Photoinitiated thermolysis of poly(phenylenevinylene) precursor and photochemical doping of poly(phenylenevinylene)

The photoinitiated elimination of methoxy groups of poly(p-phenylene-1-methoxyethylene) and the photochemical doping of the resulting poly(phenylenevinylene) (PPV) were investigated. Upon irradiation and then heat treatment at 150°C, poly(p-phenylene-1-methoxyethylene) containing triphenylsulfonium hexafluoroantimonate was converted to PPV. The resulting PPV was observed to be conductive, and its conductivity was 10⁻²–10⁻³ S/cm. By a lithographic procedure, we produced a conducting pattern doped photochemically in a nonconjugated poly(p-phenylene-1-methoxyethylene) matrix.     

Highly proton conducting proton‐exchange membranes based on fluorinated poly(arylene ether ketone)s with octasulfonated segments

A new bisphenol monomer containing a pair of electron‐rich tetra‐arylmethane units was designed and synthesized. Based on this monomer, along with commercial 4,4′‐(hexafluoroisopropylidene)diphenol A and 4,4′‐difluorobenzophenone, a series of novel poly(arylene ether ketone)s containing octasulfonated segments of varying molar percentage (x) (6F‐SPAEK‐x) were successfully synthesized by polycondensation reactions, followed by sulfonation. Tough, flexible, and transparent membranes, exhibiting excellent thermal stabilities and mechanical properties were obtained by casting. 6F‐SPAEK‐x samples exhibited appropriate water uptake and swelling ratios at moderate ion exchange capacities (IECs) and excellent proton conductivities. The highest proton conductivity (215 mS cm⁻¹) is observed for hydrated 6F‐SPAEK‐15 (IEC = 1.68 meq g⁻¹) at 100 °C, which is more than 1.5 times that of Nafion 117. Furthermore, the 6F‐SPAEK‐10 membrane exhibited comparable proton conductivity (102 mS cm⁻¹) to that of Nafion 117 at 80 °C, with a relatively low IEC value (1.26 meq g⁻¹). Even under 30% relative humidity, the 6F‐SPAEK‐20 membrane (2.06 meq g⁻¹) showed adequate conductivity (2.1 mS cm⁻¹) compared with Nafion 117 (3.4 mS cm⁻¹). The excellent comprehensive properties of these membranes are attributed to well‐defined nanophase‐separated structures promoted by strong polarity differences between highly ionized and fluorinated hydrophobic segments. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 25–37     

Preparation and ion conductivities of the plasticized polymer electrolytes based on the poly(acrylonitrile‐ co‐lithium methacrylate)

The polymer electrolytes composed of poly(acrylonitrile‐co‐lithium methacrylate) [P(AN‐co‐LiMA)], ethylene carbonate (EC), and LiClO₄ salts have been prepared. The ion groups in the P(AN‐co‐LiMA) were found to prevent EC from crystallization through their ion–dipole interactions with the polar groups in the EC. This suppression of the EC crystallization could lead to the enhancement of the ion conductivity at subambient temperature. The polymer electrolytes based on the PAN ionomer with 4 mol % ion content exhibited ion conductivities of 2.4 × 10⁻⁴ S/cm at −10°C and 1.9 × 10⁻³ S/cm at 25°C by simply using EC as a plasticizer. In the polymer electrolytes based on the PAN ionomer, ion motions seemed to be coupled with the segmental motions of the polymer chain due to the presence of the ion–dipole interaction between the ion groups in the ionomer and the polar groups in the EC, while the ion transport in the PAN‐based polymer electrolytes was similar to that of the liquid electrolytes. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 247–252, 1999     

Highly phosphonated poly(N‐phenylacrylamide) for proton exchange membranes

A novel highly phosphonated poly(N‐phenylacrylamide) ( PDPAA ) with an ion‐exchange capacity (IEC) of 6.72 mequiv/g was synthesized by the radical polymerization of N‐[2,4‐bis(diethoxyphosphinoyl)phenyl]acrylamide ( DEPAA ), followed by the hydrolysis with trimethylsilyl bromide. Then, the crosslinked PDPAA membrane was successfully prepared by the electrophilic substitution reaction between the aromatic rings of PDPAA and the carbocation formed from hexamethoxymethylmelamine (CYMEL) as a crosslinker in the presence of methanesulfonic acid. The crosslinked PDPAA membrane had high oxidative stability against Fenton's reagent at room temperature. The proton conductivity of the crosslinked PDPAA membrane was 8.8 × 10^?2 S/cm at 95% relative humidity (RH) and 80 °C, which was comparable to Nafion 112. Under low RH, the crosslinked PDPAA membrane showed the proton conductivity of 1.9 × 10^?3 and 4.7 × 10^?5 S/cm at 50 and 30% RH, respectively. The proton conductivity of the crosslinked PDPAA membrane lied in the highest class among the reported phosphonated polymers, and, consequently, the very high local concentration of the acids of PDPAA (IEC = 6.72 mequiv/g) achieved high and effective proton conduction under high RH. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Investigation of some physicochemical properties of camphor sulfonic acid (CSA)–doped poly(o-anisidine) (PoAN) and CSA-doped PoAN/ABS composites

Camphor sulfonic acid (CSA)–doped poly(o-anisidine) (PoAN) has been found to possess the electrical conductivity of 10 S/cm. This value is rather low compared to that of (≈200 S/cm) CSA-doped polyaniline, which may arise from a limited transformation of coil-like conformation to an expanded one. Viscosity data and optical absorption spectra provided strong evidence for the existence of coil-like CSA-doped PoAN chains in m-cresol. The shift of IR bands of benzenoid and quinoid rings toward a lower wave number and the appearance of the bands at ≈1600 and 1173 cm⁻¹ (the IR is inactive but becomes active on doping) suggested the protonation of CSA-doped PoAN. The thermogravimetric profile of CSA-doped PoAN showed a five-step decomposition pattern with the thermal stability up to 134 °C. The mass spectra taken simultaneously with the thermogram revealed that dopant CSA is completely eliminated around 360 °C, but the breakdown of polymer chains does not occur very briskly at this temperature. Composites of CSA-doped PoAN with insulating acrylonitrile–butadiene–styrene copolymer (ABS) were fabricated, and it was found that the composites showed a percolation behavior in which the electrical conductivity rose sharply at about 4 weight % of CSA-doped PoAN in the ABS composite. The STM data demonstrated the formation of a continuous path at the percolation threshold. The Poole–Frenkel effect was observed for the conduction scheme in the CSA-doped PoAN/ABS composite. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4596–4604, 1999     

Spectral,thermal, and electrical properties of poly(o- and m-toluidine)-polystyrene blends prepared by emulsion pathway

Conducting poly(o-toluidine) (POT) and poly(m-toluidine) (PMT) blends containing 10, 30, 50, 70, and 90 % wt/wt of polystyrene (PSt) were prepared by employing a two-step emulsion pathway. The bands characteristic of both polystyrene and POT/PMT are present in the IR spectra of POT–PSt and PMT–PSt blends. The UV-visible spectra of POT–PSt and PMT–PSt blends exhibit two bands around 313 and 610 nm, confirming that some amount of POT/PMT base is present in the blends. The EPR parameters such as line width and spin concentration reveal the presence of POT/PMT salt in the respective blends. The TGA, DTA, and DSC results suggest a higher thermal stability for the POT and PMT blends than that for the respective salts. The conductivity values of POT(70)–PSt(30) and POT(90)–PSt(10) blends are almost the same (1.1 × 10⁻² and 1.3 × 10⁻² S cm⁻¹, respectively) and these values are very close to that of pure POT salt, suggesting that POT can be blended with up to 30% wt/wt of PSt to improve its mechanical properties without a significant drop in its conductivity. The conductivity values of PMT–PSt blends are lower than those of the corresponding POT–PSt blends by two to three orders of magnitude, indicating that POT is a better system than PMT to prepare blends by this method. The dielectric constant and tan δ values of the blends increase with the amount POT/PMT and are greater than that of polystyrene. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2291–2299, 1998     

Simultaneous synthesis of silver nanoparticles and poly(2,5‐dimethoxyaniline) in poly(styrene sulfonic acid)

Silver nanoparticles were formed in situ along with poly(2,5‐dimethoxyaniline) (PDMA) in an interconnected network matrix (reactor), comprising the electronic conductive polymer, PDMA, and a polyelectrolyte, poly(styrene sulfonic acid) (PSS), through the simultaneous reduction of Ag⁺ ions and polymerization of 2,5‐dimethoxyaniline. In situ ultraviolet‐visible spectroscopy showed that peaks corresponding to the plasmon resonance of silver nanoparticles at 411 nm and the polaronic transition of PDMA at 438 nm provided evidences for the simultaneous formation of silver nanoparticles and PDMA. Transmission electron microscopy and size distribution analysis revealed the presence of spherical silver nanoparticles with an average diameter of 12 nm in the composite. X‐ray photoelectron spectroscopy showed that the amine units in PDMA changed to imine units upon the formation of silver nanoparticles. A comprehensive mechanism for the formation of the PDMA‐PSS‐Ag nanocomposite is proposed. A 10‐fold increase in the conductivity was noticed for the PDMA–PSS–Ag nanocomposite (1 S/cm) in comparison with the PDMA–PSS composite (0.1 S/cm). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3843–3852, 2006     

Poly(thieno[3,4‐b]‐1,4‐oxathiane) and poly(3,4‐ethylenedioxythiophene‐co‐thieno[3,4‐b]‐1,4‐oxathiane)/poly(styrene sulfonic sodium): Preparation,characterization, and optoelectronic performance

In this work, the asymmetrical analog of 3,4‐ethylenedioxythiophene (EDOT), thieno[3,4‐b]‐1,4‐oxathiane (EOTT), was synthesized and chemically polymerized first in aqueous solution using poly(styrene sulfonic sodium) (PSS) as the polyelectrolyte to yield poly(thieno[3,4‐b]‐1,4‐oxathiane) (PEOTT)/PSS. As‐formed film exhibited low electrical conductivity (～10^?4 S/cm). Alternatively, EOTT together with EDOT (in different molar ratio of 1:1 and 1:5) was copolymerized and the polymer poly(EOTT‐co‐EDOT)/PSS had electrical conductivity of 10^?1 S/cm. After dimethyl sulfoxide (DMSO) treatment, the electrical conductivity was enhanced to 10⁰ S/cm; however, the conductivity of the above homopolymer was reduced (～10^?5 S/cm). Raman spectroscopy was used to interpret conductivity enhancement or reduction after DMSO treatment. The conductivity decrease of PEOTT/PSS compared to poly(EOTT‐co‐EDOT)/PSS may arise from the conformational change of PEOTT backbone from the quasi‐planar to the distorted planar mode induced by PSS^–/PSSH through ionic interaction. Kinetic studies revealed that the copolymer had high coloration efficiencies (375 cm²/C), low switching voltages (?0.8 to +0.6 V), decent contrast ratios (45%), moderate response time (1.0 s), excellent stability, and color persistence. An electrochromic device employing poly(3‐methylthiophene) and poly(EOTT‐co‐EDOT)/PSS as the anode and cathode materials was also studied. From these results, poly(EOTT‐co‐EDOT)/PSS would be a promising candidate material for organic electronics. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2285–2297     

Effects of coronands on ionic conductivities of complexes of poly[2-(4-vinylphenoxy)-2,4,4,6,6-penta(methoxyethoxyethoxyethoxy)cyclotriphosphazene] with LiClO4

The effects of coronands such as crown ether and azacrown on the conductivity of complexes of LiClO₄ with poly[2-(4-vinylphenoxy)-penta(methoxyethoxyethoxyethoxy)cyclotriphosphazene] [poly(STEP)] were investigated. The extent of T_g elevation of poly(STEP)-LiClO₄ with 18-crown-6 was comparable to that of the poly(STEP)-LiClO₄ system. A similar behavior was observed for the system containing 12-crown-4. However, the increase in T_g values is considerably suppressed when tetraazacyclotetradecane with methoxyethoxy group as a side arm (MTAC) is used. All of the additives are effective to improve the conductivity, and the maximum conductivities of 10⁻⁴ S/cm at 30°C and 10⁻³ S/cm at 90°C have been achieved for the complex of the poly(STEP)-LiClO₄-MTAC system with Li⁺/O = 0.06, which are 3.5–7 times higher than those of poly(STEP)-LiClO₄ complexes. From the behaviors of T_g elevation and the conductivity, the role of the coronands for the conduction of the multi-armed poly(STEP)-LiClO₄ system is discussed. © 1996 John Wiley & Sons, Inc.     

Electrical conductivity change of polyaniline–dodecyl benzene sulfonic acid complex with temperature

Polyaniline–dodecylbenzene sulfonic acid (PAn–DBSA) complex was thermally treated and its conductivity and structure change were investigated. The conductivity increased linearly from 1.1 × 10⁻⁴ to 3.0 × 10⁻¹ S/cm on thermal heating until 140°C, but decayed above 200°C. The increase was caused by an additional thermal doping resulting from an increasing mobility of undoped dopants. After the thermal doping, the formation of the layered structure of PAn–DBSA is made. The decrease was caused by the thermal decomposition of dopants. The conductivity changes at a high temperature was strongly dependent on the nature of the dopant. The results were confirmed by means of X-ray patterns and Fourier transform infrared spectra obtained in the heating and cooling processes of polyaniline.     

Proton transportation in an organic–inorganic hybrid polymer electrolyte based on a polysiloxane/poly(allylamine) network

A new class of proton‐conducting polymer was developed via the sol–gel process from amino‐containing organic–inorganic hybrids by the treatment of poly(allylamine) with 3‐glycidoxypropyltrimethoxysilane doped with ortho‐phosphoric acid. The polymer matrix contains many hydrophilic sites and consists of a double‐crosslinked framework of polysiloxane and amine/epoxide. Differential scanning calorimetry results suggest that hydrogen bonding or electrostatic forces are present between H₃PO₄ and the amine nitrogen, resulting in an increase in the glass‐transition temperature of the poly(allylamine) chain with an increasing P/N ratio. The ³¹P magic‐angle spinning NMR spectra indicate that three types of phosphate species are involved in the proton conduction, and the motional freedom of H₃PO₄ is increased with increasing P/N ratios. The conductivity above 80 °C does not drop off but increases instead. Under a dry atmosphere, a high conductivity of 10^?3 S/cm at temperatures up to 130 °C has been achieved. The maximum activation energy obtained at P/N = 0.5 suggests that a transition of proton‐conducting behavior exits between Grotthus‐ and vehicle‐type mechanisms. The dependence of conductivity on relative humidity (RH) above 50% is smaller for H₃PO₄‐doped membranes compared with H₃PO₄‐free ones. These hybrid polymers have characteristics of low water content (23 wt %) and high conductivity (10^?2 S/cm at 95% RH), making them promising candidates as electrolytes for fuel cells. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3359–3367, 2005     

Synthesis and ionic conductivity of hyperbranched poly(glycidol)

A novel hyperbranched poly(glycidol) (HPG) was prepared and characterized. The synthesized HPG was used as a substrate of a polymer electrolyte. The ionic conductivity of a blend of HPG, polyurethane (PU), and salt was studied. The ionic conductivity of HPG/PU/LiClO₄ was about 6.6 × 10^?6 S · cm^?1 at 20 °C and 6.3 × 10^?4 S · cm^?1 at 60 °C. The results indicated that HPG showed higher solubility for salt than linear polyether when both had the same [O]/[Li⁺] molar ratio. The main reason was that more cavities and a lower degree of chain entanglement in HPG resulted in a lower glass‐transition temperature and were beneficial for decreasing the aggregation of salt or enhancing the ionic conductivity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2225–2230, 2001     

Cyclopolymerization of 3-phenyl[5]ferrocenophane-1,5-dimethylene: Synthesis and electronic properties of a polyferrocenophane

Radical cyclopolymerization of 3-phenyl[5]ferrocenophane-1,5-dimethylene ( 2 ) and copolymerization with styrene gave polymers ( 3 and 4 ) with [3]ferrocenophane moieties pendant to the backbone. Cyclic voltammetry (CV) on polymer 3 in CH₂Cl₂ showed two oxidation waves at −0.13 and +0.05 V (versus ferrocene/ferrocenium) and CV on copolymer 4 showed one oxidation potential at −0.03 V. CV on 3 in dimethylacetamide showed only one oxidation potential at −0.10 V. Near-IR spectroscopy of partially oxidized 3 showed a broad intervalence band at ca. 2000 nm, indicative of low-energy barriers to electron hopping. Conductivity measurements on 3 and poly(vinylferrocene) (PVFc) oxidatively doped with iodine vapors under an argon atmosphere showed a maximum conductivity ca. 5 × 10⁻⁵ S/cm before the samples cracked, while 4 exhibited a maximum conductivity of 1.6 × 10⁻⁶ S/cm. On iodine doping under ambient conditions, polymers 3 , 4 , and PVFc showed maximum conductivities of 7.6 × 10⁻⁴, 9.5 × 10⁻⁵, and 5.5 × 10⁻⁵ S/cm, respectively. Conductivity measurement were also performed on samples of 3 ⁺BF₄⁻ with oxidation levels ranging from 8 to 56%. Conductivities of these samples ranged from ca. 10⁻¹⁰ to 10⁻⁹ S/cm under vacuum and ca. 10⁻⁶ S/cm under ambient conditions, indicating that atmospheric moisture has a strong effect on the conductivity. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3365–3376, 1997     

Infrared characterization of poly(vinyl cinnamate) and its blends with poly(4-vinyl phenol) before and after UV exposure

The results of an infrared spectroscopic characterization of poly(vinyl cinnamate) (PVCIN) and its blends with poly(4-vinyl phenol) (PVPh) are reported before and after photo-crosslinking the PVCIN by exposure to UV radiation. The purpose of this article is to demonstrate methodology, and it is shown that quantitative analysis of the fraction of unsaturated ( CC ) double bonds, “free” (non-hydrogen bonded) and hydrogen bonded unsaturated ( CO CC ) and saturated ( CO C C ) acetoxy carbonyl groups is feasible in these blends as a function of UV exposure time. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1579–1590, 1998     

Synthesis and characterization of sulfonated poly(benzoxazole ether ketone)s by direct copolymerization as novel polymers for proton-exchange membranes

A new series of sulfonated poly(benzoxazole ether ketone)s (SPAEKBO-X) were prepared by the aromatic nucleophilic polycondensation of 4,4′-(hexafluoroisopropylidene)-diphenol with 2,2′-bis[2-(4-fluorophenyl)benzoxazol-6-yl]hexafluoropropane and sodium 5,5′-carbonylbis-2-fluorobenzenesulfonate in various ratios. Fourier transform infrared and ¹H NMR were used to characterize the structures and sulfonic acid contents of the copolymers. The copolymers were soluble in N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, and N,N-dimethylformamide and could form tough and flexible membranes. The protonated membranes were thermally stable up to 320 °C in air. The water uptake, hydrolytic and oxidative stability, and mechanical properties were evaluated. At 30–90 °C and 95% relative humidity, the proton conductivities of the membranes increased with the sulfonic acid content and temperature and almost reached that of Nafion 112. At 90–130 °C, without external humidification, the conductivities increased with the temperature and benzoxazole content and reached above 10⁻² S/cm. The SPAEKBO-X membranes, especially those with high benzoxazole compositions, possessed a large amount of strongly bound water (>50%). The experimental results indicate that SPAEKBO-X copolymers are promising for proton-exchange membranes in fuel cells, and their properties might be tailored by the adjustment of the copolymer composition for low temperatures and high humidity or for high temperatures and low humidity; they are especially promising for high-temperature applications. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2273–2286, 2007     

Single-ion and salt conductor polymer electrolytes based on poly(4-vinylpyridine) quaternized with poly(ethylene oxide) side chains

A new type of single-ion conductor with fixed cation was synthesized by spontaneous anionic polymerization of 4-vinylpyridine in the presence of short polyethylene oxide ( PEO ) chains as alkylating agents. These comblike polymers have low T_gs and are amorphous with the shorter PEO s. Their conductivities are unaffected by the nature of the anion ( Br ⁻, ClO ₄⁻, and tosylate) and are controlled by the free volume and the mobility of the pendant cation. By comparison of the results at constant free volume, it is shown that the charge density decreases with the increasing length of pendant PEO demonstrating that PEO acts only as a plasticizing agent. Best conductivity results (σ = 10⁻⁵ S cm⁻¹ at 60°C) are obtained with PEO side chains of molecular weight 350. With this sample, the conductivity in the presence of various amounts of added salt (LiTFSI) was studied. A best value of 10⁻⁴ S cm⁻¹ at 60°C is obtained with a molar ratio EO/Li of 10. It is shown that, over the range of examined concentrations (0.2–1.3 mol Li kg⁻¹), the reduced conductivity σ_r/c increases linearly with increasing salt concentration showing that the ion mobility increases continuously. Such behavior is quite unusual since in this concentration range a maximum is generally observed with PEO systems. To interpret this result and by analogy with the behavior of this type of polymer in solution, it is proposed that the conformation of these polymers in the solid state is segregated with the P4VP skeleton more or less confined inside the dense coils surrounded by the PEO side chains. Under the influence of the increasing salt concentration, this microphase separation vanishes progressively: The LiTFSI salt exchanges with the tosylate anions and acts as a miscibility improver agent. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2719–2728, 1997     

Cross‐linked poly(aryl ether sulfone) membranes for direct methanol fuel cell applications

Partially sulfonated poly(aryl ether sulfone) (PESS) was synthesized and methacrylated via reaction with glycidyl methacrylate (PESSGMA) and cross‐linked via radical polymerization with styrene and vinyl‐phosphonic acid (VPA). The chemical structures of the synthesized pre‐polymers were characterized via FTIR and ¹H NMR spectroscopic methods and molecular weight was determined via GPC. Membranes of these polymers were prepared via solution casting method. The crosslinking of the PESS polymer reduced IEC, proton conductivity, swelling in water, and methanol permeability of the membranes while increasing the modulus and the glass transition temperature. However, the introduction of the VPA comonomer increased the proton conductivity while maintaining excellent resistance to methanol cross‐over, which was significantly higher as compared with both PESS and the commercial Nafion membranes. Membranes of PESSGMA copolymers incorporating VPA, exhibited proton conductivity values at 60 °C in the range of 16–32 mS cm⁻¹ and methanol permeability values in the range of 6.52 × 10⁻⁹ – 1.92 × 10⁻⁸ cm² s⁻¹. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 558–575     

New aromatic benzazole polymers. I. Benzobisthiazole and benzobisoxazole polymers with main-chain triarylamino units

Thermally stable, nonrigid-rod poly(benzobisthiazoles), (R)TPA-PBZT , where R = H, Me, NMe₂, and OH, and poly(benzobisoxazoles), (R)TPA-PBO , where R = Me, NMe₂ containing electron-rich triarylamine groups with various para-substituents (Rs) on the pendent phenyl ring, were synthesized from either 2,5-diamino-1,4-benzenedithiol dihydrochloride or 2,4-diamino-1,5-benzenediol dihydrochloride and the respective triarylamine-based dinitrile or diacid monomer in polyphosphoric acid. Whereas (R)TPA-PBZT polymers were obtained in moderate molecular weights, analogous (R)TPA-PBO polymers were only prepared in low molecular weights. No lyotropic behaviors, characteristic of the unmodified rigid-rod benzazole polymers, as evidenced by the absence of either stir opalescence or birefringence under crosspolarizers, were observed for these homopolymers at about 10 wt % polymer concentration. Among these polymers, only (Me)TPA-PBZT and (NMe₂)TPA-PBZT formed cast films with good mechanical integrity. In their pristine state, their film conductivity values were in the range of 10⁻¹⁰–10⁻⁹ S/cm at room temperature. Upon exposure to iodine vapor, their conductivities were increased to the maximal values of 5.0 × 10⁻⁵ S/cm ( (Me)TPA-PBZT ) and 4.1 × 10⁻⁴ S/cm ( (NMe₂)TPA-PBZT ). © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1909–1924, 1997     

Improving electrochemical performance of poly(vinyl butyral)-based electrolyte by reinforcement with network of ceramic nanofillers

This study has concerned the development of polymer composite electrolytes based on poly(vinyl butyral) (PVB) reinforced with calcinated Li/titania (CLT) for use as an electrolyte in electrochemical devices. The primary aim of this work was to verify our concept of applying CLT-based fillers in a form of nano-backbone to enhance the performance of a solid electrolyte system. To introduce the network of CLT into the PVB matrix, gelatin was used as a sacrificial polymer matrix for the implementation of in situ sol–gel reactions. The gelatin/Li/titania nanofiber films with various lithium perchlorate (LiClO₄) and titanium isopropoxide proportions were initially fabricated via electrospinning, and ionic conductivities of electrospun nanofibers were then examined at 25 °C. In this regard, the highest ionic conductivity of 2.55 × 10⁻⁶ S/cm was achieved when 10 wt% and 7.5 wt% loadings of LiClO₄ and titania precursor were used, respectively. The nanofiber film was then calcined at 400 °C to remove gelatin, and the obtained CLT film was then re-dispersed in solvated PVB-lithium bis(trifluoromethanesulfonyl)imide (PVB-LiTFSI) solution before casting to obtain reinforced composite solid electrolyte film. The reinforced composite PVB polymer electrolyte film shows high ionic conductivity of 2.22 × 10⁻⁴ S/cm with a wider electrochemical stability window in comparison to the one without nanofillers.

     

New aromatic benzazole polymers II: Synthesis and conductivity of benzobisthiazole-co-polymers incorporated with 4-N,N-dimethylaminotriphenylamine groups

New aromatic benzobisthiazole copolymers containing 10–70 mol % of 4-N,N-dimethylamino-triphenylamine functionality were prepared from the respective dinitrile or dicarboxylic acid monomers, terephthalic acid, and 2,5-diamino-1,4-benzene-dithiol dihydrochloride in polyphosphoric acid. At the first approximation, the copolymers containing 10 mol % or less of the triarylamino moieties in the polymer chains still preserve the capability to form anisotropic (nematic) solutions at 10 wt % polymer concentration. This is an important requirement for processing the copolymers into fibers and films with good to excellent mechanical properties. Films with good mechanical integrity were cast from the dilute methanesulfonic acid solutions of the copolymers under reduced pressure. They showed electrical conductivity values of the order of 10⁻¹¹–10⁻¹⁰ S/cm in pristine state, with four to seven orders of magnitude increase upon exposure to mild oxidizing agents such as iodine vapor. On the contrary, the parent polymer, poly(p-phenylene benzobisthiazole) is an insulator with conductivity of less than 10⁻¹² S/cm, and its conductivity does not improve at all with exposure to iodine vapor. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 713–724, 1998