Photomechanical response of amorphous polymer films containing azobenzene chromophores in side chains is studied. By invoking the trans-cis isomerization mech- anism, the steady-state deformation of the film induced b...Photomechanical response of amorphous polymer films containing azobenzene chromophores in side chains is studied. By invoking the trans-cis isomerization mech- anism, the steady-state deformation of the film induced by uniform illumination of linearly polarized light is obtained analytically. The deformation turns out to be of entropic origin,produced to compensate the entropy decrease due to photo-induced redistribution of azobenzene chromophores normal to the polarization direction. The predicted elongation direction of the film is consistent with previous experimental observations.展开更多
The fundamental optical storage mechanism of the laser light eddressable azobenzene moiety is briefly introduced.A modular and flexible synthesis design furnishes polyester matrices covalently integrating cyanoazobenz...The fundamental optical storage mechanism of the laser light eddressable azobenzene moiety is briefly introduced.A modular and flexible synthesis design furnishes polyester matrices covalently integrating cyanoazobenzene in regularlyspaced side chains. Thin films of these materials are particularly well suited for holographic storape. Notable figures of meritsof liquid crystalline polyesters are response time to blue-green laser light of the order of nanoseconds, storage capacityexpressed as 5000 lines/mm, and high, permanent (almost nine years) diffraction efficiency of the order of 50% or greater,and erasability, The implications of the main chain nature for polyester morphology and for the permanency of the inducedanisotropy are discussed, The design and methods of preparation of other significantly different polymer scaffolds supportingcyanoazobenzene are elaborated. Oligopeptides always result in amorphous materials, whereas copolymethacrylates anddendritic or hyperbranched polyesters provide some materials that exhibit liquid crystallinity. However, none of these scaffolds affords materials that result in permanent anisotropy when exposed to interfering laser light.展开更多
基金supported by the National Natural Science Foundation of China (11072231, 11132009)
文摘Photomechanical response of amorphous polymer films containing azobenzene chromophores in side chains is studied. By invoking the trans-cis isomerization mech- anism, the steady-state deformation of the film induced by uniform illumination of linearly polarized light is obtained analytically. The deformation turns out to be of entropic origin,produced to compensate the entropy decrease due to photo-induced redistribution of azobenzene chromophores normal to the polarization direction. The predicted elongation direction of the film is consistent with previous experimental observations.
文摘The fundamental optical storage mechanism of the laser light eddressable azobenzene moiety is briefly introduced.A modular and flexible synthesis design furnishes polyester matrices covalently integrating cyanoazobenzene in regularlyspaced side chains. Thin films of these materials are particularly well suited for holographic storape. Notable figures of meritsof liquid crystalline polyesters are response time to blue-green laser light of the order of nanoseconds, storage capacityexpressed as 5000 lines/mm, and high, permanent (almost nine years) diffraction efficiency of the order of 50% or greater,and erasability, The implications of the main chain nature for polyester morphology and for the permanency of the inducedanisotropy are discussed, The design and methods of preparation of other significantly different polymer scaffolds supportingcyanoazobenzene are elaborated. Oligopeptides always result in amorphous materials, whereas copolymethacrylates anddendritic or hyperbranched polyesters provide some materials that exhibit liquid crystallinity. However, none of these scaffolds affords materials that result in permanent anisotropy when exposed to interfering laser light.
