Molecular Design of Post-functionalizing Block Copolymers for Versatile Morphologies*

One of the challenges in block copolymer study is to produce bicontinuous structures with various types of polymers with high reproducibility. Conventionally, two methods are known: a method of synthesizing a polymer having a target composition ratio by precise polymerization, and a polymer blend in which fine adjustment of the composition ratio is performed while accurately blending one polymer. However, there are some problems such as lack of reproducibility, limited polymers that can be used, and macrophase separation.
In this study, we demonstrated a new approach for creating bicontinuous microphase-separated structures using the post-functionalization of side-chain type block copolymers. The molecular design of the block copolymers having a vinyl group or glycidyl group in the side chain group was carried out, and the composition ratio was precisely controlled based on the high-yield reactions in the post-functionalization. It was found that the bicontinuous gyroid structure can be obtained with good reproducibility by precisely controlling the amount of side chains introduced.