A new material with photomechanical switching ability was developed. The material is a binary polymer blend composed of a poly(vinylether) having azobenzene moiety in the side chain and a polycarbonate as a matrix. Upon switching UV-irradiation on and off, the developed polymer blend showed deformation that was both rapid and reversible. This observed photomechanical effect is attributed to a reversible modulus change in the polymer blend, arising from an UV-controlled isomerization of the azobenzene moiety, causing a switching behavior between its highly aggregated and dissociated states. These two states are the physical crosslinking and decrosslinking of the polymer chains. (c) 2005 Elsevier Ltd. All rights reserved.