Comparative studies of polymer‐dispersed liquid crystal films via a thiol‐ene click reaction

Abstract

In this work, the thiol‐ene click reaction is employed to fabricate polymer‐dispersed liquid crystal (PDLC) films by photoinitiated polymerization. The PDLC films are prepared by systematic variation of key conditions: variety and content of ‐ene monomer, liquid crystal (LC) content, curing time, and curing light intensity. We find that both the morphologies and electro‐optic properties of these films are adjustable. When increasing the length of alkyl main chain of ‐ene monomers, the driving voltages reduce, but in turn, the contrast ratio decreases. Increasing ‐ene monomer content raises the driving voltages as well as the response time, and the increase of LC content lowers the driving voltages but has a negative effect on the contrast ratio. The changes to the curing conditions (both curing time and UV light intensity) can be used to modify the driving voltages, response time, and contrast ratios of PDLC films. These comparative studies will elucidate new insights in commercial applications of intelligent PDLC films.

Liquid crystallinity and thermal properties of polyhedral oligomeric silsesquioxane/side-chain azobenzene hybrid copolymer

“…Due to the structural ordering of POSS, the incorporation of POSS to LC has been extensively investigated. The LC element was incorporated into POSS to produce LCP-POSS hybrid, in which the degree of order increase, by Goodby and coworkers [43,44]. The LC phase was transformed from nematic phase to smectic phase with increasing LC temperature.…”

“…The LC phase was transformed from nematic phase to smectic phase with increasing LC temperature. Then, they incorporated chiral POSS molecules to LC, which increased the LC phase temperature [43,44]. The azobenzene LCP-POSS copolymers that have increased the LC temperature and reversible light-responsive properties were synthesized for the first time in our work.…”

Study on the Effect of α-Substituted Acrylate Monomers on the Electro-Optical Properties of Polymer-Dispersed Liquid Crystal Films

“…As a result, the light transmittance can be changed. Without voltage applied, the PDLC film appears in a milky white scattering state due to the random orientation of LC droplets in the polymer matrix and the mismatching refractive indices. − However, it turns transparent under high voltage because the LC molecules arrange along the electric field and the ordinary refractive index of the liquid crystal ( n o ) matches n p. − …”

Polymer Dispersed Liquid Crystals (PDLCs): A Mini Review

“…PDLC composite films are made up of liquid crystal (LC) droplets that are micrometre or nanoscale in size and placed in a polymer matrix. Because of the random orientation of LC droplets in the polymer matrix, these films have a milky white scattering state [1][2][3]. As a result of the use of PDLC in display technologies, research on these materials has boomed in recent decades, encompassing areas such as quantum dots (QDs) film [4], antipeeping film, diffuse film [5], and organic light emitting diode (OLEDs) components [6], field effect transistors (FETs) [7], solar-energy harvesting [8], and energy storage [9].…”