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.
Comparative Study of Photomechanical Effects in Linear and Star Azopolymers / Camorani, P.; Cristofolini, Luigi; Fontana, M. P.; Angiolini, L.; Cryst, F. PARIS COMPARATIVE STUDY OF PHOTOMECHANICAL EFFECTS IN LINEAR AND STAR AZOPOLYMERS M. O. L. C. R. Y. S. T. L. I. Q.. - In: MOLECULAR CRYSTALS AND LIQUID CRYSTALS. - ISSN 1542-1406. - 500(2009), pp. 1-9. [10.1080/15421400802713645]
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