CO2-driven vesicle to micelle regulation of amphiphilic copolymer: random versus block strategy
作者：Hanbin Liu, Zanru Guo, Shuai He, Hongyao Yin, Chenhong Fei, Yujun Feng
關鍵字：CO2-responsive, vesicle
論文來源：期刊
具體來源：Polymer Chemistry
發表時間：2014年
Precise morphological control over self-assemblies is attractive due to their promising applications, especially in biotherapy. Block copolymer is a common choice for morphological control, since the geometry of self-assemblies can be easily predicted by the hydrophilic volume fraction. However, random copolymers are rarely taken into consideration. Here, starting from the same hydrophilic segment poly(ethylene oxide) (PEO), and using CO2-responsive 2-(diethylamino)ethyl methacrylate (DEAEMA) and hydrophobic styrene (St), we designed and synthesized a random and an entire block copolymer with similar polymerization degrees but different monomer sequences: PEO45-b-(DEAEMA90-r-St66) (Pr) and PEO45-b-DEAEMA93-b-St66 (Pb). In aqueous solution, the two polymers both aggregate into vesicles. Upon CO2-stimulus, however, the vesicle of the random copolymer Pr transforms into a spherical micelle, whereas that of the triblock copolymer Pb shows an expansion instead of a morphological transition. The restricted hydration in the random structure of Pr accounts for such a morphological transition, and the random strategy in polymer design might be useful in self-assembly regulation.