Electro-optical Properties and Application of POA Intercataled Inorganic Layered Materials in Polymer-dispersed Liquid Crystals

• Main Authors: Chen-Ju Lee, 李貞儒
• Other Authors: Tsung-Yen Tsai
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/39941496283105237325

碩士 === 中原大學 === 奈米科技碩士學位學程 === 101 === Inorganic nanoparticles are used as nanofillers into the polymer-dispersed liquid crystal (PDLC) film. The morphology of LC droplets in the hybridization PDLC film and electro-optical properties are studied in this work. The PDLC film is composed with nematic liquid crystal E7 and photosensitivity polymer norland optical adhesive (NOA65) as the polymer matrices. The inorganic nano-layerd materials can sort into two types, both of whose constructs are piled the layers between which the interaction are ionic bonded, one is the synthetic layered double hydroxides, and the other is a natural layered clay material. Then, the organic modifier (SAS) and the electroactive oligomer (POA) , contains benzene ring structure, perform as organic modification of double hydroxide for artificial and natural inorganic layered materials, respectively. The small amount of nanofillers are doped into the PDLC matrix and then those are measured the photoelectric effect through the appropriate electric field. Wide Angle X-Ray Diffraction (WXRD), Fourier Transform Infrared (FTIR), and Thermogravimetry Analyzer (TGA) are used to learn the characteristics of organically modified layered material. After doping the nano-layered materials into the PDLC matrix, the morphology of LC droplets is observed by Scanning Electron Microscope (SEM). It is proved that doped nano-layered materials can increase the crystallinity of liquid crystal and exist in liquid crystals by XRD and the nano-layered materials also exist in the polymer’s phase by using Transmission Electron Microscopy (TEM). Then it is measured threshold voltage, driving voltage, contrast rate, and optical properties of the voltage-transmittance and time-transmittance curves, which explain the charge-retention effect under the application of AC bias voltage. It is observed that the best formula is dopped of 0.9：0.1 wt% of CL120/CL120-POA in PDLC can effectively reduce 24.13 % (from 109 Vrms to 8.27 Vrms) of threshold voltage, 55.96 % (from 42.23 Vrms to 18.6 Vrms) of driving voltage, and 87.94 % (from 30.6ms to 3.69 ms on 25 Vrms) of response time; furthermore, improve 150.77 % (from 9.73 to 24.4) of contrast rate. Without the POA modified CL120, the rise of the driving voltage is apparently increased compared to the POA modified CL120 in PDLC matrix after a long-duration exposure.