화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals, Vol.500, 1-9, 2009
Comparative Study of Photomechanical Effects in Linear and Star Azo-Polymers
We investigated the influence of the polymer macromolecular geometry and chain length in azobenzene containing polymeric liquid crystals (azo-PLC). In particular we studied the photomechanical effects (photoinduced expansion and shrinking) on monodispersed azo-PLCs (polydispersity index 1.08-1.17) prepared from the same monomer and different molecular weights, both in linear and 3-arm star conformation. The characterization has been carried out in thin films by high resolution null ellipsometry for a simultaneous and independent determination of both mechanical and optical properties (e. g., thickness and refractive index). The measurement system has been set up in a pump probe configuration for a real time characterization of the photoinduced dynamics. The effect of coupling introduced by the polymer star configuration is discussed.