Styrene Sulfonic Acid Research Articles

Dynamic mechanical analysis and broadband electromagnetic interference shielding characteristics of poly (vinyl alcohol)-poly (4-styrenesulfonic acid)-titanium dioxide nanoparticles based tertiary nanocomposites

ABSTRACTNovel tertiary nanocomposite films comprising of poly (vinyl alcohol) (PVA), poly (4-styrenesulfonic acid) (PSSA) and titanium dioxide (TiO2) nanoparticles (NPS) were prepared using simple solvent casting method. The structural, thermal, morphological, thermo-mechanical and electromagnetic interference (EMI) shielding properties of PVA/PSSA/TiO2 nanocomposite films were investigated. The EMI shielding effectiveness (SE) of PVA/PSSA/TiO2 nanocomposite films in the X and Ku band was found to be 12 dB and 13 dB respectively at 25 wt% TiO2 NPs loading. These results demonstrate the possible applications of PVA/PSSA/TiO2 nanocomposite films as low cost, lightweight and flexible material for EMI shielding.

Enhancing Phosphorescence through Rigidifying the Conformation to Achieve High-Efficiency OLEDs by Modified PEDOT.

Bis(diphenylphosphinomethyl)phenylphosphine (dpmp)-supported Pt2Au heterotrinuclear complexes [Pt2Au(dpmp)2(C≡CPh)4](ClO4) (1), [Pt2Au(dpmp)2(DEBf)(C≡CPh)2](ClO4) (2), and [Pt2Au(dpmp)2(DECz)(C≡CPh)2](ClO4) (3) were prepared and used in organic light-emitting diodes (OLEDs) as a new class of light emitters, where DEBf = dibenzofuran-4,6-diacetylide and DECz = 3,6-di-tert-butylcarbazole-1,8-diacetylide. Although the flexible structure of Pt2Au complex 1 (λem = 503 nm, Φem < 0.1%) results in weak photoluminescence in fluid CH2Cl2, complexes 2 (λem = 585 nm, Φem = 4.9%) and 3 (λem = 589 nm, Φem = 3.2%) with a rigid conformation give a much stronger phosphorescence. The displacement of two σ-bonded phenylacetylide ligands with a diacetylide ligand such as DEBf and DECz to fasten Pt2Au structures facilitates greatly luminescent emission so that the emissive quantum yield in doping film is as high as 89% for 2 and 93% for 3. As revealed by a theoretical study, the severe structural distortion of diacetylide-linked Pt2Au complexes 2 (λem = 585 nm) and 3 (λem = 589 nm) in a triplet excited state gives rise to significant red shifts of phosphorescent emission spectra relative to that of complex 1 (λem = 503 nm). By means of Pt2Au complexes as phosphorescent emitters, solution-processed OLEDs achieved a relatively low external quantum efficiency (EQE < 9.5%) when commercial poly(ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) was used as the hole-injection layer (HIL). In contrast, the peak EQE was increased to 18.3% with a dramatic increase of efficiency by the use of modified HILs composed of PEDOT:PSS and PSS-Na, which provide a higher work function and a better film morphology.

High-Performance Inverted Planar Perovskite Solar Cells Enhanced by Thickness Tuning of New Dopant-Free Hole Transporting Layer.

A new hole transporting material (HTM) named DMZ is synthesized and employed as a dopant-free HTM in inverted planar perovskite solar cells (PSCs). Systematic studies demonstrate that the thickness of the hole transporting layer can effectively enhance the morphology and crystallinity of the perovskite layer, leading to low series resistance and less defects in the crystal. As a result, the champion power conversion efficiency (PCE) of 18.61% with JSC = 22.62 mA cm-2 , VOC = 1.02 V, and FF = 81.05% (an average one is 17.62%) is achieved with a thickness of ≈13 nm of DMZ (2 mg mL-1 ) under standard global AM 1.5 illumination, which is ≈1.5 times higher than that of devices based on poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonic acid) (PEDOT:PSS). More importantly, the devices based on DMZ exhibit a much better stability (90% of maximum PCE retained after more than 556 h in air (relative humidity ≈ 45%-50%) without any encapsulation) than that of devices based on PEDOT:PSS (only 36% of initial PCE retained after 77 h in same conditions). Therefore, the cost-effective and facile material named DMZ offers an appealing alternative to PEDOT:PSS or polytriarylamine for highly efficient and stable inverted planar PSCs.

Precise 2D-Patterned Incompatible Catalysts for Reactions in One-Pot.

Precise and direct two-dimensional (2D) printing of the incompatible polymer acid-base catalysts and their utility in one-pot two-step reactions were shown. Multistep catalytic reactions using incompatible catalysts in a one-pot reaction cascade requires special methods and materials to isolate the catalysts from each other. In general, this is a tedious process requiring special polymer architectures as the carrier for the catalysts to preserve the activity of otherwise incompatible catalysts. We propose the immobilization of incompatible polymer catalysts, such as polymer acid and base catalysts, on a substrate in variable sizes and amounts by precise 2D printing. The terpolymers with basic (4-vinylpyridine) and acidic (styrene sulfonic acid) functionalities and methacryloyl benzophenone as a UV cross-linking unit were used for 2D printing on poly(ethylene terephthalate) (PET). The printed meshes were immersed together in a reaction solution containing (dimethoxymethyl)benzene and ethyl cyanoformate, resulting in a two-step acid-base catalyzed cascade reaction; that is, deacetalization followed by carbon-building reaction. The time-dependent consumption of (dimethoxymethyl)benzene to the intermediate benzaldehyde and the product was monitored, and a kinetic model was developed to investigate the underlying reaction dynamics. The complexity of multistep Wolf-Lamb-type reactions was generally significantly decreased by using our approach because of the easy polymerization and immobilization procedure.

Sulfonic acid-functionalized poly(4-styrenesulfonic acid) mesoporous graphene oxide hybrid for one-pot preparation of coumarin-based pyrido[2,3-d]pyrimidine-dione derivatives

Sulfonic acid-functionalized poly(4-styrenesulfonic acid) mesoporous graphene oxide hybrid (PSSA-MGO) is prepared by polymerization of 4-styrenesulfonic acid on the surface of mesoporous graphene oxide. The catalyst is fully characterized by several methods including Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller adsorption–desorption analysis, scanning and transmission electron microscopy. PSSA-MGO is used as an efficient acidic catalyst for the one-pot preparation of some novel chromenopyridopyrimidine-dione derivatives via the three-component reaction of 4-aminocoumarin, thiobarbituric acid and aromatic aldehydes. All the obtained products were also characterized. This synthetic procedure presents some advantages including an eco-friendly procedure, high yield of the products and recyclability of the catalyst.

Enhancement of transient thermal stability and flame retardancy of hydrophobic silica xerogel composites via carbon family material doping

ABSTRACTIn this study, we investigated the influence of the addition of carbon materials on the heat resistance and flame retardancy of silica xerogels. A mixed dispersion prepared by adding 0.1 to 2.5 wt% each of the carbon materials, graphene oxide (GO), poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) (PEDOT:PSS), and carbon black (CB) to waterglass (SiO2 6%) was used as the raw material. By adding acid to this dispersion, a sol-gel reaction was carried out and the hydrogel obtained was hydrophobized with hydrochloric acid and a mixed solution of siloxane/isopropylalcohol . Finally, novel carbon-silica xerogel composites (SX-Carbon-X) were prepared via ambient pressure drying. Similarly, glass-fiber-reinforced silica xerogel composite sheets (GFR-SX-Carbon-X) were prepared by impregnating glass fibers with sol. The bulk densities of the samples obtained ranged from 0.204 to 0.217 g/cm3, their thermal conductivities ranged from 0.0187 to 0.0203 W/(m · K). As the amount of carbon material added was increased, the thermal decomposition temperature of the SX-Carbon-X shifted to higher temperatures. In the cone calorimeter test of GFR-SX-Carbon-X, moreover, adding at least 0.5% of the carbon material significantly reduced the combustion time and the peak heat release rate (PHRR), and the flame retardancy improved remarkably.

The Mechanism of Dedoping PEDOT:PSS by Aliphatic Polyamines.

Poly(3,4-ethylenedioxythiophene) blended with polystyrenesulfonate and poly(styrenesulfonic acid), PEDOT:PSS, has found widespread use in organic electronics. Although PEDOT:PSS is commonly used in its doped electrically conducting state, the ability to efficiently convert PEDOT:PSS to its undoped nonconducting state is of interest for a wide variety of applications ranging from biosensors to organic neuromorphic devices. Exposure to aliphatic monoamines, acting as an electron donor and Brønsted–Lowry base, has been reported to be partly successful, but monoamines are unable to fully dedope PEDOT:PSS. Remarkably, some—but not all—polyamines can dedope PEDOT:PSS very efficiently to very low conductivity levels, but the exact chemical mechanism involved is not understood. Here, we study the dedoping efficacy of 21 different aliphatic amines. We identify the presence of two or more primary amines, which can participate in an intramolecular reaction, as the key structural motif that endows polyamines with high PEDOT:PSS dedoping strength. A multistep reaction mechanism, involving sequential electron transfer and deprotonation steps, is proposed that consistently explains the experimental results. Finally, we provide a simple method to convert the commonly used aqueous PEDOT:PSS dispersion into a precursor formulation that forms fully dedoped PEDOT:PSS films after spin coating and subsequent thermal annealing.

New Family of Water-Soluble Sulfo-Fluoro Polyphosphazenes and Their Assembly within Hemocompatible Nanocoatings.

In this work, novel sulfo-fluoro polyphosphazenes (PPzs) were synthesized via macromolecular substitution of polydichlorophosphazene utilizing "non-covalent protection" methodology by converting acid functionalities into hydrophobic alkylammonium salts. Resulting PPzs showed excellent solubility in aqueous solutions over a broad pH range and contained ∼25% sulfo- groups and 20% either trifluoroethoxy- (FESP) or trifluoromethylphenoxy- (FPSP) side groups, as determined by NMR spectroscopy. Their polyelectrolyte behavior was evaluated by binding with an oppositely charged polyion, branched polyethylenimine (PEI), which resulted in the formation of interpolymer complexes as shown by dynamic light scattering (DLS). Contrary to a sulfonated, nonfluorinated PPz homopolymer (SP), fluorinated macromolecules effectively bound human serum albumin (HSA) as revealed by dynamic light scattering and asymmetric flow field flow fractionation (AF4) studies. Moreover, FESP and FPSP both displayed low hemolytic activity as evaluated in solution using porcine red blood cells. Using the layer-by-layer (LbL) technique, FESP and FPSP were assembled into nanocoatings with PEI. Both fluorinated and nonfluorinated sulfo PPzs showed linear growth with PEI because of strong ionic pairing between sulfo and amino groups. However, films of fluorinated PPzs displayed higher hydrophobicity, lower swelling, and improved stability in high ionic strength environment when compared to coatings formed by a sulfonated, nonfluorinated SP, or a carbon-chain polymer poly(styrene sulfonic acid). Hemocompatibility of FESP and FPSP nanofilms was demonstrated in vitro using whole rabbit blood hemolysis tests, which showed less than 1% hemolysis. Altogether, the present study introduces a new class of hemocompatible, sulfo-fluoropolymers that shows promise for life science applications.

Bias‐Induced Electrochemical Electron Doping of Organic Semiconductor Contacts

AbstractIt is well‐known that thin polyethylenimine and polyethylenimine (ethoxylated) (PEIE) layers can reduce the work function of metals, metal oxides, and conducting polymers by 1 eV or more through an interface dipole, but this is not generally sufficient to produce an ohmic electron contact. Here, it is shown that a short, positive‐bias preconditioning can switch the injection characteristics of a self‐assembled monolayer of PEIE on poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDT:PSSH) from electron‐blocking to electron‐injecting into poly(N,N′‐bis(2‐octyldodecyl)‐1,4,5,8‐naphthalenebis(dicarboxy‐imide)‐2,6‐diyl)‐alt‐(2,2′‐bithiophene)‐5,5′‐diyl). Despite its low work function (4.0 eV) and favorable energy level alignment, the PEIE‐modified contact is initially blocking because the tunneling barrier limits carrier accumulation. The prebias boosts this accumulation density through an interfacial solid‐state electrochemical process that positively charges the PEIE, which induces charge compensation by mobile electron carriers in the adjacent semiconductor layer through the field effect. This mechanism to trigger the ohmic transition appears to be general, as similar effects, albeit to a small extent, is found in semiconductors with even smaller electron affinity. This is the first example of ohmic electron injection from PEDT:PSSH into an organic semiconductor, which would be useful for fabricating tandem and other cells.

Tunable Organic Polymer/Inorganic Silicon Diode Using an Ionic Liquid Gel Gate Dielectric

A diode is fabricated using poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonic acid) (PEDOT‐PSS) and n‐doped Si. Using an ionic liquid (IL) gel as the gate dielectric, the diode rectification ratio is tunable up to four orders of magnitude at very low operating voltages. Both p–n and Schottky type diodes are observed in the same device depending on the polarity of the gate voltage. IL‐gated electrostatic/electrochemical doping in PEDOT‐PSS is believed to be responsible for this switch. The turn‐on voltage in the first quadrant of the current–voltage (I–V) curve for the p–n diode is in the range 0.2–0.4 V. The Schottky diode operates in the third quadrant. This is the first report on a tunable diode using an IL to control its operation, and the low operating voltages make these diodes excellent candidates for use in reduced power consumption electronics.

White-light emission of single carbon dots prepared by hydrothermal carbonization of poly(diallyldimethylammonium chloride): Applications to fabrication of white-light-emitting films

Different-sized carbon dots (CDs) with full-color emissions have immerse potentials as a novel class of light source in the field of light-emitting diodes (LED). However, few studies have been devoted to the development of the one-step process for preparing white-light-emitting CDs (WLECDs). Herein, we present a facile and one-pot synthesis of the WLECDs through microwave-assisted hydrothermal carbonization of poly(diallyldimethylammonium chloride) (PDDA). The as-synthesized WLECDs had a round shape with a mean particle size of 2.22 nm and their zeta potential reached up to 47 mV. Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy revealed the appearance of nitrogen and oxygen-containing functional groups on the CD surface, generating many surface state emissive traps. Additionally, photoluminescence spectroscopy showed that the CDs exhibited excitation-dependent surface-state emission and excitation-independent core-state emission. When excited at 350 nm, an aqueous solution of the WLECDs emitted white light with an absolute quantum yield of 11% and a correlated color temperature of 5999 K at Commission International de l'Eclairage (CIE) coordinates of (0.321, 0.348). Single-particle photoluminescence spectroscopy demonstrated that the WLECDs still possessed broadband white-light emission from 400 to 800 nm at a single particle level. Furthermore, a white-light-emitting polymer composite film excited by 365-nm UV light was fabricated by embedding the WLECDs into a polyvinyl alcohol matrix. This flexible solid-state film showed a correlated color temperature of 7023 K at CIE coordinates of (0.303, 0.332) and. Given that the WELCDs have highly positive charges, the fabrication of a white-light-illuminating film was successfully conducted by layer-by-layer assembly of the WELCD and poly(4-styrenesulfonic acid).

Bacteria-Resistant, Transparent, Free-Standing Films Prepared from Complex Coacervates.

We report the fabrication, properties, and bacteria-resistance of polyelectrolyte complex (PEC) coatings and free-standing films. Poly(4-styrenesulfonic acid), poly(diallyldimethyl-ammonium chloride), and salt were spin-coated into PEC films. After thermal annealing in a humid environment, highly transparent, mechanically strong, and chemically robust films were formed. Notably, we demonstrate that PEC coatings significantly reduce the attachment of Escherichia coli K12 without killing the micro-organisms. We suggest that forming bacteria-resistant surface coatings from commercially available polymers holds the potential for use across a wide range of applications including high-touch surfaces in medical settings.

Synthesis and Charge Transport of Polymer Nanocomposite of Polyaniline: Polystyrene Sulfonate.

We demonstrate the preparation of water-dispersible polyaniline:polystyrene sulfonate (PANI:PSS), which was doped with camphorsulfonic acid (CSA) and co-doped with poly (4-styrenesulfonic acid) (PSS). The proper formation of the PANI and PANI:PSS was verified by FTIR measurements. The synthesized samples were further characterized via UV-vis spectroscopy. The intensive study on the current density (J)-voltage (V) characteristics within the temperature range (143-303 K) of the synthesized sample was performed systematically. The electrical study shows that the doping of PANI with CSA as a dopant and PSS as a co-dopant significantly improves the overall semi-conducting property of PANI. The detailed analysis of the current density (J)-voltage (V) curve at various temperatures reveals the electrical conduction behavior, which follows the trap-dependent space-charge limited conduction (SCLC) mechanism.

Preparation and Properties of Oil/Water Separation Membranes Synthesized via One-Step Grafting Poly(styrene sulfonic acid) onto Poly(vinylidene fluoride) Modified by Tetramethylammonium Hydroxide

Preparation and Properties of Oil/Water Separation Membranes Synthesized via One-Step Grafting Poly(styrene sulfonic acid) onto Poly(vinylidene fluoride) Modified by Tetramethylammonium Hydroxide

Feasible Modification of PEDOT:PSS by Poly(4-styrenesulfonic acid): A Universal Method to Double the Efficiencies for Solution-Processed Organic Light-Emitting Devices

A feasible, universal, and low-cost strategy for solution-processed organic light-emitting diodes (OLEDs) was provided to significantly enhance the electroluminescent performances. The commercially available poly(4-styrenesulfonic acid) (PSSA) aqueous solution was mixed into poly(styrene sulfonic acid)-doped poly(3,4-ethylenedioxythiphene) (PEDOT:PSS) to modify its chemical and physical properties. The corresponding work function can be easily elevated from 5.04 to 5.63 eV. The modification of PEDOT:PSS by PSSA is found to be a universal method to demonstrate highly efficient OLEDs with different solution-processed host/emitter combinations, covering phosphorescent and thermally activated delayed fluorescence devices. The benchmarking solution-processed OLEDs based on 2,4,5,6-tetrakis(carbazol-9-yl)-1,3-dicyanobenzene and bis[2-(4,6-difluorophenyl)pyridinato-C2,N](picolinato)iridium(III) achieved the maximum external quantum efficiencies of 26.6 and 22.4%, respectively, simply by modifying PEDOT:PSS with PSSA, corresponding to the improvement factors of 2.7 and 2.2. It is confirmed that such performances originate simultaneously from reduced interfacial fluorescence quenching, elevated work function, and reduced lateral conduction of the commonly used PEDOT:PSS (Clevios P VP Al 4083).

Deformable Ionic Polymer Artificial Mechanotransducer with an Interpenetrating Nanofibrillar Network.

We demonstrate an ionic polymer artificial mechanotransducer (i-PAM) capable of simultaneously yielding an efficient wide bandwidth and a blocking force to maximize human tactile recognition in soft tactile feedback. The unique methodology in the i-PAM relies on an ionic interpenetrating nanofibrillar network that is formed at the interface of (i) an ionic thermoplastic polyurethane nanofibrillar matrix with an ionic liquid of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM]+[TFSI]-) and (ii) ionic poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) conducting polymer electrodes with dimethyl sulfoxide and [EMIM]+[TFSI]- as additives. The i-PAM-based actuator with the ionic PEDOT:PSS exhibits a stable operation up to 200 Hz at low voltage as well as a blocking force of 0.4 mN, which can be potentially adapted to soft tactile feedback. Furthermore, on the basis of this fast i-PAM, we realized alphabet tactile rendering by using a 3 × 3 i-PAM array stimulated by a dc input of 2 V. We believe that our proposed approach can provide a rational guide to the human-machine soft haptic interface.

Microneedle device samples fluid from skin

Applying a microneedle patch to the skin might one day replace the uncomfortable needle stick required to perform some blood tests. As a step toward that goal, researchers have demonstrated a prototype device that combines microneedles and plasmonic sensor paper to sample interstitial fluid from the skin and analyze it directly using surface-enhanced Raman spectroscopy (SERS) (ACS Sens. 2019, DOI: 10.1021/acssensors.9b00258). Mark R. Prausnitz of the Georgia Institute of Technology, Srikanth Singamaneni of Washington University in St. Louis, and colleagues demonstrated their device by detecting a positively charged fluorescent dye, rhodamine 6G, infused into rats. The researchers grew gold nanoparticles and coated them with negatively charged poly(4-styrenesulfonic acid). Then they concentrated the coated nanoparticles into an ink, wrote the ink onto a strip of filter paper, and attached the paper to a strip of 650 µm long steel microneedles. After applying the microneedles to the skin of hairless rats se...

Simultaneous Hot Electron and Hole Injection upon Excitation of Gold Surface Plasmon.

We have successfully investigated the simultaneous injection of hot electrons and holes upon excitation of gold localized surface plasmon resonance (LSPR). The studies were performed on all-solid-state plasmonic system composed of titanium dioxide (TiO2)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) p-n junctions with gold nanoparticles (Au NPs). The study revealed that both charge carriers are transferred within 200 fs to the respective charge acceptors, exhibiting a free carrier transport behavior. We also confirmed that the transfer of charge carriers are accompanied by change in the initial relaxation dynamics of Au NPs.

All-polymer based polymorph skin with controllable surface texture

Smart skins are integrating an increasing number of functionalities to improve the interactions between the equipped systems (robots or artificial systems) and their ambient environment. Here, we introduce a controllable texture as a new functionality, based on an innovative soft technology that leverages the strong electro-mechanical coupling of our all-polymer design, which can be easily embedded to a wide range of systems. The device comprises a polymer-based heating element [doped PEDOT:PSS (poly-(3,4 ethylenedioxythiophene): poly (styrene sulfonic acid))], a polymer-based soft actuator (Ecoflex 00–50/ethanol) and a polymer-based casing [PDMS (polydimethylsiloxane)]. We introduce a smart pipe prototype module and use our controllable polymorph skin to tailor the interaction between the pipe and the fluid. This allows us to obtain a 50% reduction of the friction coefficient in turbulent regime, between non-actuated and actuated configurations. This concept may find applications in engineering fields such as smart skin-based touch control and controllable friction coefficients.

A synergetic layered inorganic\u2013organic hybrid film for conductive, flexible, and transparent electrodes

Conductive electrodes are major components of flexible optoelectronic devices. However, existing materials are either very conductive but brittle (e.g., ITO [indium tin-oxide]), or non-brittle but less conductive, with an environment-dependent conductivity (e.g., PEDOT:PSS [poly-(3,4 ethylenedioxythiophene): poly (styrene sulfonic acid)]). Here, we propose a new design that simultaneously takes advantage of both the high conductivity of ITO and the high flexibility of PEDOT:PSS. In our design, a PEDOT:PSS interface is inserted between the film substrate and the ITO layer, creating a hybrid layered structure that retains both its high conductivity and high stability, when the film is deformed. The rational behind the creation of this structure, is that PEDOT:PSS, used as an interface between the locally delaminated ITO layer and the substrate, substantially reduces the detrimental effects of cracks on the electrode’s conductivity. These results open the path for a new generation of transparent electrodes in advanced flexible devices.