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Transparent, film-forming fluorinated arylene vinylene ether (FAVE) polymers with enchained triarylamine (TAA) moieties were prepared and characterized. Control over fluoro-olefin content within the backbone, as a function of base, was confirmed and postpolymerization dehydrofluorination was shown to increase fluoroolefin content from 5 to 31 mol %. Thermal cross-linking was found to occur approximately 100 °C lower than in traditional FAVE polymers (ca. 160 °C). Electrochemical analysis demonstrated the enchained TAA retained its established electrochemical character. The latent reactivity of the TAA was explored via electrophilic aromatic substitution and formylation reactions toward precise functionalization for specific electro-optic applications and others.

Perfluorocycohexenyl (PFCH) aromatic ether polymers were synthesized by step-growth polycondensation of polycyclic aromatic hydrocarbon (PAH) bisphenols and decafluorocyclohexene (DFCH) affording a new class of unsaturated semi-fluoropolymers containing the rigid PAH linkage. Two acenaphthenequinone and two phenanthrenedione derived PAH bisphenols underwent base-mediated step-growth vinyl addition/elimination polymerization with DFCH to give polymers with well-defined unsaturation, moderate molecular weights, and variable glass transition (Tg) and thermal decomposition (Td) temperatures based on the starting PAH bisphenol monomer. With one exception exhibiting a low degree of crystallinity, PFCH polymers with PAH bisphenols were amorphous with Tg ranging from 184 to 240 °C. The new polymers contain intact unsaturation and reactive PAH moieties amenable for selective post-polymerization functionalization and crosslinking.

Epoxy resins are one of the most widely used thermosetting materials in industrial and practical applications because they exhibit excellent mechanical, thermal, and dielectric performance at commodity volume and cost. In particular, multifunctional epoxies—dense and cross-linked structured resins—are used as molding compounds, sealants, and protective coatings for many barrier-related applications. In this work, we used a tetrafunctional epoxy-amine resin as a coating for mild steel and used electrochemical impedance spectroscopy (EIS) to investigate its protection performance in a 3.5 wt % NaCl solution. The results indicate that the coating was able to resist corrosion and maintain a very high impedance modulus for more than 30 d of continuous exposure to the NaCl solution. Different resistance behaviors, as indicated by EIS, were observed for the coatings with artificially introduced damage. The coating also showed high thermal resistance and good adhesion to mild steel surfaces. This tetrafunctional epoxy-amine resin could effectively function as a high performance and corrosion resistant coating material for semiconductor, aerospace, and marine applications.

Semi-fluorinated arylene vinylene ether (FAVE) telechelomers and their chain extended PFCB polymers were synthesized via base catalyzed step-growth polymerization of polycyclic aromatic hydrocarbon (PAH) bisphenols and commercially available 4,4ꞌ-bis(4-trifluorovinyloxy)biphenyl (TFVE-BP) monomer. Soluble polymers were obtained in good yield, gave transparent free-standing films, and were characterized by 19F NMR, TGA, DSC, GPC, water contact angle and AFM. Thermal analysis by differential scanning calorimetry (DSC) revealed Tg values ranging from 150 to 168 °C. The new polycyclic aromatic FAVE polymers possess intact trifluorovinyl ether (TFVE) end groups susceptible to thermal chain extension leading to perfluorocyclobutyl (PFCB) aryl ether polymers with Tg ranging from 149 to 174 °C. Semi-fluorinated telechelic polymers with controlled terminal and enchained unsaturation with latent crosslinking ability may find use in specialty applications such as photonics or gas separation technologies.

Suzuki polycondensation (SPC) as an alternative strategy has been utilized for the first time to readily yield functional perfluorocyclobutyl (PFCB) aryl ether polymers, which are difficult to obtain via the traditional [2+2] thermal cyclopolymerization strategy. Using two reactive PFCB aryl ether molecules as monomers, the biphenyl PFCB aryl ether polymer without any functionality was first prepared and exhibited good thermal stability, up to 450 °C at 8% weight loss (N2). By choosing appropriate functional monomers, aldehyde-functionalized PFCB aryl ether polymer precursor was also successfully prepared. Post-polymerization modification of this polymer precursor via Knoevenagel condensation yielded three distinct PFCB aryl ether polymers containing thermally stable triarylamine-based electro-optic chromophores.

A novel partially fluorinated arylene vinylene ether (FAVE) polymer containing ester groups was synthesized, which was used to prepare three reactive FAVE polymers containing carboxylic acid groups, alcohol groups, and acid chloride groups, respectively. Post-polymerization modifications of the FAVE polymer's carboxylic acid groups (via a DCC coupling procedure with the desired alcohol), alcohol groups (via DCC coupling or an acid chloride esterification procedure with the desired carboxylic acid or acid chloride), and acid chloride groups (via an optimized nucleophilic substitution reaction with the desired alcohol or amine) were successfully performed. Several examples have been successfully prepared to demonstrate the versatility of these developed modification methods. FAVE polymers have been prepared with NHS active ester groups, Disperse Red 1 chromophores, benzyl bromide groups, aryl trifluorovinyl ether groups, ATRP initiator groups, vinyl groups, propargyl groups, Disperse Orange 3 chromophores, and benzaldehyde groups. In most cases, analytical data are consistent with a quantitative conversion of the reactive or functional groups. It is demonstrated that no degradation of the FAVE polymer matrix occurs after multistep post-polymerization modification reactions.

Here the microscopic mechanism that leads to the surprising formation of a nanopattern upon methanol reacting with a H-terminated Si(111) surface [Michalak et al., Nat. Mater. 2010, 9, 266–271] is reinvestigated from both theory and experiment. First-principles calculations determine the fully OCH3-terminated Si(111) surface as the thermodynamic ground state in the presence of methanol, seemingly in contrast to the experimentally found nanopattern. At 65 °C the presence of H2 initiates desorption of the methoxy groups and thereby leads to a dynamic equilibrium of the reaction of methanol with the H-terminated Si(111) surface, which is a 1/3 OCH3-terminated and 2/3 H-terminated Si(111) surface, with all OCH3 groups standing as NNNs, corresponding to the nanopattern observed earlier. Investigating fluorine group termination of Si(111) as a test system the present study demonstrates that the combination of theoretical and experimental techniques used here is in fact sufficiently sensitive to resolve complex ...

A method for the preparation of AB-type monomers with complimentary fluoro-olefin and phenol functionalities is described. The three-step process is amenable to commercial scale up and uses widely-available, commercial reagents including bisphenols and perfluorocycloalkene (PFCA) compounds. Title compounds and intermediates were characterized via multi-nuclear NMR and FT-IR spectroscopy providing structural and mechanistic elucidation of PFCA step-growth polymerizations. The formation of vinyl and allyl substituted products were quantified and shown to be dependent on PFCA ring size and reaction medium. Nearly equal amounts of vinyl- and allyl-substituted products were observed with perfluorocyclohexene (PFCH) while 2–11% allyl-substitution was observed with perfluorocyclopentene (PFCP), depending on reaction medium polarity. Previous PFCA research and characterization of title compounds suggests that fluoride-catalyzed rearrangement is primarily responsible the formation of two substitution products. Polymerization of an AB-type monomer derived from bisphenol A is demonstrated and was shown to reproducibly result in film-forming polymers with higher molecular weights than previously described methods.

A variety of perfluorocycloalkenyl (PFCA) aryl ether monomers and polymers with enchained triarylamine units were successfully synthesized, characterized and reported here. These polymers are highly thermally stable and show variable thermal properties. Successful conversion of the newly synthesized TAA enchained perfluorocyclopentenyl (PFCP) aryl ether polymers via formylation and EAS demonstrates the synthetic versatility of TAA moiety and provides an excellent option for application specific post polymerization reactions. The cross-linking behavior of PFCP aryl ether polymers was studied under different reaction conditions. The combination of processability, thermal stabilities, and tailorability makes these polymers suitable for a wide variety of applications including electro-optics, proton exchange membranes and super-hydrophobic applications.

A series of N-alkyl/aryl carbazole 3,6-substituted arylene trifluorovinyl ether (TFVE) monomers were synthesized in high purity and yield from a concise four-step synthesis using carbazole as a starting material. Condensate-free, step-growth chain extension of the monomers afforded perfluorocyclobutyl (PFCB) arylene ether homo- and copolymers as solution processable, optically transparent blue-light emissive materials. Arylene TFVE monomers and conversion to PFCB arylene ether polymers were structurally elucidated and purity confirmed by high resolution mass spectroscopy, NMR (1H, 13C, and 19F) spectroscopy, gel permeation chromatography, and attenuated total reflectance Fourier transform infrared analysis. Thermal analysis by differential scanning calorimetry and thermogravimetric analysis revealed glass transition temperatures >150 °C and onset of decomposition in nitrogen >410 °C with 40 wt % char yield up to 900 °C. Optical and electrochemical studies included solution (tetrahydrofuran) and solid state (spin cast thin film) UV–vis/fluorescence spectroscopy and cyclic voltammetry which showed structure dependence of these blue emissive systems on the nature of the N-alkyl/aryl carbazole substitution in either homo- or copolymer configurations. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 552–560

A novel class of semifluorinated perfluorocyclohexenyl (PFCH) aryl ether homo/copolymers was successfully synthesized with high yield through the step-growth polymerization of commercially available bisphenols and decafluorocyclohexene in the presence of a triethylamine base. The synthesized polymers exhibit variable thermal properties depending on the functional spacer group (R). PFCH aryl ether copolymers with random and alternating architectures were also prepared from versatile bis-perfluorocyclohexenyl aryl ether monomers. The PFCH polymers show high thermal stabilities with a 5% decomposition temperature ranging from 359 to 444 °C in air and nitrogen atmosphere. These semifluorinated PFCH aromatic ether polymers contain intact enchained PFCH olefin moieties, making further reactions such as crosslinking and application specific functionalization possible. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 232–238

A unique class of perfluorocycloalkenyl (PFCA) aryl ether monomers was synthesized from commercially available perfluorocycloalkenes (PFCAs) and bisphenols in good yields. This facile one pot reaction of perfluorocycloalkenes, namely, octafluorocyclopentene (OFCP), and decafluorocyclohexene (DFCH), with bisphenols occurs at room temperature via an addition–elimination reaction in the presence of a base. The synthesis of PFCA monomers and their condensation with bisphenols lead to perfluorocycloalkenyl (PFCA) aryl ether homopolymers and copolymers with random and/or alternating polymer architectures.

A new class of partially fluorinated alternating aryl/alkyl vinylene ether (FAVE) polymers were prepared from addition polymerization of aryl trifluorovinyl ethers (TFVEs) with 1,4-butanediol or 4-hydroxybenzyl alcohol. Monodisperse FAVE telechelic polymers were also prepared possessing latent thermal reactivity which afforded chain-extended perfluorocyclobutyl (PFCB) aryl ethers via step-growth [2 + 2] cyclodimerization of the aryl TFVEs. Both linear and PFCB chain-extended FAVE polymers produced thermally robust, optically transparent, flexible spin-cast films. The FAVE polymers and their telechelic polymers were characterized using 19F NMR and 1H NMR complemented with molecular weight analysis using gel permeation chromatography and thermal analysis employing differential scanning calorimetry and thermogravimetry. © 2013 Society of Chemical Industry

Nitric oxide (NO) plays an important role in physiological functions in the body, naturally synthesized by nitric oxide synthase. NO was discovered as the endothelium-derived relaxing factor, allowing for vasodilation to occur in blood vessels, thus preventing platelet aggregation. It is also known as an antimicrobial agent. As it has been shown to enhance wound healing, recent efforts have been made to incorporate NO into thromboresistant polymers for medical devices. In this work, an acrylonitrile-co-1-vinylimidazole (AN/VIM) copolymer was melt-spun to produce a surgical suture type material with high durability and tensile strength which can store and release NO. The acrylonitrile (AN) comonomers are stabilized in the melt-spinning process, allowing for the formation of the NO molecular donor group, a diazeniumdiolate or NONOate. When AN/VIM is reacted with NO, the NONOate will form on AN segments. Each NONOate releases two molar equivalents of NO upon reaction with a proton source. The fiber mechanica...

A statically non-wetting, electrospun surface of non volatile room temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate, (BMIM-PF 6 ), hosted in a solution-processable, semi-fluorinated perfluorocyclobutyl (BP-PFCB) aryl ether polymer was successfully prepared by electrospinning and compared with a surface prepared by spin casting. The surface properties of undoped and BMIM-PF 6 doped systems were analyzed by water contact angle (WCA) and atomic force microscopy (AFM). BMIM-PF 6 doped BP-PFCB surfaces prepared by spin casting showed a WCA of 90° while non-woven electrospun surfaces with the same BMIM-PF 6 concentration showed high degree of hydrophobicity with a WCA greater than 150°. Morphologies of the electrospun surfaces were characterized by scanning electron microscopy (SEM). The surface composition was analyzed by energy-dispersive X-ray spectroscopy (EDXS) and attenuated total reflectance infrared spectroscopy (ATR-IR). Thermal analysis of the electrospun, non-woven surfaces of the doped and the undoped system of BP-PFCB were done by TGA.

A unique class of aromatic ether polymers containing perfluorocyclopentenyl (PFCP) enchainment was prepared from the simple step growth polycondensation of commercial bisphenols and octafluorocyclopentene (OFCP) in the presence of triethylamine. Model studies indicate that the second addition/elimination on OFCP is fast and polycondensation results in linear homopolymers and copolymers without side products. The synthesis of bis(heptafluorocyclopentenyl) aryl ether monomers and their condensation with bisphenols further led to PFCP copolymers with alternating structures. This new class of semifluorinated polymers exhibit surprisingly high crystallinity in some cases and excellent thermal stability.

Fluorinated arylene vinylene ether (FAVE) polymers were prepared from the base-promoted addition of commercial 2,2-bis(4-hydroxyphenyl)hexafluoropropane (6F bisphenol A) to aryl trifluorovinyl ether (TFVE), 2,2′-bis(4-trifluorovinyloxybiphenyl)-1,1,1,3,3,3-hexafluoropropane. The step-growth polymerization kinetics by using stoichiometric NaH and catalytic Cs2CO3 were investigated by monitoring the 19F NMR signals of the aryl TFVEs. The nth order kinetic model was used to determine rate constants over a series of programmed temperatures. Polymerization using stoichiometric NaH resulted in second-order kinetics with an activation energy of 59 kJ/mol. This model kinetic study provided insight into the mechanistic pathways of the FAVE polymer system that has recently shown a lot of interest in many areas of materials science. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Acrylonitrile/1-vinylimidazole (AN/VIM) copolymers containing various mol% of VIM were synthesized by free radical solution polymerization. The copolymers were characterized by Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, 1H NMR spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). Char yields of the copolymers were 40–48% as determined by thermogravimetric analysis (TGA) while gel fractions were found to be 90–99% depending upon the composition, temperature and time. The complex viscosity of the precursor copolymers was measured as a function of composition and temperature. 82/18 mol% of AN/VIM copolymer based carbon fiber precursor was successfully processed by solvent-free melt spinning at 192 °C and the melt-spun fiber was characterized by DSC, ATR-IR, and X-ray Diffraction (XRD).

Laboratory-scale synthesis and morphological and surface energy characterization of triblock A–B–A copolymers based on poly(lactic acid) (PLA; A segment) containing various block lengths of perfluoropolyether (PFPE; B segment) at 5 wt% PFPE content are reported. Incorporation of PFPE segments in PLA lowers significantly both the polar and dispersive components of total surface energy. Total surface energy is lowered from ca 35 to ca 17 mN m−1 on copolymerization of PLA with 5 wt% PFPE. Thermal analysis data reveal that lower molecular weight PFPE segments lower significantly the glass transition, crystallization and melting temperatures of the PLA matrix. Although block length variation of the PFPE segment does not affect surface energies of copolymer films, smaller PFPE segments increase significantly the low-temperature modulus as observed from dynamic mechanical analysis. Copyright © 2010 Society of Chemical Industry

A diverse pool of aryl bistrifluorovinyl ether (BTFVE) compounds with reactive pendant groups were prepared in a facile, high yielding three step “one-pot” synthesis from commercial 4-bromo(trifluorovinyloxy)benzene. Monomers were confirmed from ATR–FTIR, 1H, 13C, and 19F NMR, and HRMS analysis. Aryl BTFVE compounds were thermally polymerized to afford perfluorocyclobutyl (PFCB) aryl ether polymers with high number–average molecular weight (Mn) for homopolymers (17,050–27,090) and copolymers with 4,4′-bis(trifluorovinyloxy)biphenyl monomers (27,860–56,500). The PFCB aryl ether homo- and copolymers collectively possess high thermal stability (>299 °C in N2) and are readily solution processable producing optically transparent films. The thermal polymerization was achieved and reactive moieties remained intact, aside from those functionalized with acrylates. In the case with acrylate functionalized polymers, orthogonal polymerization was achieved by first photopolymerizing the acrylates followed by thermal curing of the aryl trifluorovinyl ether endgroups. Preliminary results in this study produced the successful preparation of photodefinable PFCB aryl ether material. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1887–1893, 2010

Perfluorocyclobutyl (PFCB) aryl ether polymers have various applications in the field of optics due to their synthetic versatility and availability, solution and melt processability, high temperature and photo stability, excellent optical transparency. Nanoparticle matrix materials, encapsulants, and chemical sensors are just a few examples of recent developments.

High molecular weight perfluorocyclobutyl-containing polybenzimidazoles (PFCB–PBI) were synthesized from 4,4′-((1,2,3,3,4,4-hexafluorocyclobutane-1,2-diyl)bis(oxy))dibenzoic acid (PFCB diacid) and 3,3′,4,4′-tetraaminobiphenyl (TAB) in phosphorous pentoxide/methanesulfonic acid (PPMA). PPMA was used as a reaction medium to replace PPA due to the higher monomer solubility. High molecular weight polymer was achieved via optimization of the monomer/solvent ratio, polymerization temperature, and polymerization time. The resulting polymer showed good thermal and chemical stability. Several different phosphoric acid doping membrane preparation processes were investigated. Conventional DMAc solvent casting and direct-casting of the PBI/PPMA solution did not produce sufficiently strong membranes to fabricate into MEAs. A modified PPA process was developed that produced improved membranes. The mechanical properties of these membranes were low compared to other PBI membranes; however, they were sufficiently strong to fabricate into membrane electrode assemblies and tested in single cell fuel cells under various conditions. The polymer dissolved in phosphoric acid at temperatures above 140 °C, which limited the operation of fuel cells below 140 °C. The maximum power densities of fuel cells operated with these membranes were similar to meta-PBI membranes prepared by the conventional casting process and lower than para-PBI membranes prepared by the PPA process.

New fluorinated arylene vinylene ether (FAVE) polymers were prepared by a facile, metal-free condensation polymerization of fluorene, phenylenevinylene, dithiophene, or thiadiazole chromophore-containing bisphenols with bis(trifluorovinyloxy)biphenyl. The addition of chromophores encapsulated into the polymers were prepared in good yields and characterized by 1H and 19F NMR and GPC. Thermal analysis by differential scanning calorimetry (DSC) confirmed the polymers are entirely amorphous and are easy to solution process, producing optically transparent, flexible films. Thermal gravimetric analysis (TGA) showed they possess high thermal stability with decomposition temperatures of 340−387 °C and 308−443 °C in nitrogen and air, respectively. Chromophore inclusion was confirmed by ultraviolet−visible (UV−vis) spectroscopy, which demonstrated tailorable photoluminescence (PL) in both the solution and the solid state by selective substitution of the chromophore. Polymer thin film PL studies revealed notable red...

4-(Trifluorovinyloxy)benzaldehyde was treated under Wittig conditions with 4-dihexyloxy-2,5-xylenebis(triphenylphosphoniumbromide) to form 1,4-bis(2′-(4-trifluorovinyloxyphenyl)ethenyl)-2,5-dihexyloxybenzene, a novel phenylene vinylene-bistrifluorovinyl ether monomer. Cyclopolymerization afforded an insoluble, non-luminescent material likely due to cross-addition reactions between phenylene vinylene olefin and trifluorovinyl ether (TFVE). However, 1,2-bis(4-formylphenoxy)hexafluorocyclobutane was polymerized with 1,4-dihexyloxy-2,5-xylenebis(triphenylphosphoniumbromide) and 1-methoxy-4-(2-ethylhexyloxy)-2,5-xylenebis(triphenylphosphoniumbromide) under Wittig conditions to yield two novel poly(perfluorocyclobutyl- co -phenylene vinylene) polymers. The polymers are of moderate molecular weight (8600–8700 M n ), show excellent thermal stability ( T d = 390–405 °C), and are readily soluble in common organic solvents. The materials are highly fluorescent in both solution and thin film with solution quantum yields of 68 and 71%.

International audience; Post functionalization of aryl ether perfluorocyclobutyl (PFCB) polymers with fluoroalkyl side chains was accomplished with Umemoto's FITS reagents. The fluoroalkylated PFCB polymers (20 % functionalized) showed increases in both hydrophobicity and oleophobicity. Static contact angle for hexadecane was increased after fluoroalkylation from 0° to greater than 30° for the two PFCB polymers tested. Increased oil repellency makes these materials potential candidates for various coatings applications.

The synthesis and characterization of solution processable, semi-fluorinated perfluorocyclobutyl (PFCB) aryl ether polymers possessing covalently bound pendant polyhedral oligomeric silsesquioxanes (POSS) cages is reported. The synthesis of POSS aryl trifluorovinyl ether (TFVE) monomers was accomplished by the condensation of commercial monosilanolalkyl-POSS with a TFVE-functionalized chlorosilane. POSS TFVE monomers were elucidated by 1H, 19F, 13C, and 29Si NMR spectroscopy, ATR-FTIR analysis, and elemental (C, H, and F) combustion analysis. Bulk thermal copolymerization of POSS TFVE monomers afforded random and block PFCB aryl ether copolymers functionalized with various POSS loadings. Quantitative monomer conversion was monitored by 19F NMR, which produced copolymer number-average molecular weights (Mn) of (19.5−24.9) × 103 (in CHCl3 using polystyrene as standard) determined by gel permeation chromatography (GPC). Thermal properties of POSS PFCB aryl ether copolymers were evaluated by differential scan...

A novel approach to property enhancement of poly(l-lactic acid) (PLLA) through the use of perfluoropolyether (PFPE) enchainment is described. Segmented copolymers (FluoroPLA) exhibit tailored surface properties with reasonably high molecular weights and low polydispersities compared to PLLA alone using standard ring-opening polymerization procedures in the presence of tin catalysts. Low loadings of PFPE content (ca. 1−5 wt %) decreases surface energies compared to PLLA from 35 to 38 to 15−18 mN/m2, similar to values reported for poly(tetrafluoroethylene). Ultimate strain studies of FluoroPLA fibers and films have shown a dramatic increase (>300% elongation) over PLLA. This new class of polymer may further expand the use of renewable resources in a variety of applications such as flame retardants, chemical resistant fibers and/or fabrics with tailorable surface energies and wetting properties.

Versatile intermediates 4-bromo(trifluorovinyloxy)benzene or 4-trifluorovinyloxyphenylboronic acid pinacol ester undergo a one step Suzuki coupling reaction with commercial aryl diboronic acids or aryl dibromides and afforded three new aryltrifluorovinylether chromophore monomers. The structures of these monomers were confirmed by 1H, 19F, and 13C NMR spectroscopy and elemental (C, H, and N) combustion analysis. The monomers were readily polymerized via thermal [2 + 2] cyclopolymerization to form chromophore containing PFCB polymers with high molecular weights (Mn = 16 700−22 000), superb thermal stability Td > 450 °C, and excellent processability. Photoluminescence studies reveal that the fluorinated ether linkage has no effect on lumiphore emission wavelength or solution quantum yields. Copolymerization affords a facile route to tailored emission from a linear polymeric system that includes a broad range of the visible spectrum. The properties of these polymers were analyzed by differential scanning cal...

A new semi-fluorinated perfluorocyclobutyl (PFCB) aryl ether containing polymer was prepared in high yield via the condensation of a commercial 4,4'-((1,2,3,3,4,4-hexafluorocyclobutane-1,2-diyl)bis(oxy))bisphenol (bisphenol T) and bis(trifluorovinyloxyether)biphenyl producing transparent, flexible films. The polymer system was structurally characterized using 1H and 19F NMR and exhibited a high degree of thermal stability as determined by thermogravimetric analysis capacity. The sulfonated analogue showed the highest degree of sulfonation at 27% from ion-exchange chromatography, producing a conductivity of 0.011 S cm-1 at 100% relative humidity.

High-pressure phase behavior data reported here demonstrate the nuanced impact fluorine exerts on polymer solubility in supercritical fluid solvents. Copolymers are used that contain a perfluorocyc...

This study focuses on the preparation, polymerization, characterization, and optical properties of a new bis-(4-trifluoromethanesulfonyloxyphenyl)phenylamine monomer. This is the first nitrogen-containing monomer having nitrogen atoms as bridges between phenyl rings, and it was synthesized in three steps. The polymerization was carried out through the Ni(0)-catalyzed homocoupling reaction of the bis-(4-trifluoromethanesulfonyloxyphenyl)phenylamine compound. The resulting polymer, polybis(paraphenyl)phenylamine, emitted an intense blue color (where λ = 415 nm) upon irradiation by ultraviolet light. The photoluminescence quantum yield was found to be 36% with a long excited-state lifetime of 3.3 ns. Electrical conductivity data for an HCl-doped film of the polymer were also examined. This novel polymer is of interest as an organic emitting material for electroluminescent devices.

The thermal cyclopolymerization of three trifluorovinyl aromatic ether monomers 1,1,1-tris (4-trifluorovinyloxyphenyl)ethane (1), 4,4′-bis(4-trifluorovinyloxy)biphenyl (2) and 2,2-bis(4-trifluorovinyloxy- phenyl)-1,1,1,3,3,3-hexafluoropropane (3) were monitored in situ using time-resolved electron paramagnetic resonance spectroscopy over a temperature range of 150–210 °C. The signals observed during the early stages of perfluorocyclobutyl polymer production suggest the formation of a triplet state corresponding to the proposed biradical intermediate with a strong dipole–dipole interaction. A doublet splitting shows the presence of hyperfine coupling due to fluorine. The characterization of radical species formed during the polymerization of monomer 1 using model compounds and polymerization kinetics of monomer 2 are also presented. Copyright © 2007 Society of Chemical Industry

New thermally cross-linkable and/or post-functionalizable perfluorocyclobutyl (PFCB) polymers containing Meldrum's acid moieties have been successfully prepared via the thermal cyclopolymerization of a new Meldrum's acid functionalized aromatic trifluorovinyl ether (TFVE) monomer.

This study focuses on the preparation, characterization, and optical properties of new bis(3,4-diphenylethynylphenyl)phenylamine. This is the first nitrogen-containing bis-ortho-diynylarene (BODA) monomer having a nitrogen atom as the spacer group. BODA monomers are usually prepared from common bisphenols, thereby providing great synthetic versatility and the opportunity to develop a wide array of novel polyarylene thermosets by varying the aromatic spacer group. The new bis(3,4-bisphenylethynylphenyl)phenylamine was synthesized in five steps. This compound emits an intense blue color (λ = 438 nm) upon irradiation by UV light and may be suitable for use as an emitting layer in electroluminescent devices. Bis-(3,4-bisphenylethynylphenyl)phenylamine and its polymer have photoluminescence quantum yields 34 and 38%, respectively, and long excited-state lifetimes of 3.2 and 3.6 ns, respectively. The structure of the monomer and its polymer were characterized using spectroscopic techniques including Ultraviolet–visible Spectrophotometer, Photoluminescence Spectrophotometer, Fourier Transform infrared spectroscopy, and Gel Permeation Chromatography. The polymerizations were studied by Differential Scanning Calorimeter. The amount of weight loss and the thermostability of the nitrogen-containing polymer were determined from thermogravimetric analysis. The electrical conductivity of neat HCl-doped BODA-derived polymer film was measured according to the standard four-point probe technique. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6988–6996, 2006

Department of Chemistry, School of Materials Science andEngineering and Center for Optical Materials Science andEngineering Technologies (COMSET), Clemson UniVersity,Clemson, South Carolina 29634-0973, and Department ofPhysics, Kent State UniVersity, Kent, Ohio 44242ReceiVed March 6, 2006ReVised Manuscript ReceiVed May 17, 2006Introduction. Poly(p-phenylene)s (PPP) are highly extendedlinear macromolecules due to their rigid structure, and as a result,unmodified PPP is an insoluble and intractable material.

Three phenylphosphine oxide (PPO) containing trifluorovinyl aryl ether monomers were synthesized and polymerized via thermal cyclodimerization affording perfluorocyclobutyl (PFCB) polymers containing PPO pendent groups. The new polymers exhibited moderate to high glass transition temperatures (Tg=145–217 °C) and good thermal stability in nitrogen (5% weight loss, Td>402 °C). Copolymerization with traditional PFCB forming monomers such as 4,4′-(trifluorovinyloxy)biphenyl resulted in film forming transparent thermoplastic copolymers with improved solubility and further enhanced thermal stability. Semi-fluorinated PPO containing polymers of this type may find potential application as space environment durable materials.

The synthesis and hyperpolarizabilities of a series of push–pull chromophores containing bis-(4-methoxyphenyl)-amine donor and efficient acceptors bridged with ring locked polyene are presented. The chromophores are readily soluble in common organic solvents and exhibit high thermal decomposition temperatures (highest T d = 330 °C). Molecular hyperpolarizabilities ( β ) of the chromophores were measured by Hyper Rayleigh Scattering (HRS) at 1604 nm (highest β = 20,000 × 10 −30 esu). These chromophores can be used to develop electro-optic (EO) materials due to their large optical nonlinearities, good absorption characteristics, high thermal decomposition temperatures, and excellent solubility with organic solvents and polymeric materials.

The synthesis and thermal cyclopolymerization of aryl trifluorovinyl ether monomers containing novel sulfonimide acid functionalities are described. The monomers are prepared starting from commercially available 4-bromophenol in five steps. These novel polymers explore a new versatile class of partially fluorinated polymers for potential use in fuel cells and other electrochemical applications.

Oligoethylene-end-capped polylactides were synthesized through the ring- opening polymerization of L-lactide with alcohol-terminated oligoethylenes as macro- initiators. The polymerization of L-lactide was carried out in bulk at 130 8C in the presence of stannous octoate and primary alcohols with four different molecular weights: 350, 425, 550, and 700 g/mol. The end-capped copolymers that formed had a number-average molecular weight of approximately 40,000 (weight-average molecular weight/number-average molecular weight ¼ 1.7) according to gel permeation chroma- tography and were highly crystalline in comparison with the similarly formed homo- polymer of L-lactide. The copolymer structure was characterized by Fourier transform infrared, NMR, matrix-assisted laser desorption/ionization time-of-flight mass spec- trometry, and differential scanning calorimetry analysis. This work focused on devel- oping more crystallizable and hydrolytically stable polylactide derivatives that could potentially be used as compatibilizers in polylactide-polyolefin blends or as nucleat- ing agents for poly(L-lactide) or other polyesters. V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5257-5266, 2005

The thermal cyclopolymerization of 2,2-bis(4-trifluorovinyloxyphenyl)-1,1,1,3,3,3-hexafluoropropane affords the first example of a semi-crystalline perfluorocyclobutyl (PFCB) polymer and an anomalous feature for a polymer containing the hexafluoroisopropylidene (6F) linkage. Fluoroalkylation of 2,2-bis(hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane (6F bisphenol A) with 1,2-dibromotetrafluoroethane, followed by zinc mediated elimination affords the bis(trifluorovinyloxyphenyl) monomer in good yield. High molecular weight polymer (Mw=66,700) with molecular weight distribution approaching 2 was obtained by heating neat monomer at 180 °C for 24 h and 220 °C for 8 h. The stereo-random polymer (ca. 48 to 52 cis- to trans-1,2-disubstituted perfluorocyclobutyl groups) is easily crystallized from the melt despite the presence of the 6F group and a substantial increased fluorocarbon content per repeat unit compared to traditional PFCB polymers. A melting temperature approaching 200 °C was measured by DSC and the crystallinity was characterized by WAXD. Remarkably, the high melting semi-crystalline polymer could be easily dissolved in common solvents in greater than 50 wt% solutions.

The synthesis of a series of high temperature triaryl amino chromophores with unprecedented hyperpolarizability values for potential EO applications is described. 4-( N , N -di- p -anisylamino)phenyl donors are for the first time bridged to powerful acceptors such as tricyanovinyldihydrofuran via vinyl thiophene linkages. The chromophores are readily soluble in common organic solvents, exhibit useful absorptions and high thermal decomposition temperatures (highest T d =358 °C). Molecular hyperpolarizabilities ( β ) of the chromophores were measured by Hyper Rayleigh Scattering (HRS) at 1604 nm, which gave β values from 1000 to 20,000 × 10 −30 esu. The electrochemical behavior of the chromophores were studied by cyclic voltametry, and agree well with the intrinsic nonlinearities observed. These chromophores are of particular interest due to their large optical nonlinearities, transparency in the near IR, high thermal decomposition temperatures, and their potential to be incorporated into polymeric materials.

Summary: The synthesis and polymerization of novel 18-crown-6 and 24-crown-8 bis aryl trifluorovinyl ethers is described. Thermally induced polymerization yields linear crown ether fluoropolymers with hexafluorocyclobutyl linkages. The polymers exhibit Tg's above 120 °C and show good thermal stability with no appreciable weight loss below 350 °C. Incorporation of crown ether macrocycles into the polymer is expected to increase cationic uptake of an otherwise electroneutral fluoropolymer.

A novel aryl trifluorovinyl ether monomer, 1,1,1-tris(4-trifluorovinyloxy-phenyl)-2,2,2-trifluoroethane (5), was prepared via a multistep reaction sequence adapted from previously reported procedures. Monomer 5 polymerizes by free-radical mediated thermal cyclodimerization to produce a crosslinked perfluorocyclobutyl (PFCB) polymer. Substituting CH 3 for CF 3 did not affect the polymerization kinetics as measured by differential scanning calorimetry. Surprisingly, the refractive index of poly5 (1.4931 at 1550 nm) is slightly higher than that measured for poly6 (1.4876 at 1550 nm) despite the significant increase in fluorine content. Compared to the CH 3 -containing monomer 6, fluorinated analogue 5 exhibits increased thermal and thermal oxidative stability and thus we expected lower optical loss for long-term high performance applications. Copolymerization with existing aryl trifluorovinyl ether monomers should allow access to new PFCB network copolymers with a tailored performance.

A novel class of phenylphosphine oxide (PPO) containing perfluorocyclobutyl (PFCB) polymers has been developed for potential use as multifunctional materials in space environments. The reaction of p-BrArOCFCF2 (for Ar = phenyl and biphenyl) with tert-butyllithium affords the lithium reagent smoothly below −20 °C. Subsequent substitution with phenylphosphonic dichloride provides the first bis(trifluorovinyl ether) monomers containing the PPO group. Polymerization proceeds thermally above 150 °C to give polymers that exhibit glass transition temperatures of 169 and 224 °C, respectively, and catastrophic weight loss by TGA in N2 and air above 450 °C (10 °C/min). Copolymerization with bis(4,4‘-trifluorovinyloxy)biphenyl affords film-forming transparent thermoplastic copolymers with high Tg (>140 °C) and good thermal stability (>450 °C). Initial evaluations with ground-based simulation of atomic oxygen (AO) rich space environments indicate that the PPO group imparts significant space durability to PFCB polymers.

4-Bromotrifluorovinyloxybenzene (4-Br-TFVE) undergoes cyclodimerization upon heating at 150 °C affording cis and trans isomers of 1,2-bis(4-bromophenoxy)hexafluorocylcobutane. Stereoisomers were separated by selective crystallization, confirmed by single crystal X-ray, and further characterized by NMR. Remarkable difference in the solid state structures include aryl to aryl dihedral angles of 12° for the trans isomer and 88° for the cis isomer. Polymers containing roughly equal amounts of cis and trans fused perfluorocyclobutyl (PFCB) rings should be expected to have low crystallinity due to the marked difference in the two unit cells as is observed.

Ullmann coupling of benzyl ether protected 4-iodophenol with 4-nitrophenylazo aniline followed by deprotection in trifluoroacetic acid affords novel 4′-(4-nitrophenylazo)-N,N-bis(4-hydroxyphenyl)aniline. Co-condensation of this azo bisphenol and 9,9′-bis(4-hydroxyphenyl)fluorene (BHPF) with phosgene gave high molecular weight polycarbonate with and high thermal stability. The polymer was soluble in common organic solvents and high quality films were prepared and subjected to poling and electro-optic (EO) analysis. The copolymer exhibited a r33 value of 3.7 pm/V. Synthesis, characterization, and thermal properties are described.