Synthesis, Crystallization And Photoresponsive Behavior of Azobenzene-Containing Diblock Copolymers

High-density functional groups can be introduced into block copolymer single crystals, by designing appropriate noncrystalline blocks. However, maintaining material functionality requires sufficient local free volume, which has received limited attention to date. Herein, a series of diblock copolymers bearing multiple azobenzene moieties were synthesized. Crystals with varying morphologies were obtained via both cocrystallization and epitaxial growth strategies. The photoresponsive behavior of the resulting crystals was systematically investigated. The isomerization rate of azobenzene moieties is directly correlated with the surface functional group density, while the isomerization efficiency is further influenced by the crystal morphology. These findings highlight the importance of balancing surface group density with available local free volume, offering valuable insights into the design of hierarchical two-dimensional nanomaterials with tunable properties.