Azobenzene‐Incorporated Single‐ and Double‐Stranded Polynorbornenes: Facile Synthesis and Diverse Photoresponsive Property

Abstract

AbstractDouble‐stranded polymeric ladderphane using azobenzene as linkers and the single‐stranded polynorbornene with azobenzene pendants are synthesized by the ring‐opening metathesis polymerization using Grubbs ruthenium‐based catalyst. Hydrolysis of these as‐prepared polynorbornenes gives the corresponding isotactic single‐stranded polynorbornene having similar polydispersity and degree of polymerization as those of the original polymers. The photosensitive property of double‐stranded ladderphane indicates significant interactions between adjacent chromophores. These single‐ and double‐stranded polynorbornenes incorporating azobenzene chromophores exhibit distinct photoresponsive performance in the dilute solutions. The rate of photoisomerization for double‐stranded ladderphane is found to be from 6 to 9 times slower than that obtained for single‐stranded polymer. This is ascribed to the differences in structure of polymers and the interaction between azobenzene chromophores in the polymers.