Evaporation Induced Crystallization of Poly(L-lactide acid)-b-Poly(ethylene glycol) at Liquid-Liquid Interface

The self-assembly nature of amphiphilic block copolymer (BCP) has been widely studied to create complex structures with controlled size, shape, and distribution. To date, most efforts have been devoted to the study of self-assembly of BCPs in bulk or in solutions, in which the structure are determined primarily by polymer molecular weight, volume fraction, and the Flory-Huggins parameter. Liquid-liquid interface provides additional control for crystallization and self-assembly as the asymmetric interface is vital to the structure formation. In this presentation, we report the evaporation induced assembly behavior of a series of amphiphilic BCP Poly(L-lactide acid)-b-Poly(ethylene glycol) (PLLA-b-PEO) at liquid/liquid interface. Our work showed that the crystallization pathway and self-assembly behavior of the BCP are dramatically different from solution self-assembly and crystallization. Effects of the block length, polymer concentration and assembly kinetics have been systematically investigated. Our work demonstrated that liquid/liquid interface provides an important control for BCP structure formation and crystallization.