The investigation of molecular affinity involved in poly(ethylene glycol)-based polymer-dispersed liquid crystal display

Abstract

Acrylic polyethylene glycol(PEG)-based polymer-dispersed liquid crystal (PDLC) films have been fabricated to investigate the effect of intermolecular interactions on PDLC performance. For this purpose, the amphiphilic liquid crystal and polymers are selected as PDLC composite materials. The acrylic PEG contents are varied from 0 to 66.66 mol wt.% in order to understand the effects of different levels of additions on the microstructure and electro-optical properties of the PDLC films. For this intention, polarized optical microscopy and UV-vis spectroscopy are used. The extent of phase separation and anchoring energy are also examined using Fourier transform infrared (FTIR) spectroscopy and contact angle measurements in consequence of acrylic PEG addition. The contrast ratio, threshold voltage, as well as saturation voltage, tended to increase with the addition of acrylic PEG. The molecular affinity involved in the polymer matrix and LC molecules affected the phase separation which is responsible for the formation of domain size; this accordingly changed the electro-optical properties of PDLC film.

Ordering kinetics of a conserved binary mixture with a nematic liquid crystal component

“…The systems involving liquid crystals are investigated via simulation [47,53,31,45,11] and the phase diagram indicating where transitions between the nematic and isotropic phases of the liquid crystal occur is analyzed [47,53,40]. Recently, applications of models for similar systems include polymer-dispersed liquid crystals [44,1,34,48,19,21,22,39,29], diblock copolymers [32,46], and other cases of problems involving phase separation [5,27,33,38,6,41,42,61].…”

Surfactant-doped reverse-mode polymer-dispersed liquid crystal display with enhanced properties

“…It has been reported that the contact angles of conventional PDLC films are in general >60°. [22,25] However, the contact angle for monomer C6M and LC is observed as 38°. According to the result from expression 3, the surface free energy is found to be 50 for this system.…”

“…For this purpose, the contact angle and surface free energy is determined. [21,22] Previously, the contact angle and surface free energies have been studied for PDLCs. Earlier, it is established that the surfactants containing the polymerizable functional groups, polarity or alkyl chain may weaken the surface free energy between LC droplets and polymer interface.…”

“…This relation can be described by the following the Young's equations. [22,25] The surface free energy was further calculated by using Equation (3) as described below. The dimensions of surface free energy are same as to the surface tension.…”

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

“…The PIPS method is versatile and usually applied for fabricating PDLC films because of its stability, fast curing speed, uniformity, and controllability under photoinitiated polymerization conditions . Applied PDLC devices in the present typically have high driving voltages (greater than 50 V), long response times (greater than 50 ms), and low contrast ratios (less than 100), which can be achieved by varying the morphology of the PDLCs, via changing the LCs and the monomers employed such as the polymerizable group and the polymerization conditions …”