Synthesis of reversibly photocleavable pseudo-ladder polymers

Designing stimuli-responsive polymers derived from reversibly cleavable main chains provides a strategy for fabricating smart materials with responsive properties and functions upon desired stimuli. Herein, we report the synthesis of reversibly photocleavable pseudo-ladder polymers (PPLPs). These polymers consist of stiff ladder and reversibly cleavable hexaarylbiimidazole (HABI) backbone linkages to enable molecular weight control of PPLPs upon photoirradiation. Moreover, the concept has been successfully extended to the synthesis of amphiphilic graft copolymers with PPLP main chains and poly(ethylene oxide) side chains. Self-assembly of these graft copolymers in H2O afforded spherical micelles with ca. 100–200 nm in diameter, and interestingly, the size of these micelles doubled upon photoirradiation.