Tetraarylphosphonium perfluorocyclobutyl polyelectrolyte with low critical surface energy,high thermal stability,and high alkaline resistance

Two tetraarylphosphonium polyelectrolytes having perfluorocyclobutyl units in their backbones have been prepared in which the counteranion is either bromide ( PFP· Br) or bis(trifluoromethyl)sulfonimide ( PFP· NTf₂). These polymers exhibit high thermal stability as assessed by thermogravimetric analysis, with a decomposition temperature of 460 °C for PFP· NTf₂. Even after heating at 300 °C for 72 h, PFP· NTf₂ shows no signs of degradation detectable by nuclear magnetic resonance spectrometry. As is typical for many tetraarylphosphonium species, films of these polymers can be quite resistant to degradation by alkaline solution. Upon alkaline challenge by exposure to 6 M NaOH at 65 °C for 24 h, for example, only 16% of the phosphonium centers in PFP ·NTf₂ are degraded, making PFP ·NTf₂ one of the most alkaline‐stable phosphonium polymers to date. Despite having ionic backbones, PFP· Br and PFP· NTf₂ exhibit very low critical surface energies of 26.1 and 22.9 mJ m^?1, respectively. These values are on par with the values for poly(vinylene fluoride) and dimethylsiloxane. Such low surface energy polycations capable of high alkaline stability may find application as components of alkaline fuel cell membranes. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2267–2272     

Novel triarylamine‐based alternating conjugated polymer with high hole mobility: Synthesis,electro‐optical,and electronic properties

Novel bi‐triphenylamine‐containing aromatic dibromide M3 , N,N‐bis(4‐bromophenyl)‐N′,N′‐dipheny‐l,4‐phenylenediamine, was successfully synthesized. The novel conjugated polymer P1 having number‐average molecular weight of 1.31 × 10⁴ was prepared via Suzuki coupling from the dibromide M3 and 9,9‐dioctylfluorene‐2,7‐diboronic acid bis(1,3‐propanediol) ester. Polymer P1 had excellent thermal stability associated with a high glass‐transition temperature (T_g = 141 °C). The hole‐transporting and UV‐vis‐near‐infrared electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the conjugated polymer films cast onto indium‐tin oxide‐coated glass substrates exhibited two reversible oxidation redox couples at E_1/2 values of 0.73 and 1.13 V versus Ag/Ag⁺ in acetonitrile solution. The hole mobility of the conjugated polymer P1 revealed ～10^?3 cm² V^?1 s^?1, which is much higher than that of other conjugated polymer systems. The observed UV‐vis‐near‐infrared absorption change in the conjugated polymer film P1 at applied potentials ranging from 0.00 to 1.23 V are fully reversible and associated with strong color changes from pale yellowish in its neutral form to green and blue in its oxidized form. Using a combination of experimental study and theoretical investigation, we proposed an oxidation mechanism based on molecular orbital theory, which explains the cyclic voltammetry experimental results well. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis and nonlinear optical properties of polyacetylenes containing oxadiazole and thiophene pendant groups with high thermal stability

A series of random copolymers poly(3‐ethynylthiophene)‐copoly(2‐(4‐decyloxyphenyl)‐5‐(4‐ethynylphenyl)‐1,3,4‐oxadiazole) with different oxadiazole content ( P2 – P4 ) and homopolymer poly(3‐ethynylthiophene) ( P1 ) as well as poly(2‐(4‐decyloxyphenyl)‐5‐(4‐ethynylphenyl)‐1,3,4‐oxadiazole) ( P5 ) were prepared. The copolymers ( P2 – P4 ) are completely soluble in common organic solvents. The structures and properties of all polymers were characterized and evaluated by FTIR, ¹H NMR, ¹³C NMR, TGA, UV, PL, GPC, and nonlinear optical (NLO) analyses. The incorporation of diaryl‐oxadiazole into polyacetylene‐containing thiophene significantly endows copolymers with higher thermal stability, which may origin from the synergetic effect of the “jacket effect” of diaryl‐oxadiazole units and the effect of retarding or eliminating a few 6π‐electrocycliaztion proceeds of oxadiazole‐containing polyacetylene due to the hindrance of thiophene units. When the copolymer ( P3 ) posses more regular alternating thiophene pendants and oxadiazole pendants arrangement along the polymer backbone, it shows good thermal stability (T_d up to 388 °C) and larger third‐order nonlinear optical susceptibility (χ(3) up to 11.0 × 10^?11 esu). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

A comparative study of fluorine substituents for enhanced stability of flexible and ITO‐free high‐performance polymer solar cells

Two low‐band gap polymer series based on benzo[1,2‐b:4,5‐b′]dithiophene (BDT) and dithienylbenzothiadiazole, with different numbers of fluorine substituents on the 2,3,1‐benzothiadiazole unit, have been synthesized and explored in a comparative study of the photochemical stability and operational lifetime in flexible large area roll‐coated bulk heterojunction solar cells. The two polymer series have different side chains on the BDT unit, namely 2‐hexyldecyloxy (BDT_HDO) ( P1–P3 ) or 2‐hexyldecylthiophene (BDT_THD) ( P4–P6 ). The photochemical stability clearly shows that the stability enhances along with the number of fluorine atoms incorporated on the polymer backbone. Fabrication of the polymer solar cells based on the materials was carried out in ambient atmosphere on a roll coating/printing machine employing flexible and indium‐tin‐oxide‐free plastic substrates. Solar cells based on the P4–P6 series showed the best performance, reaching efficiencies up to 3.8% for an active area of 1 cm², due to an enhanced current compared to P1–P3 . Lifetime measurements, carried out according to international summit on OPV stability (ISOS), of encapsulated devices reveals an initial fast decay for P1–P6 in the performance followed by a much slower decay rate, still retaining 40–55% of their initial performance after 250 h of testing under ISOS‐L‐1 conditions. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 893–899     

A new route to phosphonium polymer network solids via cyclotrimerization

An organo‐main group network solid having tetrahedral phosphonium vertices was prepared from a diacetyl monomer via a straightforward cyclotrimerization reaction. The network solid composition was examined by FT‐IR spectroscopy and elemental microanalysis, revealing quantitative reaction of carbonyl moieties and a 67% degree of cross‐linking. The reaction yielded a material having a layered structure that is comprised of an amorphous polymer and which is thermally stable up to 370 °C in air with a char yield of 40% upon heating as high as 800 °C under N₂. The polymer is stable to 6 M NaOH(aq ) at 60 °C for 24 h and takes up only 10.63% of water by mass at room temperature. The surface morphology, as examined by AFM, revealed a very smooth as‐prepared film (RMS roughness of 3 nm). The specific surface area measured by BET analysis with N₂ gas is 9 m² g^?1, indicating a type II, nonporous material. Physisorption with CO₂ revealed that the phosphonium network solid has additional affinity for CO₂, suggesting that such materials may have use for applications such as CO₂ capture. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1620–1625     

Pyrene‐cored covalent organic polymers by thiophene‐based isomers,their gas adsorption,and photophysical properties

Two new pyrene‐cored covalent organic polymers (COPs), CK‐COP‐1 and CK‐COP‐2 , were synthesized via the one‐step polymerization of two thiophene‐based isomers, 1,3,6,8‐tetra(thiophene‐2‐yl) pyrene ( L₁ ) and 1,3,6,8‐tetra(thiophene‐3‐yl) pyrene ( L₂ ). The resulting pyrene‐cored COPs exhibit rather different surface areas of 54 m² g^?1 and 615 m²g^?1 for CK‐COP‐1 and CK‐COP‐2 , respectively. The CO₂ uptake capacities of CK‐COP‐1 and CK‐COP‐2 also show different values of 2.85 and 9.73 wt % at 273 K, respectively. Furthermore, CK‐COP‐2 offers not only a larger CO₂ adsorption capacity but also a better CO₂/CH₄ selectivity at 273 K compared with CK‐COP‐1 . CK‐COP‐1 and CK‐COP‐2 also exhibit considerable differences in their photophysical property. The different structure and properties of CK‐COPs could be attributed to the isomer effect of their corresponding thiophene‐based monomers. © 2017 Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2383–2389     

Synthesis and stability study of dental monomers containing methacrylamidoethyl phosphonic acids

Three new dental monomers containing methacrylamidoethyl phosphonic acids were synthesized. The structures of the synthesized monomers were determined with electrospray mass spectrometry (ESMS), Fourier transform infrared, and NMR. The hydrolytic stabilities of the synthesized monomers and a commercial monomer, 2‐methacryloyloxyethyl phosphoric acid (MEP; used as a control), were studied with flow injection (FI)/ESMS, ¹H NMR, and ³¹P NMR analysis of a CD₃OD/D₂O (4:1 v/v) solution of each monomer before and after storage at 60 °C for 2 months. The ¹H NMR and ³¹P NMR chemical shifts of the monomers 2‐methacrylamidoethylphosphonic acid ( I ) and N,N′‐[4,4′‐(propane‐2,2‐diyl)‐bis(phenoxy‐2‐hydroxypropyl)]‐bis(2‐methacrylamidoethylphosphonic acid) ( II ) showed little change after storage at 60 °C for 2 months, but those of MEP changed significantly. FI/ESMS also showed that MEP was nearly completely decomposed, whereas monomers I and II remained largely intact. MEP could react with H₂ZrF₆ to form ternary zirconium fluoride complexes that were partially soluble in methanol, but all the monomers containing phosphonic acids formed precipitates. This study demonstrates that ESMS is a more sensitive and effective method than NMR for studying the hydrolytic stability or degradation of dental monomers. The new monomers containing methacrylamidoethyl phosphonic acids have higher hydrolytic stability than methacrylate phosphate monomers and may be used in dental bonding agents and other dental materials. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 99–110, 2007     

Synthesis and NMR Study of α‐Keto Stabilized Ylides of the Type RCOCH=PAr3, (R=MeO‐C6H4, Cl‐C6H4, NO2‐C6H4, α‐Thiophenyl and Naphthyl; Ar = p‐Tolyl or Phenyl)

Synthesis and characterization of five new phosphonium salts and related phosphorus ylides of the type R‐COCH=PAr₃ are reported. The reaction of bromo 4′‐methoxo/chloro/nitro acetophenone, α‐thiophenyl and naphthoyl acetophenone with triphenylphosphine or triparatolylphosphine in acetone gives phosphonium salts. Dehydrogenation of these salts in aqueous sodium hydroxide solution form ylides. Characterization of obtained compounds was performed by IR, ¹H, ¹³C, ³¹PNMR and elemental analysis.     

Porphyrin‐based covalent triazine frameworks: Porosity,adsorption performance,and drug delivery

Two porous porphyrin‐based covalent triazine frameworks (PCTFs), in which porphyrin is incorporated as building block, have been synthesized by the Friedel–Crafts reaction. The copolymer PCTFs show large Brunauer–Emmett–Teller specific surface area of up to 1089 m² g^?1, high CO₂ uptake capacity reaching 139.9 mg g^?1 at 273 K/1.0 bar, and good selectivity for CO₂/CH₄ adsorption attaining 6.1 at 273 K/1.0 bar. The resulting porous solids also can be used as matrices for drug delivery of ibuprofen in vitro. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2594–2600     

Synthesis,characterization, and gas permeation properties of adamantane‐containing polymers of intrinsic microporosity

A new bis(catechol) monomer, namely, 4,4′‐((1r,3r)‐adamantane‐2,2‐diyl)bis(benzene‐1,2diol) (THADM) was synthesized by condensation of 2‐adamantanone with veratrole followed by demethylation of the formed (1r,3r)‐2,2‐bis(3,4 dimethoxyphenyl)adamantane. Polycondensation of THADM and various compositions of THADM and 5,5,6′,6′‐tetrahydroxy‐3,3,3′,3′‐tetramethylspirobisindane was performed with 2,3,5,6‐tetrafluoroterephthalonitrile (TFTPN) to obtain the homopolymer and copolymers. These polymers demonstrated good solubility in common organic solvents such as dichloromethane, chloroform, and tetrahydrofuran and could be cast into tough films from their chloroform solutions. GPC analysis revealed that number average molecular weights of polymers were in the range 48,100–61,700 g mol⁻¹, suggesting the formation of reasonably high molecular weight polymers. They possessed intrinsic microporosity with Brunauer‐Emmett‐Teller (BET) surface area in the range 703–741 m² g⁻¹. Thermogravimetric analysis of polymers indicated that 10% weight loss temperature was in the range 513–518 °C demonstrating their excellent thermal stability. THADM‐based polymer of intrinsic microporosity (PIM) showed P(CO₂) = 1080, P(O₂) = 232 and appreciable selectivity [α(CO₂/CH₄) = 22.6, α(CO₂/N₂) = 26.7, and α(O₂/N₂)= 5.7]. The gas permeability measurements revealed that with increase in the content of adamantane units in PIMs, selectivity increased and permeability decreased, following the trade‐off relationship. The gas separation properties of PIMs containing adamantane units were located close to 2008 Robeson upper bound for gas pairs such as CO₂/CH₄, CO₂/N₂, H₂/N₂, and O₂/N₂. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 16–24     

Balancing high thermal stability with high activity in diaryliminoacenaphthene‐nickel(II) catalysts for ethylene polymerization

The N,N‐diaryliminoacenaphthenes, 1,2‐[2,4‐{(4‐FC₆H₄)₂CH}₂‐6‐MeC₆H₄N]₂‐C₂C₁₀H₆ ( L1 ) and 1‐[2,4‐{(4‐FC₆H₄)₂CH}₂‐6‐MeC₆H₄N]‐2‐(ArN)C₂C₁₀H₆ (Ar = 2,6‐Me₂C₆H₃ L2 , 2,6‐Et₂C₆H₃ L3 , 2,6‐i‐Pr₂C₆H₃ L4 , 2,4,6‐Me₃C₆H₂ L5 , 2,6‐Et₂‐4‐MeC₆H₂ L6 ), incorporating at least one N ?2,4‐bis(difluoro benzhydryl)‐6‐methylphenyl group, have been synthesized and fully characterized. Interaction of L1 – L6 with (DME)NiBr₂ (DME = 1,2‐dimethoxyethane) generates the corresponding nickel(II) bromide N,N‐chelates, L NiBr₂ ( 1 – 6 ), in high yield. The molecular structures of 3 and 6 reveal distorted tetrahedral geometries at nickel with the ortho‐substituted difluorobenzhydryl group providing enhanced steric protection to only one side of the metal center. On activation with various aluminum alkyl co‐catalysts, such as methylaluminoxane (MAO) or Et₂AlCl, 1 – 6 displayed outstanding activity toward ethylene polymerization (up to 1.02 × 10⁷ g of PE (mol of Ni)^?1 h^?1). Notably 1 , bearing equivalent fluorobenzhydryl‐substituted N‐aryl groups, was able in the presence of Et₂AlCl to couple high activity with exceptional thermal stability generating high molecular weight branched polyethylenes at temperatures as high as 100 °C. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1971–1983     

Investigation on the dynamics of aromatic polyesters by means of high resolution solid state CPMAS 13C NMR

The dynamics of amorphous aromatic polyesters consisting of poly(ethylene terephthalate) (PET), poly(ethylene isophthalate) (PEI), and poly(ethylene 2,6-naphthalenedicarboxylate) (PEN) has been investigated by means of solid state CPMAS ¹³C NMR. Proton T₂, ¹³C T_1ρ, and proton T_1ρ decays have been measured in particular, and the experimental data fitted to suitable model functions to determine best relaxation parameters. The fitting results show for proton T₂ and ¹³C T_1ρ measurements the presence of two components with different relaxation times and intensities, arising from different motional domains. The proton T_1ρ, on the contrary, shows a single component which limits the dimensions of the two regions to less than 20 Angstroms. The dependence of ¹³C T_1ρ values on two different irradiating field strengths (H₁ = 38 KHz, H₁ = 60 KHz) allowed the assignment of each component to relatively rigid and mobile regions. By comparing the three polymers we observe that PEN and PEI have a similar relaxation behavior, while a higher fraction of mobile components was found for PET. These differences are believed to arise mainly from local motions of the aromatic rings. The relaxation measurements have been evaluated to suggest a correspondence to O₂ and CO₂ gas permeabilities in PET, PEI, and PEN. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1557–1566, 1998     

Synthesis and properties of novel Y‐type nonlinear optical polyimides with high thermal stability of second harmonic generation

2,4‐Bis‐(3,4‐dicarboxyphenylcarboxyethoxy)‐1‐(2,2‐dicyanovinyl)benzene dianhydride (4) was prepared and reacted with 4,4′‐oxydianiline, 4,4′‐diaminobenzanilide and 4,4′‐(hexafluoroisopropylidene)dianiline to yield novel Y‐type polyimides 5‐7 containing 2,4‐dioxybenzylidenemalononitrile groups as nonlinear optical (NLO) chromophores, which constitute parts of the polymer backbone. The resulting polyimides 5‐7 are soluble in polar solvents such as dimethylsulfoxide and N,N‐dimethylformamide. Polymers 5‐7 showed a thermal stability up to 330 °C in thermogravimetric analysis thermograms with T_g values obtained from differential scanning calorimetry thermograms in the range 179–194 °C. The second harmonic generation (SHG) coefficients (d₃₃) of poled polymer films at the 1064 nm fundamental wavelength were around 5.56 × 10^?9 esu. The dipole alignment exhibited exceptionally high thermal stability even at 20 °C higher than the glass‐transition temperature there was no SHG decay below 215 °C because of the partial main‐chain character of polymer structure, which is acceptable for NLO device applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3078–3087, 2008     

Microporous La–Metal–Organic Framework (MOF) with Large Surface Area

A microporous La–metal‐organic framework (MOF) has been synthesized by the reaction of La(NO₃)₃ ? 6 H₂O with a ligand 4,4′,4′′‐s‐triazine‐1,3,5‐triyltri‐p‐aminobenzoate (TATAB) featuring three carboxylate groups. Crystal structure analysis confirms the formation of 3D MOF with hexagonal micropores, a Brunauer–Emmett—Teller (BET) surface area of 1074 m² g^?1 and high thermal and chemical stability. The CO₂ adsorption capacities are 76.8 cm³ g^?1 at 273 K and 34.6 cm³ g^?1 at 293 K, a highest measured CO₂ uptake for a Ln–MOFs.     

Polycyclotrimerization of aromatic diynes: Synthesis,thermal stability,and light‐emitting properties of hyperbranched polyarylenes

New aromatic diyne monomers of 1,4‐diethynyl‐2,5‐(dihexyloxy)benzene ( 1 ), 1,6‐diethynyl‐2‐(hexyloxy)naphthalene ( 2 ), and 9,9‐bis(4‐ethynylphenyl)fluorene ( 3 ) are synthesized. Their homopolymerizations and copolymerizations with 1‐octyne ( 4 ) or phenylacetylene ( 5 ) are effected by TaBr₅–Ph₄Sn and CpCo(CO)₂–hν, giving soluble hyperbranched polyarylenes with high molecular weights (M_w up to ～ 2.9 × 10⁵) in high yields (up to 99%). The structures and properties of the polymers are characterized and evaluated by IR, NMR, UV, PL, and TGA analysis. The polymers show excellent thermal stability (T_d > 400 °C) and carbonize when pyrolyzed at 900 °C. Upon photoexcitation, the polymers emit deep blue light in the vicinity of ～400 nm with fluorescence quantum yields up to 92%. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4249–4263, 2007     

Synthesis of sulfonated poly(diphenylacetylene)s with high CO2 permselectivity

High‐molecular‐weight poly[1‐phenyl‐2‐(4‐t‐butylphenyl)acetylene], poly[1‐phenyl‐2‐(4‐trimethylsilylphenyl) acetylene], and their copolymers were synthesized by the polymerization with TaCl₅–n‐Bu₄Sn. The obtained polymers were sulfonated by using acetyl sulfate to give sulfonated poly(diphenylacetylene)s with different degrees of substitution. The degrees of sulfonation of poly[1‐phenyl‐2‐(4‐t‐butylphenyl)acetylene] and copolymers were in the range of 0.57–0.85. When poly[1‐phenyl‐2‐(4‐trimethylsilylphenyl)acetylene] was sulfonated, the sulfonated poly(diphenylacetylene) with the highest degree of sulfonation was obtained among all the polymers in this study. Its degree of sulfonation was 1.55. All the sulfonated polymers exhibited high CO₂ permselectivity, and their CO₂/N₂ separation factor were over 31. The sulfonated poly(diphenylacetylene) with the highest degree of sulfonation showed the highest CO₂/N₂ separation factor of 75. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6463–6471, 2009     

The design,synthesis, and nonlinear optical properties of novel X‐type polyurethane containing dicyanovinylnitroresorcinoxy group with enhanced SHG thermal stability

Novel X‐type polyurethane 5 containing 4‐(2′,2′‐dicyanovinyl)‐6‐nitroresorcinoxy groups as nonlinear optical (NLO) chromophores, which constitute parts of the polymer backbone, was prepared and characterized. Polyurethane 5 is soluble in common organic solvents such as acetone and N,N‐dimethylformamide. It shows thermal stability up to 280 °C from thermogravimetric analysis with a glass transition temperature (T_g) obtained from differential scanning calorimetry thermogram of around 120 °C. The second harmonic generation (SHG) coefficient (d₃₃) of poled polymer film at 1064‐nm fundamental wavelength is around 6.12 × 10^?9 esu. The dipole alignment exhibits a thermal stability even at 5 °C higher than T_g, and there was no SHG decay below 125 °C due to the partial main chain character of the polymer structure, which is acceptable for NLO device applications. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Highly alkaline stable anion exchange membranes from nonplanar polybenzimidazole with steric hindrance backbone

The anion exchange membranes (AEMs) with both high ionic conductivity and alkali stability are always the research focus of the AEM fuel cells. Here, a novel nonplanar polymer for AEMs manufacture, mPBI‐TP‐x‐R, with excellent hydroxide stability and satisfactory processability is reported for the first time. The serial mPBI‐TP‐x resins with steric hindrance were prepared by copolymerization among 3,3′,4,4′‐tetraaminobiphenyl, isophthalic acid and tetraphenyl‐terephthalic acid (TP) in different ratios under microwave condensation. The copolymers mPBI‐TP‐x were quaternized at N1/N3‐sites of benzimidazole unit in backbone with alkyl groups (R?CH₃, C₂H₅, n‐C₃H₇, or n‐C₄H₉) to prepare soluble ionomers, and the corresponding membranes in hydroxyl ion form were prepared by a solution casting method and subsequent ion‐exchange process. The chemical structure of all membranes was characterized using FTIR and ¹H NMR spectroscopy. The properties of ion exchange capacity, water uptake, swelling ratio, tensile strength, ionic conductivity, and alkaline stability were measured. Among the prepared membranes, the mPBI‐TP‐15%‐(n‐Bu) exhibited the excellent alkaline stability (only degradation ca. 5% under 1M NaOH aqueous solution at 60 °C for 800 h) and satisfactory OH^? conductivity (46.66 mS/cm at 80 °C). The current research provides a useful exploration to commercial application of alkaline fuel cell. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 1087–1096     

Molecular design,synthesis, and nonlinear optical properties of novel T‐type polyimides with exceptionally high thermal stability of the second harmonic generation

2,5‐Bis‐(3,4‐dicarboxyphenylcarboxyethoxy)‐4′‐nitrostilbene dianhydride was prepared and reacted with 1,4‐phenylenediamine, 4,4′‐oxydianiline, 4,4′‐diaminobenzanilide, and 4,4′‐(hexafluoroisopropylidene)dianiline to yield unprecedented novel T‐type polyimides ( 4 – 7 ) containing 2,5‐dioxynitrostilbenyl groups as nonlinear optical chromophores, which constituted parts of the polymer backbones. 4 – 7 were soluble in polar solvents such as acetone and N,N‐dimethylformamide. They showed thermal stability up to 300 °C in thermogravimetric analysis thermograms; the glass‐transition temperatures obtained from differential scanning calorimetry thermograms were around 153 °C. The second harmonic generation (SHG) coefficients (d₃₃) of poled polymer films at the 1064‐cm^?1 fundamental wavelength were around 4.35 × 10^?9 esu. The dipole alignment exhibited exceptionally high thermal stability even at 45 °C higher than the glass‐transition temperature, and there was no SHG decay below 200 °C because of the partial main‐chain character of the polymer structure, which was acceptable for nonlinear optical device applications. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3189–3199, 2004     

Synthesis and nonlinear optical properties of novel Y‐type polyurethane containing tricyanovinylthiazole with enhanced thermal stability of second harmonic generation

A novel Y‐type poly[iminocarbonyloxyethyl‐5‐methyl‐4‐{2‐thiazolylazo‐4‐(1,2,2‐tricyanovinyl)}resorcinoxyethyloxycarbonylimino‐(3,3′‐dimethoxy‐4,4′‐biphenylene)] 4 containing 5‐methyl‐4‐{5‐(1,2,2‐tricyanovinyl)‐2‐thiazolylazo}resorcinoxy groups as nonlinear optical (NLO) chromophores, which constitute part of the polymer backbone, was prepared and characterized. Polyurethane 4 is soluble in common organic solvents such as acetone and N,N‐dimethylformamide. It showed a thermal stability up to 250 °C in thermogravimetric analysis thermogram and the glass‐transition temperature (T_g) obtained from differential scanning calorimetry thermogram was around 118 °C. The second harmonic generation coefficient (d₃₃) of poled polymer films at 1560 nm fundamental wavelength was around 8.43 × 10^?9 esu. The dipole alignment exhibited a thermal stability even at 12 °C higher than T_g, and there was no SHG decay below 130 °C due to the partial main‐chain character of the polymer structure, which is acceptable for NLO device applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1166–1172, 2010