Effect of Liquid Crystal Material on Polymer Network Structure in Polymer Stabilized Liquid Crystal Cell

Abstract

Polymer stabilized liquid crystal (PSLC) cells have been fabricated by using a reactive mesogen (RM) and various LC materials. It is clarified that a polymer network structure changes by selecting not only RM but also LC materials. Using the LC with a tolane substance, a "rice grain like" morphology can be obtained, which results in low threshold and driving voltages even if a dielectric constant anisotropy of the LC is very small. On the other hand, a "smooth stranded network" morphology causes the high driving voltage. When two LC materials which contribute to the smooth stranded network morphology are mixed and the LC mixture is used to fabricate the PSLC cell, the rice grain like morphology is formed. The driving voltage is lower than that in cells using two pure LCs. A relationship between solubility of the RM in the LC and the morphology formation is not observed.

Effect of Polymer Network Topology on the Electro‐Optical Performance of Polymer Stabilized Liquid Crystal (PSLC) Devices

“…[ 20–23 ] The performance of PSLC device can be further optimized by improve network structure, which plays a decisive role in the PSLC response characteristics. [ 24–26 ] At present, a number of groups confirmed that the structure of polymer network has great influence on the electro‐optical performance of PSLC devices, [ 27 ] such as different polymer morphologies generated by varying curing conditions, [ 12 ] different size of the mesh and different main chain polymer lengths. [ 7,24 ] However, the influence of the crosslink density in the polymer network on the performance of PSLC devices has not been studied systematically.…”

Driving Voltage in Reverse Mode Cell Using Reactive Mesogen : Effect of UV Absorption of Liquid Crystal

“…Figure 5(a) shows the electro-optical property in the cell by using the LC mixture of E7 of 75 wt% and ZLI-4792 of 25%. We have reported that the driving voltage in the cell using E7 and ZLI-4792 mixture was lower than that using only E7 or ZLI-4792 [15]. In this case, the UV-LED was used to polymerize the RM.…”

Process for a Reactive Monomer Alignment Layer for Liquid Crystals Formed on an Azodye Sublayer

“…Depending on the location where the full polymerization of the reactive monomer (RM) completes from a low molecular weight liquid crystal solvent, the formed structure can be generally classified as a bulk polymer network or a surface localized polymer. Most prior studies were focused on the polymer network that stabilized LC on a rubbed polyimide layer and have shown that some parameters such as solubility parameters of RM in LC [ 12 ], the RM concentration in LC [ 13 , 14 ], LC materials [ 15 , 16 ], reactive monomers [ 17 ], ultraviolet (UV) curing intensity [ 18 ], and the UV curing temperature [ 19 , 20 ] could affect the resulting morphology and subsequent electro-optical behaviors. I. Dierking et al reported that monomer solubility played a primary role in determining network morphology in the polymer stabilized liquid crystal (PSLC) [ 12 ].…”

“…R. Yamaguchi et al reported that the morphology of polymer stabilized liquid crystal cells can be changed by selecting liquid crystal materials. Using an LC with a tolane substance, a “rice grain like” morphology can be obtained and can lower the driving voltage [ 15 ]. S. Hudson and L.C.…”