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Query: UMLS:C1832588 (PSS)
 2,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Precipitates of polyelectrolyte complexes were transformed into rugged shapes suitable for bioimplants by ultracentrifugation in the presence of high salt concentration. Salt ions dope the complex, creating a softer material with viscous fluid-like properties. Complexes that were compacted under the centrifugal field (CoPECs) were made from poly(diallyldimethyl ammonium), PDADMA, as polycation, and poly(styrene sulfonate), PSS, or poly(methacrylic acid), PMAA, as polyanion. Dynamic mechanical testing revealed a rubbery plateau at lower frequencies for PSS/PDADMA with moduli that decreased with increasing salt concentration, as internal ion pair cross-links were broken. CoPECs had significantly lower modulii compared to similar polyelectrolyte complexes prepared by the "multilayering" method. The difference in mechanical properties was ascribed to higher water content (located in micropores) for the former and, more importantly, to their nonstoichiometric polymer composition. The modulus of PMAA/PDADMA CoPECs, under physiological conditions, demonstrated dynamic mechanical properties that were close to those of the nucleus pulposus in an intervertebral disk.
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PMID:Compact polyelectrolyte complexes: "saloplastic" candidates for biomaterials. 1983 12

Among the conjugate polymers, poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) has been paid a great deal of attention for various application fields. The absorption intensity of the whole UV-visible range increases linearly, as the concentration of PEDOT:PSS increases. When a small amount of TiO(2) nanoparticles are dispersed in the PEDOT:PSS solution, the absorption in the visible range normally increases, but the UV range absorption (TiO(2) absorption area) is greatly depressed as the concentration of PEDOT:PSS increases. Various weight ratios of TiO(2) nanoparticles in PEDOT:PSS were prepared. The TiO(2)/PEDOT:PSS solution was spin-coated onto the Al electrode and thermally treated to remove water molecules and densify the film. These thermal processes generated nanocracks and nanoholes on the surface of the TiO(2)/PEDOT:PSS film. As the heating temperature increased, wider and longer nanocracks were generated. These nanocracks and nanoholes can be removed by subsequent coating and heating processes. Schottky diodes were fabricated using four different concentrations of TiO(2)-PEDOT:PSS solution. The forward current increased nearly two orders of magnitude by doping approximately 1% of TiO(2) nanoparticles in PEDOT:PSS. Increasing the TiO(2) nanoparticles in the PEDOT:PSS matrix, the forward current was continuously enhanced. The enhancement of forward current is nearly four orders of magnitude with respect to the pristine PEDOT:PSS Schottky diode. The possible conduction mechanisms were examined by using various plotting and curve-fitting methods including a space-charge-limited conduction mechanism [Ln(J) versus Ln(V)], Schottky emission mechanism [Ln(J) versus E(1/2)], and Poole-Frenkel emission mechanism [Ln(J/V) versus E(1/2)]. The plot of Ln(J) versus Ln(V) shows a linear relationship, implying that the major conduction mechanism is SCLC. As the concentration of TiO(2) increased, the conduction mechanism slightly detracted from the ideal SCLC mechanism.
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PMID:The TiO(2) nanoparticle effect on the performance of a conducting polymer Schottky diode. 1994 63

Quantitative in situ attenuated total internal reflection Fourier transform infrared (ATR FTIR) spectroscopy has been used to study the isotherm of poly(sodium 4-styrene sulfonate), PSS, adsorption to a TiO(2) surface in aqueous solution at a pH of 3.5. The effect of adding surfactant cetylpyridinium bromide monohydrate (CPBM) on the adsorption isotherm of PSS was investigated at CPBM concentrations of 3.60 x 10(-7), 1.02 x 10(-5), and 1.04 x 10(-4) M. The use of in situ ATR FTIR allowed for the calculation of the concentration of both PSS and CPBM at the TiO(2)/water interface over the entire course of all experiments. It was found that the addition of a small amount of CPBM, 3.60 x 10(-7) M, to PSS solutions resulted in 23 +/- 3% less PSS accumulating at the TiO(2)/water interface compared to isotherm studies with no CPBM present. The mole ratio of CPBM to PSS varies from 4 +/- 1 to 1 to 20 +/- 4 to 1 in a stepwise manner as the solution concentration of PSS is increased for solutions with a CPBM concentration of 3.60 x 10(-7). The addition of CPBM at concentrations of 1.02 x 10(-5) and 1.04 x 10(-4) M showed distinct differences in the behavior of the PSS isotherm, but at the highest solution PSS concentrations, the amount of PSS at the TiO(2)/water interface compared to that of PSS solutions with no CPBM added is indistinguishable within the experimental uncertainties. For these higher concentrations of CPBM, both PSS and CPBM appear to come to the TiO(2) surface as aggregates and the mole ratio of CPBM to PSS at the TiO(2)/water interface decreases as the concentration of PSS is increased. For a CPBM concentration of 1.02 x 10(-5) M, the mole ratio of CPBM to PSS changes from 139 +/- 29 to 1 to 33 +/- 7 to 1 as the solution PSS concentration is increased. For a CPBM concentration of 1.04 x 10(-4) M, the mole ratio of CPBM to PSS changes from 630 +/- 130 to 1 to 110 +/- 21 to 1 as the solution PSS concentration is increased. Despite the large differences in the CPBM to PSS mole ratios, the amount of PSS that adsorbs to the surface is statistically indistinguishable for CPBM concentrations of 0, 1.02 x 10(-5), and 1.04 x 10(-4) M, indicating that the structure of the PSS molecules in each of the systems does not significantly change in the presence of CPBM.
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PMID:Quantitative in situ attenuated total internal reflection Fourier transform infrared study of the isotherms of poly(sodium 4-styrene sulfonate) adsorption to a TiO2 surface over a range of cetylpyridinium bromide monohydrate concentration. 2006 83

We present a study on water-soluble interpolyelectrolyte complexes (IPECs) formed by cationic cylindrical polyelectrolyte brushes (CPBs) and linear anionic poly(sodium styrenesulfonate) (PSSNa) using atomic force microscopy (AFM). The IPECs were prepared by dialysis of salt-containing solutions of the two polymeric components. The morphologies of the IPECs could be tuned by changing the charge ratio between the two polyelectrolytes, Z(-/+). Addition of increasing numbers of short PSSNa chains induced morphology changes of host CPBs from worms through intermediate pearl-necklace structures to fully collapsed spheres. Extremely long guest PSSNa caused the full collapse of the brushes to spheres even at very low charge ratios without intermediate states. In both cases we observe "disproportionation", that is, inhomogeneous distribution of the PSS chains between the CPB for Z(-/+) < 1. Unexpected micrometer-scale core-shell cylindrical objects were found by directly mixing CPBs with long PSSNa, which might be nonequilibrium structures caused by the kinetically controlled IPEC formation.
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PMID:Manipulating the morphologies of cylindrical polyelectrolyte brushes by forming interpolyelectrolyte complexes with oppositely charged linear polyelectrolytes: an AFM study. 2022 89

In this article, a layer-by-layer (LbL)-assembled coordination multilayer on planar and 3D substrates was explored by the alternate deposition of a transition-metal-containing polyelectrolyte and a ligand-containing polymer via the formation of complexes. The metal-ligand coordination between the building blocks of Co(2+)-exchanged poly(styrene sulfonate) (PSS) and poly(4-vinyl pyridine) (P4 VP) has been demonstrated using UV-vis, FTIR, and XPS. The film thickness, structure, and morphology as well as the wettability as a function of bilayer number have been systematically investigated by profilometry, SEM, AFM, and contact angle analyzers. For the purpose of separation applications, the metal-ligand-coordinated multilayer was assembled on both flat sheet and hollow fiber polymeric porous substrates using a dynamic pressure-driven LbL technique. It was demonstrated that the LbL-assembled PSS(Co)(1/2)/P4 VP multilayer membrane had high dehydration performance with respect to different solvent-water mixtures; it also had aromatic compound permselectivity from aromatic-aliphatic hydrocarbons and water-softening capacity. Meanwhile, the successful assembly of multilayers on hollow fibers indicates that the dynamic pressure-driven LbL technique is a unique approach to the construction of multilayers on porous 3-D substrates. Therefore, the metal-ligand-coordinated self-assembly could emerge as a powerful technique for the preparation of a range of separation membranes in different types of modules.
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PMID:Construction of metal-ligand-coordinated multilayers and their selective separation behavior. 2035 9

We fabricated photopatternable and conductive polymer/multiwalled carbon nanotube (MWNT) composites by dispersing MWNTs with poly(4-styrenesulfonic acid) (PSS) and poly(acrylic acid) (PAA) in water. PAA enables photo-cross-linking in the composite by adding ammonium dichromate, and PSS assists the dispersion of MWNTs in the composites, leading to higher conductivity. Composite films of PAA/PSS-MWNTs were characterized by conductivities of 1.4-210 S/cm and a work function of 4.46 eV, which could be increased to 4.76 eV during UV photo-cross-linking. By using PAA/PSS-MWNT composites as source/drain electrodes, 6,13-bis(triisopropylsilylethynyl)pentacene field-effect transistors (FET) exhibited a field-effect mobility of 0.101 +/- 0.034 cm(2)/(V s), which is 9 times higher than that of FETs fabricated with gold as source/drain electrodes (0.012 +/- 0.003 cm(2)/(V s)).
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PMID:Photopatternable source/drain electrodes using multiwalled carbon nanotube/polymer nanocomposites for organic field-effect transistors. 2035 70

Metal-mediated coordination polyelectrolyte multilayers with a bisterpyridine ligand (Bisterpy) have been self-assembled at air-water interfaces via coordination reactions of the bidentate ligand Bisterpy with inorganic salts in the subphases. To avoid dissolution of the viologen-like coordination polyelectrolyte monolayers, anionic poly(styrenesulfonic acid-o-maleic) (PSS) acid was added in the subphases as a supporting layer. The average molecular area of the ligand Bisterpy could reach 1.2-1.5 nm(2) on the surfaces of the subphases containing mixtures of inorganic salts (M) and PSS, although the ligand was unable to form a stable monolayer on the pure water surface. The Langmuir-Blodgett (LB) method was used to deposit the Bisterpy/PSS and M-Bisterpy/PSS hybrid multilayers on the substrate surfaces, which were characterized by using absorption and fluorescence spectroscopy as well as electrochemical analysis. Quasi-reversible redox waves were recorded and centered at about -0.68 and -0.92 V (vs Ag/AgCl), respectively, corresponding to the two-electron process of the ligand, Bisterpy2+ <--> Bisterpy(*+) <--> Bisterpy(0), which were slightly shifted to lower potentials in the LB films of metal-mediated coordination polymers. The film compositions were determined by using X-ray photoelectron spectroscopy. The as-prepared LB films showed strong stability and good electrochromic response upon the applied potential of -1.1 V vs Ag/AgCl and thus could act as potential materials in the development of redox-based molecular switches and display devices.
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PMID:Interfacial self-assembly of metal-mediated viologen-like coordination polyelectrolyte hybrids of the bisterpyridine ligand and their optical, electrochemical, and electrochromic properties. 2035 20

Electrostatic layer-by-layer assembly was the basis for the synthesis of multilayer nanorod/polymer composite films. Cationic and water-soluble CdSe nanorods (NRs) were synthesized and partnered with anionic polymers including poly(sodium 4-styrenesulfonate) (PSS) and two polythiophene-based photoactive polymers, sodium poly[2-(3-thienyl)-ethoxy-4-butylsulfonate (PTEBS) and poly[3-(potassium-6-hexanoate)thiophene-2,5-diyl] (P3KHT). Controlled multilayer growth is shown through UV-vis spectroscopy, cross-sectional SEM and surface analytical techniques including atomic force microscopy. The formation of an intimate nanorod/conducting polymer bulk heterojunction is confirmed through cross-sectional SEM, TEM, and scanning Auger analysis. A series of photovoltaic devices was fabricated on ITO electrodes using CdSe NRs in combination with PTEBS or P3KHT. A thorough device analysis showed that performance was limited by low short circuit current although charge transfer was confirmed in the ELBL nanocomposite thin films.
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PMID:Electrostatic layer-by-layer assembly of CdSe nanorod/polymer nanocomposite thin films. 2035 38

In this work, we have fabricated TIPS-pentacene TFTs with conductive polymer (3,4-ethylenedioxythiophene):poly(4-stylenesulfonate) (PEDOT:PSS) source/drain electrodes which is patterned by maskless laser direct patterning (LDP). The 5-microm resolution of source and drain patterns with PEDOT:PSS were clearly defined. Furthermore, the OTFTs with 10-microm channel length were successfully achieved by exposing the focused Neodymium:Yttrium Aluminum Garnet (Nd:YAG) laser beam onto the spin-coated PEDOT:PSS films and developing with deionized water. The electrical performance of the TIPS-pentacene TFTs with PEDOT:PSS source/drain electrodes were improved with decrease of the sheet resistance of PEDOT:PSS films when the PEDOT:PSS films were annealed at the temperature above 200 degrees C.
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PMID:Maskless laser direct patterning of PEDOT/PSS layer for soluble process organic thin film transistor. 2035 18

Polyelectrolyte multilayer (PEM) thin films prepared using the layer-by-layer technique are proposed as a matrix for the immobilization of 1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-2,5-dione (curcumin), a lipophilic model drug. The PEM assembly was based on the layer-by-layer deposition of cationic poly(diallyldimethyl-ammonium chloride) (PDADMAC) and anionic poly(4-styrene sulfonate, sodium salt) (PSS) onto a quartz slide. Curcumin was loaded by dipping the PEM film into a dilute solution of curcumin dispersed in an 80/20% v/v water/ethanol solution. Within a few minutes, the film turned bright yellow as a result of the curcumin loading. The effect of the solvent composition, curcumin concentration and film thickness on the final concentration of curcumin in the PEM films was measured by UV-vis spectroscopy. The loading of curcumin was driven by its partitioning in the PEM film, and its partitioning coefficient between the 80/20 solvent and the PEM thin film was found to have a value of 2.07 x 10(5). The extinction coefficient of curcumin loaded into PEM was calculated to 64,000 M(-1) cm(-1). Results show that the loading of curcumin into the PEM films increased with the number of deposited layers, implying that curcumin partitioned into the bulk of the thin film. The maximum curcumin dose in the PEM film was measured by exposing films of various thicknesses to a high concentration (0.01% w/v) of curcumin and recording the maximum absorbance after saturation. The films thicknesses were controlled by the number of deposited PDADMAC/PSS layers (10, 20, 30, 40, 50, and 60). Results show that increasing amounts of curcumin could be loaded into the film with an increasing number of layers and up to 8 microg/cm(2) of curcumin could be loaded into a 20-layer film. These results demonstrate that the loading of lipophilic curcumin in PEM thin films is done through a partitioning mechanism and that the PDADMAC/PSS film can be used as a loading matrix for lipophilic drugs.
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PMID:Loading of curcumin in polyelectrolyte multilayers. 2040 63


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