High dielectric properties, TiO <sub>2</sub> nanoparticles doped PDLC devices for lower switching voltage
Miaomiao Jia, Yuzhen Zhao, Hong Gao, Dong Wang, Zongcheng Miao, Hui Cao, Zhou Yang
Abstract
Polymer dispersed liquid crystal (PDLC) films were prepared using a nematic liquid crystal, photo-curable polymer and TiO2 nanoparticles by polymerisation-induced phase separation (PIPS) method. Electro-optical properties of doped and undoped samples including transmittance, driving voltage, contrast ratio and response time of the transmittance-voltage were measured, compared and analysed. The morphology of polymer network has been investigated by means of SEM. The phase separation of LC droplets was found to be dependent on the content of prepolymer, LC and nanoparticles used. The high dielectric properties and high refractive index of TiO2 nanoparticles make PDLC have low driving voltage and high contrast. In particular, the nanoparticles concentration can be optimised to obtain promising electronic materials with minimum threshold and high contrast for display applications.