Synthesis and properties of novel polymers having S-methyldibenzothiophenium salt moieties

A polymer having dibenzothiophenium salt moieties [poly(sulfonium salt), 2 ] was prepared by the reaction of poly(2-vinyldibenzothiophene) ( 1 ) with CH₃I and AgBF₄ in CH₂ClCH₂Cl at room temperature for 24 h. The obtained polymer 2 was found to contain 71% of the methyldibenzothiophenium tetrafluoroborate unit. A monomer carrying the sulfonium salt moiety, i.e., 5-methyl-2-vinyldibenzothiophenium tetrafluoroborate ( 4 ), was independently prepared and subjected to radical polymerization to give a polymer ( 5 ) in 88% yield (methyldibenzothiophenium tetrafluoroborate unit: 79%). The thermal decompositions of 2 and 5 took place in two steps; the first step involved the formation of polymer 1 by demethylation. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1779–1784, 1998     

Molecular and collective relaxations of ferroelectric side chain liquid crystalline polysiloxanes

The influences of mesogenic group chemical structures on dielectric relaxation behavior were investigated for ferroelectric side chain liquid crystalline polymers (FLCPs). The relaxation time and activation energies of the Goldstone mode, α‐, and β‐relaxations decrease with increasing spacer length because of the plasticizer effect of the spacer. Moreover, the relaxation intensity increases with increasing spacer length for FLCPs. An FLCP with a longer spacer length exhibits a higher mesogenic group mobility, and subsequently leads to easier reorientation toward the alternating electrical field. An increase in mesogenic core rigidity results in an increase in the relaxation time and activation energies, and a decrease in the relaxation intensities for the Goldstone mode, α‐, and β‐relaxations. Moreover, the β‐relaxation is suppressed and cannot be observed in the glassy state for FLCPs containing naphthyl biphenylcarboxylate as the mesogenic group. Shorter relaxation time, smaller activation energies, and higher intensity of the α‐, and β‐relaxations were obtained for FLCPs containing chiral moiety with a flexible heptyl alkyl chain. However, the relaxation intensity of the Goldstone mode for FLCPs containing this chiral moiety was smaller than that for FLCPs containing the chiral moiety with a butyl alkyl chain. For FLCPs containing a chiral moiety with two asymmetrical centers, their Goldstone mode relaxation showed larger amplitude. The α‐ and β‐relaxations are suppressed for these FLCPs because of the dense packing and memory effect of the smectic phase. The relationship between the chemical structure of the mesogenic group and dielectric relaxations is discussed in great detail. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2035–2049, 2006     

A new soluble conducting polymer and its electrochromic devices

A new polythiophene derivative was synthesized by both chemical and electrochemical oxidative polymerization of 1‐(1‐phenylethyl)‐2,5‐di(2‐thienyl)‐1H‐pyrrole (PETPy). Of which the chemical method produces a polymer that is completely soluble in organic solvents. The structures of both the monomer and the soluble polymer were elucidated by nuclear magnetic resonance (¹H and ¹³C NMR) and Fourier transform infrared (FTIR) spectroscopy. The average molecular weight has been determined by gel permeation chromatography to be M_n = 3.29 × 10³ for the chemically synthesized polymer. Polymer of PETPy was synthesized via potentiostatic electrochemical polymerization in acetonitrile (AN)/NaClO₄/LiClO₄ (0.1 M) solvent–electrolyte couple. Characterizations of the resulting polymer were performed by cyclic voltammetry, FTIR, scanning electron microscopy, and UV–vis spectroscopy. Four‐probe technique was used to measure the conductivities of the samples. Moreover, the spectroelectrochemical and electrochromic properties of the polymer films were investigated. In addition, dual‐type polymer electrochromic devices based on P(PETPy) with poly(3,4‐ethylenedioxythiophene) were constructed. Spectroelectrochemistry, electrochromic switching, and open circuit stability of the devices were studied. They were found to have good switching times, reasonable contrasts, and optical memories. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2215–2225, 2006     

Synthesis of a pyrrole‐based methine bridge type liquid‐crystalline conjugated polymer

Conjugated polymers consisting of pyrrole or an N‐substituted pyrrole bridged by methine with a mesogenic group were synthesized. Chemical structures of the products were confirmed with IR, NMR, UV–visible (UV–vis) spectroscopy, and gel permeation chromatography analysis. Liquid crystallinity was examined with differential scanning calorimetry measurements and polarizing optical microscopy observations. Liquid crystal domains of the polymer were macroscopically oriented in one direction by an external magnetic force (10 Tesla). The polymer orientation was confirmed by optical microscopy and X‐ray analysis. One of the polymers exhibited a striated fan‐shaped texture when observed with a polarizing optical microscope. This is attributed to the formation of a chiral smectic C (SmC^*) phase, which is a property of ferroelectricity. Spontaneous polarization of the polymer occurred at 110 nC/cm². © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 616–629, 2005     

Syntheses and alignment behavior of liquid crystalline polymethacrylates having 2‐ and 4‐styrylpyridine moieties

Two kinds of polymethacrylates, 1 and 2 , with 2‐styrylpyridine and 4‐styrylpyridine moiety as a photoreactive group, which have a benzoate group as a mesogenic unit, and hexylene group as a flexible spacer in the same side chain, were synthesized to characterize their alignment behaviors. The UV absorption and fluorescence studies on the two polymers revealed that the latter polymer with the 4‐stylrylpyridine moiety is more aggregative than the former polymer with the 2‐styrylpyridine moiety. The polymer 1 showed a nematic phase structure at 170 °C, while 2 appeared in a partially bilayered smectic A phase structure in the homeotropic direction at 175 °C. The polymer 1 film generated an in‐plane alignment by a linearly polarized UV light irradiation and subsequent annealing, and its direction was parallel with respect to the irradiation. On the other hand, the polymer 2 film with the same treatments gave a high out‐of‐plane order parameter of 0.73 in a wide temperature range of 120–240 °C. The significant differences in the aggregation behavior, the liquid‐crystalline structure, and the alignment between the two polymers were discussed by the structural differences between the 2‐ and 4‐styrylpyridine moieties in the two polymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5371–5380, 2008     

Thermo-oxidatively stable polyimides and their chemical structures

A series of aromatic diamines having ether and/or carbonyl moieties in their structures were synthesized. By using these synthesized diamines and commercially available tetracarboxylic dianhydrides, various kinds of polyimides having ether and/or carbonyl moieties were synthesized. The thermo-oxidative stability of the obtained polyimides was investigated by focusing on the chemical structures of their repeating structure units. The reason for the improved thermo-oxidative stability of the ether–carbonyl polyimide structure was explained by an electronically balanced condition, i.e., the balance of electron donor moiety (—O—) and electron acceptor moiety (—CO—) in a chemical structure, and the degree of electron deficiency of the benzene–imide ring structure. The possibility of the formation of a charge transfer complex (CT-complex) was also mentioned as an explanation of the improved thermo-oxidative stability of ether–carbonyl polyimide structures. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1717–1723, 1998     

Unusually facil cis to trans isomerization of a polypropiolate bearing a long alkyl chain polymerized using a [Rh(norbornadiene)Cl]2 catalyst: An ESR study

Alkylpropiolate having n-hexadecyl moiety in the ester group was stereospecifically polymerized with a [Rh(norbornadiene)Cl]₂ complex catalyst in alcohol to give rise to cis-transoid polyacetylenes in high yields. The unusually facile cis to trans isomerization for the polymer was found to be induced when the polymer was warmed to even less than ca. 57°C. Under these conditions ESR spectra bearing hyperfine structures due to the radicals generated by the rotational scission in the cis–π bond were observed. This isomerization induced a large g value shift in the ESR spectra together with an increase of the radical concentration during the isomerization, indicating formation of planar conjugated trans sequences that stabilize mobile unpaired electrons as solitons. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2457–2461, 1998     

Nanostructured ion-conductive films: Layered assembly of a side-chain liquid-crystalline polymer with an imidazolium ionic moiety

An ion-conductive mesogenic monomer with an imidazolium ionic moiety has been designed to obtain self-assembled materials forming ionic layers. Self-standing polymer films are prepared by in situ photopolymerization of the monomer that forms homeotropic monodomain on a normal glass substrate in the smectic A phase. Macroscopically oriented, layered nanostructures are formed in the film. The ionic conductivity parallel to the smectic layer has been measured for the oriented film. In the smectic A phase at 150 °C, the magnitude of conductivity is about 10⁻² S cm⁻¹. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3486–3492, 2003     

Optical anisotropy of a photoreacted side-chain liquid-crystalline polymer induced by linearly polarized UV light

Linearly polarized (LP) UV photoreaction of a photo-crosslinkable side-chain liquid-crystalline polymer (SLCP) containing photoreactive cinnamoyl and biphenyl mesogenic groups ( 1 ) was studied. The optical anisotropy of the polymer film was induced by the LP-UV photoreaction and was investigated by the temperature-controlled polarized UV absorption spectroscopy and polarized FT-IR measurements. The reorientation of the nonreacted mesogenic groups along to the Ê direction of the incident LP-UV light during the photoreaction occurred at the LC temperature range of the polymer, and the induced birefringence Δn was about 0.02. Because of the high-density photo-crosslinking, the LP-UV photoreacted film showed orientational stability up to 160°C. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1521–1526, 1998     

Influence of alkoxy tail length and unbalanced mesogenic core on phase behavior of mesogen‐jacketed liquid crystalline polymers

When the flexible terminal substituent changes from butoxy to hexyloxy or longer, smectic C (S_C) liquid crystalline phase was firstly reported to develop from a kind of mesogen‐jacketed liquid crystalline polymer (MJLCP) whose mesogenic side groups are unbalancedly bonded to the main chain without spacers. A series of MJLCPs, poly[4,4′‐bis(4‐alkoxyphenyl)‐2‐vinylbiphenyl(carboxide)] (nC2Vp, n is the number of the carbons in the alkoxy groups, n = 2, 4, 6, 8, 10, and 12) were designed and synthesized successfully via free radical polymerization. The molecular weights of the polymers were characterized with gel permeation chromatography, and the liquid crystalline properties were investigated by differential scanning calorimetry, polarized light microscopy experiments, and 1D, 2D wide‐angle X‐ray diffraction. Comparing with the butoxy analog, the polymer with unbalanced mesogenic core and shorter flexible substituents (n = 2, 4) keeps the same smectic A (S_A) phase, but other polymers with longer terminal flexible substituents (n = 6, 8, 10, and 12) can develop into a well‐defined S_C phase instead of S_A phase. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 505–514, 2009     

Electrochemical polymerization of imidazolum‐ionic liquids bearing a pyrrole moiety

A series of imidazolium‐based ionic liquid monomers bearing a terminal pyrrole moiety were synthesized and electrochemically polymerized. It is found that the polymerizability of the synthesized ionic liquids is strongly dependent on the type of the counteranions. Although bromide monomer is not polymerizable, well‐defined polymeric films can be formed on various substrates in the cases of flour‐containing anions (BF₄^?, PF₆^?). The performed characterizations show that all resulting polypyrrole films are electroactive, and the imidazolium‐based ionic liquid moieties are correctly incorporated in polymer films during the electropolymerization process. This work not only provides a facile new method to immobilize ionic liquids on solid surface. Interestingly, without use of any template unique “knit” morphology and nanostructure, even hierarchical structures could also be produced by the electropolymerization of these new functionalized pyrrole monomers. We found that the properties of the pendant ionic liquid units on the surface of the formed polymer films preserved, and by simple anion exchange their surface energy and tension could be easily tuned without loss of the electrical, optical properties, and morphology of the polypyrrole films. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4151–4161, 2008     

Preparation and characterization of a poly(vinylbenzyl sulfonic acid)‐grafted FEP membrane

In this study, a novel polymer electrolyte membrane, poly(vinylbenzyl sulfonic acid)‐grafted poly(tetrafluoroethylene‐co‐hexafluoropropylene) (FEP‐g‐PVBSA), has been successfully prepared by simultaneous irradiation grafting of vinylbenzyl chloride (VBC) monomer onto a FEP film and taking subsequent chemical modification steps to modify the benzyl chloride moiety to the benzyl sulfonic acid moiety. The chemical reactions for the sulfonation were carried out via the formation of thiouronium salt with thiourea, base‐catalyzed hydrolysis for the formation of thiol, and oxidation with hydrogen peroxide. Each chemical conversion process was confirmed by FTIR, elemental analysis, and SEM‐EDX. A chemical stability study performed with Fenton's reagent (3% H₂O₂ solution containing 4 ppm of Fe²⁺) at 70 °C revealed that FEP‐g‐PVBSA has a higher chemical stability than the poly(styrene sulfonic acid)‐grafted membranes (FEP‐g‐PSSA). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 563–569, 2010     

A new near‐infrared switchable electrochromic polymer and its device application

A new near‐infrared switchable electrochromic polymer containing carbazole pendant (poly‐SNSC), synthesized by electrochemical polymerization of 2,5‐bis‐dithienyl‐1H‐pyrrole (SNS) main chain, has been prepared. The electrochemical and optical properties of SNSC monomer and its polymer have been investigated. Because of having two different electro‐donor moieties; that is, carbazole and SNS, SNSC gave two separate electrochemical oxidation and also light brown color of the film in the neutral state turn into gray on oxidation. An electrochromic device, contructed in the sandwich configuration [indium tin oxide (ITO)‐coated glass/anodically coloring polymer (poly‐SNSC)//gel electrolyte//cathodically coloring polymer (PEDOT)/ITO‐coated glass] and exhibited a high coloration efficiency (1216 cm² C^–1), a very short response time (about 0.3 s), low driving voltage, and a high redox stability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Model structures of thermoplastic polyesters having regularly alternated aromatic and fluorinated segments

Linear segmented polyesters containing soft perfluoropolyether (PFPE) and hard aromatic segments are obtained by an interfacial polycondensation reaction of an acyl chloride-ended fluorinated prepolymer with various aromatic diphenols in the presence of phase transfer catalysts (PTC) as accelerators. Experimental conditions for reaching high molecular weights are discussed. The calorimetric analysis (DSC) of all the polyesters synthesized shows a typical biphasic morphology, where a very low T_g (< −110°C) corresponding to the segregated PFPE moiety, is always accompanied by another T_g or a higher melting temperature, depending on the nature of the hard phase. Dynamic-mechanical analysis (DMA) has been carried out confirming the DSC results and suggesting diversified mechanical behaviors at the various temperatures in line with the amorphous or semicrystalline nature of the polymer. Chemical resistance was finally tested by dipping in several solvents and chemicals. The new polyesters show high contact angles, a moderate swelling in many organic solvents and excellent stability in aggressive hydrolytic environments. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 939–947, 1998     

Synthesis of a novel epoxy resin containing diphenylether moiety and thermal properties of its cured polymer with phenol novolac

A new type of epoxy resin containing 4,4′-diphenylether moiety in the backbone (2) was synthesized, and was confirmed by gel permeation chromatography, infrared spectroscopy, and ¹H nuclear magnetic resonance spectroscopy. In addition, in order to evaluate the influence of 4,4′-diphenylether moiety in the structure, epoxy resins having 4,4′-biphenylene moiety (4) and having 1,4-phenylene moiety (6) in place of 4,4′-diphenylether moiety were synthesized. The cured polymer obtained through the curing reaction between the new diphenylether-containing epoxy resin and phenol novolac was used for making a comparison of its thermal and physical properties with those obtained from 4, 6, and bisphenol-A (4,4′-isopropylidenediphenol) type epoxy resin. The cured polymer obtained from 2 showed markedly higher anaerobic char yield at 700°C of 44.0 wt %, higher fracture toughness, and higher mechanical strength and modulus. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3687–3693, 1999     

Thermo- and photooxidation of polyisobutylene. I. Evolutions at temperatures above 50°C

Polyisobutylene films (PIB) were submitted to a thermal oxidation at 100°C and to a photooxidation by exposure to long-wavelength radiations (λ ≥ 300 nm) at 60°C. The modifications of the chemical structure resulting from the oxidation were determined by FT-IR analysis of the polymer films, coupled to chemical treatments that converted specifically the oxidation products. Dissolution of oxidized samples permitted analysis of the polymer by ¹³C- and ¹H-NMR. The structure of the volatile products was determined by mass spectroscopy analysis of the gas phase. Identification of the numerous products formed permitted the proposal of a scheme that accounts for the oxidation of PIB. When the irradiations are carried out at a temperature above 50°C, the depolymerization is favored and the mechanism involves two main routes of oxidation. A direct oxidation starts with the oxidation of radicals obtained by homolysis of the C C bonds on the main chain, and an induced oxidation involves hydrogen abstraction on the methylene and methyl groups by radicals formed by the direct oxidation of the polymer. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1689–1701, 1997     

Polymer having a trithiocarbonate moiety in the main chain: Application to reversible addition–fragmentation chain transfer controlled thermal and photoinduced monomer insertion polymerizations

A polymer having a trithiocarbonate moiety in its main chain was synthesized with a cyclic, five‐membered dithiocarbonate as a building block. The trithiocarbonate in the polymer acted as a reversible addition–fragmentation chain transfer reagent to mediate a controlled insertion polymerization of styrene into the polymer main chain, giving the corresponding sequence‐ordered polymer having a well‐defined polystyrene segment in the main chain. During the polymerization, the polystyrene segment in the main chain gained its molecular weight, which maintained a linear relationship with the conversion of styrene. The insertion polymerization of styrene was induced not only thermally but also by ultraviolet irradiation. This photoinduced polymerization was well controlled by the trithiocarbonate moiety to give the corresponding polymer, whose structure was virtually the same as that obtained by the thermal polymerization. © 2006 Wiley Periodicals, Inc. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6324–6331, 2006     

Synthesis of an amphiphilic polymer having hydrophobic acetal and hydrophilic pyrrolidone moieties and its application to persisting release of aldehyde as a pro‐fragrance

A polymer having acetal moiety in the side chain was synthesized by a reaction of 1,3‐diol structure of poly(vinyl alcohol‐co‐N‐vinylpyrrolidone) and octanal. The hydrophobicity of the resulting acetal moiety and the hydrophilicity of the pyrrolidone moiety allowed the polymer to exhibit amphiphilicity. The polymer released octanal by hydrolysis of the acetal side chains under acidic conditions. The release of octanal was enhanced by the increased hydrophilicity of the polymer because of the presence of pyrrolidone moiety. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3816–3822, 2010     

Synthesis,structure, and properties of chiral liquid crystal monomers and polymers based on menthol

To study structure–mesomorphism relationships of the monomers and polymers based on menthol, four new chiral monomers ( M₁ – M₄ ) and the corresponding homopolymers ( P₁ – P₄ ) with menthyl group were synthesized. Their chemical structures, formula, phase behavior, and thermal stability were characterized by FTIR, ¹H NMR, ¹³C NMR, elemental analyses, differential scanning calorimetry, polarizing optical microscopy, X‐ray diffraction, and thermogravimetric analysis. The selective reflection of light was investigated with ultraviolet/visible spectrometer. The influence of the mesogenic core rigidity, spacer length, and menthyl steric effect on the mesomorphism of M₁ – M₄ and P₁ – P₄ was examined. By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, four target monomers and polymers could form the expected mesophase. Moreover, their melting temperature (T_m), glass transition temperature (T_g), clearing temperature (T_i), and mesophase range (ΔT) increased with increasing the mesogenic core rigidity; whereas the T_m and T_g decreased, T_i and ΔT increased with an increase of the spacer length. M₁ and M₂ showed monotropic and enantiotropic cholesteric phase, respectively, whereas M₃ and M₄ all revealed chiral smectic C (SmC*), cholesteric and cubic blue phases. In addition, with increasing temperature, the selective reflection of light shifted to the long wavelength region at the SmC* phase range and to the short wavelength region at the cholesteric range, respectively. P₁ and P₂ only showed a smectic A (SmA) phase, whereas P₃ and P₄ exhibited the SmC* and SmA phases. All the obtained polymers had very good thermal stability. © 2012 Wiley Periodicals, Inc. J. Polym. Sci. Part A: Polym Chem, 2012     

Polymers with electron-deficient olefin moieties by oxidation of precursors containing “push–pull” olefin (β-alkylmercaptoenoate) moieties in the main chain

Oxidation of a polymer (1) having β-alkylmercaptoenoate moieties in the main chain by m-chloroperbenzoic acid (MCPBA) is described. Oxidation of 1 proceeded selectively to give polymers having vinyl sulfoxide or vinyl sulfone moieties in the main chain by using an appropriate amount of MCPBA. In the case of 1.1 equiv of MCPBA (relative to the sulfur atom), a polymer (4) having vinyl sulfoxide moieties selectively in the main chain was obtained in quantitative yield without side reactions. Likewise, a polymer (5) having vinyl sulfone moieties was obtained in quantitative yield by using 2.6 equiv of MCPBA. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2589–2592, 1998