Photodegradation of Networked Polymers Composed of Photolabile Crosslinkers

Abstract

Photolabile crosslinkers are compounds composed of photolabile units and polymerizing units. As well as conventional crosslinkers, photolabile crosslinkers can be introduced easily and homogeneously into networked polymers. In recent studies, o-nitrobenzylcarbonyl, coumarinmethyl, tertiary ester, and ruthenium complex units are incorporated as the photolabile units and are polymerized with hydrophilic monomers mainly in free-radical, ene－thiol, and click polymerization modes. Resulting hydrogels are used in the fields of medical applications mainly. Oxime-ester based photolabile crosslinkers are also proposed and incorporated in networked polyacrylates and polyurethanes. Their formation and degradation were successfully demonstrated, and photorheometers were useful tools for the evaluation of the formation and degradation behaviors on irradiation.