title: Cooperation of Amphiphilicity and Crystallization for Regulating the Self-Assembly of Poly(ethylene glycol)-block-poly(lactic acid) Copolymers.
abstract: Tuning the amphiphilicity of block copolymers has been extensively exploited to manipulate the morphological transition of aggregates. The introduction of crystallizable moieties into the amphiphilic copolymers also offers increasing possibilities for regulating self-assembled structures. In this work, we demonstrate a detailed investigation of the self-assembly behavior of amphiphilic poly(ethylene glycol)-block-poly(l-lactic acid) (PEG-b-PLLA) diblock copolymers with the assistance of a common solvent in aqueous solution. With a given length of the PEG block, the molecular weight of the PLA block has great effect on the morphologies of self-assembled nanoaggregates as a result of varying molecular amphiphilicity and polymer crystallization. Common solvents including N,N-dimethylformamide, dioxane, and tetrahydrofuran involved in the early stage of self-assembly led to the change in chain configuration, which further influences the self-assembly of block copolymers. This study expanded the scope of PLA-based copolymers and proposed a possible mechanism of the sphere-to-lozenge and platelet-to-cylinder morphological transitions.
authors: Department of Chemistry, Renmin University of China , Beijing 100872, China.
authors: Zhen
authors: Z
authors: Wang
authors: Department of Chemistry, Renmin University of China , Beijing 100872, China.
authors: Yuanyuan
authors: Y
authors: Cao
authors: Department of Chemistry, Renmin University of China , Beijing 100872, China.
authors: Jiaqi
authors: J
authors: Song
authors: State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Science , Changchun 130022, China.
authors: Zhigang
authors: Z
authors: Xie
authors: Department of Chemistry, Renmin University of China , Beijing 100872, China.
authors: Yapei
authors: Y
authors: Wang