Reversible Electrochromic Pattern in 3D Photonic Crystals Film from Thiol‐Acrylate‐Based Polymer‐Stabilized Blue Phase Liquid Crystals

Abstract

mechanical force, and chemical or electrochemical reactions, have attracted much attention in the fields of optoelectronic devices, sensors, anticounterfeiting, displays, and labeling technology. [1][2][3] Among various organic and inorganic materials, chiral liquid crystal-based soft materials have become promising candidates for creating novel photonic crystals with improved stimuli-responsive performance due to their distinctive features of selfassembly, softness, and multiple responsiveness under various stimulus. [4][5][6] Chiral liquid crystalline materials possess self-organized periodic superstructures and selective reflection of circularly polarized light determined by the chiral dopants, thus exhibiting photonic bandgaps (PBGs) with circular dichroism. [7] For 1D PCs, the cholesteric liquid crystals exhibit 1D photonic superstructures and have achieved remarkable research results in dynamic actuation by light, [8][9][10][11][12][13] temperature, [14,15] pH, [16] stretching, [17] or electric. [18,19] Blue phase liquid crystals (BPLCs) with 3D PBG that can control or manipulate the flow of visible light have recently drawn vast and increasing attention. [20] Because of the spontaneous organization inherent of their 3D periodic structures, the fabrication procedures of BPLCs may be easily implemented to achieve high-quality 3D PCs. [21] Thus, it is attractive to the development of 3D photonic nanostructures Endowing advanced 3D photonic nanoarchitectures with dynamic controllability is currently in the spotlight of soft-matter photonics research. Herein, a well-defined photopatterned polymer-stabilized blue phase (PSBP) film with 3D electrically tunable photonic bandgap is fabricated by a liquid crystalline thiol-acrylate monomers system. Remarkably, the addition of thiol monomers can effectively improve the electrical tuning performance of the PSBP film and maintain excellent thermal stability simultaneously. The proportions of acrylate and thiol monomers are proved to be a key factor on the morphology structure of the polymer network in the PSBP system. By masked UV photopolymerization, a patterned sample with a high-quality image and reversible nonsynergistic electrochromism is obtained. With increasing electric field, the patterned region changes from initial green reflection color to a red one, while no obvious visual color change occurs for the shading region with initial blue reflection color. The distinct electrically responsive behaviors are mainly caused by the microstructural difference of polymer networks, which is engendered by the migration of polymerizable monomers during polymerization. The research disclosed herein may provide new insights into the development of patterned 3D self-assembled liquid crystalline photonic crystal toward anticounterfeiting, displays, colorimetric sensors, labeling technology, and programming photonics.

When quantum dots meet blue phase liquid crystal elastomers: visualized full-color and mechanically-switchable circularly polarized luminescence

“…The structures of BPLCs (BPLCs) exhibit crystal periodicity in the range of several hundred nanometers, allowing them to reflect light within the visible spectrum [58][59][60][61][62] . The unique soft matter properties of BPLCs make them naturally responsive to various external stimuli, such as temperature 63 , electricity [64][65][66] , and humidity [67][68][69][70][71] . BPLCs have a narrower photonic bandgap (PBGs) and chiral environment, which may be beneficial for improving g lum value in the consequent CPL system.…”

Double‐State Anticounterfeiting Labels Based on Light‐Emitting Polymer‐Stabilized Blue Phase

“…Moreover, as a soft material, BPLCs, can respond to various external stimuli sources such as temperature, [34][35][36] electric field, [37][38][39][40][41][42][43][44] and light, [45][46][47][48][49][50][51][52][53] generating tunable photonic bandgap (PBG) of the blue phase. Among them, electric fields and photo irradiation are considered to be advantageous in tuning the PBG of BPLCs, such as the light driven tunable widely wavelength from red, green to blue on the visible region through designing novel axial chiral azobenzene molecules.…”

Progress in Fabrication and Applications of Cholesteric Liquid Crystal Microcapsules

“…[15][16][17][18][19][20][21] In 1888, the LC phase was first discovered by Austrian scientist F. Reinitzer and Germany physicist O. Lehmann, [22] and then many studies have been conducted on its preparation, performance exploration and applications. [23][24][25][26][27][28][29] Among the diverse range of LC phases, the nematic phase is one of the most common types as display materials for information propagation and exhibition, wherein the molecules exhibit orientational order only along the long molecular axis (called the director). The smectic phase presents a layered structure with director along the layer normal and tilts.…”