3D Confined Assembly of Chiral Block Copolymers in Evaporative Emulsion Droplets
발표자
()
초록
내용
Self-assembly of chiral block copolymers (BCPs*) has attracted myriad attentions, due to intriguing abilities of BCPs* to form chiral structures and potential applications in chiral adsorption, chiral separation, and others. Yet, efforts to tailor their assembly structures were usually challenged by the intricate assembly behavior of BCPs*.1 Herein, we presented three-dimensional (3D) confined assembly of polystyrene-block-poly(D-lactide) (PS-b-PDLA) BCPs* in evaporative emulsion droplets. When good solvents to both blocks were employed, PS-b-PDLA featured a kinetically dependent assembly behavior, while enhancing assembly temperature did not show an apparent impact on this trend. It was found that a rapid solvent evaporation was essential to a chiral transfer from PDLA configuration (molecular level) to PDLA microphase separated structure (assembly level) and hence to form chiral particles with an internal helical structure. Moreover, the chirality transfer and the formation of chiral particles were interrupted by the aggregation of PS-b-PDLA chains in selective solvents, but they could be resumed once the aggregates were removed by filtration or employing mixed solvents composed of both good and selective solvents. Accordingly, we highlighted a good dissolution state and rapid assembly kinetics as two prerequisites to the chiral transfer process and the formation of a helical structure under 3D confinement. Our finding enriched the portfolio of assembly scenarios of BCPs* and deepened the understanding on the chiral transfer of BCPs* under 3D confinement. (1) H. Li et al., Macromolecules, 53, 4214 (2020).