Efficient Synthesis and Self-Assembly of Segmented Hyperbranched Block Copolymers via RAFT-Mediated Dispersion Polymerization Using Segmented Hyperbranched Macro-RAFT Agents
Weibin Cai, Shuaiqi Yang, Lunqiang Zhang, Lunqiang Zhang, Ying Chen, Li Zhang, Li Zhang, Jianbo Tan
Abstract
Although linear block copolymer assemblies derived from polymerization-induced self-assembly (PISA) have been prepared with a wide variety of structures, examples with hyperbranched block copolymer assemblies have remained elusive. In this work, efficient synthesis and self-assembly of segmented hyperbranched block copolymers (SHBCs) were achieved via reversible addition–fragmentation chain-transfer (RAFT)-mediated dispersion polymerization-induced self-assembly (PISA) using segmented hyperbranched macro-RAFT agents. Two different approaches including the R-RAFT approach and the Z-RAFT approach were employed to synthesize SHBCs with an important structural difference. Using the Z-RAFT approach, the solvophobic block always grows in the inner of SHBCs, allowing the efficient synthesis of colloidally stable SHBC assemblies with a variety of morphologies. Finally, further structural control over SHBCs and morphological control over SHBC assemblies were achieved by combining the R-RAFT approach and the Z-RAFT approach or adding a chain-transfer monomer into the RAFT-mediated PISA. This work not only develops a facile method for the efficient synthesis of SHBCs and SHBC assemblies but also provides important insights into the PISA process of nonlinear block copolymers.