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Yi‐Chun Kung Sheng‐Huei Hsiao 《Journal of polymer science. Part A, Polymer chemistry》2011,49(16):3475-3490
A series of novel aromatic polyamides with pyrenylamine in the backbone were prepared from a newly synthesized dicarboxylic acid monomer, N,N‐di(4‐carboxyphenyl)‐1‐aminopyrene, and various aromatic diamines via the phosphorylation polyamidation technique. These polyamides were readily soluble in many organic solvents and could be solution‐cast into tough and amorphous films. They had useful levels of thermal stability with glass‐transition temperatures in the range of 276–342 °C and 10% weight loss temperatures in excess of 500 °C. The dilute N‐methyl‐2‐pyrrolidone (NMP) solutions of these polymers exhibited fluorescence maxima around 455–540 nm with quantum yields up to 56.9%. The polyamides also showed remarkable solvatochromism of the emission spectra. Their films showed reversible electrochemical oxidation and reduction accompanied by strong color changes from colorless neutral state to purple oxidized state and to yellow reduced state. The polyamide 4g containing the pyrenylamine units in both diacid and diamine sides exhibited easily accessible p‐ and n‐doped states, together with multicolored electrochromic behaviors. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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Benchuan Zhu Guannan Qian Yuli Xiao Sheng Deng Meng Wang Aiguo Hu 《Journal of polymer science. Part A, Polymer chemistry》2011,49(24):5330-5338
Employing enediynes as crosslinking precursors, a novel yet efficient strategy, namely photo‐triggered Bergman cyclization, was integrated with intramolecular chain collapse to yield polymeric nanoparticles with the size regime below 20 nm. Enediyne motif was designed delicately to possess a high photo‐reactivity, with the double bond locked in a methyl benzoate ring while triple bonds substituted with phenyls. Single electron transfer‐living radical polymerization was conducted to provide linear acrylate copolymers with controlled molecular weights and narrow polydispersities. Poly(butylarylate‐co‐ 5 ) went through UV‐irradiation with a concurrent Bergman cyclization, resulting in well‐defined ultrafine polymeric nanoparticles. Results from NMR, Raman scattering, photoluminescence and UV‐vis spectra corroborated the presence of conjugative structures in the polymeric nanoparticles, indicating the occurrence of photo‐induced Bergman cyclization. A series of other acrylate‐based nanoparticles were investigated to confirm the applicability of such a unique strategy in thermal sensitive but UV‐stable polymeric structures, making photo‐Bergman cyclization a promising tool towards polymeric nanoparticles. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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Dong‐Cai Zhao Geng‐Jie Xiao Ni Ren Zhan‐Ji Ma Sheng‐Hu Wu 《Surface and interface analysis : SIA》2011,43(11):1392-1396
The composites, such as CFRP and GFRP, have been widely applied in spaceflight, for their low specific gravity, low cost, and additional structural stability. However, the high resistivity of the composites severely inhibits their further applications. Therefore, Cr/Al films with low resistivity and high adhesion were deposited on composites by cathodic arc technique. The films were characterized by pull test, Dektak 8 Stylus Profilometer, SEM, XPS, XRD and Z‐82 standard four probes. Results show that the aluminum film of fcc structure is compact and uniform, with resistivity as low as bulk Al. The adhesion between Cr buffer layer and composite substrate was greatly enhanced because of the formation of the chemical bonds, such as Cr? C, Cr? O and Cr? N, at the Cr/composite interface. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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We report herein an exonuclease-assisted aptamer-based target recycling amplification strategy for sensitive and selective chemiluminescence (CL) determination of adenosine. This aptasensor is based on target-induced release of aptamers from capture probes immobilized on the 96-well plate surface, and thus leading to a decreased hybridization with gold nanoparticle-functionalized reporter sequences followed by a CL signal. The introduction of exonuclease III catalyzes the stepwise removal of mononucleotides from 3′-hydroxyl termini of duplex DNAs of aptamers, liberating the adenosine. Therefore, a single copy of target adenosine can lead to the release and digestion of numerous aptamer strands from the 96-well plates and ultimately an enhanced sensitivity is achieved. Experimental results revealed that the exonuclease-assisted recycling strategy enabled the monitoring of adenosine with wide working ranges and low detection limits (LOD: 0.5 nM). This new CL strategy might create a novel technology for the detection of various targets and could find wide applications in the environmental and biomedical fields. 相似文献
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