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

Abstract

Polymer-dispersed liquid crystals (PDLCs), an indispensable class of electrically switchable materials, where nano- or microsized liquid crystal (LC) droplets are phase-separated from the polymer matrix, have been widely used in the fabrication of highly efficient and systematic smart windows. In this paper, we explored the effect of the photoinitiator concentration on the morphology and electro-optical properties of PDLC films based on thiol and acrylates. We prepared PDLC films using various concentrations of the photoinitiator, while keeping the concentrations of LC and monomers constant. We observed that the concentration of the photoinitiator directly influences the phase separation process, which in turn determines the morphology and electro-optical characteristics of the PDLC film. Thus, an optimized amount of the photoinitiator is required to prepare PDLC films with high transmittance and low switching time, haze, and power consumption. The optimized photoinitiator concentration can have a transmittance ΔT (difference between on- and off-state transmittances) of >85% at a low driving voltage.

Preparation of Highly Durable Reverse-Mode Polymer-Stabilized Liquid Crystal Films with Polymer Walls

“…Figure S4 showed that with the introduction of polymer walls, the t on decreased and the t off increased because the size of LC droplets increased (consistent with Figure S3). ,, …”

“…Figure S4 showed that with the introduction of polymer walls, the t on decreased and the t off increased because the size of LC droplets increased (consistent with Figure S3). 17,35,36 Figure 3 illustrated that the polymer walls could significantly improve the stability of reverse-mode PSLC films. The sparse and fine polymer networks were more easily destroyed after multiple cycles for the films without polymer walls.…”

“…With an applied electric field, the LC molecules prefer to rotate and the polymer networks will disturb and impede the rotation of LC molecules. Multi-domain structures will be formed and the incident light will be scattered, causing the device to become opaque. , The reverse-mode electrically switchable light-transmittance controllable films are prepared mainly by the PSLC systems based on nematic LCs, − cholesteric LCs − or dual frequency LCs . In PSLC, LC is the major component and is confined by networks of a small amount of polymer (ca.…”

“…Multi-domain structures will be formed and the incident light will be scattered, causing the device to become opaque. 17 lable films are prepared mainly by the PSLC systems based on nematic LCs, 19−21 cholesteric LCs 22−24 or dual frequency LCs. 18 In PSLC, LC is the major component and is confined by networks of a small amount of polymer (ca.…”

Reverse Mode Polymer-Stabilized Liquid Crystal Films via Thiol and Acrylic Azobenzene

“…Polymer/liquid crystal (LC) composites have attained significant attention in the recent past because of the burgeoning interest in their potential photoelectrical applications, such as switchable windows, microlenses, reflective displays, multicolor displays, light shutters, and sensors. − These composites are structurally divided into two types depending on the LC concentration: polymer-dispersed LC (PDLC) and polymer-stabilized LC (PSLC). , The former contains up to 80% LC content in the form of randomly oriented droplets dispersed in a phase-separated polymer framework. The latter, however, contains 90% or more LC content, and LC molecules are stabilized in the polymer network.…”