In situ photopolymerization and photoinduced alignment of ferroelectric liquid crystalline guest-host system based on acrylate and cinnamate groups containing monomers

• Main Author: 戴興杰
• Other Authors: 莊祚敏
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/29461799937597370524

碩士 === 國立交通大學 === 應用化學系 === 90 === Ferroelectric liquid crystals (FLCs) have great electro-optical properties of fast response time (τ), large spontaneous polarization (Ps) value, high contrast ratio (gray-scale), wide view angle, bistable character, and memory effect. However, the drawbacks of FLC materials such as thin cell gap are impeded the application of display and other uses of electro-optical devices. In this work, we combine the advantages of guest-host system, in situ polymerization, and photoinduced reorientation to improve the drawbacks of FLCs. The monomers containing with acrylate and cinnamste groups were synthesized. The liquid crystal (LC) thermal properties were characterized by differential scanning calorimetry, optical polarizing microscopy, temperature-dependent power X-ray diffraction measurements. The detailed relationships between chemical structures and liquid crystalline behaviors were discussed. In the results, it shows that all of the compounds have LC behaviors, except ACI812N and ACI1012N. As the dipole moment of tails increases, the crystalline point decreases, then widen the range of smectic phase. In the case of two chiral centers, the SC* phase can be achieved about 50℃ (including room temperature). In the guest-host system, photoinduced reorientation can be achieved by ordered cross-type network via irradiated with 313nm linearly polarized ultraviolet light (LP-UV light). The ordered cross-type network can improve the electro-optical properties (higher spontaneous polarization value, constant response time, and higher contrast ratio) of the guest-host system. Furthermore, the cell gape of FLC display can be up to 5μm (potentially larger than 5μm). Upon irradiation, theses mixture-filled 5μm cells exhibit similar electro-optical properties as compared to those in the 2μm cells.