The physical phenomena and application of Mesoporous silica hollow sphere in nematic and chiral nematic liquid crystal

Abstract

Mesoporous silica hollow spheres (MPSHSs) is a kind of hollow microsphere that have large surface/volume ratio the pore on the silica hollow spheres let the liquid crystals molecular arrange disorderly There is a thin and disorder liquid crystals layer around the MPSHSs called that disorder layer (DOL) The order parameter in the DOL is low The outer liquid crystals layer cannot feel the director axis from the DOL so the anchoring of the MPSHSs is weak According the topological defect theorem topological defect won’t exist when R?K/W R is the radius of the sphere K is the elastic constant of the liquid crystals W is the surface anchoring of the sphere MPSHSs will disperse in the nematic liquid crystals DOL will not distort the surrounding director axis the liquid crystals go through nothing Base on the weak anchoring of MPSHSs when we apply voltage on liquid crystal bulk the brightness of the MPSSSs is smaller than SSS When apply 20 V the brightness of MPSSS is larger than SSS because the DOL on MPSSS’s surface On the other hand we reduce the size of MPSHSs to 100 nm 150 nm and 300 nm and mixed MPSHSs with blue phase liquid crystals (BPLC) by different weight percent The temperature range of BPLC will extend The most effective one is 300nm MPSHSs the temperature range increased by a factor of 1 2 in average

Date of Award	2019
Original language	English
Supervisor	Kuang-Yao Lo (Supervisor)