光酸响应聚合物胶束的分子捕捉、转移与释放性能

"What calls birds together and let them fly in flocks?" Similarly in microscopic field, how to conduct collection, phase transfer delivery and localized release of specified molecules? In this program, such a photo-responsive physical micelle is designed: the core consists of a multifunctional hyperbranched polymer, and the shell is composed of a chain with reverse polarity to the core, where the shell attaches to the core via a photo-responsive azobenzyl/cyclodextrin inclusion complexation. This micelle is of such features: pH responsive due to the aliphatic nitrogen atoms in the core; owing to the multifunctional groups in the core, chemical modification can lead to active and highly selective entrapment of specified molecules; most importantly, because the core is a hyperbranched polymer, repeated self-assembly/disassembly is feasible for the micelle, with the irradiation of certain photo, self-assembled micelle entraps the guest and migrates into organic (aqueous) phase, while under the trigger of another photo, micelle collapses and the released guests move back into aqueous (organic) phase. Owing to the reversibility of this process, the micelle can be used for catalyst recycle, mixture separation and removal of pollutants. Additionally, the micelle is ready for function integration, when poly(ethylene glycol)s are attached to the core via acid-labile Schiff bonds and two-photo responsive photo-acid generators are encapsulated in the resulting micelle, precisely localized drug release is possible for the micelle.

"苍鸟群飞，何使萃之？" 同样，在微观领域如何控制特定分子的收集、相转移迁移与定点释放？本项目设计了这样一类光响应物理胶束：胶束的核由一个多官能团的超支化聚合物构成，壳则由极性与核相反的分子构成，核-壳间通过光敏的环糊精和偶氮苯基团间的包结作用连接。该胶束具有以下特点：因核内带有多个脂肪氮原子而具有酸碱响应性；核带有大量官能团，经化学修饰后能主动地、高选择性地收集指定的客体分子；最重要的是核为单个超支化聚合物分子，使胶束能反复自组装/自拆卸，在某种光的照射下，自组装胶束捕捉客体分子并定向迁移至油相（水相），在另一波长的光照下胶束解体，客体分子重返水相（油相）。由于该过程可以反复进行，胶束可用于催化剂回收、混合物分离和水污染物清除。另外，胶束还具有强大的功能集成能力，当将聚环氧乙烷以酸敏的希夫碱与核共价连接，并在所得的胶束内装载双光子响应的光生酸剂后，胶束就能进行精确定位的药物释放。

本项目的目标是设计合适的核壳聚合物胶束来实现对特定客体分子的高效捕捉、转移与释放，可用于催化剂回收、混合物分离和水污染物清除。在准球形的超支化聚乙撑亚胺（PEI）外围接上一定数目的亲油链即获得核壳树状两亲体（胶囊）。其中PEI核构成一个特有的微环境，其开放度可通过外围亲油链数控制，其电子环境可通过对PEI官能团的化学修饰调控。所得胶囊能进行尺寸和电荷选择性客体捕捉并伴随液-液相转移分离。另外，上述纳米胶囊可作为浓乳液的稳定剂调控聚合，藉此一釜获得表面完全由树状两亲体表达的多孔块料。这类新材料的成功合成是本项目最大的突破，其意义在于简便地实现宏观材料表面的精细结构化，即赋予多孔材料表面精细微观拓扑特征（胶囊开放度）和裁制电子微环境，成为一类新型的吸附剂。这类吸附剂能高效提取微量客体，还因酸碱响应性而能反复使用。实验表明该材料能同时清除水中微量痕量芳烃、有机染料和表面活性剂等广谱污染物，使其残留浓度创文献新低。机理探索表明在PEI上引入亲油链可使主客体结合强度提高十万倍；同时树状拓扑效应使吸附剂与客体的结合常数提高了50倍（与线性两亲体相比）。这使得清除水中痕量致癌物变得可行。初步研究还表明，这种表面结构化的多孔材料非常适合催化剂负载。