Fabrication of polymer‐dispersed liquid crystals with low driving voltage based on the thiol‐ene click reaction

Abstract

Polymer‐dispersed liquid crystals (PDLCs) with a well‐defined polymer matrix were successfully fabricated by the thiol‐ene click reaction based on poly(ethylene glycol) diacrylate (PEGDA) and trimethylolpropanetris‐(3‐mercaptopropionate) (TMTP). UV−visible spectrophotometry, Fourier transform IR spectroscopy, SEM and polarized optical microscopy were employed to explore the PDLC films obtained. Electro‐optical properties were studied with a UV−visible spectrophotometer. It was found that the PDLC films with optimal thiol content fabricated by the thiol‐ene click reaction showed high transmittance, low driving voltage and a low memory effect. It was concluded that the driving voltage change of PDLCs with different thiol concentrations was caused by the polymerization rate and the structure of the polymer matrix. © 2017 Society of Chemical Industry

A Stable PDLC Film with High Ageing Resistance from an Optimized System Containing Rigid Monomer

“…PDLC consists of randomly scattered liquid-crystal (LC) droplets embedded in the polymer matrix [ 12 , 13 , 14 , 15 ]. The alignment of LC droplets in the polymer matrix can be changed by the electric field, which can change the transmittance of the PDLC film.…”

Effect of the Photoinitiator Concentration on the Electro-optical Properties of Thiol–Acrylate-Based PDLC Smart Windows

“…Seok et al made a comparative study on the structure, driving voltage, and contrast ratio of PDLCs using different types of photoinitiators . Most of the PDLC reports are based on the commercial monomer NOA65 and thiol–ene based monomers, in which the polymerization occurs by a free radical-initiated reaction. − However, the studies on thiol–acrylate-based PDLCs are few. ,,, In thiol–acrylate systems, the polymerization occurs via the free radical pathway and by the thiol-Michael addition or via the anion pathway . In this context, Saeed et al have studied the electro-optical properties of the PDLCs making use of different acrylates with different functional groups.…”

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

“…The thiol‐ene click reaction is the hydrothiolation of a C═C bond, defined by Kolb et al, and has often conducted via the dissociation of a photoinitiator into a radical species . Moreover, the thiol‐ene click reaction has simplicity, robustness, and fast reaction speed in the field of polymer and materials chemistry . The reactivity in the radical thiol‐ene reaction can vary considerably depending on the chemical structure of the ‐ene and thiol components and the ‐ene reactivity with alkyl 3‐mercaptopropionates, alkyl thioglycolates, and alkyl thiols under radical conditions, following the order: vinyl ether > allyl ether > acrylate .…”

“…39,40 Moreover, the thiol-ene click reaction has simplicity, robustness, and fast reaction speed in the field of polymer and materials chemistry. [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] The reactivity in the radical thiol-ene reaction can vary considerably depending on the chemical structure of the -ene and thiol components and theene reactivity with alkyl 3-mercaptopropionates, alkyl thioglycolates, and alkyl thiols under radical conditions, following the order: vinyl ether > allyl ether > acrylate. 40 Herein, we employed the thiol-ene click reaction between the vinyl ether and thiol to fabricate PDLC…”