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.
L. Angiolini, L. Giorgini, F. Paris, P. Camorani, L. Cristofolini, M. P. Fontana (2009). Comparative Study of Photomechanical Effects in Linear and Star Azo-Polymers. MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 500, 1-9 [10.1080/15421400802713645].
Comparative Study of Photomechanical Effects in Linear and Star Azo-Polymers
ANGIOLINI, LUIGI;GIORGINI, LORIS;PARIS, FABIO;
2009
Abstract
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
