One-Pot Heteroepitaxial Living Growth to Liquid Crystalline Block Copolymer Heteroaxial Nanowires and Their Disassembly/Reassembly Behavior

Abstract

Great efforts have been devoted to studying the self-assembly of block copolymers (BCPs) in solution owing to their vast morphological dispersity and immense potential in biomedicine and nanodevices. Among the assembly processes, the heterogeneous connection has always been a problem to be solved. Moreover, the fabrication of heterogeneous assemblies with advanced functionalities, such as stimulus responsiveness and, particularly, cyclic assembly capabilities, represents a significant challenge in the field. In this work, we propose a novel approach to fabricate heteroaxial nanowires by joining two liquid crystalline (LC) cores using a heteroepitaxial growth strategy via directly mixing two LC BCPs in 1-hexanol and subsequent thermal annealing in one pot. Their formation is affected by the temperatures and compatibilizing segments within the tri-BCP. At the annealing temperature, the tri-BCP with higher aggregation temperatures spontaneously formed nanorod-like micelles as the seeds, while the other di-BCP, which was completely dissolved, served as the growing components. The lengths of the obtained heteroaxial nanowires are controllable and interconvertible by tuning the ratio of seed and growing components, exhibiting living characteristics. Furthermore, these segmented cylindrical micelles can undergo disassembly and reassembly processes via ultraviolet (UV) irradiation and reannealing, respectively. This work provides a valuable example of precisely regulating the structures and functions of heterogeneous assemblies.