| Holographic polymer dispersed liquid crystals(HPDLCs) is a kind of material that combines the excellent processability of polymers and the unique optical properties of liquid crystals. Compared to the general materials with periodic structure, it shows some significant advantages like low cost, simple preparation and suitable for mass production. It has been widely used as optical switches, dynamic filters, flat-panel displays and other devices, and it has great application prospects in many other fields, such as optical communications, information storages, anti-counterfeiting. But, how to make holographic grating with high diffractive efficiency, high photosensitivity, low volume shrinkage and quick electronic-optic response is still a challenge.In this dissertation, gold nanoparticles modified by dodecyl mercaptan were chosen as doping materials. The mixture systems included N-phenylglycine(NPG) as the photoinitiator, N,N-dimethylacrylamide(DMAA), hyperbranched acrylic ester(6361-100) as monomers, P0616 A as the liquid crystals, 3,3?-carbonylbis(7-diethylaminocoumarin)(KCD) or rose bengal(RB) as the photosensitizer. Two kind of different HPDLCs doped by gold nanoparticles were prepared by laser holography method. The polymerization kinetics and gel behavior of the syrups were characterized by a photo-differential scanning calorimeter(P-DSC) and a photo-rheology technology(P-Rheology), respectively. We systematically studied the effects of the loading of gold nanoparticles on the electro-optic properties, response time, microstructure and thermal stability of the gratings. The results showed that, by doping gold nanoparticles, the reaction rate of the two systems was decreased, and the gel time was prolonged. The viscosity of the systems as well as the glass transition temperature(Tg) hardly changed after polymerization. But, the degree of phase separation of the gratings increased, and the regularity of structure enhanced. In addition, with the increase of the content of gold nanoparticles, the threshold voltage(Vth) and saturation voltage(Vsat) gradually increased. Under the pulse voltage of 28 V/?m, the switch on time, ?on, was about 2 ms. |
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