Electro-Optical Properties of Nanoparticle-Doped Polymer Dispersed Liquid Crystals

• Main Authors: Meng-Jie Lin, 林孟頡
• Other Authors: Jy-Shan Hsu
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/and3c9

碩士 === 中原大學 === 物理研究所 === 99 === 　　Polymer dispersed liquid crystal (PDLC) are the polymer matrixes uniformly dispersed with liquid crystal droplets. When there is no electric field, PDLC appears to be white due to the mismatched refractive index of polymer and LC droplet, therefore the light is scattered from the droplets. When an electric field is applied across the cell, the LC molecules rotate to the direction of the electric field, and the PDLC is transparent. The opaque and transparent states can be switched by the external electric field through the changes of the refractive index of the LC droplet. 　　In this thesis, we have investigated the influence of doping nanoparticals, such as Titanium dioxide, Barium titanate and Iron oxide, on the threshold voltage and the LC droplet size of PDLC. Doping nanoparticle Titanium dioxide and Barium titanate in the PDLC, the threshold voltages decrease and are saturated when the doping concentration increases. However, the size of LC droplet does not change obviously. This phenomenon is quite different when Iron oxide nanoparticles are doped in the PDLC, the changes of threshold voltage are not observed in our study and the LC droplet size is changed apparently. Finally we analyze the changes of the threshold voltage through the changes of droplet size and nanopartical concentrations.