Research On Preparation And Application Of Polymer Dispersed Liquid Crystal Film

Polymer dispersed liquid crystal(PDLC) film is a kind of display material that consists of low molecular liquid crystal dispersed in a polymer matrix. Based on the properties of liquid crystal, PDLC has strong electro-optical characteristics. The polymer matrix provides a network structure for liquid crystal. PDLC film can exhibit transparent and opaque states under the switching action of the applied electric field. Because of the high contrast and simple preparations of PDLC, it finds a wide application in the fields of smart window, project display, and E-books these years.The preparation of excellent performance films of PDLC is the research focus in this paper. Large numbers of samples about PDLC have been fabricated in terms of the ratio of materials, preparation process and electro-optical properties. Thermal curing initiated polymerization phase separation has been used for the preparation of PDLCs. The electro-optical properties of PDLC films are affected by many processing factors, for example, the weight ratio of the pre-polymer and liquid crystal, the curing temperature and curing time. We have studied the effect of these factors on the electro-optical properties. The performance parameters such as contrast ratio, threshold voltage and the saturation voltage have been calculated as well. The optimal preparation conditions put forward in this paper was 65% liquid crystal content with a curing time of 6 hours at 65 oC. The PDLC films prepared under optimum conditions showed a threshold voltage of 14.11 V and a saturation voltage of 49.47 V. The influence of the film thickness on the electro-optical properties of the polymer dispersed liquid crystal films has been studied as well. The experiments show that as the film thickness increases, threshold voltage and saturation voltage of PDLC increases.The feasibility study on the application of PDLC in the high-voltage electric equipment has been analyzed in this paper. PDLC film can exhibit transparent and opaque states under the switching of the applied electric field resulting in reflecting the state of the high voltage electrical equipment accurately and intuitively as the high voltage display device. It has provided a theoretical and technical support for the application of PDLC in the field of high voltage display technology.