摘要/Abstract

分子刷聚合物伸展的高分子主链、高密度的侧链和较低的侧链空间缠结, 使其展现出独特的流变学、力学性能和特殊的分子聚集状态, 在纳米技术、表面科学等领域有着广泛的应用前景. 基于同时含有2-羰基溴与炔基基团的大分子试剂聚2-((2-溴代丙酰氧基)甲基)丙烯酸丙炔酯, 引发偶氮苯丙烯酸酯单体的原子转移自由基聚合(ATRP)与叠氮功能化的巴比妥酸衍生物的点击反应, 合成了新型含偶氮苯侧链的分子刷聚合物聚丙烯酸酯-g-聚(6-(4-丁基-4′-氧偶氮苯)正己基丙烯酸酯)/巴比妥酸(PA-g-PAzo/Bar), 研究了其在溶液中的自组装和光响应性行为. 随着分子刷聚合物浓度的增加, 聚集体由柱状胶束向复合胶束转变. 由于光响应性偶氮苯侧链的存在, 在紫外光的照射下偶氮苯生色团发生trans-cis异构化转变, 促使柱状胶束融合形成多孔网状聚集体, 同时球形复合胶束融合形成珍珠项链状聚集体.
关键词: 偶氮苯, 分子刷聚合物, 光响应性, 超分子自组装
Molecular brushes (MBs) are a unique type of branched macromolecules which graft polymeric chains onto a linear polymeric backbone densely. Crowded tethered side chains generate strong steric repulsion and force the backbone to stretch out, resulting in a persistent cylindrical shape and low density of entanglements of brushes. Owing to the unique rheological and mechanical properties and self-assembly behaviors, MBs show a great potential in nanotechnology and surface science. Herein, the synthesis of novel MBs of polyacrylate-g-poly(6-(4-butyl-4'-oxyazobenzene)hexylacrylate)/barbituric acid (PA-g-PAzo/Bar) was reported, in which PAzo brushes and hydrogen-bonding barbituric acid were grafted using the combination of concurrent atom transfer radical polymerization (ATRP) and click reaction. MBs-based aggregates change from cylinder to compound micelle by increasing the concentration. It is interesting that morphology transitions of cylinder-to-porous nanosheet and compound micelle-to-pearl-necklace were observed upon UV irradiation, that was ascribed to thetrans-to-cis isomerization of PAzo brushes.
Key words: azobenzene, molecular brushes, photo-responsiveness, supramolecular self-assembly


PDF全文下载地址:

点我下载PDF