Photomechanic Behavior of Main-chain Type of Polycoumarates

Hydroxycinnamate derivatives which are polymerizable phenolic acids show two-types photoreactions such as intramolecular E-Z isomerization and intermolecular [2 + 2] cycloaddition. Although five derivatives of hydroxycinnamic acid were tried to polymerize by a conventional one-bottle method, only two polymers of poly(3-hydroxycinnamic acid) (P3HCA) and poly(3,4-dihydroxycinnamic acid) (PDHCA) were successfully prepared. Because these polymers had cinnamoyl moiety in every main-chain unit, the polymers should show efficient photoreactions by the UV irradiation. The hard-film of these polymers showed a photo-bending behavior. Furthermore, the photo-bending showed generation of high-power (170μN).