Study on polyvinylidene fluoride as alignment layer in twist-nematic liquid crystal display

The material with high dielectric constant can significantly affect the distribution of the electric field, so this kind of material has great potential in liquid crystal display. In this paper, polyvinylidene fluoride (PVDF) as alignment layer in liquid crystal display was analysed. The optical property, mechanical property, thermal stability and electrical property of PVDF were measured. Experiments show that the absorbance of PVDF material is 0.2 (or less) in visible light, which is better than the conventional alignment material polyimide (PI). The alignment effect can be generated by mechanical friction and the liquid crystal molecules are ordered or aligned, and PVDF can maintain good thermal stability as temperature is lower than 400°C. Since the dielectric constant of PVDF is usually between 6.0 and 8.0, it has significant effect on the distribution of the electric field in the liquid crystal display, and its dielectric loss is also less than PI. The lower operating voltage and the faster response time are obtained from the experiment. It can be confirmed by the experiments that PVDF could be used in liquid crystal display (LCD) as the alignment layer to improve LCD’s characteristics.