Jiang Tao, Aseyev Vladimir, Niskanen Jukka, Hietala Sami, Zhang Qilu, Tenhu Heikki
Department of Chemistry, University of Helsinki, P.O. Box 55, 00014 Helsinki, Finland.
Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
Macromolecules. 2020 Oct 13;53(19):8267-8275. doi: 10.1021/acs.macromol.0c01708. Epub 2020 Sep 17.
Manipulation of self-assembly behavior of copolymers via environmental change is attractive in the fabrication of smart polymeric materials. We present tunable self-assembly behavior of graft copolymers, poly(sulfobetaine methacrylate)--poly[oligo(ethylene glycol) methyl ether methacrylate)--di(ethylene glycol) methyl ether methacrylate] (PSBM--P(OEGMA--DEGMA)). Upon heating the aqueous solutions, the graft copolymers undergo a transition from micelles with PSBM cores to unimers (i.e., individual macromolecules) and then to reversed micelles with P(OEGMA--DEGMA) cores, thus demonstrating the tunability of the self-assembling through temperature change. In the presence of salt the temperature response of PSBM is eliminated, and the structure of the micelles with the P(OEGMA--DEGMA) core changes. Moreover, for the graft copolymer with long side chains, micelles with aggregation number 2 were formed with a PSBM core at low temperature, which is ascribed to the steric effect of the P(OEGMA--DEGMA) shell.
通过环境变化来调控共聚物的自组装行为，在智能高分子材料的制备中颇具吸引力。我们展示了接枝共聚物聚（甲基丙烯酸磺酸甜菜碱）-聚[聚（乙二醇）甲基醚甲基丙烯酸酯-二乙二醇甲基丙烯酸酯]（PSBM-P（OEGMA-DEGMA））的可调自组装行为。加热水溶液时，接枝共聚物会经历从以PSBM为核的胶束转变为单分子（即单个大分子）然后再转变为以P（OEGMA-DEGMA）为核的反胶束的过程，从而证明了通过温度变化实现自组装的可调性。在盐存在的情况下，PSBM的温度响应消失，且以P（OEGMA-DEGMA）为核的胶束结构发生变化。此外，对于具有长侧链的接枝共聚物，在低温下会形成聚集数为2且以PSBM为核的胶束，这归因于P（OEGMA-DEGMA）壳的空间位阻效应。
