for fabricating such electrodes for use in a chemical fuel cell can include sintering an electrode. Such membranes and electrodes can be assembled into chemical fuel cells.

Structural, morphological and optical properties of PEDOT:PSS/QDs nano-composite films prepared by spin-casting

NASA Astrophysics Data System (ADS)

Najeeb, Mansoor Ani; Abdullah, Shahino Mah; Aziz, Fakhra; Ahmad, Zubair; Rafique, Saqib; Wageh, S.; Al-Ghamdi, Ahmed A.; Sulaiman, Khaulah; Touati, Farid; Shakoor, R. A.; Al-Thani, N. J.

2016-09-01

This paper describes the structural, morphological and optical properties of the nano-composite of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and quantum dots (QDs). The ZnSe and CdSe QDs have been synthesized, with the aid of Mercaptoacetic acid (MAA), by a colloidal method with an average size of 5 to 7 nm. QDs have been embedded in PEDOT:PSS using a simple solution processing approach and has been deposited as thin films by spin coating technique. The QDs embedded PEDOT:PSS enhances the light absorption spectra of samples, prominently in terms of absorption intensity which may consequently improve sensitivity of the optoelectronic devices.

Stretchable Dry Electrodes with Concentric Ring Geometry for Enhancing Spatial Resolution in Electrophysiology.

PubMed

Wang, Kaiping; Parekh, Udit; Pailla, Tejaswy; Garudadri, Harinath; Gilja, Vikash; Ng, Tse Nga

2017-10-01

The multichannel concentric-ring electrodes are stencil printed on stretchable elastomers modified to improve adhesion to skin and minimize motion artifacts for electrophysiological recordings of electroencephalography, electromyography, and electrocardiography. These dry electrodes with a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate interface layer are optimized to show lower noise level than that of commercial gel disc electrodes. The concentric ring geometry enables Laplacian filtering to pinpoint the bioelectric potential source with spatial resolution determined by the ring distance. This work shows a new fabrication approach to integrate and create designs that enhance spatial resolution for high-quality electrophysiology monitoring devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polyelectrolyte bundles

NASA Astrophysics Data System (ADS)

Limbach, H. J.; Sayar, M.; Holm, C.

2004-06-01

Using extensive Molecular Dynamics simulations we study the behavior of polyelectrolytes with hydrophobic side chains, which are known to form cylindrical micelles in aqueous solution. We investigate the stability of such bundles with respect to hydrophobicity, the strength of the electrostatic interaction, and the bundle size. We show that for the parameter range relevant for sulfonated poly-para-phenylenes (PPP) one finds a stable finite bundle size. In a more generic model we also show the influence of the length of the precursor oligomer on the stability of the bundles. We also point out that our model has close similarities to DNA solutions with added condensing agents, hinting to the possibility that the size of DNA aggregates is under certain circumstances thermodynamically limited.

Perfluorinated alkyl substances (PFASs) in northern Spain municipal solid waste landfill leachates.

PubMed

Fuertes, I; Gómez-Lavín, S; Elizalde, M P; Urtiaga, A

2017-02-01

Landfill leachates have been recognized as significant secondary sources of poly- and perfluoroalkyl substances (PFASs). This study presents data on the occurrence and concentration of 11 perfluoroalkyl carboxylates (PFCAs) and 5 perfluoroalkyl sulfonates (PFSAs) in leachates from 4 municipal solid waste landfill sites located across northern Spain. To the best of our knowledge, this is the first report of the presence of PFASs in Spanish landfill leachates. Two of the landfill sites applied on-site treatment using membrane bioreactors (MBR), and its effect on PFASs occurrence is also reported. Total PFASs (∑PFASs) in raw leachates reached 1378.9 ng/L, while in treated samples ∑PFASs was approximately two-fold (3162.3 ng/L). PFCAs accounted for the majority of the detected PFASs and perfluorooctanoic acid (PFOA) was the dominant compound in raw leachates (42.6%), followed by shorter chain PFHxA (30.1%), PFPeA and PFBA. The age of the sites might explain the PFASs pattern found in raw leachates as all of them were stabilized leachates. However, PFASs profile was different in treated samples where the most abundant compound was PFHxA (26.5%), followed by linear perfluorobutane sulfonate (L-PFBS) (18.7%) and PFOA (17.7%). The overall increase of the PFASs content as well as the change in the PFASs profile after the MBR treatment, could be explained by the possible degradation of PFASs precursors such as fluorotelomer alcohols or fluorotelomer sulfonates. Using the volume of leachates generated in the landfill sites, that served 1.8 million people, the discharge of 16 ∑PFASs contained in the landfill leachates was estimated as 1209 g/year. Copyright © 2016 Elsevier Ltd. All rights reserved.

Novel Pendant Benzene Disulfonic Acid Blended SPPO Membranes for Alkali Recovery: Fabrication and Properties.

PubMed

Mondal, Abhishek N; Dai, Chunhua; Pan, Jiefeng; Zheng, Chunlei; Hossain, Md Masem; Khan, Muhammad Imran; Wu, Liang; Xu, Tongwen

2015-07-29

To reconcile the trade-off between separation performance and availability of desired material for cation exchange membranes (CEMs), we designed and successfully prepared a novel sulfonated aromatic backbone-based cation exchange precursor named sodium 4,4'-(((((3,3'-disulfo-[1,1'-biphenyl]-4,4'-diyl)bis(oxy)) bis(4,1-phenylene))bis(azanediyl))bis(methylene))bis(benzene-1,3-disulfonate) [DSBPB] from 4,4'-bis(4-aminophenoxy)-[1,1'-biphenyl]-3,3'-disulfonic acid [BAPBDS] by a three-step procedure that included sulfonation, Michael condensation followed by reduction. Prepared DSBPB was used to blend with sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) to get CEMs for alkali recovery via diffusion dialysis. Physiochemical properties and electrochemical performance of prepared membranes can be tuned by varying the dosage of DSBPB. All the thermo-mechanical properties like DMA and TGA were investigated along with water uptake (WR), ion exchange capacity (IEC), dimensional stability, etc. The effect of DSBPB was discussed in brief in connection with alkali recovery and ion conducting channels. The SPPO/DSBPB membranes possess both high water uptake as well as ion exchange capacity with high thermo-mechanical stability. At 25 °C the dialysis coefficients (UOH) appeared to be in the range of 0.0048-0.00814 m/h, whereas the separation factor (S) ranged from 12.61 to 36.88 when the membranes were tested for base recovery in Na2WO4/NaOH waste solution. Prepared membranes showed much improved DD performances compared to traditional SPPO membrane and possess the potentiality to be a promising candidate for alkali recovery via diffusion dialysis.

The effect of the hole injection layer on the performance of single layer organic light-emitting diodes

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

Wenjin, Zeng; Ran, Bi; Hongmei, Zhang, E-mail: iamhmzhang@njupt.edu.cn, E-mail: iamwhuang@njupt.edu.cn

2014-12-14

Efficient single-layer organic light-emitting diodes (OLEDs) were reported based on a green fluorescent dye 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7–tetramethyl-1H,5H,11H-(1) benzopyropyrano (6,7-8-I,j)quinolizin-11-one (C545T). Herein, poly(3,4-ethylenedioxy thiophene) poly(styrene sulfonate) were, respectively, applied as the injection layer for comparison. The hole transport properties of the emission layer with different hole injection materials are well investigated via current-voltage measurement. It was clearly found that the hole injection layers (HILs) play an important role in the adjustment of the electron/hole injection to attain transport balance of charge carriers in the single emission layer of OLEDs with electron-transporting host. The layer of tris-(8-hydroxyquinoline) aluminum played a dual role of hostmore » and electron-transporting materials within the emission layer. Therefore, appropriate selection of hole injection layer is a key factor to achieve high efficiency OLEDs with single emission layer.« less

Tessellated gold nanostructures from Au144(SCH2CH2Ph)60 molecular precursors and their use in organic solar cell enhancement

NASA Astrophysics Data System (ADS)

Bauld, Reg; Hesari, Mahdi; Workentin, Mark S.; Fanchini, Giovanni

2014-06-01

We report for the first time the fabrication of nanocomposite hole-blocking layers consisting of poly-3,4-ethylene-dioxythiophene:poly-styrene-sulfonate (PEDOT:PSS) thin films incorporating networks of gold nanoparticles assembled from Au144(SCH2CH2Ph)60, a molecular gold precursor. These thin films can be prepared reproducibly on indium tin oxide by spinning on it Au144(SCH2CH2Ph)60 solutions in chlorobenzene, annealing the resulting thin film at 400 °C, and subsequently spinning PEDOT:PSS on top. The use of our nanocomposite hole-blocking layers for enhancing the photoconversion efficiency of bulk heterojunction organic solar cells is demonstrated. By varying the concentration of Au144(SCH2CH2Ph)60 in the starting solution and the annealing time, different gold nanostructures were obtained ranging from individual gold nanoparticles (AuNPs) to tessellated networks of gold nanostructures (Tess-AuNPs). Improvement in organic solar cell efficiencies up to 10% relative to a reference cell is demonstrated with Tess-AuNPs embedded in PEDOT:PSS.

Acidity-Controlled Conducting Polymer Films for Organic Thermoelectric Devices with Horizontal and Vertical Architectures

PubMed Central

Lee, Woongki; Song, Myeonghun; Park, Soohyung; Nam, Sungho; Seo, Jooyeok; Kim, Hwajeong; Kim, Youngkyoo

2016-01-01

Organic thermoelectric devices (OTEDs) are recognized one of the next generation energy conversion platforms because of their huge potentials for securing electricity continuously from even tiny heat sources in our daily life. The advantage of OTEDs can be attributable to the design freedom in device shapes and the low-cost fabrication by employing solution coating processes at low temperatures. As one of the major OTE materials to date, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has been used, but no study has been yet carried out on its acidity control even though the acidic components in OTEDs can seriously affect the device performance upon operation. Here we demonstrate that the addition of aniline (a weak base) can control the acidity of PEDOT:PSS and enhance the performance of OTEDs. In particular, the vertical OTEDs with aniline-doped PEDOT:PSS films (active area = 1.0 cm2) could continuously generate electricity (0.06 nW) even at low temperatures (<38 °C) when they were mounted on a desk lamp (power = 24 W). PMID:27667013

Heuristic method of fabricating counter electrodes in dye-sensitized solar cells based on a PEDOT:PSS layer as a catalytic material

NASA Astrophysics Data System (ADS)

Edalati, Sh; Houshangi far, A.; Torabi, N.; Baneshi, Z.; Behjat, A.

2017-02-01

Poly(3,4-ethylendioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was deposited on a fluoride-doped tin oxide glass substrate using a heuristic method to fabricate platinum-free counter electrodes for dye-sensitized solar cells (DSSCs). In this heuristic method a thin layer of PEDOT:PPS is obtained by spin coating the PEDOT:PSS on a Cu substrate and then removing the substrate with FeCl3. The characteristics of the deposited PEDOT:PSS were studied by energy dispersive x-ray analysis and scanning electron microscopy, which revealed the micro-electronic specifications of the cathode. The aforementioned DSSCs exhibited a solar conversion efficiency of 3.90%, which is far higher than that of DSSCs with pure PEDOT:PSS (1.89%). This enhancement is attributed not only to the micro-electronic specifications but also to the HNO3 treatment through our heuristic method. The results of cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and Tafel polarization plots show the modified cathode has a dual function, including excellent conductivity and electrocatalytic activity for iodine reduction.

Synthesis of zinc oxide porous structures by anodization with water as an electrolyte

NASA Astrophysics Data System (ADS)

Shetty, Amitha; Nanda, Karuna Kar

2012-10-01

We report a simple, reliable and one-step method of synthesizing ZnO porous structures at room temperature by anodization of zinc (Zn) sheet with water as an electrolyte and graphite as a counter electrode. We observed that the de-ionized (DI) water used in the experiment is slightly acidic (pH=5.8), which is due to the dissolution of carbon dioxide from the atmosphere forming carbonic acid. Porous ZnO is characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and photoluminescence (PL) studies. The current-transient measurement is carried out using a Gamry Instruments Reference 3000 and the thickness of the deposited films is measured using a Dektak surface profilometer. The PL, Raman and X-ray photoelectron spectroscopy are used to confirm the presence of ZnO phase. We have demonstrated that the hybrid structures of ZnO and poly (3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) exhibit good rectifying characteristics. The evaluated barrier height and the ideality factor are 0.45 eV and 3.6, respectively.

Localized entrapment of green fluorescent protein within nanostructured polymer films

NASA Astrophysics Data System (ADS)

Ankner, John; Kozlovskaya, Veronika; O'Neill, Hugh; Zhang, Qiu; Kharlampieva, Eugenia

2012-02-01

Protein entrapment within ultrathin polymer films is of interest for applications in biosensing, drug delivery, and bioconversion, but controlling protein distribution within the films is difficult. We report on nanostructured protein/polyelectrolyte (PE) materials obtained through incorporation of green fluorescent protein (GFP) within poly(styrene sulfonate)/poly(allylamine hydrochloride) multilayer films assembled via the spin-assisted layer-by-layer method. By using deuterated GFP as a marker for neutron scattering contrast we have inferred the architecture of the films in both normal and lateral directions. We find that films assembled with a single GFP layer exhibit a strong localization of the GFP without intermixing into the PE matrix. The GFP volume fraction approaches the monolayer density of close-packed randomly oriented GFP molecules. However, intermixing of the GFP with the PE matrix occurs in multiple-GFP layer films. Our results yield new insight into the organization of immobilized proteins within polyelectrolyte matrices and open opportunities for fabrication of protein-containing films with well-organized structure and controllable function, a crucial requirement for advanced sensing applications.

Self-Consistent Charge Density Functional Tight-Binding Study of Poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) Ammonia Gas Sensor.

PubMed

Marutaphan, Ampaiwan; Seekaew, Yotsarayuth; Wongchoosuk, Chatchawal

2017-12-01

Geometric and electronic properties of 3,4-ethylenedioxythiophene (EDOT), styrene sulfonate (SS), and EDOT: SS oligomers up to 10 repeating units were studied by the self-consistent charge density functional tight-binding (SCC-DFTB) method. An application of PEDOT:PSS for ammonia (NH 3 ) detection was highlighted and investigated both experimentally and theoretically. The results showed an important role of H-bonds in EDOT:SS oligomers complex conformation. Electrical conductivity of EDOT increased with increasing oligomers and doping SS due to enhancement of π conjugation. Printed PEDOT:PSS gas sensor exhibited relatively high response and selectivity to NH 3 . The SCC-DFTB calculation suggested domination of direct charge transfer process in changing of PEDOT:PSS conductivity upon NH 3 exposure at room temperature. The NH 3 molecules preferred to bind with PEDOT:PSS via physisorption. The most favorable adsorption site for PEDOT:PSS-NH 3 interaction was found to be at the nitrogen atom of NH 3 and hydrogen atoms of SS with an average optimal binding distance of 2.00 Å.

Surface passivation investigation on ultra-thin atomic layer deposited aluminum oxide layers for their potential application to form tunnel layer passivated contacts

NASA Astrophysics Data System (ADS)

Xin, Zheng; Ling, Zhi Peng; Nandakumar, Naomi; Kaur, Gurleen; Ke, Cangming; Liao, Baochen; Aberle, Armin G.; Stangl, Rolf

2017-08-01

The surface passivation performance of atomic layer deposited ultra-thin aluminium oxide layers with different thickness in the tunnel layer regime, i.e., ranging from one atomic cycle (∼0.13 nm) to 11 atomic cycles (∼1.5 nm) on n-type silicon wafers is studied. The effect of thickness and thermal activation on passivation performance is investigated with corona-voltage metrology to measure the interface defect density D it(E) and the total interface charge Q tot. Furthermore, the bonding configuration variation of the AlO x films under various post-deposition thermal activation conditions is analyzed by Fourier transform infrared spectroscopy. Additionally, poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) is used as capping layer on ultra-thin AlO x tunneling layers to further reduce the surface recombination current density to values as low as 42 fA/cm2. This work is a useful reference for using ultra-thin ALD AlO x layers as tunnel layers in order to form hole selective passivated contacts for silicon solar cells.

Polyelectrolyte brushes in mixed ionic medium studied via intermolecular forces

NASA Astrophysics Data System (ADS)

Farina, Robert; Laugel, Nicolas; Pincus, Philip; Tirrell, Matthew

2011-03-01

The vast uses and applications of polyelectrolyte brushes make them an attractive field of research especially with the growing interest in responsive materials. Polymers which respond via changes in temperature, pH, and ionic strength are increasingly being used for applications in drug delivery, chemical gating, etc. When polyelectrolyte brushes are found in either nature (e.g., surfaces of cartilage and mammalian lung interiors) or commercially (e.g., skin care products, shampoo, and surfaces of medical devices) they are always surrounded by mixed ionic medium. This makes the study of these brushes in varying ionic environments extremely relevant for both current and future potential applications. The polyelectrolyte brushes in this work are diblock co-polymers of poly-styrene sulfonate (N=420) and poly-t-butyl styrene (N=20) which tethers to a hydrophobic surface allowing for a purely thermodynamic study of the polyelectrolyte chains. Intermolecular forces between two brushes are measured using the SFA. As multi-valent concentrations are increased, the brushes collapse internally and form strong adhesion between one another after contact (properties not seen in a purely mono-valent environment).

Avidin/PSS membrane microcapsules with biotin-binding activity.

PubMed

Endo, Yoshihiro; Sato, Katsuhiko; Sugimoto, Kentaro; Anzai, Jun-ichi

2011-08-15

Polyelectrolyte microcapsules with avidin-poly(styrene sulfonate) (PSS) membrane were prepared by a layer-by-layer deposition technique. The uptake and release of biotin-labeled fluorescein (b-FITC) as well as immobilization of biotin-labeled glucose oxidase (b-GOx) to the microcapsule were studied. The polyelectrolyte microcapsules were prepared by coating the surface of calcium carbonate (CaCO(3)) microparticles with an avidin/PSS multilayer membrane, followed by dissolution of CaCO(3) core in an ethylenediaminetetraacetic acid solution. Inner and outer poly(allylamine)/PSS films were required to isolate the microcapsules, whereas microcapsules could not be formed without the support. The uptake of b-FITC into the microcapsule was highly enhanced through a strong binding of b-FITC to avidin as compared with the uptake of biotin-free FITC. Release of b-FITC from the microcapsule was accelerated upon addition of biotin due to a competitive binding of the added biotin to the binding site of avidin. Similarly, the surface of microcapsule was modified with b-GOx with retaining its catalytic activity. Copyright © 2011 Elsevier Inc. All rights reserved.

Acidity-Controlled Conducting Polymer Films for Organic Thermoelectric Devices with Horizontal and Vertical Architectures

NASA Astrophysics Data System (ADS)

Lee, Woongki; Song, Myeonghun; Park, Soohyung; Nam, Sungho; Seo, Jooyeok; Kim, Hwajeong; Kim, Youngkyoo

2016-09-01

Organic thermoelectric devices (OTEDs) are recognized one of the next generation energy conversion platforms because of their huge potentials for securing electricity continuously from even tiny heat sources in our daily life. The advantage of OTEDs can be attributable to the design freedom in device shapes and the low-cost fabrication by employing solution coating processes at low temperatures. As one of the major OTE materials to date, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has been used, but no study has been yet carried out on its acidity control even though the acidic components in OTEDs can seriously affect the device performance upon operation. Here we demonstrate that the addition of aniline (a weak base) can control the acidity of PEDOT:PSS and enhance the performance of OTEDs. In particular, the vertical OTEDs with aniline-doped PEDOT:PSS films (active area = 1.0 cm2) could continuously generate electricity (0.06 nW) even at low temperatures (<38 °C) when they were mounted on a desk lamp (power = 24 W).

Synthesis of HNTs@PEDOT composites via in situ chemical oxidative polymerization and their application in electrode materials

NASA Astrophysics Data System (ADS)

Wang, Fang; Zhang, Xianhong; Ma, Yuhong; Yang, Wantai

2018-01-01

The hybrid composite of poly(3,4-ethylenedioxythiophene) (PEDOT) and halloysite nanotubes (HNTs) was synthesized by a two-step process. First, poly(sodium styrene sulfonate) (PSSNa) was grafted onto HNTs via surface initiated atom transfer radical polymerization. Then with the HNTs-g-PSS as a template and the grafted PSS chains as the counterion dopant, PEDOT was precipitated onto the template via in situ oxidization polymerization of EDOT to form HNTs@PEDOT hybrid composites. The conductivity of HNTs@PEDOT can reach up to 9.35 S/cm with the content of 40% HNTs-g-PSS, which increased almost 78 times than that of pure PEDOT (about 0.12 S/cm) prepared at the similar condition. Further treated with p-toluenesulfonic acid (TsOH) as external dopant, the conductivity of HNTs@PEDOT increased to 24.3 S/cm. The electrochemical properties of the composites were investigated with cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy with three-electrode cell configuration. The results showed that the capacitance of HNTs@PEDOT composite increased 55% than that of pure PEDOT.

pH-responsive ion transport in polyelectrolyte multilayers of poly(diallyldimethylammonium chloride) (PDADMAC) and poly(4-styrenesulfonic acid-co-maleic acid) (PSS-MA) bearing strong- and weak anionic groups.

PubMed

Maza, Eliana; Tuninetti, Jimena S; Politakos, Nikolaos; Knoll, Wolfgang; Moya, Sergio; Azzaroni, Omar

2015-11-28

The layer-by-layer construction of interfacial architectures displaying stimuli-responsive control of mass transport is attracting increasing interest in materials science. In this work, we describe the creation of interfacial architectures displaying pH-dependent ionic transport properties which until now have not been observed in polyelectrolyte multilayers. We describe a novel approach to create pH-controlled ion-rectifying systems employing polyelectrolyte multilayers assembled from a copolymer containing both weakly and strongly charged pendant groups, poly(4-styrenesulfonic acid-co-maleic acid) (PSS-MA), alternately deposited with poly(diallyldimethylammonium chloride) (PDADMAC). The conceptual framework is based on the very contrasting and differential interactions of PSS and MA units with PDADMAC. In our setting, sulfonate groups play a structural role by conferring stability to the multilayer due to the strong electrostatic interactions with the polycations, while the weakly interacting MA groups remain "silent" within the film and then act as on-demand pH-responsive units. When these multilayers are combined with a strong cationic capping layer that repels the passage of cationic probes, a pH-gateable rectified transport of anions is observed. Concomitantly, we also observed that these functional properties are significantly affected when multilayers are subjected to extensive pH cycling as a consequence of irreversible morphological changes taking place in the film. We envision that the synergy derived from combining weak and strong interactions within the same multilayer will play a key role in the construction of new interfacial architectures displaying tailorable ion transport properties.

Highly elevated levels of perfluorooctane sulfonate and other perfluorinated acids found in biota and surface water downstream of an international airport, Hamilton, Ontario, Canada.

PubMed

de Solla, S R; De Silva, A O; Letcher, R J

2012-02-01

Per- and poly-fluorinated compounds (PFCs), which include perfluorinated carboxylates (PFCAs) and sulfonates (PFSAs) and various precursors, are used in a wide variety of industrial, commercial and domestic products. This includes aqueous film forming foam (AFFF), which is used by military and commercial airports as fire suppressants. In a preliminary assessment prior to this study, very high concentrations (>1 ppm wet weight) of the PFSA, perfluorooctane sulfonate (PFOS), were discovered in the plasma of snapping turtles (Chelydra serpentina) collected in 2008 from Lake Niapenco in southern Ontario, Canada. We presently report on a suite of C(6) to C(15) PFCAs, C(4), C(6), C(8) and C(10) PFSAs, several PFC precursors (e.g. perfluorooctane sulfonamide, PFOSA), and a cyclic perfluorinated acid used in aircraft hydraulic fluid, perfluoroethylcyclohexane sulfonate (PFECHS) in surface water from the Welland River and Lake Niapenco, downstream of the John C. Munro International Airport, Hamilton, Ontario, Canada. Amphipods, shrimp, and water were sampled from the Welland River and Lake Niapenco, as well as local references. The same suite of PFCs in turtle plasma from Lake Niapenco was compared to those from other southern Ontario sites. PFOS dominated the sum PFCs in all substrates (e.g., >99% in plasma of turtles downstream the Hamilton Airport, and 72.1 to 94.1% at all other sites). PFOS averaged 2223(±247.1SE) ng/g in turtle plasma from Lake Niapenco, and ranged from 9.0 to 171.4 elsewhere. Mean PFOS in amphipods and in water were 518.1(±83.8)ng/g and 130.3(±43.6) ng/L downstream of the airport, and 19.1(±2.7) ng/g and 6.8(±0.5) ng/L at reference sites, respectively. Concentrations of selected PFCs declined with distance downstream from the airport. Although there was no known spill event or publicly reported use of AFFF associated with a fire event at the Hamilton airport, the airport is a likely major source of PFC contamination in the Welland River. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Gating capacitive field-effect sensors by the charge of nanoparticle/molecule hybrids.

PubMed

Poghossian, Arshak; Bäcker, Matthias; Mayer, Dirk; Schöning, Michael J

2015-01-21

The semiconductor field-effect platform is a powerful tool for chemical and biological sensing with direct electrical readout. In this work, the field-effect capacitive electrolyte-insulator-semiconductor (EIS) structure - the simplest field-effect (bio-)chemical sensor - modified with citrate-capped gold nanoparticles (AuNPs) has been applied for a label-free electrostatic detection of charged molecules by their intrinsic molecular charge. The EIS sensor detects the charge changes in AuNP/molecule inorganic/organic hybrids induced by the molecular adsorption or binding events. The feasibility of the proposed detection scheme has been exemplarily demonstrated by realizing capacitive EIS sensors consisting of an Al-p-Si-SiO2-silane-AuNP structure for the label-free detection of positively charged cytochrome c and poly-d-lysine molecules as well as for monitoring the layer-by-layer formation of polyelectrolyte multilayers of poly(allylamine hydrochloride)/poly(sodium 4-styrene sulfonate), representing typical model examples of detecting small proteins and macromolecules and the consecutive adsorption of positively/negatively charged polyelectrolytes, respectively. For comparison, EIS sensors without AuNPs have been investigated, too. The adsorption of molecules on the surface of AuNPs has been verified via the X-ray photoelectron spectroscopy method. In addition, a theoretical model of the functioning of the capacitive field-effect EIS sensor functionalized with AuNP/charged-molecule hybrids has been discussed.

Characterization of poly(Sodium Styrene Sulfonate) Thin Films Grafted from Functionalized Titanium Surfaces

PubMed Central

Zorn, Gilad; Baio, Joe E.; Weidner, Tobias; Migonney, Veronique; Castner, David G.

2011-01-01

Biointegration of titanium implants in the body is controlled by their surface properties. Improving surface properties by coating with a bioactive polymer is a promising approach to improve the biological performance of titanium implants. To optimize the grafting processes, it is important to fully understand the composition and structure of the modified surfaces. The main focus of this study is to provide a detailed, multi-technique characterization of a bioactive poly(sodium styrene sulfonate) (pNaSS) thin film grafted from titanium surfaces via a two-step procedure. Thin titanium films (~50 nm thick with an average surface roughness of 0.9±0.2nm) prepared by evaporation onto silicon wafers were used as smooth model substrates. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed that the titanium film was covered with a TiO2 layer that was at least 10nm thick and contained hydroxyl groups present at the outermost surface. These hydroxyl groups were first modified with a 3-methacryloxypropyltrimethoxysilane (MPS) cross linker. XPS and ToF-SIMS showed that a monolayer of the MPS molecules were successfully attached onto the titanium surfaces. The pNaSS film was grafted from the MPS modified titanium through atom transfer radical polymerization. Again, XPS and ToF-SIMS were used to verify that the pNaSS molecules were successfully grafted onto the modified surfaces. Atomic force microscopy analysis showed that the film was smooth and uniformly covered the surface. Fourier transform infrared spectroscopy indicated an ordered array of grafted NaSS molecules were present on the titanium surfaces. Sum frequency generation vibration spectroscopy and near edge X-ray absorption fine structure spectroscopy illustrated that the NaSS molecules were grafted onto the titanium surface with a substantial degree of orientational order in the styrene rings. PMID:21892821

Current and historical concentrations of poly and perfluorinated compounds in sediments of the northern Great Lakes - Superior, Huron, and Michigan.

PubMed

Codling, Garry; Hosseini, Soheil; Corcoran, Margaret B; Bonina, Solidea; Lin, Tian; Li, An; Sturchio, Neil C; Rockne, Karl J; Ji, Kyunghee; Peng, Hui; Giesy, John P

2018-05-01

Current and historical concentrations of 22 poly- and perfluorinated compounds (PFASs) in sediment collected from Lake Superior and northern Lake Michigan in 2011 and Lake Huron in 2012 are reported. The sampling was performed in two ways, Ponar grabs of surface sediments for current spatial distribution across the lake and dated cores for multi-decadal temporal trends. Mean concentrations of the sum of PFASs (∑PFASs) were 1.5, 4.6 and 3.1 ng g -1 dry mas (dm) in surface sediments for Lakes Superior, Michigan and Huron, respectively. Of the five Laurentian Lakes, the watersheds of Superior and Huron are the less densely populated by humans, and concentrations observed were typically less and from more diffuse sources, due to lesser urbanization and industrialization. However, some regions of greater concentrations were observed and might indicate more local, point sources. In core samples concentrations ranged from 7 that include perfluoro-n-octane sulfonate (PFOS) bind more strongly to sediment, which resulted in more accurate analyses of temporal trends. Shorter-chain PFASs, such as perfluoro-n-butanoic acid which is the primary replacement for C8 PFASs that have been phased out, are more soluble and were identified in some core layers at depths corresponding to pre-production periods. Thus, analyses of temporal trends of these more soluble compounds in cores of sediments were less accurate. Total elemental fluorine (TF) and extractable organic fluorine (EOF) indicated that identified PFASs were not a significant fraction of fluorine containing compounds in sediment (<0.01% in EOF). Copyright © 2018 Elsevier Ltd. All rights reserved.

Surface initiated atom transfer radical polymerization grafting of sodium styrene sulfonate from titanium and silicon substrates.

PubMed

Foster, Rami N; Keefe, Andrew J; Jiang, Shaoyi; Castner, David G

2013-11-01

This study investigates the grafting of poly-sodium styrene sulfonate (pNaSS) from trichlorosilane/10-undecen-1-yl 2-bromo-2-methylpropionate functionalized Si and Ti substrates by atom transfer radical polymerization (ATRP). The composition, molecular structure, thickness, and topography of the grafted pNaSS films were characterized with x-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), variable angle spectroscopic ellipsometry (VASE), and atomic force microscopy (AFM), respectively. XPS and ToF-SIMS results were consistent with the successful grafting of a thick and uniform pNaSS film on both substrates. VASE and AFM scratch tests showed the films were between 25 and 49 nm thick on Si, and between 13 and 35 nm thick on Ti. AFM determined root-mean-square roughness values were ∼2 nm on both Si and Ti substrates. Therefore, ATRP grafting is capable of producing relatively smooth, thick, and chemically homogeneous pNaSS films on Si and Ti substrates. These films will be used in subsequent studies to test the hypothesis that pNaSS-grafted Ti implants preferentially adsorb certain plasma proteins in an orientation and conformation that modulates the foreign body response and promotes formation of new bone.

Surface initiated atom transfer radical polymerization grafting of sodium styrene sulfonate from titanium and silicon substrates

PubMed Central

Foster, Rami N.; Keefe, Andrew J.; Jiang, Shaoyi; Castner, David G.

2013-01-01

This study investigates the grafting of poly-sodium styrene sulfonate (pNaSS) from trichlorosilane/10-undecen-1-yl 2-bromo-2-methylpropionate functionalized Si and Ti substrates by atom transfer radical polymerization (ATRP). The composition, molecular structure, thickness, and topography of the grafted pNaSS films were characterized with x-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), variable angle spectroscopic ellipsometry (VASE), and atomic force microscopy (AFM), respectively. XPS and ToF-SIMS results were consistent with the successful grafting of a thick and uniform pNaSS film on both substrates. VASE and AFM scratch tests showed the films were between 25 and 49 nm thick on Si, and between 13 and 35 nm thick on Ti. AFM determined root-mean-square roughness values were ∼2 nm on both Si and Ti substrates. Therefore, ATRP grafting is capable of producing relatively smooth, thick, and chemically homogeneous pNaSS films on Si and Ti substrates. These films will be used in subsequent studies to test the hypothesis that pNaSS-grafted Ti implants preferentially adsorb certain plasma proteins in an orientation and conformation that modulates the foreign body response and promotes formation of new bone. PMID:24482558

Electrochemosensor for trace analysis of perfluorooctane sulfonate in water based on a molecularly imprinted poly o-phenylenediamine polymer.

PubMed

Karimian, Najmeh; Stortini, Angela Maria; Moretto, Ligia Maria; Costantino, Claudio; Bogialli, Sara; Ugo, Paolo

2018-06-18

This work is aimed at developing an electrochemical sensor for the sensitive and selective detection of trace levels of perfluorooctane sulfonate (PFOS) in water. Contamination of waters by perfluorinated alkyl substances (PFAS) is a problem of global concern due to their suspected toxicity and ability to bioaccumulate. PFOS is the perfluorinated compound of major concern, as it has the lowest suggested control concentrations. The sensor reported here is based on a gold electrode modified with a thin coating of a molecularly imprinted polymer (MIP), prepared by anodic electropolymerization of o-phenylenediamine (o-PD) in the presence of PFOS as the template. Activation of the sensor is achieved by template removal with suitable a solvent mixture. Voltammetry, a quartz crystal microbalance, scanning electron microscopy and elemental analysis were used to monitor the electropolymerization process, template removal and binding of the analyte. Ferrocenecarboxylic acid (FcCOOH) has been exploited as an electrochemical probe able to generate analytically useful voltammetric signals by competing for the binding sites with PFOS, as the latter is not electroactive. The sensor has a low detection limit (0.04 nM), a satisfactory selectivity, and is reproducible and repeatable, giving analytical results in good agreement with those obtained by HPLC-MS/MS analyses.

Film patterned retarder for stereoscopic three-dimensional display using ink-jet printing method.

PubMed

Lim, Young Jin; Yu, Ji Hoon; Song, Ki Hoon; Lee, Myong-Hoon; Ren, Hongwen; Mun, Byung-June; Lee, Gi-Dong; Lee, Seung Hee

2014-09-22

We propose a film patterned retarder (FPR) for stereoscopic three-dimensional display with polarization glasses using ink-jet printing method. Conventional FPR process requires coating of photo-alignment and then UV exposure using wire-grid mask, which is very expensive and difficult. The proposed novel fabrication method utilizes a plastic substrate made of polyether sulfone and an alignment layer, poly (4, 4' - (9, 9 -fluorenyl) diphenylene cyclobutanyltetracarboximide) (9FDA/CBDA) in which the former and the latter aligns reactive mesogen along and perpendicular to the rubbing direction, respectively. The ink-jet printing of 9FDA/CBDA line by line allows fabricating the cost effective FPR which can be widely applied for 3D display applications.

Electrochromic switching in ionically self-assembled nanostructures

NASA Astrophysics Data System (ADS)

Janik, Jerzy A.; Heflin, James R.; Marciu, Daniela; Miller, Michael B.; Wang, Hong; Gibson, Harry W.; Davis, Rick M.

2001-11-01

Ionically self-assembled monolayers (ISAMs), fabricated by alternate adsorption of cationic and anionic components, yield exceptionally homogeneous thin films with sub- nanometer control of the thickness and relative special location of the component materials. Using organic electrochromic materials such as polyaniline, we report studies of electrochromic responses in ISAM films. Reversible changes in the absorption spectrum are observed with the application of voltages on the order of 1.0 V. Measurements are made using both liquid electrolytes and in all-solid state devices incorporating solid polyelectrolytes such as poly(2-acylamido 2-methyl propane sulfonic acid) (PAMPS). Due to the precise nanometer scale control of thickness and composition of the electrochromic composite system, switching times faster than 50 ms have been demonstrated.

Water dynamics in rigid ionomer networks.

PubMed

Osti, N C; Etampawala, T N; Shrestha, U M; Aryal, D; Tyagi, M; Diallo, S O; Mamontov, E; Cornelius, C J; Perahia, D

2016-12-14

The dynamics of water within ionic polymer networks formed by sulfonated poly(phenylene) (SPP), as revealed by quasi-elastic neutron scattering (QENS), is presented. These polymers are distinguished from other ionic macromolecules by their rigidity and therefore in their network structure. QENS measurements as a function of temperature as the fraction of ionic groups and humidity were varied have shown that the polymer molecules are immobile while absorbed water molecules remain dynamic. The water molecules occupy multiple sites, either bound or loosely constrained, and bounce between the two. With increasing temperature and hydration levels, the system becomes more dynamic. Water molecules remain mobile even at subzero temperatures, illustrating the applicability of the SPP membrane for selective transport over a broad temperature range.

Mechanical and transport properties of layer-by-layer electrospun composite proton exchange membranes for fuel cell applications.

PubMed

Mannarino, Matthew M; Liu, David S; Hammond, Paula T; Rutledge, Gregory C

2013-08-28

Composite membranes composed of highly conductive and selective layer-by-layer (LbL) films and electrospun fiber mats were fabricated and characterized for mechanical strength and electrochemical selectivity. The LbL component consists of a proton-conducting, methanol-blocking poly(diallyl dimethyl ammonium chloride)/sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (PDAC/sPPO) thin film. The electrospun fiber component consists of poly(trimethyl hexamethylene terephthalamide) (PA 6(3)T) fibers in a nonwoven mat of 60-90% porosity. The bare mats were annealed to improve their mechanical properties, which improvements are shown to be retained in the composite membranes. Spray LbL assembly was used as a means for the rapid formation of proton-conducting films that fill the void space throughout the porous electrospun matrix and create a fuel-blocking layer. Coated mats as thin as 15 μm were fabricated, and viable composite membranes with methanol permeabilities 20 times lower than Nafion and through-plane proton selectivity five and a half times greater than Nafion are demonstrated. The mechanical properties of the spray coated electrospun mats are shown to be superior to the LbL-only system and possess intrinsically greater dimensional stability and lower mechanical hysteresis than Nafion under hydrated conditions. The composite proton exchange membranes fabricated here were tested in an operational direct methanol fuel cell. The results show the potential for higher open circuit voltages (OCV) and comparable cell resistances when compared to fuel cells based on Nafion.

A single-walled carbon nanotubes/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/copper hexacyanoferrate hybrid film for high-volumetric performance flexible supercapacitors

NASA Astrophysics Data System (ADS)

Li, Jianmin; Li, Haizeng; Li, Jiahui; Wu, Guiqing; Shao, Yuanlong; Li, Yaogang; Zhang, Qinghong; Wang, Hongzhi

2018-05-01

Volumetric energy density is generally considered to be detrimental to the actual application of supercapacitors, which has provoked a range of research work on increasing the packing density of electrodes. Herein, we fabricate a free-standing single-walled carbon nanotubes (SWCNTs)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/copper hexacyanoferrate (CuHCF) nanoparticles (NPs) composite supercapacitor electrode, with a high packing density of 2.67 g cm-3. The pseudocapacitive CuHCF NPs are decorated onto the SWCNTs/PEDOT:PSS networks and filled in interspace to increase both of packing density and specific capacitance. This hybrid electrode exhibits a series of outstanding performances, such as high electric conductivity, ultrahigh areal and volumetric capacitances (969.8 mF cm-2 and 775.2 F cm-3 at scan rate of 5 mV s-1), long cycle life and superior rate capability. The asymmetric supercapacitor built by using the SWCNTs/PEDOT:PSS/CuHCF film as positive electrode and Mo-doped WO3/SWCNTs film as negative electrode, can deliver a high energy density of 30.08 Wh L-1 with a power density of 4.25 kW L-1 based on the total volume of the device. The approach unveiled in this study could provide important insights to improving the volumetric performance of energy storage devices and help to reach the critical targets for high rate and high power density demand applications.

Patterned free-standing conductive nanofilms for ultraconformable circuits and smart interfaces.

PubMed

Greco, Francesco; Zucca, Alessandra; Taccola, Silvia; Mazzolai, Barbara; Mattoli, Virgilio

2013-10-09

A process is presented for the fabrication of patterned ultrathin free-standing conductive nanofilms based on an all-polymer bilayer structure composed of poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) and poly(lactic acid) (PEDOT:PSS/PLA). Based on the strategy recently introduced by our group for producing large area free-standing nanofilms of conductive polymers with ultrahigh conformability, here an inkjet subtractive patterning technique was used, with localized overoxidation of PEDOT:PSS that caused the local irreversible loss of electrical conductivity. Different pattern geometries (e.g., interdigitated electrodes with various spacing, etc.) were tested for validating the proposed process. The fabrication of individually addressable microelectrodes and simple circuits on nanofilm having thickness ∼250 nm has been demonstrated. Using this strategy, mechanically robust, conformable ultrathin polymer films could be produced that can be released in water as free-standing nanofilms and/or collected on surfaces with arbitrary shapes, topography and compliance, including human skin. The patterned bilayer nanofilms were characterized as regards their morphology, thickness, topography, conductivity, and electrochemical behavior. In addition, the electrochemical switching of surface properties has been evaluated by means of contact angle measurements. These novel conductive materials can find use as ultrathin, conformable electronic devices and in many bioelectrical applications. Moreover, by exploiting the electrochemical properties of conducting polymers, they can act as responsive smart biointerfaces and in the field of conformable bioelectronics, for example, as electrodes on tissues or smart conductive substrates for cell culturing and stimulation.

The effect of functionalized polycarboxylate structures as corrosion inhibitors in a simulated concrete pore solution

NASA Astrophysics Data System (ADS)

Fazayel, A. S.; Khorasani, M.; Sarabi, A. A.

2018-05-01

In this study, the effects of polycarboxylate derivatives with different comonomers and functional groups on the control or reduction of corrosion in steel specimens were evaluated through electrochemical impedance spectroscopy (EIS) and potentiodynamic analysis. A highly alkaline contaminated concrete pore solution (CPS) containing chlorides was used to simulate the pitting corrosion, and according to the results, the mechanism of inhibitive action was determined. Both the inhibition efficiency and pitting corrosion inhibition of methacrylate-copolymers were in the order of poly methacrylate-co acrylamide > poly methacrylate-co-2-acrylamido-2 methylpropane sulfonic acid > poly methacrylate-co-hydroxyethyl methacrylate. In addition, the corrosion potential of steel specimens in all studied concentrations of NaCl with different concentrations of polymethacrylate-co acrylamide (as the best inhibitor in this study) in saturated Ca(OH)2 solution showed almost an identical trend. Polymethacrylic acid-co-acrylamide showed a 92.35% inhibitor efficiency in the saturated Ca(OH)2 solution containing 1.8 wt.% chlorides and could effectively reduce the corrosion rate. Even at 3.5 wt.% of NaCl, this inhibitor could remarkably reduce the destructive effect of chloride ion attacks on the steel surface and passive film. The inhibition effect of these polymeric inhibitors seemed to be due to the formation of a barrier layer on the metal surface, approved by the well-known adsorption mechanism of organic molecules at the metal/solution interface. The results of SEM, EDS and AFM investigations were also in agreement with the outcomes of electrochemical studies.

Influences of device structures on microstructure-correlated photovoltaic characteristics of organic solar cells

NASA Astrophysics Data System (ADS)

Wu, Fu-Chiao; Yang, Cheng-Chi; Tseng, Po-Tsung; Chou, Wei-Yang; Cheng, Horng-Long

2017-02-01

Photovoltaic characteristics of organic solar cells (OSCs) are correlated with microstructural qualities of active layers (ALs). Numerous efforts focused on improving process conditions of ALs to attain effective microstructures to achieve high-efficiency OSCs. Aside from AL process conditions, layer properties under AL can also influence microstructural qualities of AL. In this study, we adopted poly(3-hexylthiophene) (P3HT):(6,6)-phenyl C61-butyric acid methyl ester (PCBM) mixture as AL, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) as hole extraction layer, and branched polyethyleneimine (BPEI) as electron extraction layer to prepare OSCs with different device structures, that is, normal type (PEDOT:PSS/P3HT:PCBM/BPEI) and inverted type (BPEI/P3HT:PCBM/PEDOT:PSS) structures. We discovered that although devices have similar layer components, they have different photovoltaic characteristics. Inverted devices demonstrated higher power conversion efficiency than normal devices. Various methods, including absorption spectroscopy and microscopy, were used to study AL microstructures of different devices. We observed that P3HT crystallites grown on BPEI had longer vertical size and shorter horizontal size compared with those grown on PEDOT:PSS; these properties could result from larger interfacial tension of P3HT with BPEI than with PEDOT:PSS. Observed shape of P3HT crystallites in inverted devices facilitated efficient charge transport to electrodes and suppressed current leakage. As a result, inverted devices generated improved photovoltaic performance.

Frequency-dependent photothermal measurement of transverse thermal diffusivity of organic semiconductors

NASA Astrophysics Data System (ADS)

Brill, J. W.; Shahi, Maryam; Payne, Marcia M.; Edberg, Jesper; Yao, Y.; Crispin, Xavier; Anthony, J. E.

2015-12-01

We have used a photothermal technique, in which chopped light heats the front surface of a small (˜1 mm2) sample and the chopping frequency dependence of thermal radiation from the back surface is measured with a liquid-nitrogen-cooled infrared detector. In our system, the sample is placed directly in front of the detector within its dewar. Because the detector is also sensitive to some of the incident light, which leaks around or through the sample, measurements are made for the detector signal that is in quadrature with the chopped light. Results are presented for layered crystals of semiconducting 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pn) and for papers of cellulose nanofibrils coated with semiconducting poly(3,4-ethylene-dioxythiophene):poly(styrene-sulfonate) (NFC-PEDOT). For NFC-PEDOT, we have found that the transverse diffusivity, smaller than the in-plane value, varies inversely with thickness, suggesting that texturing of the papers varies with thickness. For TIPS-pn, we have found that the interlayer diffusivity is an order of magnitude larger than the in-plane value, consistent with previous estimates, suggesting that low-frequency optical phonons, presumably associated with librations in the TIPS side groups, carry most of the heat.

Probing long-range carrier-pair spin–spin interactions in a conjugated polymer by detuning of electrically detected spin beating

PubMed Central

van Schooten, Kipp J.; Baird, Douglas L.; Limes, Mark E.; Lupton, John M.; Boehme, Christoph

2015-01-01

Weakly coupled electron spin pairs that experience weak spin–orbit interaction can control electronic transitions in molecular and solid-state systems. Known to determine radical pair reactions, they have been invoked to explain phenomena ranging from avian magnetoreception to spin-dependent charge-carrier recombination and transport. Spin pairs exhibit persistent spin coherence, allowing minute magnetic fields to perturb spin precession and thus recombination rates and photoreaction yields, giving rise to a range of magneto-optoelectronic effects in devices. Little is known, however, about interparticle magnetic interactions within such pairs. Here we present pulsed electrically detected electron spin resonance experiments on poly(styrene-sulfonate)-doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) devices, which show how interparticle spin–spin interactions (magnetic-dipolar and spin-exchange) between charge-carrier spin pairs can be probed through the detuning of spin-Rabi oscillations. The deviation from uncoupled precession frequencies quantifies both the exchange (<30 neV) and dipolar (23.5±1.5 neV) interaction energies responsible for the pair's zero-field splitting, implying quantum mechanical entanglement of charge-carrier spins over distances of 2.1±0.1 nm. PMID:25868686

Strong Photo-Amplification Effects in Flexible Organic Capacitors with Small Molecular Solid-State Electrolyte Layers Sandwiched between Photo-Sensitive Conjugated Polymer Nanolayers

PubMed Central

Lee, Hyena; Kim, Jungnam; Kim, Hwajeong; Kim, Youngkyoo

2016-01-01

We demonstrate strong photo-amplification effects in flexible organic capacitors which consist of small molecular solid-state electrolyte layers sandwiched between light-sensitive conjugated polymer nanolayers. The small molecular electrolyte layers were prepared from aqueous solutions of tris(8-hydroxyquinoline-5-sulfonic acid) aluminum (ALQSA3), while poly(3-hexylthiophene) (P3HT) was employed as the light-sensitive polymer nanolayer that is spin-coated on the indium-tin oxide (ITO)-coated poly(ethylene terephthalate) (PET) film substrates. The resulting capacitors feature a multilayer device structure of PET/ITO/P3HT/ALQSA3/P3HT/ITO/PET, which were mechanically robust due to good adhesion between the ALQSA3 layers and the P3HT nanolayers. Results showed that the specific capacitance was increased by ca. 3-fold when a white light was illuminated to the flexible organic multilayer capacitors. In particular, the capacity of charge storage was remarkably (ca. 250-fold) enhanced by a white light illumination in the potentiostatic charge/discharge operation, and the photo-amplification functions were well maintained even after bending for 300 times at a bending angle of 180o. PMID:26846891

Strong Photo-Amplification Effects in Flexible Organic Capacitors with Small Molecular Solid-State Electrolyte Layers Sandwiched between Photo-Sensitive Conjugated Polymer Nanolayers.

PubMed

Lee, Hyena; Kim, Jungnam; Kim, Hwajeong; Kim, Youngkyoo

2016-02-05

We demonstrate strong photo-amplification effects in flexible organic capacitors which consist of small molecular solid-state electrolyte layers sandwiched between light-sensitive conjugated polymer nanolayers. The small molecular electrolyte layers were prepared from aqueous solutions of tris(8-hydroxyquinoline-5-sulfonic acid) aluminum (ALQSA3), while poly(3-hexylthiophene) (P3HT) was employed as the light-sensitive polymer nanolayer that is spin-coated on the indium-tin oxide (ITO)-coated poly(ethylene terephthalate) (PET) film substrates. The resulting capacitors feature a multilayer device structure of PET/ITO/P3HT/ALQSA3/P3HT/ITO/PET, which were mechanically robust due to good adhesion between the ALQSA3 layers and the P3HT nanolayers. Results showed that the specific capacitance was increased by ca. 3-fold when a white light was illuminated to the flexible organic multilayer capacitors. In particular, the capacity of charge storage was remarkably (ca. 250-fold) enhanced by a white light illumination in the potentiostatic charge/discharge operation, and the photo-amplification functions were well maintained even after bending for 300 times at a bending angle of 180(°).

Studies on the Electrical Properties of Graphene Oxide-Reinforced Poly (4-Styrene Sulfonic Acid) and Polyvinyl Alcohol Blend Composites

NASA Astrophysics Data System (ADS)

Deshmukh, Kalim; Sankaran, Sowmya; Basheer Ahamed, M.; Khadheer Pasha, S. K.; Sadasivuni, Kishor Kumar; Ponnamma, Deepalekshmi; Al-Ali Almaadeed, Mariam; Chidambaram, K.

In the present study, graphene oxide (GO)-reinforced poly (4-styrenesulfonic acid) (PSSA)/polyvinyl alcohol (PVA) blend composite films were prepared using colloidal blending technique at various concentrations of GO (0-3wt.%). The morphological investigations of the prepared composites were carried out using polarized optical microscopy and scanning electron microscopy. The electrical properties of composites were evaluated using an impedance analyzer in the frequency range 50Hz to 20MHz and temperature in the range 40-150∘C. Morphological studies infer that GO was homogeneously dispersed in the PSSA/PVA blend matrix. Investigations of electrical property indicate that the incorporation of GO into PSSA/PVA blend matrix resulted in the enhancement of the impedance (Z) and the quality factor (Q-factor) values. A maximum impedance of about 4.32×106Ω was observed at 50Hz and 90∘C for PSSA/PVA/GO composites with 3wt.% GO loading. The Q-factor also increased from 8.37 for PSSA/PVA blend to 59.8 for PSSA/PVA/GO composites with 3wt.% GO loading. These results indicate that PSSA/PVA/GO composites can be used for high-Q capacitor applications.

Probing long-range carrier-pair spin–spin interactions in a conjugated polymer by detuning of electrically detected spin beating

DOE PAGES

van Schooten, Kipp J.; Baird, Douglas L.; Limes, Mark E.; ...

2015-04-14

Here, weakly coupled electron spin pairs that experience weak spin–orbit interaction can control electronic transitions in molecular and solid-state systems. Known to determine radical pair reactions, they have been invoked to explain phenomena ranging from avian magnetoreception to spin-dependent charge-carrier recombination and transport. Spin pairs exhibit persistent spin coherence, allowing minute magnetic fields to perturb spin precession and thus recombination rates and photoreaction yields, giving rise to a range of magneto-optoelectronic effects in devices. Little is known, however, about interparticle magnetic interactions within such pairs. Here we present pulsed electrically detected electron spin resonance experiments on poly(styrene-sulfonate)-doped poly(3,4-ethylenedioxythiophene) (PEDOT:PSS) devices,more » which show how interparticle spin–spin interactions (magnetic-dipolar and spin-exchange) between charge-carrier spin pairs can be probed through the detuning of spin-Rabi oscillations. The deviation from uncoupled precession frequencies quantifies both the exchange (<30 neV) and dipolar (23.5±1.5 neV) interaction energies responsible for the pair’s zero-field splitting, implying quantum mechanical entanglement of charge-carrier spins over distances of 2.1±0.1 nm.« less

Investigation of thioglycerol stabilized ZnS quantum dots in electroluminescent device performance

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

Ethiraj, Anita Sagadevan, E-mail: anita.ethiraj@vit.ac.in; Center for Nanotechnology Research, VIT University, Vellore, TamilNadu-632014; Rhen, Dani

2016-05-06

The present work is focused on the investigation of thioglycerol (TG) stabilized Zinc Sulfide Quantum dots (ZnS QDs) in the hybrid electroluminescence (EL) device. Optical absorption spectroscopy clearly indicates the formation of narrow size distributed ZnS in the quantum confinement regime. X-ray Diffraction (XRD), Photoluminescence (PL), Energy Dispersive X-ray Spectroscopy (EDS) data supports the same. The hybrid EL device with structure of ITO (indium tin oxide)//PEDOT:PSS ((poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate)//HTL (α NPD- N,N′-diphenyl-N,N′-bis(1-naphthyl)-(1,1′-phenyl)-4,4′-diamine// PVK:ZnS QDs//ETL(PBD- 2-tert-butylphenyl- 5-biphenyl-1,3,4-oxadiazole)//LiF:Al (Device 1) was fabricated. Reference device without the ZnS QDs were also prepared (Device 2). The results show that the ZnS QDs based device exhibitedmore » bright electroluminescence emission of 24 cd/m{sup 2} at a driving voltage of 16 Volts under the forward bias conditions as compared to the reference device without the ZnS QDs, which showed 6 cd/m{sup 2} at ∼22 Volts.« less

Structured Ionomer Thin Films at Water Interface: Molecular Dynamics Simulation Insight

DOE PAGES

Aryal, Dipak; Agrawal, Anupriya; Perahia, Dvora; ...

2017-08-23

Controlling the structure and dynamics of thin films of ionizable polymers at water interfaces is critical to their many applications. As the chemical diversity within one polymer is increased, controlling the structure and dynamics of the polymer, which is a key to their use, becomes a challenge. Here molecular dynamics simulations (MD) are used to obtain molecular insight into the structure and dynamics of thin films of one such macromolecule at the interface with water. The polymer consists of an ABCBA topology with randomly sulfonated polystyrene (C), tethered symmetrically to flexible poly(ethylene- r-propylene) blocks (B), and end-capped by a poly(more » t-butylstyrene) block (A). The compositions of the interfacial and bulk regions of thin films of the ABCBA polymers are followed as a function of exposure time to water. We find that interfacial rearrangements take place where buried ionic segments migrate toward the water interface. The hydrophobic blocks collapse and rearrange to minimize their exposure to water. In conclusion, the water that initially drives interfacial reengagements breaks the ionic clusters within the film, forming a dynamic hydrophilic internal network within the hydrophobic segments.« less

Control over position, orientation, and spacing of arrays of gold nanorods using chemically nanopatterned surfaces and tailored particle-particle-surface interactions.

PubMed

Nepal, Dhriti; Onses, M Serdar; Park, Kyoungweon; Jespersen, Michael; Thode, Christopher J; Nealey, Paul F; Vaia, Richard A

2012-06-26

The synergy of self- and directed-assembly processes and lithography provides intriguing avenues to fabricate translationally ordered nanoparticle arrangements, but currently lacks the robustness necessary to deliver complex spatial organization. Here, we demonstrate that interparticle spacing and local orientation of gold nanorods (AuNR) can be tuned by controlling the Debye length of AuNR in solution and the dimensions of a chemical contrast pattern. Electrostatic and hydrophobic selectivity for AuNR to absorb to patterned regions of poly(2-vinylpyridine) (P2VP) and polystyrene brushes and mats was demonstrated for AuNR functionalized with mercaptopropane sulfonate (MS) and poly(ethylene glycol), respectively. For P2VP patterns of stripes with widths comparable to the length of the AuNR, single- and double-column arrangements of AuNR oriented parallel and perpendicular to the P2VP line were obtained for MS-AuNR. Furthermore, the spacing of the assembled AuNR was uniform along the stripe and related to the ionic strength of the AuNR dispersion. The different AuNR arrangements are consistent with predictions based on maximization of packing of AuNR within the confined strip.

Hydrolytically degradable poly(ethylene glycol) hydrogel scaffolds with tunable degradation and mechanical properties

PubMed Central

Zustiak, Silviya P.

2011-01-01

The objective of this work was to create three-dimensional (3D) hydrogel matrices with defined mechanical properties, as well as tunable degradability for use in applications involving protein delivery and cell encapsulation. Thus, we report the synthesis and characterization of a novel hydrolytically degradable poly(ethylene glycol) (PEG) hydrogel composed of PEG vinyl sulfone (PEG-VS) cross-linked with PEG-diester-dithiol. Unlike previously reported degradable PEG-based hydrogels, these materials are homogeneous in structure, fully hydrophilic and have highly specific cross-linking chemistry. We characterized hydrogel degradation and associated trends in mechanical properties, i.e., storage modulus (G′), swelling ratio (QM), and mesh size (ξ). Degradation time and the monitored mechanical properties of the hydrogel correlated with cross-linker molecular weight, cross-linker functionality, and total polymer density; these properties changed predictably as degradation proceeded (G′ decreased, whereas QM and ξ increased) until the gels reached complete degradation. Balb/3T3 fibroblast adhesion and proliferation within the 3D hydrogel matrices were also verified. In sum, these unique properties indicate that the reported degradable PEG hydrogels are well poised for specific applications in protein and cell delivery to repair soft tissue. PMID:20355705

Doped Interlayers for Improved Selectivity in Bulk Herterojunction Organic Photovoltaic Devices

DOE PAGES

Mauger, Scott A.; Glasser, Melodie P.; Tremolet de Villers, Bertrand J.; ...

2016-01-21

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is less selective for holes in inverted-architecture organic photovoltaic (OPV) than it is in a conventional-architecture OPV device due differences between the interfacial-PSS concentration at the top and bottom of the PEDOT:PSS layer. In this work, thin layers of polysulfonic acids are inserted between the P3HT:ICBA bulk heterojunction (BHJ) active layer and PEDOT:PSS to create a higher concentration of acid at this interface and, therefore, mimic the distribution of materials present in a conventional device. Upon thermal annealing, this acid layer oxidizes P3HT, creating a thin p-type interlayer of P3HT+/acid- on top of the BHJ. Using x-raymore » absorption spectroscopy, Kelvin probe and ellipsometry measurements, this P3HT+/acid- layer is shown to be insoluble in water, indicating it remains intact during the subsequent deposition of PEDOT:PSS. Current density - voltage measurements show this doped interlayer reduces injected dark current while increasing both open-circuit voltage and fill factor through the creation of a more hole selective BHJ-PEDOT:PSS interface.« less

Stability of self-assembled polymer films investigated by optical laser reflectometry.

PubMed

Dejeu, Jérôme; Diziain, Séverine; Dange, Catherine; Membrey, François; Charraut, Daniel; Foissy, Alain

2008-04-01

We studied the influence of post-treatment rinsing after the formation of self-assembled polyelectrolyte films made with the weak base poly(allylamine hydrochloride) (PAH) and the strong acid poly(styrene sulfonate) (PSS). The stability of the film was studied using optical fixed-angle laser reflectometry to measure the release of polymeric material and AFM experiments to reveal the change of morphology and thickness. We found that the polymer films were stable upon rinsing when the pH was the same in the solution as that used in the buildup (pH 9). The films released most of the polymeric material when rinsed at higher pH values, but a layer remained that corresponded to a PAH monolayer directly bound with the silica surface. Films containing at least four bilayers were stable upon rinsing at lower pH values, but the stability of thinner films depended on the type of the last polymer deposited. They were stable in the case of PSS as an outermost deposit, but they released a large part of their material in the case of PAH. The stability results were determined using a simple model of the step-by-step assembly of the polymer film described formerly.

Solution-processed highly conductive PEDOT:PSS/AgNW/GO transparent film for efficient organic-Si hybrid solar cells.

PubMed

Xu, Qiaojing; Song, Tao; Cui, Wei; Liu, Yuqiang; Xu, Weidong; Lee, Shuit-Tong; Sun, Baoquan

2015-02-11

Hybrid solar cells based on n-Si/poly(3,4-ethylenedioxythiophene):poly(styrene- sulfonate) (PEDOT:PSS) heterojunction promise to be a low cost photovoltaic technology by using simple device structure and easy fabrication process. However, due to the low conductivity of PEDOT:PSS, a metal grid deposited by vacuum evaporation method is still required to enhance the charge collection efficiency, which complicates the device fabrication process. Here, a solution-processed graphene oxide (GO)-welded silver nanowires (AgNWs) transparent conductive electrode (TCE) was employed to replace the vacuum deposited metal grid. A unique "sandwich" structure was developed by embedding an AgNW network between PEDOT:PSS and GO with a figure-of-merit of 8.6×10(-3) Ω(-1), which was even higher than that of sputtered indium tin oxide electrode (6.6×10(-3) Ω(-1)). A champion power conversion efficiency of 13.3% was achieved, because of the decreased series resistance of the TCEs as well as the enhanced built-in potential (Vbi) in the hybrid solar cells. The TCEs were obtained by facile low-temperature solution process method, which was compatible with cost-effective mass production technology.

Evaluation of Thermostabilities of Enzymes, Mediators and Immobilizing Membranes for Enzyme Sensors

NASA Astrophysics Data System (ADS)

Yamada, Yohei; Ohnishi, Yuki; Hayashi, Tetsuya; Isobe, Yoshifumi; Yabutani, Tomoki

The stability of the constituents of electrochemical measurement, electron mediators, enzymes and enzyme-immobilizing membranes was evaluated under high temperature (maximum 75°C) by electrochemical analysis, UV-Vis spectrometry (UV-Vis) and UV circular dichroism (CD). As a result of stability evaluation of mediators at 75°C, electrochemical activity of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid ammonium salt (ABTS), potassium ferricyanide (K3[Fe(CN)6]) and ferrocenemethanol (FcOH) were not changed, but 2,6-dichloroindophenol (DCIP), p-benzoquinone (p-BQ), vitaminK3 (VK3) were greatly decreased. The stability of diaphorase from Bacillus stearothermophilus (DI) were compared between in-solution and in several types of membranes, Agarose H, Poly-L-lysine (PLL) and poly-ion-complex (PIC) by electrochemical analysis. In solution, activity and secondary structure of DI were changed at 65°C or higher. This tendency of activity was not much different in Agarose H but in PLL, the activity was almost kept until 70°C. It was suggested that DI was fixed on the electrodes in high concentration and the elimination of DI seldom arise in PLL from the magnitude of the current response and the results of prolonged stability evaluation.

Poly(p-Phenylene Sulfonic Acids). PEMs with frozen-in free volume

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

Litt, Morton

2016-01-21

Early work with rigid rod aromatic polyelectrolytes implied that steric hindrance in packing of the rigid rods left unoccupied volumes that could absorb and hold water molecules strongly. We called this “frozen in free volume). It is illustrated and contrasted with the packing of flexible backbone polyelectrolytes (Reference 5 of this report). This was quantified for poly(biphenylene disulfonic acid) (PBDSA) and poly(phenylene disulfonic acid) (PPDSA). We found that PPDSA held three water molecules per acid group down to 11% relative humidity (RH) and had very high conductivity even at these low RHs. (Reference 1 of report.) The frozen-in free volumemore » was calculated to be equivalent to a λ of 3.5. The work reported below concentrated on studying these polymers and their copolymers with biphenylene disulfonic acid. As expected, the polyelectrolytes are water soluble. Several approaches towards making water stable films were studied. Grafting alkyl benzene substituents on sulfonic acid groups had worked for PBPDSA (1) so it was tried with PPDSA and a 20%/80% copolymer of BPDSA and PDSA (B20P80). T-butyl, n-octyl and n-dodecyl benzene were grafted. Good films could be made. Water absorption and conductivity were studied as a function of RH and temperature (Reference 2). When less than 20% of the sulfonic acid groups were grafted, conductivity was much higher than that of Nafion NR212 at all RHs. At low graft levels, conductivity was ten times higher. Mechanical properties and swelling were acceptable below 90% RH. However, all the films were unstable in water and slowly disintegrated. The proposed explanation was that the molecules formed nano-aggregates in solution held together by hydrophobic bonding. Their cast films disintegrated when placed in water since hydrophobic bonding between the nano-aggregates was poor. We then shifted to crosslinking as a method to produce water stable films (References 3 and 4). Biphenyl could easily be reacted with the polymer, generating biphenyl sulfone grafts. Films were cast and then crosslinked by heating to 210°C for at least one hour. There was no loss of acid groups even after heating at 225°C for two hours. PPDSA and B20P80 polymers were grafted and crosslinked. Conductivity and water absorption were measured on polymers with grafting degrees from 3 to 16%. As before they all had much higher conductivity than Nafion NR212. One sample was tested as a fuel cell membrane. Unfortunately it tore; the tear was mended with a 3M ionomer. There was some hydrogen leakage. However, the current at a given voltage was about 95% that of a Nafion NR212 membrane over the whole useful range. Considering that this was the first test for such a system, this is remarkable performance. A mechanically better membrane was tested at the end of the grant period. This did not have tears or micro cracks (Reference 5). Testing confirmed earlier data (Sergio Granados-Focil, Ph. D. Thesis, CWRU. 2006) that such very polar membranes were excellent barriers to hydrogen diffusion. Standard measurements showed no hydrogen leakage. This was confirmed by open circuit voltage measurements. They were higher than those of the Nafion NR212 cells. Again the single cell performance was about 95% that of the Nafion SR212 cell over the whole range. These films show great promise. They are very stable and perform very well at very low humidity. They should be able to outperform the present cells with relatively little further development. A second project is reported fully in the final report since it was not published. Its goal was to make membranes with high conductivity and good mechanical strength that would have a constant volume at all RHs. We made large planar 2-D polymers containing 1.5 nm holes lined with sulfonic acid groups. These should hold water very strongly. The largest made was calculated to have a number average diameter of 29 nm. It was expected that when they were cast, they would aggregate and create channels for proton conduction. However, they were so large that they aggregated in solution during preparation. Measurements showed that the aggregates developed long channels. This was demonstrated and is reported. Unfortunately, the aggregates could not be cast with the channels perpendicular to the film plane. If methods are developed to keep the molecules in solution until they are cast, their planes should be parallel and the channels perpendicular to the film direction. They could be very interesting and perhaps important materials.« less

Studies on the effect of dispersoid(ZrO2) in PVdF-co-HFP based gel polymer electrolytes

NASA Astrophysics Data System (ADS)

Sivakumar, M.; Subadevi, R.; Muthupradeepa, R.

2013-06-01

Gel polymer electrolytes containing poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) / Lithium bis(trifluoromethane sulfon)imide (LiTFSI) / mixture of ethylene carbonate and propylene carbonate (EC+PC) with different concendration of ZrO2 has been prepared using the solution casting technique. The conductivity of the prepared electrolyte sample has been determined by AC impedance technique in the range 303-353K. The temperature dependent ionic conductivity plot seems to obey VTF relation. The maximum ionic conductivity value of 4.46 × 10-3S/cm has been obtained for PVdF-co-HFP(32%) - LiTFSI(8%) - EC+PC (60%) + ZrO2(6wt%) based polymer electrolyte. The surface morphology of the prepared electrolyte sample has been studied using SEM.

Performance assessment of polymer based electrodes for in vitro electrophysiological sensing: the role of the electrode impedance

NASA Astrophysics Data System (ADS)

Medeiros, Maria C. R.; Mestre, Ana L. G.; Inácio, Pedro M. C.; Santos, José M. L.; Araujo, Inês M.; Bragança, José; Biscarini, Fabio; Gomes, Henrique L.

2016-09-01

Conducting polymer electrodes based on poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) are used to record extracellular signals from autonomous cardiac contractile cells and glioma cell cultures. The performance of these conducting polymer electrodes is compared with Au electrodes. A small-signal impedance analysis shows that in the presence of an electrolyte, both Au and polymer electrodes establish high capacitive double-layers. However, the polymer/electrolyte interfacial resistance is 3 orders of magnitude lower than the resistance of the metal/electrolyte interface. The polymer low interfacial resistance minimizes the intrinsic thermal noise and increases the system sensitivity. However, when measurements are carried out in current mode a low interfacial resistance partially acts as a short circuit of the interfacial capacitance, this affects the signal shape.

Ion-beam-spurted dimethyl-sulfate-doped PEDOT:PSS composite-layer-aligning liquid crystal with low residual direct-current voltage

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

Liu, Yang; Lee, Ju Hwan; Seo, Dae-Shik, E-mail: dsseo@yonsei.ac.kr

2016-09-05

Thin ion-beam (IB)-spurted dimethyl sulfate/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (DMS/PEDOT:PSS) layers with improved electro-optic performance are presented for aligning liquid crystals. IB spurting is effective for enhancing the conductivity of such layers, as well as the anchoring energy of the liquid crystals sandwiched between them. Compared with a commercial twisted-nematic cell assembled with polyimide alignment layers, the same cell assembled with 3.0-keV IB-spurted DMS/PEDOT:PSS alignment layers shows a 38% faster switching and a 93% lower residual direct current. The improved electro-optic performance here is likely due to the enhanced electric field effect and the charge-releasing ability of thin IB-spurted DMS/PEDOT:PSS layers.

Electrochromic Behaviors of Water-Soluble Polyaniline with Covalently Bonded Acetyl Ferrocene

NASA Astrophysics Data System (ADS)

Xiong, Shanxin; Wang, Ru; Li, Shuaishuai; Wu, Bohua; Chu, Jia; Wang, Xiaoqin; Zhang, Runlan; Gong, Ming

2018-04-01

A novel ferrocene-containing hybrid electrochromic material was synthesized via copolymerization of aniline with p-phenylenediamine functionalized acetyl ferrocene in the presence of poly (styrene sulfonate) dopant in an aqueous medium, and neat polyaniline (PANI) was prepared for comparison. The polymerization characteristics and the structure of the copolymer were systematically studied by Fourier-transform infrared, meanwhile, their electrochromic properties and electrochemical behaviors were tested by UV-vis spectra, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). It was found that the strong covalent bond and large conjugated system between PANI and ferrocene enhance the electron transfer rate and electron delocalization in the ferrocene-polyaniline (Fc-PANI) hybrid. In particular, the electrochromic device with Fc-PANI as the active layer shows significant enhancement in optical contrast over the PANI-based device.

Simulation study of sulfonate cluster swelling in ionomers

NASA Astrophysics Data System (ADS)

Allahyarov, Elshad; Taylor, Philip L.; Löwen, Hartmut

2009-12-01

We have performed simulations to study how increasing humidity affects the structure of Nafion-like ionomers under conditions of low sulfonate concentration and low humidity. At the onset of membrane hydration, the clusters split into smaller parts. These subsequently swell, but then maintain constant the number of sulfonates per cluster. We find that the distribution of water in low-sulfonate membranes depends strongly on the sulfonate concentration. For a relatively low sulfonate concentration, nearly all the side-chain terminal groups are within cluster formations, and the average water loading per cluster matches the water content of membrane. However, for a relatively higher sulfonate concentration the water-to-sulfonate ratio becomes nonuniform. The clusters become wetter, while the intercluster bridges become drier. We note the formation of unusual shells of water-rich material that surround the sulfonate clusters.

21 CFR 177.2210 - Ethylene polymer, chloro-sulfonated.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) Ethylene polymer, chloro-sulfonated is produced by chloro-sulfonation of a carbon tetrachloride solution of... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ethylene polymer, chloro-sulfonated. 177.2210... as Components of Articles Intended for Repeated Use § 177.2210 Ethylene polymer, chloro-sulfonated...

21 CFR 172.824 - Sodium mono- and dimethyl naphthalene sulfonates.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium mono- and dimethyl naphthalene sulfonates... sulfonates. The food additive sodium mono- and dimethyl naphthalene sulfonates may be safely used in... statement declaring the presence of sodium mono- and dimethyl naphthalene sulfonates. [42 FR 14491, Mar. 15...

Poly(N-isopropylacrylamide)-coated thermo-responsive nanoparticles for controlled delivery of sulfonated Zn-phthalocyanine in Chinese hamster ovary cells in vitro and zebra fish in vivo

NASA Astrophysics Data System (ADS)

He, Jia; Chen, Ji-Yao; Wang, Pu; Wang, Pei-Nan; Guo, Jia; Yang, Wu-Li; Wang, Chang-Chun; Peng, Qian

2007-10-01

Poly(N-isopropylacrylamide) (PNIPAM)-coated Fe3O4@SiO2@CdTe multifunctional nanoparticles with photoluminescent (PL), thermosensitive and magnetic properties, were investigated as carriers to deliver water-soluble, fluorescent sulfonated Zn-phthalocyanine (ZnPcS), a photosensitizing drug for photodynamic therapy of cancer, in Chinese hamster ovary (CHO) cells in vitro and zebra fish in vivo. PNIPAM is a well-known thermo-responsive polymer with a volume phase transition temperature. This property allows it to be swollen in water at temperatures lower than 32-34 °C to take up ZnPcS and shrunken to expel the drug at higher temperatures. Since the PL band of CdTe quantum dots (QDs) as indicators for the nanoparticles is at 585 nm and the emission band of ZnPcS is at 680 nm, it is possible to study the temperature-dependent release of ZnPcS from the nanoparticles by fluorescence measurements. ZnPcS was embedded in the PNIPAM of the nanoparticles at 25 °C in phosphate buffered saline (PBS) solution and released at 37 °C, measured with a spectrophotometer. When CHO cells had been incubated with the ZnPcS-loaded nanoparticles at 27 °C, a similar intracellular localization pattern of CdTe QDs and ZnPcS was seen by multichannel measurements in confocal laser scanning microscopy (CLSM), but a diffuse pattern of only ZnPcS fluorescence was detected in the cytoplasm of the cells at 37 °C, indicating a release of ZnPcS from the nanoparticles. Similar results were also found in the intestinal tract of zebra fish in vivo after intake of the nanoparticles. Since the nanoparticles contain magnetic (Fe3O4) material, the nanoparticles could also be manipulated to change their location in the intestinal tract of the zebra fish with an external magnetic field gradient of 300 G mm-1. The results presented suggest that such multifunctional nanoparticles may have combined potential for temperature-dependent drug delivery, QD photodetection and magnetic manipulation in diagnosis and therapy of diseases.

High work-function hole transport layers by self-assembly using a fluorinated additive

DOE PAGES

Mauger, Scott A.; Li, Jun; Özmen, Özge Tüzün; ...

2013-10-30

The hole transport polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) derives many of its favorable properties from a PSS-rich interfacial layer that forms spontaneously during coating. Since PEDOT:PSS is only usable as a blend it is not possible to study PEDOT:PSS without this interfacial layer. Through the use of the self-doped polymer sulfonated poly(thiophene-3-[2-(2-methoxyethoxy) ethoxy]-2,5-diyl) (S-P3MEET) and a polyfluorinated ionomer (PFI) it is possible to compare transparent conducting organic films with and without interfacial layers and to understand their function. Using neutron reflectometry, we show that PFI preferentially segregates at the top surface of the film during coating and forms a thermally stable surfacemore » layer. Because of this distribution we find that even small amounts of PFI increase the electron work function of the HTL. We also find that annealing at 150°C and above reduces the work function compared to samples heated at lower temperatures. Using near edge x-ray absorption fine structure spectroscopy and gas chromatography we show that this reduction in work function is due to S-P3MEET being doped by PFI. Organic photovoltaic devices with S-P3MEET/PFI hole transport layers yield higher power conversion efficiency than devices with pure S-P3MEET or PEDOT:PSS hole transport layers. Additionally, devices with a doped interface layer of S-P3MEET/PFI show superior performance to those with un-doped S-P3MEET.« less

Polyelectrolyte Multilayer-Treated Electrodes for Real-Time Electronic Sensing of Cell Proliferation

PubMed Central

Mijares, Geraldine I.; Reyes, Darwin R.; Geist, Jon; Gaitan, Michael; Polk, Brian J.; DeVoe, Don L.

2010-01-01

We report on the use of polyelectrolyte multilayer (PEM) coatings as a non-biological surface preparation to facilitate uniform cell attachment and growth on patterned thin-film gold (Au) electrodes on glass for impedance-based measurements. Extracellular matrix (ECM) proteins are commonly utilized as cell adhesion promoters for electrodes; however, they exhibit degradation over time, thereby imposing limitations on the duration of conductance-based biosensor experiments. The motivation for the use of PEM coatings arises from their long-term surface stability as promoters for cell attachment, patterning, and culture. In this work, a cell proliferation monitoring device was fabricated. It consisted of thin-film Au electrodes deposited with a titanium-tungsten (TiW) adhesion layer that were patterned on a glass substrate and passivated to create active electrode areas. The electrode surfaces were then treated with a poly(ethyleneimine) (PEI) anchoring layer and subsequent bilayers of sodium poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH). NIH-3T3 mouse embryonic fibroblast cells were cultured on the device, observed by optical microscopy, and showed uniform growth characteristics similar to those observed on a traditional polystyrene cell culture dish. The optical observations were correlated to electrical measurements on the PEM-treated electrodes, which exhibited a rise in impedance with cell proliferation and stabilized to an approximate 15 % increase as the culture approached confluency. In conclusion, cells proliferate uniformly over gold and glass PEM-treated surfaces, making them useful for continuous impedance-based, real-time monitoring of cell proliferation and for the determination of cell growth rate in cellular assays. PMID:27134780

Study on the generation of perfluorooctane sulfonate from the aqueous film-forming foam.

PubMed

Kishi, Takahiro; Arai, Mitsuru

2008-11-15

Perfluorooctane sulfonate (C(8)HF(17)SO(3)) and perfluorooctane acid (C(8)HF(15)O(2)) are artificial chemicals and have been used all over the world, mainly as water repellent agents, fluorochemical surfactants, coating agents, etc. However, perfluorooctane sulfonate and perfluorooctane acid are environmental contaminants because of their stability, bio-accumulativeness, and long-term persistence in the ecological environment. At the present day, they are diffused all over the world. Lately, this diffusion is viewed with suspicion and there is a movement towards their restriction, even if the environmental fate of them is still under investigation. Fluorochemical surfactants are key compounds in the aqueous film-forming foam (AFFF) formulations. AFFFs are used for massive conflagration such as industrial fire and petroleum fire because of their efficient fire control. On the other hand, a lot of AFFFs are used in case of massive conflagration and most of them enter ocean and groundwater. Actually, perfluorooctane sulfonate and perfluorooctane sulfonate related substances were detected from the fire-fighting facility of US forces. Therefore, there is the possibility of generating perfluorooctane sulfonate and perfluorooctane sulfonate related substances from fluorochemical surfactants in the AFFFs. In this study, activated sludge added AFFF were analyzed for perfluorooctane sulfonate and perfluorooctane acid with time. And the perfluorooctane sulfonate was directly detected after 2 days using LC-MS. This shows that AFFF can be decomposed perfluorooctane sulfonate by microorganisms easily. However, perfluorooctane sulfonate would not decompose at all. Additionally, activated sludge added N-polyoxyethylene-N-propyl perfluorooctane sulfonamide which is one of the fluorochemical surfactants used in the AFFF was analyzed for perfluorooctane sulfonate and perfluorooctane acid with time and the perfluorooctane sulfonate was detected too.

Surface treated carbon catalysts produced from waste tires for fatty acids to biofuel conversion

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

Hood, Zachary D.; Adhikari, Shiba P.; Wright, Marcus W.

A method of making solid acid catalysts includes the step of sulfonating waste tire pieces in a first sulfonation step. The sulfonated waste tire pieces are pyrolyzed to produce carbon composite pieces having a pore size less than 10 nm. The carbon composite pieces are then ground to produce carbon composite powders having a size less than 50 .mu.m. The carbon composite particles are sulfonated in a second sulfonation step to produce sulfonated solid acid catalysts. A method of making biofuels and solid acid catalysts are also disclosed.

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

Pezeshki, Alan M.; Fujimoto, Cy; Sun, Che -Nan

In this paper, we report on the performance of Diels Alder poly(phenylene) membranes in vanadium redox flow batteries. The membranes were functionalized with quaternary ammonium groups to form an anion exchange membrane (QDAPP) and with sulfonic acid groups to form a cation exchange membrane (SDAPP). Both membrane classes showed similar conductivities in the battery environment, suggesting that the ion conduction mechanism in the material is not strongly affected by the moieties along the polymer backbone. The resistance to vanadium permeation in QDAPP was not improved relative to SDAPP, further suggesting that the polarity of the functional groups do not playmore » a significant role in the membrane materials tested. Both QDAPP and SDAPP outperformed Nafion membranes in cycling tests, with both achieving voltage efficiencies above 85% while maintaining 95% coulombic efficiency while at a current density of 200 mA/cm 2.« less

Biochemical synthesis of water soluble conducting polymers

NASA Astrophysics Data System (ADS)

Bruno, Ferdinando F.; Bernabei, Manuele

2016-05-01

An efficient biomimetic route for the synthesis of conducting polymers/copolymers complexed with lignin sulfonate and sodium (polystyrenesulfonate) (SPS) will be presented. This polyelectrolyte assisted PEG-hematin or horseradish peroxidase catalyzed polymerization of pyrrole (PYR), 3,4 ethyldioxithiophene (EDOT) and aniline has provided a route to synthesize water-soluble conducting polymers/copolymers under acidic conditions. The UV-vis, FTIR, conductivity and cyclic voltammetry studies for the polymers/copolymer complex indicated the presence of a thermally stable and electroactive polymers. Moreover, the use of water-soluble templates, used as well as dopants, provided a unique combination of properties such as high electronic conductivity, and processability. These polymers/copolymers are nowadays tested/evaluated for antirust features on airplanes and helicopters. However, other electronic applications, such as photovoltaics, for transparent conductive polyaniline, actuators, for polypyrrole, and antistatic films, for polyEDOT, will be proposed.

Effect of water on the low temperature conductivity of polymer electrolytes.

PubMed

Siu, Ana; Schmeisser, Jennifer; Holdcroft, Steven

2006-03-30

The proton conductivity of radiation-grafted ethylenetetrafluoroethylene-grafted-poly(styrene sulfonic) acid (ETFE-g-PSSA) and Nafion 117 membranes between 25 and -37 degrees C is reported. The freezing of water in the membranes, which strongly depends on the internal acid concentration, results in a 4-fold decrease in proton conductivity. The activation energies before and after the freezing of the membranes are approximately 0.15 and 0.4 eV, consistent with proton transport through liquid water and strongly bound water, respectively. Differential scanning calorimetry data show that up to 14 H(2)O molecules per H(+)/SO(3)(-) group remain unfrozen at subzero temperatures and are believed to be responsible for the low temperature conductivity that is observed. These results indicate that proton conductivity in membranes may be achieved via strongly bound and highly polarized water.

Strategically functionalized carbon nanotubes as the ultrasensitive electrochemical probe for picomolar detection of sildenafil citrate (Viagra).

PubMed

Gopalan, Anantha Iyengar; Lee, Kwang Pill; Komathi, Shanmugasundaram

2011-02-15

The present work demonstrates the utility of the functionalized carbon nanotubes, poly(4-aminobenzene sulfonic acid) (PABS) grafted multiwalled carbon nanotubes, MWNT-g-PABS, as an electrode modifier towards achieving ultrasensitive detection of a model drug, sildenafil citrate (SC). PABS units in MWNT-g-PABS interact with SC, pre-concentrate and accumulate at the surface. The electron transduction from SC to electrode is augmented via MWNT-g-PABS. As a result, the MWNT-g-PABS modified electrode exhibited ultrasensitive (57.7 μA/nM) and selective detection of SC with a detection limit of 4.7 pM. The present work provides scope towards targeting ultrasensitivity for the detection of biomolecules/drug through rational design and incorporation of appropriate chemical components to carbon nanotubes. Copyright © 2010 Elsevier B.V. All rights reserved.

Radiation-grafted fluoropolymers soaked with imidazolium-based ionic liquids for high-performance ionic polymer-metal composite actuators.

PubMed

Lee, Jang Yeol; Wang, Hyuck Sik; Yoon, Bye Ri; Han, Man Jae; Jho, Jae Young

2010-11-01

On purpose to develop a polymer actuator with high stability in air-operation as well as large bending displacement, a series of ionic polymer-metal composites (IPMC) was constructed with poly(styrene sulfonate)-grafted fluoropolymers as ionomeric matrix and immidazolium-based ionic liquids (IL) as inner solvent. The prepared IPMC actuators exhibited greatly enhanced bending displacement compared to Nafion-based actuators. The actuators were stable in air-operation, maintaining initial displacement for up to 10(4) cycles or 24 h. Investigating the material parameters and morphology of the IPMCs, high ion exchange capacity of the ionomers resulted in high ion conductivity and robust electrode of IPMC, which synergistically contributed to the high bending performance. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stable and null current hysteresis perovskite solar cells based nitrogen doped graphene oxide nanoribbons hole transport layer

PubMed Central

Kim, Jeongmo; Mat Teridi, Mohd Asri; Mohd Yusoff, Abd. Rashid bin; Jang, Jin

2016-01-01

Perovskite solar cells are becoming one of the leading technologies to reduce our dependency on traditional power sources. However, the frequently used component poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) has several shortcomings, such as an easily corroded indium-tin-oxide (ITO) interface at elevated temperatures and induced electrical inhomogeneity. Herein, we propose solution-processed nitrogen-doped graphene oxide nanoribbons (NGONRs) as a hole transport layer (HTL) in perovskite solar cells, replacing the conducting polymer PEDOT:PSS. The conversion efficiency of NGONR-based perovskite solar cells has outperformed a control device constructed using PEDOT:PSS. Moreover, our proposed NGONR-based devices also demonstrate a negligible current hysteresis along with improved stability. This work provides an effective route for substituting PEDOT:PSS as the effective HTL. PMID:27277388

Different Effects of NSF and PCE Superplasticizer on Adsorption, Dynamic Yield Stress and Thixotropy of Cement Pastes

PubMed Central

2018-01-01

This study compares the differences and similarities of two types of superplasticizers—NSF (Naphthalene Sulfonate Formaldehyde) and PCE (PolyCarboxylate Ester)—in fresh cement paste systems, in terms of adsorption, dynamic yield stress, and thixotropic index. Results show that with either NSF or PCE addition, the more superplasticizer is added, the more it is adsorbed and the more it remains in the interstitial pore solution. The dynamic yield stress and thixotropic index also decrease with increasing addition the amount of either superplasticizer. However, NSF is less efficient in decreasing the dynamic yield stress than PCE. More importantly, the decreasing patterns of dynamic yield stress and thixotropic index are different with NSF and PCE additions; this is tied to the adsorption and dispersing mechanisms of these two types of superplasticizers. PMID:29710782

Layer-by-Layer Polyelectrolyte Encapsulation of Mycoplasma pneumoniae for Enhanced Raman Detection

PubMed Central

Rivera-Betancourt, Omar E.; Sheppard, Edward S.; Krause, Duncan C.; Dluhy, Richard A.

2014-01-01

Mycoplasma pneumoniae is a major cause of respiratory disease in humans and accounts for as much as 20% of all community-acquired pneumonia. Existing mycoplasma diagnosis is primarily limited by the poor success rate at culturing the bacteria from clinical samples. There is a critical need to develop a new platform for mycoplasma detection that has high sensitivity, specificity, and expediency. Here we report the layer-by-layer (LBL) encapsulation of M. pneumoniae cells with Ag nanoparticles in a matrix of the polyelectrolytes poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS). We evaluated nanoparticle encapsulated mycoplasma cells as a platform for the differentiation of M. pneumoniae strains using surface enhanced Raman scattering (SERS) combined with multivariate statistical analysis. Three separate M. pneumoniae strains (M129, FH and II-3) were studied. Scanning electron microscopy and fluorescence imaging showed that the Ag nanoparticles were incorporated between the oppositely charged polyelectrolyte layers. SERS spectra showed that LBL encapsulation provides excellent spectral reproducibility. Multivariate statistical analysis of the Raman spectra differentiated the three M. pneumoniae strains with 97 – 100% specificity and sensitivity, and low (0.1 – 0.4) root mean square error. These results indicated that nanoparticle and polyelectrolyte encapsulation of M. pneumoniae is a potentially powerful platform for rapid and sensitive SERS-based bacterial identification. PMID:25017005

Solution processed transition metal oxide anode buffer layers for efficiency and stability enhancement of polymer solar cells

NASA Astrophysics Data System (ADS)

Ameen, M. Yoosuf; Shamjid, P.; Abhijith, T.; Reddy, V. S.

2018-01-01

Polymer solar cells were fabricated with solution-processed transition metal oxides, MoO3 and V2O5 as anode buffer layers (ABLs). The optimized device with V2O5 ABL exhibited considerably higher power conversion efficiency (PCE) compared to the devices based on MoO3 and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) ABLs. The space charge limited current measurements and impedance spectroscopy results of hole-only devices revealed that V2O5 provided a very low charge transfer resistance and high hole mobility, facilitating efficient hole transfer from the active layer to the ITO anode. More importantly, incorporation of V2O5 as ABL resulted in substantial improvement in device stability compared to MoO3 and PEDOT:PSS based devices. Unencapsulated PEDOT:PSS-based devices stored at a relative humidity of 45% have shown complete failure within 96 h. Whereas, MoO3 and V2O5 based devices stored in similar conditions retained 22% and 80% of their initial PCEs after 96 h. Significantly higher stability of the V2O5-based device is ascribed to the reduction in degradation of the anode/active layer interface, as evident from the electrical measurements.

Polymer mediated layer-by-layer assembly of different shaped gold nanoparticles.

PubMed

Budy, Stephen M; Hamilton, Desmond J; Cai, Yuheng; Knowles, Michelle K; Reed, Scott M

2017-02-01

Gold nanoparticles (GNPs) have a wide range of properties with potential applications in electronics, optics, catalysis, and sensing. In order to demonstrate that dense, stable, and portable samples could be created for these applications, multiple layers of GNPs were assembled via drop casting on glass substrates by layer-by-layer (LBL) techniques. Two cationic polyelectrolytes, poly(diallyldimethylammonium chloride) and polyethyleneimine, one anionic polyelectrolyte, poly(sodium 4-styrene sulfonate), and one neutral polymer, polyvinylpyrrolidone, were combined with four different shapes of GNPs (spherical, rod, triangular prismatic, and octahedral) to prepare thin films. A subset of these polymer nanoparticle combinations were assembled into thin films. Synthesized GNPs were characterized via dynamic light scattering, UV-vis spectroscopy, and transmission electron microscopy and the LBL thin films were characterized using UV-vis spectroscopy and atomic force microscopy. Sensing applications of the nanoparticles in solution and thin films were tested by monitoring the localized surface plasmon resonance of the GNPs. LBL thin films were prepared ranging from 25 to 100 layers with optical densities at plasmon from 0.5 to 3.0. Sensitivity in solutions ranged from 14 to 1002nm/refractive index units (RIU) and films ranged from 18.8 to 135.1nm/RIU suggesting reduced access to the GNPs within the films. Copyright © 2016 Elsevier Inc. All rights reserved.

One-pot polymerization of monolith coated stir bar for high efficient sorptive extraction of perfluoroalkyl acids from environmental water samples followed by high performance liquid chromatography-electrospray tandem mass spectrometry detection.

PubMed

Yao, Xuezi; Zhou, Zhen; He, Man; Chen, Beibei; Liang, Yong; Hu, Bin

2018-06-08

In this work, poly(1-vinylimidazole-ethyleneglycol dimethacrylate) (poly(VI-EDMA)) monolith coated stir bars were synthesized by one-pot polymerization, and they exhibited higher extraction efficiency and faster extraction dynamics for selected PFAAs than commercial ethylene glycol modified silicone (EG-silicone) and polydimethylsiloxane (PDMS) coated stir bars. Taking eleven PFAAs as target analytes, including C4-C12 perfluoroalkyl carboxylates (PFCAs) and C6, C8 perfluoroalkane sulfonates (PFSAs), a method combining monolith-based stir bar sorptive extraction (SBSE) with high performance liquid chromatography (HPLC) - electrospray tandem mass spectrometry (ESI-MS/MS) was proposed for the determination of multiplex PFAAs in environmental water samples. Under the optimized conditions, low limits of detection (0.06-0.40 ng/L) and wide linear range (0.6-400 ng/L) were obtained for target PFAAs with. The developed method was then applied for the analysis of target PFAAs in environmental water samples, and recoveries of 80.1-117% and 80.3-122% were obtained for target PFAAs in spiked Yangtze River and East Lake water samples respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

Frequency-dependent photothermal measurement of transverse thermal diffusivity of organic semiconductors

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

Brill, J. W.; Shahi, Maryam; Yao, Y.

2015-12-21

We have used a photothermal technique, in which chopped light heats the front surface of a small (∼1 mm{sup 2}) sample and the chopping frequency dependence of thermal radiation from the back surface is measured with a liquid-nitrogen-cooled infrared detector. In our system, the sample is placed directly in front of the detector within its dewar. Because the detector is also sensitive to some of the incident light, which leaks around or through the sample, measurements are made for the detector signal that is in quadrature with the chopped light. Results are presented for layered crystals of semiconducting 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pn)more » and for papers of cellulose nanofibrils coated with semiconducting poly(3,4-ethylene-dioxythiophene):poly(styrene-sulfonate) (NFC-PEDOT). For NFC-PEDOT, we have found that the transverse diffusivity, smaller than the in-plane value, varies inversely with thickness, suggesting that texturing of the papers varies with thickness. For TIPS-pn, we have found that the interlayer diffusivity is an order of magnitude larger than the in-plane value, consistent with previous estimates, suggesting that low-frequency optical phonons, presumably associated with librations in the TIPS side groups, carry most of the heat.« less

Highly-wrinkled reduced graphene oxide-conductive polymer fibers for flexible fiber-shaped and interdigital-designed supercapacitors

NASA Astrophysics Data System (ADS)

Li, Bo; Cheng, Jianli; Wang, Zhuanpei; Li, Yinchuan; Ni, Wei; Wang, Bin

2018-02-01

Flexible supercapacitors have attracted great interest due to outstanding flexibility and light weight. Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) fibers have the great potential in using as electrodes for flexible supercapacitors due to the good flexibility. However, the reported conductivity and specific capacitance of these PEDOT: PSS fibers are not very high, which limit their electrochemical performances. In this work, composite fibers of reduced graphene oxide(rGO)-PEDOT: PSS with a highly-wrinkled structure on the surface and pores inside are prepared by wet spinning. The fibers with different ratios of graphene to PEDOT:PSS show a distinctly enhanced conductivity up to ca. 590 S·cm-1 and high strength up to ca. 18.4 MPa. Meanwhile, the composite fibers show an improved electrochemical performances, including a high specific areal capacitance of 131 mF cm-2 and high specific areal energy density of 4.55 μWh·cm-2. The flexible supercapacitors including fiber-shaped supercapacitors and interdigital designed supercapacitors not only could work in different bending states without obvious capacitance decay, but also have small leakage current. The interdigital design can further improve the performances of composite fibers with high capacitance and high utilization compared with traditional parallel connected structure.

Fabrication of complex free-standing nanostructures with concave and convex curvature via the layer-by-layer approach.

PubMed

Raoufi, Mohammad; Schönherr, Holger

2014-02-18

We report on the fabrication of unprecedented free-standing complex polymeric nanoobjects, which possess both concave and convex curvatures, by exploiting the layer-by-layer (LBL) deposition of polyelectrolytes. In a combined top-down/bottom-up replication approach pore diameter-modulated anodic aluminum oxide (AAO) templates, fabricated by temperature modulation hard anodization (TMHA), were replicated with multilayers of poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) to yield open nanotubes with diameters in the wide and narrow segments of 210 and 150 nm, respectively. To obtain stable pore diameter-modulated nanopores, which possess segment lengths between 1 and 5 μm and 5 and 10 μm in the narrow and wide pore portion, respectively, conventional hard anodization of aluminum was followed by a subsequent temperature-modulated anodization. After removing the backside aluminum electrode, silanizing the aluminum oxide, and passivating the exposed membrane surface with a thin layer of gold, PSS and PAH were deposited alternatingly to yield LBL multilayers. For optimized LBL multilayer thicknesses and compactness, established in separate experiments on silicon substrates and nanoporous AAO with straight pores, free-standing polymeric nanoobjects with concave and convex curvatures, were obtained. These were stable for wall thickness to pore diameter ratios of ≥0.08.

Re-examination of the Pt Particle Size Effect on the Oxygen Reduction Reaction for Ultrathin Uniform Pt/C Catalyst Layers without Influence from Nafion

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

Shinozaki, Kazuma; Morimoto, Yu; Pivovar, Bryan S.

The platinum 'particle size effect' on the oxygen reduction reaction (ORR) has been re-evaluated using commercial Pt/C catalysts (2-10 nm Pt particle) and polycrystalline Pt (poly-Pt) in 0.1 M HClO4 with a rotating disk electrode method. Nafion-free catalyst layers were employed to obtain specific activities (SA) that were not perturbed (suppressed) by sulfonate anion adsorption/blocking. By using ultrathin uniform catalyst layers, O2 diffusion limitation was minimized as confirmed from the high SAs of our supported catalysts that were comparable to unsupported sputtered Pt having controlled sizes. The specific activity (SA) steeply increased for the particle sizes in the range -2-10more » nm (0.8-1.8 mA/cm2Pt at 0.9 V vs. RHE) and plateaued over -10 nm to 2.7 mA/cm2Pt for bulk poly-Pt. On the basis of the activity trend for the range of particle sizes studied, it appears that the effect of carbon support on activity is negligible. The experimental results and the concomitant profile of SA vs. particle size was found to be in an agreement to a truncated octahedral particle model that assumes active terrace sites.« less

High-performance inverted planar heterojunction perovskite solar cells based on a solution-processed CuOx hole transport layer.

PubMed

Sun, Weihai; Li, Yunlong; Ye, Senyun; Rao, Haixia; Yan, Weibo; Peng, Haitao; Li, Yu; Liu, Zhiwei; Wang, Shufeng; Chen, Zhijian; Xiao, Lixin; Bian, Zuqiang; Huang, Chunhui

2016-05-19

During the past several years, methylammonium lead halide perovskites have been widely investigated as light absorbers for thin-film photovoltaic cells. Among the various device architectures, the inverted planar heterojunction perovskite solar cells have attracted special attention for their relatively simple fabrication and high efficiencies. Although promising efficiencies have been obtained in the inverted planar geometry based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) sulfonic acid ( PSS) as the hole transport material (HTM), the hydrophilicity of the PSS is a critical factor for long-term stability. In this paper, a CuOx hole transport layer from a facile solution-processed method was introduced into the inverted planar heterojunction perovskite solar cells. After the optimization of the devices, a champion PCE of 17.1% was obtained with an open circuit voltage (Voc) of 0.99 V, a short-circuit current (Jsc) of 23.2 mA cm(-2) and a fill factor (FF) of 74.4%. Furthermore, the unencapsulated device cooperating with the CuOx film exhibited superior performance in the stability test, compared to the device involving the PSS layer, indicating that CuOx could be a promising HTM for replacing PSS in inverted planar heterojunction perovskite solar cells.

Morphology and Proton Transport in Humidified Phosphonated Peptoid Block Copolymers

DOE PAGES

Sun, Jing; Jiang, Xi; Siegmund, Aaron; ...

2016-04-04

Polymers that conduct protons in the hydrated state are of crucial importance in a wide variety of clean energy applications such as hydrogen fuel cells and artificial photosynthesis. Phosphonated and sulfonated polymers are known to conduct protons at low water content. In this study, we report on the synthesis phosphonated peptoid diblock copolymers, poly-N-(2-ethyl)hexylglycine-block-poly-N-phosphonomethylglycine (pNeh-b-pNpm), with volume fractions of pNpm (Φ Npm) values ranging from 0.13 to 0.44 and dispersity (¯D) ≤ 1.0003. The morphologies of the dry block copolypeptoids were determined by transmission electron microscopy and in both the dry and hydrated states by synchrotron small-angle X-ray scattering. Drymore » samples with Φ Npm > 0.13 exhibited a lamellar morphology. Upon hydration, the lowest molecular weight sample transitioned to a hexagonally packed cylinder morphology, while the others maintained their dry morphologies. Water uptake of all of the ordered samples was 8.1 ± 1.1 water molecules per phosphonate group. In spite of this, the proton conductivity of the ordered pNeh-b-pNpm copolymers ranged from 0.002 to 0.008 S/cm. Finally, we demonstrate that proton conductivity is maximized in high molecular weight, symmetric pNeh-b-pNpm copolymers.« less

A kinetic study on the formation of poly(4 aminodiphenylamine)/copper nanocomposite using UV-visible spectroscopy.

PubMed

Starlet Thanjam, I; Francklin Philips, M; Manisankar, P; Lee, Kwang-Pill; Gopalan, A

2013-12-01

The course of the reaction between copper sulfate (CuSO4) and 4-aminodiphenylamine (4ADPA) was monitored by UV-visible spectroscopy in p-toluene sulfonic acid (p-TSA). Formation of poly(4-aminodiphenylamine)/copper nanoparticle composite (P4ADPA/CuNC) was witnessed through the steady increase in absorbance at 410, 580 and >700 nm. The absorbance at 410 nm as well as >700 nm are correlated to the amount of P4ADPA/CuNC formation and was subsequently used to determine the rate of formation of P4ADPA/CuNC (RP4ADPA/CuNC) at any time during the course of the reaction. RP4ADPA/CuNC shows a first-order dependence on [4ADPA] and a half-order dependence on [CuSO4]. A kinetic rate expression was established between RP4ADPA/CuNC and experimental parameters such as [4ADPA] and [CuSO4]. The rate constant for the formation of P4ADPA/CuNC was 8.98 × 10(-3) mol(-0.5) l(0.5) s(-1). Field emission scanning electron and transmission electron micrographs revealed that the morphology of the P4ADPA/CuNC was influenced by the reaction conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

The Optical Properties of Thin Film Reduced Graphene Oxide/Poly (3,4 Ethylenedioxtriophene):Poly (Styrene Sulfonate)(PEDOT:PSS) Fabricated by Spin Coating

NASA Astrophysics Data System (ADS)

Rokmana, Arinta W.; Asriani, A.; Suhendar, H.; Triyana, K.; Kusumaatmaja, A.; Santoso, I.

2018-04-01

Reduced Graphene Oxide (rGO) has been successfully synthesized from Graphite powder through chemical process using modified Hummers method by removing NaNO3 from reaction formula. Hydrazine hydrate 80 wt% has been chosen as reductor to eliminate the epoxy group in GO. FTIR and Uv-Vis spectroscopy result showed that Graphene Oxide (GO) and rGO were formed. Our produced rGO then used to fabricated the composite thin film rGO/PEDOT:PSS by spin coating at room temperature. The optical constant of thin film rGO/PEDOT:PSS were calculated from the absorbance spectrum of Uv-Visible spectra. The result showed that the value of coefficient absorbance of rGO dropped from 4.7×106 m-1 to 1.3×106 m-1 after doped with 0.02 mL PEDOT:PSS, then increase with the addition volume concentration of PEDOT:PSS. The value of extinction coefficient decrease from 0.31 to 0.08 after rGO doped with 0.02 ml PEDOT:PSS and then increase with the addition concentration of PEDOT:PSS. Our result show that thin film rGO/PEDOT:PSS was more transparent than that of thin film rGO.

Graphene oxide/PEDOT:PSS composite hole transport layer for efficient and stable planar heterojunction perovskite solar cells.

PubMed

Lee, Da-Young; Na, Seok-In; Kim, Seok-Soon

2016-01-21

We investigated a graphene oxide (GO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) ( PSS) composite as a promising candidate for the practical application of a 2-D carbonaceous hole transport layer (HTL) to planar heterojunction perovskite solar cells (PeSCs) consisting of a transparent electrode/HTL/perovskite/fullerene/metal electrode. Both the insulating properties of GO and the non-uniform coating of the transparent electrode with GO cause the poor morphology of perovskite induced low power conversion efficiency (PCE) of 6.4%. On the other hand, PeSCs with a GO/PEDOT:PSS composite HTL, exhibited a higher PCE of 9.7% than that of a device fabricated with conventional PSS showing a PCE of 8.2%. The higher performance is attributed to the decreased series resistance (RS) and increased shunt resistance (RSh). The well-matched work-function between GO (4.9 eV) and PSS (5.1 eV) probably results in more efficient charge transport and an overall decrease in RS. The existence of GO with a large bandgap of ∼3.6 eV might induce the effective blocking of electrons, leading to an increase of RSh. Moreover, improvement in the long-term stability under atmospheric conditions was observed.

The feasibility of using solution-processed aqueous La2O3 as effective hole injection layer in organic light-emitting diode

NASA Astrophysics Data System (ADS)

Zhang, Yan; Li, Wanshu; Zhang, Ting; Yang, Bo; Zheng, Qinghong; Xu, Jiwen; Wang, Hua; Wang, Lihui; Zhang, Xiaowen; Wei, Bin

2018-01-01

Low-cost and scalable manufacturing boosts organic electronic devices with all solution process. La2O3 powders and corresponding aqueous solutions are facilely synthesized. Atomic force microscopy and scanning electron microscopy measurements show that solution-processed La2O3 behaves superior film morphology. X-ray diffraction and X-ray photoelectron spectroscopy measurements verify crystal phase and typical La signals. In comparison with the most widely-used hole injection layers (HILs) of MoOx and poly(ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), enhanced luminous efficiency is observed in organic light-emitting diode (OLED) using solution-processed La2O3 HIL. Current-voltage, impedance-voltage and phase angle-voltage transition curves clarify that solution-processed La2O3 behaves nearly comparable hole injection capacity to MoOx and PEDOT:PSS, and favorably tailors carrier balance. Moreover, the hole injection mechanism of solution-processed La2O3 is proven to be predominantly controlled by Fowler-Nordheim tunneling process and the hole injection barrier height between ITO and NPB via La2O3 interlayer is estimated to be 0.098 eV. Our experiments provide a feasible application of La2O3 in organic electronic devices with solution process.

Hybrid UV-Ozone-Treated rGO-PEDOT:PSS as an Efficient Hole Transport Material in Inverted Planar Perovskite Solar Cells

NASA Astrophysics Data System (ADS)

Wang, Shuying; Huang, Xiaona; Sun, Haoxuan; Wu, Chunyang

2017-12-01

Inverted planar perovskite solar cells (PSCs), which are regarded as promising devices for new generation of photovoltaic systems, show many advantages, such as low-temperature film formation, low-cost fabrication, and smaller hysteresis compared with those of traditional n-i-p PSCs. As an important carrier transport layer in PSCs, the hole transport layer (HTL) considerably affects the device performance. Therefore, HTL modification becomes one of the most critical issues in improving the performance of PSCs. In this paper, we report an effective and environmentally friendly UV-ozone treatment method to enhance the hydrophilia of reduced graphene oxide (rGO) with its excellent electrical performance. The treated rGO was applied to doped poly(3,4-ethylenedioxythiophene) poly(styrene-sulfonate) (PEDOT:PSS) as HTL material of PSCs. Consequently, the performance of rGO/PEDOT:PSS-doped PSCs was improved significantly, with power conversion efficiency (PCE) of 10.7%, Jsc of 16.75 mA/cm2, Voc of 0.87 V, and FF of 75%. The PCE of this doped PSCs was 27% higher than that of the PSCs with pristine PEDOT:PSS as HTL. This performance was attributed to the excellent surface morphology and optimized hole mobility of the solution-processable rGO-modified PEDOT:PSS.

Use of KRS-XE positive chemically amplified resist for optical mask manufacturing

NASA Astrophysics Data System (ADS)

Ashe, Brian; Deverich, Christina; Rabidoux, Paul A.; Peck, Barbara; Petrillo, Karen E.; Angelopoulos, Marie; Huang, Wu-Song; Moreau, Wayne M.; Medeiros, David R.

2002-03-01

The traditional mask making process uses chain scission-type resists such as PBS, poly(butene-1-sulfone), and ZEP, poly(methyl a-chloroacrylate-co-a-methylstyrene) for making masks with dimensions greater than 180nm. PBS resist requires a wet etch process to produce patterns in chrome. ZEP was employed for dry etch processing to meet the requirements of shrinking dimensions, optical proximity corrections and phase shift masks. However, ZEP offers low contrast, marginal etch resistance, organic solvent development, and concerns regarding resist heating with its high dose requirements1. Chemically Amplified Resist (CAR) systems are a very good choice for dimensions less than 180nm because of their high sensitivity and contrast, high resolution, dry etch resistance, aqueous development, and process latitude2. KRS-XE was developed as a high contrast CA resist based on ketal protecting groups that eliminate the need for post exposure bake (PEB). This resist can be used for a variety of electron beam exposures, and improves the capability to fabricate masks for devices smaller than 180nm. Many factors influence the performance of resists in mask making such as post apply bake, exposure dose, resist develop, and post exposure bake. These items will be discussed as well as the use of reactive ion etching (RIE) selectivity and pattern transfer.

Ionic Driven Embedment of Hyaluronic Acid Coated Liposomes in Polyelectrolyte Multilayer Films for Local Therapeutic Delivery

NASA Astrophysics Data System (ADS)

Hayward, Stephen L.; Francis, David M.; Sis, Matthew J.; Kidambi, Srivatsan

2015-10-01

The ability to control the spatial distribution and temporal release of a therapeutic remains a central challenge for biomedical research. Here, we report the development and optimization of a novel substrate mediated therapeutic delivery system comprising of hyaluronic acid covalently functionalized liposomes (HALNPs) embedded into polyelectrolyte multilayer (PEM) platform via ionic stabilization. The PEM platform was constructed from sequential deposition of Poly-L-Lysine (PLL) and Poly(Sodium styrene sulfonate) (SPS) “(PLL/SPS)4.5” followed by adsorption of anionic HALNPs. An adsorption affinity assay and saturation curve illustrated the preferential HALNP deposition density for precise therapeutic loading. (PLL/SPS)2.5 capping layer on top of the deposited HALNP monolayer further facilitated complete nanoparticle immobilization, cell adhesion, and provided nanoparticle confinement for controlled linear release profiles of the nanocarrier and encapsulated cargo. To our knowledge, this is the first study to demonstrate the successful embedment of a translatable lipid based nanocarrier into a substrate that allows for temporal and spatial release of both hydrophobic and hydrophilic drugs. Specifically, we have utilized our platform to deliver chemotherapeutic drug Doxorubicin from PEM confined HALNPs. Overall, we believe the development of our HALNP embedded PEM system is significant and will catalyze the usage of substrate mediated delivery platforms in biomedical applications.

Geochemical and Hydrologic Factors Controlling Subsurface Transport of Poly- and Perfluoroalkyl Substances, Cape Cod, Massachusetts.

PubMed

Weber, Andrea K; Barber, Larry B; LeBlanc, Denis R; Sunderland, Elsie M; Vecitis, Chad D

2017-04-18

Growing evidence that certain poly- and perfluoroalkyl substances (PFASs) are associated with negative human health effects prompted the U.S. Environmental Protection Agency to issue lifetime drinking water health advisories for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in 2016. Given that groundwater is a major source of drinking water, the main objective of this work was to investigate geochemical and hydrological processes governing the subsurface transport of PFASs at a former fire training area (FTA) on Cape Cod, Massachusetts, where PFAS-containing aqueous film-forming foams were used historically. A total of 148 groundwater samples and 4 sediment cores were collected along a 1200-m-long downgradient transect originating near the FTA and analyzed for PFAS content. The results indicate that unsaturated zones at the FTA and at hydraulically downgradient former domestic wastewater effluent infiltration beds both act as continuous PFAS sources to the groundwater despite 18 and 20 years of inactivity, respectively. Historically different PFAS sources are evident from contrasting PFAS composition near the water table below the FTA and wastewater-infiltration beds. Results from total oxidizable precursor assays conducted using groundwater samples collected throughout the plume suggest that some perfluoroalkyl acid precursors at this site are transporting with perfluoroalkyl acids.

Correlation between the fine structure of spin-coated PEDOT:PSS and the photovoltaic performance of organic/crystalline-silicon heterojunction solar cells

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

Funda, Shuji; Ohki, Tatsuya; Liu, Qiming

2016-07-21

We investigated the relationship between the fine structure of spin-coated conductive polymer poly(3,4-ethylenedioxythiphene):poly(styrene sulfonate) (PEDOT:PSS) films and the photovoltaic performance of PEDOT:PSS crystalline-Si (PEDOT:PSS/c-Si) heterojunction solar cells. Real-time spectroscopic ellipsometry revealed that there were two different time constants for the formation of the PEDOT:PSS network. Upon removal of the polar solvent, the PEDOT:PSS film became optically anisotropic, indicating a conformational change in the PEDOT and PSS chain. Polarized Fourier transform infrared attenuated total reflection absorption spectroscopy and Raman spectroscopy measurements also indicated that thermal annealing promoted an in-plane π-conjugated C{sub α} = C{sub β} configuration attributed to a thiophene ring in PEDOTmore » and an out-of-plane configuration of -SO{sub 3} groups in the PSS chain with increasing composition ratio of oxidized (benzoid) to neutral (quinoid) PEDOT, I{sub qui}/I{sub ben}. The highest power conversion efficiency for the spin-coated PEDOT:PSS/c-Si heterojunction solar cells was 13.3% for I{sub qui}/I{sub ben} = 9–10 without employing any light harvesting methods.« less

Effect of a PEDOT:PSS modified layer on the electrical characteristics of flexible memristive devices based on graphene oxide:polyvinylpyrrolidone nanocomposites

NASA Astrophysics Data System (ADS)

Kim, Woo Kyum; Wu, Chaoxing; Kim, Tae Whan

2018-06-01

The electrical characteristics of flexible memristive devices utilizing a graphene oxide (GO):polyvinylpyrrolidone (PVP) nanocomposite charge-trapping layer with a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)-modified layer fabricated on an indium-tin-oxide (ITO)-coated polyethylene glycol naphthalate (PEN) substrate were investigated. Current-voltage (I-V) curves for the Al/GO:PVP/PEDOT:PSS/ITO/PEN devices showed remarkable hysteresis behaviors before and after bending. The maximum memory margins of the devices before and after 100 bending cycles were approximately 7.69 × 103 and 5.16 × 102, respectively. The devices showed nonvolatile memory effect with a retention time of more than 1 × 104 s. The "Reset" voltages were distributed between 2.3 and 3.5 V, and the "Set" voltages were dispersed between -0.7 and -0.2 V, indicative of excellent, uniform electrical performance. The endurance number of ON/OFF-switching and bending cycles for the devices was 1 × 102, respectively. The bipolar resistive switching behavior was explained on the basis of I-V results. In particular, the bipolar resistive switching behaviors of the LRS and the HRS for the devices are dominated by the Ohmic and space charge current mechanisms, respectively.

Raman Microscopy Insights on the Out-of-Plane Electrical Transport of Carbon Nanotube-Doped PEDOT:PSS Electrodes for Solar Cell Applications.

PubMed

Mombrú, Dominique; Romero, Mariano; Faccio, Ricardo; Mombrú, Alvaro W

2018-03-08

In the present report, we focused on the study of the out-of-plane electrical transport of multiwalled carbon nanotube (MWCNT)-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) composites (PEDOT:PSS-MWCNTs) as electrodes for solar cell applications. The out-of-plane direct current and alternating current electrical transport, rarely studied but not less relevant, was additionally supported with in-plane and out-of-plane confocal Raman microscopy and grazing incidence small-angle X-ray scattering characterizations. The main relevance of our study is the monitoring of the polymer structure all across the polymeric film by using confocal Raman spectroscopy and its correlation with electrical transport. Modifications in the PEDOT benzenoid and quinoid conformations were observed in the vicinities of MWCNTs, and the enrichment of PSS at the indium tin oxide electrode interface was also evidenced. In consequence, the low MWCNT loadings into PEDOT:PSS lead to an increase of the out-of-plane conductivity, but the heavier MWCNT loadings lead to a drastic decrease. The tuning of the doping level of these polymer composites and the understanding of the interface structure are crucial to fabricate electrodes with higher out-of-plane conductivities for organic solar cell applications.

Morphology and Proton Transport in Humidified Phosphonated Peptoid Block Copolymers

PubMed Central

2016-01-01

Polymers that conduct protons in the hydrated state are of crucial importance in a wide variety of clean energy applications such as hydrogen fuel cells and artificial photosynthesis. Phosphonated and sulfonated polymers are known to conduct protons at low water content. In this paper, we report on the synthesis phosphonated peptoid diblock copolymers, poly-N-(2-ethyl)hexylglycine-block-poly-N-phosphonomethylglycine (pNeh-b-pNpm), with volume fractions of pNpm (ϕNpm) values ranging from 0.13 to 0.44 and dispersity (Đ) ≤ 1.0003. The morphologies of the dry block copolypeptoids were determined by transmission electron microscopy and in both the dry and hydrated states by synchrotron small-angle X-ray scattering. Dry samples with ϕNpm > 0.13 exhibited a lamellar morphology. Upon hydration, the lowest molecular weight sample transitioned to a hexagonally packed cylinder morphology, while the others maintained their dry morphologies. Water uptake of all of the ordered samples was 8.1 ± 1.1 water molecules per phosphonate group. In spite of this, the proton conductivity of the ordered pNeh-b-pNpm copolymers ranged from 0.002 to 0.008 S/cm. We demonstrate that proton conductivity is maximized in high molecular weight, symmetric pNeh-b-pNpm copolymers. PMID:27134312

Geochemical and hydrologic factors controlling subsurface transport of poly- and perfluoroalkyl substances, Cape Cod, Massachusetts

USGS Publications Warehouse

Weber, Andrea K.; Barber, Larry B.; LeBlanc, Denis R.; Sunderland, Elsie M.; Vecitis, Chad D.

2017-01-01

Growing evidence that certain poly- and perfluoroalkyl substances (PFASs) are associated with negative human health effects prompted the U.S. Environmental Protection Agency to issue lifetime drinking water health advisories for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in 2016. Given that groundwater is a major source of drinking water, the main objective of this work was to investigate geochemical and hydrological processes governing the subsurface transport of PFASs at a former fire training area (FTA) on Cape Cod, Massachusetts, where PFAS-containing aqueous film-forming foams were used historically. A total of 148 groundwater samples and 4 sediment cores were collected along a 1200-m-long downgradient transect originating near the FTA and analyzed for PFAS content. The results indicate that unsaturated zones at the FTA and at hydraulically downgradient former domestic wastewater effluent infiltration beds both act as continuous PFAS sources to the groundwater despite 18 and 20 years of inactivity, respectively. Historically different PFAS sources are evident from contrasting PFAS composition near the water table below the FTA and wastewater-infiltration beds. Results from total oxidizable precursor assays conducted using groundwater samples collected throughout the plume suggest that some perfluoroalkyl acid precursors at this site are transporting with perfluoroalkyl acids.

Resveratrol-loaded polymeric nanoparticles: validation of an HPLC-PDA method to determine the drug entrapment and evaluation of its antioxidant activity.

PubMed

da Rocha Lindner, Gabriela; Khalil, Najeh Maissar; Mainardes, Rubiana Mara

2013-01-01

Poly(lactic acid) (PLA) and PLA-poly(ethylene glycol) (PLA-PEG) nanoparticles containing resveratrol (RVT) were developed, and their antioxidant activity was evaluated. An analytical method using high performance liquid chromatography (HPLC)/photodiode array (PDA) detection was also developed and validated for RVT determination in nanoparticles. The mobile phase consisted of methanol : water (51 : 49, v/v) flowed at 0.9 mL/min, and the PDA detector was set at wavelength of 306 nm. The mean diameter of the nanoparticles varied between 180 and 220 nm, and the encapsulation efficiency of RVT ranged from 60% to 88%. The nanoparticles containing RVT were evaluated for their ability to scavenge the radical (2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) (ABTS•⁺). The profile obtained from the PLA nanoparticles containing RVT demonstrated that after 24 h, there was almost no increase in antioxidant activity, which was lower than that of the free RVT and RVT-loaded PLA-PEG nanoparticles. For PLA-PEG nanoparticles, the radical-scavenging activity of RVT was shown to increase with time, and after 48 h, it was similar to that observed with free RVT.

40 CFR 721.10035 - Alkylbenzene sulfonate (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylbenzene sulfonate (generic). 721... Substances § 721.10035 Alkylbenzene sulfonate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkylbenzene sulfonate (PMN-02...

40 CFR 721.10035 - Alkylbenzene sulfonate (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkylbenzene sulfonate (generic). 721... Substances § 721.10035 Alkylbenzene sulfonate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkylbenzene sulfonate (PMN-02...

40 CFR 721.1625 - Alkylbenzene sulfonate, amine salt.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkylbenzene sulfonate, amine salt... Substances § 721.1625 Alkylbenzene sulfonate, amine salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkylbenzene sulfonate, amine...

40 CFR 721.1625 - Alkylbenzene sulfonate, amine salt.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylbenzene sulfonate, amine salt... Substances § 721.1625 Alkylbenzene sulfonate, amine salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkylbenzene sulfonate, amine...

[Synthesis, solubility, lipids-lowering and liver-protection activities of sulfonated formononetin].

PubMed

Wang, Qiu-ya; Meng, Qing-hua; Zhang, Zun-ting; Tian, Zhen-jun; Liu, Hui

2009-04-01

A water-soluble compound, sodium formononetin-3'-sulfonate with good lipid-lowering and liver-protection activities was synthesized. It was synthesized by sulfonation reaction, and its structure was characterized by IR, NMR and elemental analyses. The solubility of sodium formononetin-3'-sulfonate in water and n-octanol/water partition coefficient were determined by UV spectrophotometry. The lipid-lowering and liver-protection activities of sodium formononetin-3'-sulfonate were tested by using rat's high fat model induce by feeding with high fat food. The results showed that sodium formononetin-3'-sulfonate not only had favorable water, solubility but also had good lipid-lowering and liver-protection activities.

Bisphenol A sulfonation is impaired in metabolic and liver disease

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

Yalcin, Emine B.; Kulkarni, Supriya R.; Slitt, Angela L., E-mail: angela_slitt@uri.edu

Background: Bisphenol A (BPA) is a widely used industrial chemical and suspected endocrine disruptor to which humans are ubiquitously exposed. The liver metabolizes and facilitates BPA excretion through glucuronidation and sulfonation. The sulfotransferase enzymes contributing to BPA sulfonation (detected in human and rodents) is poorly understood. Objectives: To determine the impact of metabolic and liver disease on BPA sulfonation in human and mouse livers. Methods: The capacity for BPA sulfonation was determined in human liver samples that were categorized into different stages of metabolic and liver disease (including obesity, diabetes, steatosis, and cirrhosis) and in livers from ob/ob mice. Results:more » In human liver tissues, BPA sulfonation was substantially lower in livers from subjects with steatosis (23%), diabetes cirrhosis (16%), and cirrhosis (18%), relative to healthy individuals with non-fatty livers (100%). In livers of obese mice (ob/ob), BPA sulfonation was lower (23%) than in livers from lean wild-type controls (100%). In addition to BPA sulfonation activity, Sult1a1 protein expression decreased by 97% in obese mouse livers. Conclusion: Taken together these findings establish a profoundly reduced capacity of BPA elimination via sulfonation in obese or diabetic individuals and in those with fatty or cirrhotic livers versus individuals with healthy livers. - Highlights: • Present study demonstrates that hepatic SULT 1A1/1A3 are primarily sulfonate BPA in mouse and human. • Hepatic BPA sulfonation is profoundly reduced steatosis, diabetes and cirrhosis. • With BPA-S detectable in urine under low or common exposures, these findings are novel and important.« less

40 CFR 721.9674 - Sulfonated-copper phthalocyanine salt of a triarylmethane dye (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Sulfonated-copper phthalocyanine salt... Significant New Uses for Specific Chemical Substances § 721.9674 Sulfonated-copper phthalocyanine salt of a... chemical substance identified generically as sulfonated-copper phthalocyanine salt of a triarylmethane dye...

40 CFR 721.9674 - Sulfonated-copper phthalocyanine salt of a triarylmethane dye (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Sulfonated-copper phthalocyanine salt... Significant New Uses for Specific Chemical Substances § 721.9674 Sulfonated-copper phthalocyanine salt of a... chemical substance identified generically as sulfonated-copper phthalocyanine salt of a triarylmethane dye...

40 CFR 721.9674 - Sulfonated-copper phthalocyanine salt of a triarylmethane dye (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Sulfonated-copper phthalocyanine salt... Significant New Uses for Specific Chemical Substances § 721.9674 Sulfonated-copper phthalocyanine salt of a... chemical substance identified generically as sulfonated-copper phthalocyanine salt of a triarylmethane dye...

40 CFR 721.10564 - Mixed amino diaryl sulfone isomers (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Mixed amino diaryl sulfone isomers... Specific Chemical Substances § 721.10564 Mixed amino diaryl sulfone isomers (generic). (a) Chemical... as mixed amino diaryl sulfone isomers (PMN P-08-39) is subject to reporting under this section for...

40 CFR 721.10564 - Mixed amino diaryl sulfone isomers (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Mixed amino diaryl sulfone isomers... Specific Chemical Substances § 721.10564 Mixed amino diaryl sulfone isomers (generic). (a) Chemical... as mixed amino diaryl sulfone isomers (PMN P-08-39) is subject to reporting under this section for...

40 CFR 721.950 - Sodium salt of an alkylated, sulfonated aromatic (generic name).

Code of Federal Regulations, 2010 CFR

2010-07-01

..., sulfonated aromatic (generic name). 721.950 Section 721.950 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.950 Sodium salt of an alkylated, sulfonated... chemical substance identified generically as a sodium salt of an alkylated, sulfonated aromatic (PMN P-84...

40 CFR 721.2565 - Alkylated sulfonated diphenyl oxide, alkali and amine salts.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkylated sulfonated diphenyl oxide... New Uses for Specific Chemical Substances § 721.2565 Alkylated sulfonated diphenyl oxide, alkali and... substances identified as alkylated sulfonated diphenyl oxide, alkali salt (PMN P-93-352) and alkylated...

40 CFR 721.2565 - Alkylated sulfonated diphenyl oxide, alkali and amine salts.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkylated sulfonated diphenyl oxide... New Uses for Specific Chemical Substances § 721.2565 Alkylated sulfonated diphenyl oxide, alkali and... substances identified as alkylated sulfonated diphenyl oxide, alkali salt (PMN P-93-352) and alkylated...

40 CFR 721.950 - Sodium salt of an alkylated, sulfonated aromatic (generic name).

Code of Federal Regulations, 2011 CFR

2011-07-01

..., sulfonated aromatic (generic name). 721.950 Section 721.950 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.950 Sodium salt of an alkylated, sulfonated... chemical substance identified generically as a sodium salt of an alkylated, sulfonated aromatic (PMN P-84...

40 CFR 721.9674 - Sulfonated-copper phthalocyanine salt of a triarylmethane dye (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Sulfonated-copper phthalocyanine salt... Significant New Uses for Specific Chemical Substances § 721.9674 Sulfonated-copper phthalocyanine salt of a... chemical substance identified generically as sulfonated-copper phthalocyanine salt of a triarylmethane dye...

40 CFR 721.9674 - Sulfonated-copper phthalocyanine salt of a triarylmethane dye (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Sulfonated-copper phthalocyanine salt... Significant New Uses for Specific Chemical Substances § 721.9674 Sulfonated-copper phthalocyanine salt of a... chemical substance identified generically as sulfonated-copper phthalocyanine salt of a triarylmethane dye...

40 CFR 721.5425 - α-Olefin sulfonate, potassium salts.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an α-olefin sulfonate, potassium salt (PMN...

40 CFR 721.5425 - α-Olefin sulfonate, potassium salts.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an α-olefin sulfonate, potassium salt (PMN...

40 CFR 721.5425 - α-Olefin sulfonate, potassium salts.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an α-olefin sulfonate, potassium salt (PMN...

40 CFR 721.5450 - α-Olefin sulfonate, sodium salt.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false α-Olefin sulfonate, sodium salt. 721... Substances § 721.5450 α-Olefin sulfonate, sodium salt. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as α-olefin sulfonate, sodium salt...

40 CFR 721.5425 - α-Olefin sulfonate, potassium salts.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an α-olefin sulfonate, potassium salt (PMN...

40 CFR 721.5425 - α-Olefin sulfonate, potassium salts.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false α-Olefin sulfonate, potassium salts... Substances § 721.5425 α-Olefin sulfonate, potassium salts. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as an α-olefin sulfonate, potassium salt (PMN...

Nanoscale structure and morphology of sulfonated polyphenylenes via atomistic simulations

DOE PAGES

Abbott, Lauren J.; Frischknecht, Amalie L.

2017-01-23

We performed atomistic simulations on a series of sulfonated polyphenylenes systematically varying the degree of sulfonation and water content to determine their effect on the nanoscale structure, particularly for the hydrophilic domains formed by the ionic groups and water molecules. We found that the local structure around the ionic groups depended on the sulfonation and hydration levels, with the sulfonate groups and hydronium ions less strongly coupled at higher water contents. In addition, we characterized the morphology of the ionic domains employing two complementary clustering algorithms. At low sulfonation and hydration levels, clusters were more elongated in shape and poorlymore » connected throughout the system. As the degree of sulfonation and water content were increased, the clusters became more spherical, and a fully percolated ionic domain was formed. As a result, these structural details have important implications for ion transport.« less

Mineralization of the sulfonated azo dye Mordant Yellow 3 by a 6-aminonaphthalene-2-sulfonate-degrading bacterial consortium.

PubMed Central

Haug, W; Schmidt, A; Nörtemann, B; Hempel, D C; Stolz, A; Knackmuss, H J

1991-01-01

Under anaerobic conditions the sulfonated azo dye Mordant Yellow 3 was reduced by the biomass of a bacterial consortium grown aerobically with 6-aminonaphthalene-2-sulfonic acid. Stoichiometric amounts of the aromatic amines 6-aminonaphthalene-2-sulfonate and 5-aminosalicylate were generated and excreted into the medium. After re-aeration of the culture, these amines were mineralized by different members of the bacterial culture. Thus, total degradation of a sulfonated azo dye was achieved by using an alternating anaerobic-aerobic treatment. The ability of the mixed bacterial culture to reduce the azo dye was correlated with the presence of strain BN6, which possessed the ability to oxidize various naphthalenesulfonic acids. It is suggested that strain BN6 has a transport system for naphthalenesulfonic acids which also catalyzes uptake of sulfonated azo dyes. These dyes are then gratuitously reduced in the cytoplasm by unspecific reductases. PMID:1781678

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

In situ S-K XANES study of polymer electrolyte fuel cells: changes in the chemical states of sulfonic groups depending on humidity.

PubMed

Isegawa, Kazuhisa; Nagami, Tetsuo; Jomori, Shinji; Yoshida, Masaaki; Kondoh, Hiroshi

2016-09-14

Changes in the chemical states of sulfonic groups of Nafion in polymer electrolyte fuel cells (PEFCs) under gas-flowing conditions were studied using in situ S-K XANES spectroscopy. The applied potential to the electrodes and the humidity of the cell were changed under flowing H 2 gas in the anode and He gas in the cathode. While the potential shows no significant effect on the S-K XANES spectra, the humidity is found to induce reversible changes in the spectra. Comparison of the spectral changes with simulations based on the density functional theory calculations indicates that the humidity influences the chemical state of the sulfonic group; under wet conditions the sulfonic group is in the form of a sulfonate ion. By drying treatment the sulfonate ion binds to hydrogen and becomes sulfonic acid. Furthermore, a small fraction of the sulfonic acid irreversibly decomposes to atomic sulfur. The peak energy of the atomic sulfur suggests that the generated atomic sulfur is adsorbed on the Pt catalyst surfaces.

Design, fabrication and evaluation of intelligent sulfone-selective polybenzimidazole nanofibers.

PubMed

Ogunlaja, Adeniyi S; du Sautoy, Carol; Torto, Nelson; Tshentu, Zenixole R

2014-08-01

Molecularly imprinted polybenzimidazole nanofibers fabricated for the adsorption of oxidized organosulfur compounds are presented. The imprinted polymers exhibited better selectivity for their target model sulfone-containing compounds with adsorption capacities of 28.5±0.4mg g(-1), 29.8±2.2mg g(-1) and 20.1±1.4mg g(-1) observed for benzothiophene sulfone (BTO2), dibenzothiophene sulfone (DBTO2) and 4,6-dimethyldibenzothiophene sulfone (4,6-DMDBTO2) respectively. Molecular modeling based upon the density functional theory (DFT) indicated that hydrogen bond interactions may take place between sulfone oxygen groups with NH groups of the PBI. Further DFT also confirmed the feasibility of π-π interactions between the benzimidazole rings and the aromatic sulfone compounds. The adsorption mode followed the Freundlich (multi-layered) adsorption isotherm which indicated possible sulfone-sulfone interactions. A home-made pressurized hot water extraction (PHWE) system was employed for the extraction/desorption of sulfone compounds within imprinted nanofibers at 1mL min(-1), 150°C and 30 bar. PHWE used a green solvent (water) and achieved better extraction yields compared to the Soxhlet extraction process. The application of molecularly imprinted polybenzimidazole (PBI) nanofibers displayed excellent sulfur removal, with sulfur in fuel after adsorption falling below the determined limit of detection (LOD), which is 2.4mg L(-1)S, and with a sulfur adsorption capacity of 5.3±0.4mg g(-1) observed for application in the fuel matrix. Copyright © 2014 Elsevier B.V. All rights reserved.

40 CFR 721.6220 - Aryl sulfonate of a fatty acid mixture, polyamine condensate.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aryl sulfonate of a fatty acid mixture... Specific Chemical Substances § 721.6220 Aryl sulfonate of a fatty acid mixture, polyamine condensate. (a... generically as an aryl sulfonate of a fatty acid mixture, polyamine condensate (PMN P-91-584) is subject to...

40 CFR 721.9597 - Salt of a substituted sulfonated aryl azo compound (generic).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Salt of a substituted sulfonated aryl... New Uses for Specific Chemical Substances § 721.9597 Salt of a substituted sulfonated aryl azo... substance identified generically as salt of a substituted sulfonated aryl azo compound (PMN P-00-0094) is...

40 CFR 721.9597 - Salt of a substituted sulfonated aryl azo compound (generic).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Salt of a substituted sulfonated aryl... New Uses for Specific Chemical Substances § 721.9597 Salt of a substituted sulfonated aryl azo... substance identified generically as salt of a substituted sulfonated aryl azo compound (PMN P-00-0094) is...

Post-sulfonation of cellulose nanofibrils with a one-step reaction to improve dispersibility

Treesearch

Jeffrey Luo; Nikolay Semenikhin; Huibin Chang; Robert J. Moon; Satish Kumar

2018-01-01

Cellulose nanofibrils (CNF) were sulfonated and the dispersion quality was compared to unfunctionalized and 2,2,6,6-tetramethylpiperdine-1-oxyl radical (TEMPO) post-oxidation treatment of existing CNF (mechanically fibrillated pulp). A post-sulfonation treatment on existing CNF in chlorosulfonic acid and dimethylformamide (DMF) resulted in sulfonated CNF that retained...

40 CFR 721.644 - Amines, C12-14-tert-alkyl, sulfonates.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Amines, C12-14-tert-alkyl, sulfonates... Substances § 721.644 Amines, C12-14-tert-alkyl, sulfonates. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as amines, C12-14-tert-alkyl, sulfonates (PMN...

40 CFR 721.6220 - Aryl sulfonate of a fatty acid mixture, polyamine condensate.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aryl sulfonate of a fatty acid mixture... Specific Chemical Substances § 721.6220 Aryl sulfonate of a fatty acid mixture, polyamine condensate. (a... generically as an aryl sulfonate of a fatty acid mixture, polyamine condensate (PMN P-91-584) is subject to...

40 CFR 721.644 - Amines, C12-14-tert-alkyl, sulfonates.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amines, C12-14-tert-alkyl, sulfonates... Substances § 721.644 Amines, C12-14-tert-alkyl, sulfonates. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as amines, C12-14-tert-alkyl, sulfonates (PMN...

Sulfonates: A novel class of organic sulfur compounds in marine sediments

NASA Astrophysics Data System (ADS)

Vairavamurthy, Appathurai; Zhou, Weiqing; Eglinton, Timothy; Manowitz, Bernard

1994-11-01

X-ray absorption near-edge structure spectroscopy (XANES) used to measure sulfur speciation in a variety of organic-rich marine sediments has established sulfonates as a novel and major component of sedimentary organic sulfur. The origins of sulfonates in sediments are not clear, although both biological and geochemical mechanisms are possible. The accumulation of oxidized sulfonate sulfur in reducing marine sediments was not known previously; hence, a new perspective in sulfur geochemistry is established. The biogeochemical implications of the presence of sulfonates in marine sediments are discussed.

Preparation of Highly Conductive Yarns by an Optimized Impregnation Process

NASA Astrophysics Data System (ADS)

Amba Sankar, K. N.; Mohanta, Kallol

2017-12-01

We report the development of the electrical conductivity in textile yarns through impregnation and post-treatment of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The conductive polymer is deposited on fibers, which fills the gap space within the hierarchical structure of the yarns. Organic nonpolar solvents act as reducing agent to increase the density of PEDOT moieties on the yarns, galvanizing increment in conductivity values. Post-treatment by ethylene glycol transforms the resonance configuration of the conductive moieties of conjugated polymer, which helps in further enhancement of electrical conductivity of the yarns. We have optimized the method in terms of loading and conformal change of the polymer to have a lesser resistance of the coated conductive yarns. The minimum resistance achieved has a value of 77 Ωcm-1. This technique of developing conductivity in conventional yarns enables retaining the flexibility of yarns and feeling of softness which would find suitable applications for wearable electronics.

Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes/polymer composite thin film.

PubMed

Rajanna, Pramod Mulbagal; Gilshteyn, Evgenia; Yagafarov, Timur; Alekseeva, Alena; Anisimov, Anton; Sergeev, Oleg; Neumueller, Alex; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert

2018-01-09

We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and a thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high quality SWCNTs with an enhanced conductivity by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with different SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit Jsc, open-circuit Voc, and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and efficiency of 3.4% under simulated one-sun AM 1.5G direct illumination. © 2018 IOP Publishing Ltd.

Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes and polymer composite thin film.

PubMed

Rajanna, Pramod M; Gilshteyn, Evgenia P; Yagafarov, Timur; Aleekseeva, Alena K; Anisimov, Anton S; Neumüller, Alex; Sergeev, Oleg; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert G

2018-01-31

We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high-quality SWCNTs with conductivity enhanced by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with varying SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit J sc , open-circuit V oc , and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and an efficiency of 3.4% under simulated one-sun AM 1.5 G direct illumination.

Stable angular emission spectra in white organic light-emitting diodes using graphene/PEDOT:PSS composite electrode.

PubMed

Cho, Hyunsu; Lee, Hyunkoo; Lee, Jonghee; Sung, Woo Jin; Kwon, Byoung-Hwa; Joo, Chul-Woong; Shin, Jin-Wook; Han, Jun-Han; Moon, Jaehyun; Lee, Jeong-Ik; Cho, Seungmin; Cho, Nam Sung

2017-05-01

In this work, we suggest a graphene/ poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) composite as a transparent electrode for stabilizing white emission of organic light-emitting diodes (OLEDs). Graphene/PEDOT:PSS composite electrodes have increased reflectance when compared to graphene itself, but their reflectance is still lower than that of ITO itself. Changes in the reflectance of the composite electrode have the advantage of suppressing the angular spectral distortion of white emission OLEDs and achieving an efficiency of 16.6% for white OLEDs, comparable to that achieved by graphene-only electrodes. By controlling the OLED structure to compensate for the two-beam interference effect, the CIE color coordinate change (Δxy) of OLEDs based on graphene/PEDOT:PSS composite electrodes is 0.018, less than that based on graphene-only electrode, i.e.,0.027.

A fundamental approach to the sticking of insect residues to aircraft wings

NASA Technical Reports Server (NTRS)

Eiss, N. S., Jr.; Wightman, J. P.; Gilliam, D. R.; Siochi, E. J.

1984-01-01

A proposed testing scheme is described for obtaining data on the effects of surface roughness and surface energy on insect adhesion. The road test apparatus is discussed as well as surface preparation techniques. Uncoated and polymer coated metal substrates were analyzed by SEM/ESCA/IRS before and following collision with insects. Critical surface tensions of unexposed Nyebar and poly sulfone coatings were 10 and 33 dynes/cm, respectively, as determined from contact angles. A total of 95% of insect residues collected belong to order Diptera. Significantly less insect debris was detected on the coated plates as compared to the uncoated plates. Minimal contamination at the 5 nm level of both coated and uncoated plates occurs even after hours of exposure to road conditions as determined by ESCA analysis. The presence of nitrogen detected by ESCA on exposed plates is unequivocal evidence for insect residues left on plates.

Electrostimulated Release of Neutral Drugs from Polythiophene Nanoparticles: Smart Regulation of Drug-Polymer Interactions.

PubMed

Puiggalí-Jou, Anna; Micheletti, Paolo; Estrany, Francesc; Del Valle, Luis J; Alemán, Carlos

2017-09-01

Poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles are loaded with curcumin and piperine by in situ emulsion polymerization using dodecyl benzene sulfonic acid both as a stabilizer and a doping agent. The loaded drugs affect the morphology, size, and colloidal stability of the nanoparticles. Furthermore, kinetics studies of nonstimulated drug release have evidenced that polymer···drug interactions are stronger for curcumin than for piperine. This observation suggests that drug delivery systems based on combination of the former drug with PEDOT are much appropriated to show an externally tailored release profile. This is demonstrated by comparing the release profiles obtained in presence and absence of electrical stimulus. Results indicate that controlled and time-programmed release of curcumin is achieved in a physiological medium by applying a negative voltage of -1.25 V to loaded PEDOT nanoparticles. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biochemical synthesis of water soluble conducting polymers

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

Bruno, Ferdinando F., E-mail: Ferdinando-Bruno@uml.edu; Bernabei, Manuele

2016-05-18

An efficient biomimetic route for the synthesis of conducting polymers/copolymers complexed with lignin sulfonate and sodium (polystyrenesulfonate) (SPS) will be presented. This polyelectrolyte assisted PEG-hematin or horseradish peroxidase catalyzed polymerization of pyrrole (PYR), 3,4 ethyldioxithiophene (EDOT) and aniline has provided a route to synthesize water-soluble conducting polymers/copolymers under acidic conditions. The UV-vis, FTIR, conductivity and cyclic voltammetry studies for the polymers/copolymer complex indicated the presence of a thermally stable and electroactive polymers. Moreover, the use of water-soluble templates, used as well as dopants, provided a unique combination of properties such as high electronic conductivity, and processability. These polymers/copolymers are nowadaysmore » tested/evaluated for antirust features on airplanes and helicopters. However, other electronic applications, such as photovoltaics, for transparent conductive polyaniline, actuators, for polypyrrole, and antistatic films, for polyEDOT, will be proposed.« less

Preparation of Highly Conductive Yarns by an Optimized Impregnation Process

NASA Astrophysics Data System (ADS)

Amba Sankar, K. N.; Mohanta, Kallol

2018-03-01

We report the development of the electrical conductivity in textile yarns through impregnation and post-treatment of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The conductive polymer is deposited on fibers, which fills the gap space within the hierarchical structure of the yarns. Organic nonpolar solvents act as reducing agent to increase the density of PEDOT moieties on the yarns, galvanizing increment in conductivity values. Post-treatment by ethylene glycol transforms the resonance configuration of the conductive moieties of conjugated polymer, which helps in further enhancement of electrical conductivity of the yarns. We have optimized the method in terms of loading and conformal change of the polymer to have a lesser resistance of the coated conductive yarns. The minimum resistance achieved has a value of 77 Ωcm-1. This technique of developing conductivity in conventional yarns enables retaining the flexibility of yarns and feeling of softness which would find suitable␣applications for wearable electronics.

Large thermoelectric figure of merit in graphene layered devices at low temperature

NASA Astrophysics Data System (ADS)

Olaya, Daniel; Hurtado-Morales, Mikel; Gómez, Daniel; Alejandro Castañeda-Uribe, Octavio; Juang, Zhen-Yu; Hernández, Yenny

2018-01-01

Nanostructured materials have emerged as an alternative to enhance the figure of merit (ZT) of thermoelectric (TE) devices. Graphene exhibits a high electrical conductivity (in-plane) that is necessary for a high ZT; however, this effect is countered by its impressive thermal conductivity. In this work TE layered devices composed of electrochemically exfoliated graphene (EEG) and a phonon blocking material such as poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), polyaniline (PANI) and gold nanoparticles (AuNPs) at the interface were prepared. The figure of merit, ZT, of each device was measured in the cross-plane direction using the Transient Harman Method (THM) and complemented with AFM-based measurements. The results show remarkable high ZT values (0.81  <  ZT  <  2.45) that are directly related with the topography, surface potential, capacitance gradient and resistance of the devices at the nanoscale.

Sulfonated poly(ether ether ketone)/polypyrrole core-shell nanofibers: a novel polymeric adsorbent/conducting polymer nanostructures for ultrasensitive gas sensors.

PubMed

Wang, Wei; Li, Zhenyu; Jiang, Tingting; Zhao, Zhiwei; Li, Ye; Wang, Zhaojie; Wang, Ce

2012-11-01

Conducting polymers-based gas sensors have attracted increasing research attention these years. The introduction of inorganic sensitizers (noble metals or inorganic semiconductors) within the conducting polymers-based gas sensors has been regarded as the generally effective route for further enhanced sensors. Here we demonstrate a novel route for highly-efficient conducting polymers-based gas sensors by introduction of polymeric sensitizers (polymeric adsorbent) within the conducting polymeric nanostructures to form one-dimensional polymeric adsorbent/conducting polymer core-shell nanocomposites, via electrospinning and solution-phase polymerization. The adsorption effect of the SPEEK toward NH₃ can facilitate the mass diffusion of NH₃ through the PPy layers, resulting in the enhanced sensing signals. On the basis of the SPEEK/PPy nanofibers, the sensors exhibit large gas responses, even when exposed to very low concentration of NH₃ (20 ppb) at room temperature.

The Role of Hydrophobicity in the Cellular Uptake of Negatively Charged Macromolecules.

PubMed

Abou Matar, Tamara; Karam, Pierre

2018-02-01

It is generally accepted that positively charged molecules are the gold standard to by-pass the negatively charged cell membrane. Here, it is shown that cellular uptake is also possible for polymers with negatively charged side chains and hydrophobic backbones. Specifically, poly[5-methoxy-2-(3-sulfopropoxy)-1,4-phenylenevinylene], a conjugated polyelectrolyte with sulfonate, as water-soluble functional groups, is shown to accumulate in the intracellular region. When the polymer hydrophobic backbone is dissolved using polyvinylpyrrolidone, an amphiphilic macromolecule, the cellular uptake is dramatically reduced. The report sheds light on the fine balance between negatively charged side groups and the hydrophobicity of polymers to either enhance or reduce cellular uptake. As a result, these findings will have important ramifications on the future design of targeted cellular delivery nanocarriers for imaging and therapeutic applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photoactivated and patternable charge transport materials and their use in organic light-emitting devices

NASA Astrophysics Data System (ADS)

Liu, Jie; Lewis, Larry N.; Duggal, Anil R.

2007-06-01

Organic light-emitting devices (OLEDs) usually employ at least one organic semiconductor layer that acts as a hole-injection material. The prototypical example is a conjugated polymer such as poly(3,4-ethylenedioxythiophene) heavily p doped with polystyrene sulfonic acid. Here, the authors describe a chemical doping strategy for hole injection material formulation that enables spatial patterning of the material conductivity through optical activation. The strategy utilizes an organic photoacid generator (PAG) dispersed in a polymeric organic semiconductor host. Upon UV irradiation, the PAG decomposes and generates a strong protonic acid that subsequently p dopes the host. The authors demonstrate an OLED made with such a light-activated hole-injection material and show that arbitrary emission patterning can be accomplished. This approach may provide a simple, low cost path toward specialty lighting and signage applications for OLED technology.

Enhanced efficiency of hybrid amorphous silicon solar cells based on single-walled carbon nanotubes and polymer composite thin film

NASA Astrophysics Data System (ADS)

Rajanna, Pramod M.; Gilshteyn, Evgenia P.; Yagafarov, Timur; Aleekseeva, Alena K.; Anisimov, Anton S.; Neumüller, Alex; Sergeev, Oleg; Bereznev, Sergei; Maricheva, Jelena; Nasibulin, Albert G.

2018-03-01

We report a simple approach to fabricate hybrid solar cells (HSCs) based on a single-walled carbon nanotube (SWCNT) film and thin film hydrogenated amorphous silicon (a-Si:H). Randomly oriented high-quality SWCNTs with conductivity enhanced by means of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate are used as a window layer and a front electrode. A series of HSCs are fabricated in ambient conditions with varying SWCNT film thicknesses. The polymethylmethacrylate layer drop-casted on fabricated HSCs reduces the reflection fourfold and enhances the short-circuit J sc , open-circuit V oc , and efficiency by nearly 10%. A state-of-the-art J-V performance is shown for SWCNT/a-Si HSC with an open-circuit voltage of 900 mV and an efficiency of 3.4% under simulated one-sun AM 1.5 G direct illumination.

Stability of anti-reflection coatings via the self-assembly encapsulation of silica nanoparticles by diazo-resins

NASA Astrophysics Data System (ADS)

Metzman, Jonathan S.; Ridley, Jason I.; Khalifa, Moataz B.; Heflin, James R.

2015-12-01

A modified silica nanoparticle (MSNP) solution was formed by the encapsulation of negatively charged silica nanoparticles by the UV-crosslinkable polycation oligomer diazo-resin (DAR). Appropriate DAR encapsulation concentrations were determined by use of zeta-potential and dynamic light scattering measurements. The MSNPs were used in conjunction with poly(styrene sulfonate) (PSS) to grow homogenous ionic self-assembled multilayer anti-reflection coatings. Stability was induced within the films by the exposure of UV-irradiation that allowed for crosslinking of the DAR and PSS. The films were characterized by UV/vis/IR spectroscopy and field emission scanning electron microscopy. The transmission and reflection levels were >98.5% and <0.05%, respectively. The refractive indices resided in the 1.25-1.26 range. The solvent stability was tested by sonication of the films in a ternary solvent (H2O/DMF/ZnCl2 3:5:2 w/w/w).