Preparation and properties of poly(dimethysilyleneethynylenephenylene‐ethynylene)/graphene Composites

Polymer composites with carbon‐based nano‐fillers have generated significant interest in industry and science because of their multifunctional and valuable properties. An APA‐functionalized GO nanofiller (GO–APA) was prepared through the reaction between graphene oxide (GO) and 3‐aminophenyl acetylene (APA) in dimethylformide (DMF) with ammonia hydroxide. Furthermore the PDSEPE/GO–APA composites were made from Poly(dimethysilyleneethynylenephenylene ethynylene) (PDSEPE) and GO–APA. FT‐IR, XRD, XPS, SEM, DSC and TGA techniques were used to characterize the chemical compositions and physical and chemical properties of GO–APA and PDSEPE/GO–APA composites. As a result, the prepared PDSEPE/GO–APA composites show high thermal stabilities, excellent electrical conductivity and good flexural strength. When the weight percentage of GO–APA reaches 0.5%, the PDSEPE/GO–APA composite electrical conductivity increases by 6 orders of magnitude and the flexural strength improves by nearly 33% compared with that of cured PDSEPE resin. Copyright © 2015 John Wiley & Sons, Ltd.     

聚苯硫醚/聚四氟乙烯复合涂层研究进展

聚苯硫醚、聚四氟乙烯均是耐高温、耐腐蚀的树脂,同时聚四氟乙烯有极低表面能,而聚苯硫醚与金属有良好结合力,结合二者的优点,有望制备出集合耐腐蚀、耐高温、超疏水等优异性能为一体的功能涂层,因此以聚苯硫醚、聚四氟乙烯为主要原料的复合涂料自1992年以来便倍受关注。本文从聚苯硫醚、聚四氟乙烯各自的性能出发,综述了聚苯硫醚/聚四氟乙烯复合涂层三种不同制备工艺:分层涂覆、共混涂覆、梯度涂覆;详细说明了涂层的五大优异性能:耐腐蚀性、超疏水性能、阻垢性能、耐高温性以及耐磨性能,最后本文还描述了聚苯硫醚/聚四氟乙烯复合涂层的广阔应用前景。     

聚对苯撑乙炔咔唑薄膜对TNT挥发物的检测

以3, 6-二溴-9-辛基咔唑和2, 5-二戊烷氧基-1, 4-二乙炔基苯为单体,通过Pd催化的Sonogashira偶联反应合成了聚对苯撑乙炔咔唑衍生物PPECz。PPECz的溶液和固体薄膜都具有较好的发光性能,并且均对2, 4, 6-三硝基甲苯(TNT)有明显的响应。在常温常压条件下,微量(40 μg)的TNT挥发物在60 s内就能使聚合物PPECz薄膜的荧光强度被猝灭56%,可作为一种潜在的硝基苯类爆炸物的荧光检测材料。     

Absorption and emission properties of phenylene ethynylene oligomers: effect of substitution and π-conjugation length

The optical properties of a series of π-conjugated phenylene-ethynylene oligomers (OPEs) have been studied by advanced quantum chemical methods. The ground state and lowest singlet excited state geometries of unsubstituted and different electron donor and acceptor groups substituted OPEs are optimized by density functional theory and configuration interaction singles methods. The absorption and emission spectra of unsubstituted and substituted OPEs have been calculated using the time-dependent density functional theory (TDDFT) method. The results of theoretical calculations are in good agreement with the available experimental results. It has been found that the substitution of electron donating and withdrawing groups in the phenyl ring and conjugation length of the OPEs has significantly affect both the absorption and emission spectra     

一种侧基横挂偶极单元的聚苯撑乙炔的光学性质

以对苯二乙炔和2,5-二溴苯衍生物为单体,无水N,N-二甲基甲酰胺（DMF）为溶剂,通过Sonogashira偶联反应,采用2种Pd催化剂（Pd(PPh₃)₄和PdCl₂(PPh₃)₂）合成了一种侧基带有偶极基团的聚苯撑乙炔。 单体的化学结构通过IR、NMR和元素分析等测试技术得到确证。 聚合物外观为黄色粉状固体,室温下溶于CHCl₃和THF等有机溶剂。 2种Pd催化剂对合成聚合物的分子量以及光学性质影响不大,但对聚合物的发光效率影响较大,由Pd(PPh₃)₄催化得到的聚合物分子链具有较高的立构规整性,因此,具有较高的发光效率。 不同溶剂环境以及聚合物固体膜的紫外以及荧光光谱研究结果表明,侧基偶极基团的相互静电排斥力,可以有效阻止大分子链之间的聚集,从而有效地抑制了聚苯撑乙炔聚集体的形成。     

Meta‐linked and para‐linked water‐soluble poly(arylene ethynylene)s with amino acid side chains: Effects of different linkage on Hg2+ ion sensing properties in aqueous media

Water‐soluble, meta‐ and para‐linked poly(arylene ethynylene)s containing L ‐aspartic acid‐functionalized fluorene units (P1 and P2) and their model compounds (M1 and M2) have been synthesized, and their photophysical properties and fluorescent sensing properties were investigated in aqueous solution. P1 and M1 with the meta‐linkage show blue‐shifted absorption and emission spectra, and decreased photoluminescence quantum yields compared with those of P2 and M2 with para‐linkage. Their absorption and fluorescence spectra are pH dependent perhaps due to the aggregation of the polymer chains at low pH values. In buffer solutions, both polymers and their model compounds exhibit the excellent selectivity and sensitivity to Hg²⁺ over other common metal ions. Furthermore, the quenching constant and detection limit of P1 are determined to be 1.04 × 10⁷ M^?1 and 10 nM, and show the higher sensitivity compared to P2. Further comparison of their model compounds reveal that the sensitivity and quenching efficiency of M1 is also higher than that of M2, indicating that the meta‐linkage pattern plays a key role in improving their Hg²⁺ ion sensing properties. In addition, both meta‐ and para‐linked polymers exhibit the higher quenching efficiency than their model compounds due to the amplified fluorescence response of conjugated polymer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Hyperbranched poly(arylene ethynylene)s with triphenylamine core for polymer light‐emitting diodes

A series of light‐emitting hyperbranched poly(arylene ethynylene)s (HB‐PAEs) were prepared by the Sonogashira coupling from bisethynyl of carbazole, fluorene, or dialkoxybenzenes (A₂ type) and tris(4‐iodophenyl)amine (B₃ type). For comparison, two linear polymers (L‐PAEs) of the HB analogs were also synthesized. The polymers were characterized by Fourier transform infrared, NMR, and GPC. The HB polymers showed excellent solubility in chloroform, THF, and chlorobenzene when compared with their linear analogs. The number‐average molecular weight (M_n) of the polymers determined from GPC was found to be in the range of 18,600–34,200. The polymers were thermally stable up to 298–330 °C with only 5% weight loss. The absorption maxima of the polymers were between 354 and 411 nm with optical band gap in the range of 2.5–2.9 eV. The HB polymers were found to be highly fluorescent with photoluminescence quantum yields around 33–42%. The highest occupied molecular orbital energy levels of the polymers calculated from onset oxidation potentials were found to be in the range from ?5.83 to ?6.20 eV. Electroluminescence (EL) properties of three HB‐PAEs and one L‐PAE were investigated with device configuration ITO/PEDOT:PSS/Polymer/LiF/Al. The EL maxima of HB‐PAEs were found to be in the range of 507–558 nm with turn‐on voltages around 7.5–10 V and maximum brightness values of 316–490 cd/m². At the same time, linear analog of one HB‐PAE was found to show a maximum brightness of 300 cd/m² at a turn‐on voltage of 8.2 V. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of biodegradable conjugated polymers with controlled backbone flexibility

A series of flexible, highly bright fluorescent poly(p‐phenyleneethynylene)s (PPEs) was prepared by employing a disulfide containing nonconjugated monomer at various ratios under Sonogashira reaction conditions. PPEs with flexible linkers exhibited fluorescence properties comparable to those of a fully conjugated PPE when less than 50% of flexible monomers were incorporated into the backbone. To evaluate the self‐assembly properties of PPEs, a series of conjugated polymer nanoparticles (CPNs) was fabricated by treating PPEs with organic acids followed by dialysis. CPNs containing linkers exhibited different complexation behavior with polysaccharides, warranting further investigation into how flexibility and biodegradability of CPNs influence their cellular interaction and entry. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1403–1412     

Oligo(p-phenylene ethynylene)-BODIPY derivatives: synthesis, energy transfer, and quantum-chemical calculations

The synthesis and energy‐transfer properties of a series of oligo(p‐phenylene ethynylene)–BODIPY ( OPEB ) cassettes are reported. A series of oligo(p‐phenylene ethynylene)s ( OPE s) with different conjugated chain lengths as energy donor subunit in the energy‐transfer system were capped at both ends with BODIPY chromophores as energy‐acceptor subunits. The effect of the conjugated chain of OPE s on energy transfer in the OPEB cassettes was investigated by UV/Vis and fluorescence spectroscopy and modeling. With increasing number n of phenyl acetylene units (n=1–7), the absorption and emission maxima of OPEn are bathochromically shifted. In the OPEBn analogues, the absorption maximum assigned to the BODIPY moieties is independent of the length of the OPE spacer. However, the relative absorption intensity of the BODIPY band decreases when the number of phenyl acetylene units is increased. The emission spectra of OPEBn are dominated by a band peaking at 613 nm, corresponding to emission of the BODIPY moieties, regardless of whether excitation is at 420 or 550 nm. Furthermore, a very small band is observed with a maximum between 450 and 500 nm, and its intensity relative to that of the BODIPY emission increases with increasing n, that is, the excited state of OPE subunits is efficiently quenched in OPEBn by energy transfer to the BODIPY moieties. Energy transfer (ET) from OPEn to BODIPY in OPEBn is very efficient (all Φ_ET values are greater than 98 %) and only slightly decreases with increasing length of the OPE units. These results are supported by theoretical studies that show very high energy transfer efficiency (Φ_ET>75 %) from the OPE spacer to the BODIPY end‐groups for chains with up to 15–20 units.