Manipulation of Structural Colors in Liquid-Crystal Helical Structures Deformed by Surface Controls

Abstract

Structural colors from cholesteric liquid crystals (CLCs) are manipulated by changing the only surface anchoring energy of an alignment layer. This behavior comes from the fact that weak surface energy of the perfluoropolymer induces the tilting of the cholesteric helix. Such deformed CLC structures with durability are successfully demonstrated without any external field applications and additional solidification processes. In addition, electrical tunings of structural colors from the deformed CLCs occur at very low operating voltages, compared to those of conventional CLC structures. On the basis of easy and simple fabrication, high durability, electrical tunability at low operating voltages, and the unique optical characteristics, the new deformed CLC structure could lead to extension in applications of CLCs, including multifunctional sensors, displays, and lasers.

Smart Supramolecular Self-Assembled Nanosystem: Stimulus-Responsive Hydrogen-Bonded Liquid Crystals

“…Cholesteric LCs (CLCs) possess outstanding reflection characteristics and are widely used in colorimetric sensors and display devices [115][116][117][118]. This characteristic comes from changes of helical pitch (p), namely, uniformly periodical layer deformations.…”

Nanoscale hyperspectral imaging of tilted cholesteric liquid crystal structures

“…, however it appears that the topic of planar films with a spatially-variable orientation of the helical axis gained some revival in 2017-18 by inspiring different research. [20][21][22][23][24][25][26][27] In 2011, tuning the orientation of the twist and, in return, of the macroscopic color of a CLC slab with a polygonal texture was demonstrated. 28 Polygonal textures (Figure 2(a)), made of an array of micrometer-scale polygonal cells, can be observed in flat CLC films when the helical axis is strongly tilted with respect to the substrates.…”

Carbon Quantum Dots doped Cholesteric Liquid Crystal Films and Microdroplets for Anti-Counterfeiting

“…Because of the easy technique, the resultant achievement can contribute to anticounterfeiting applications and is more cost-effective than traditional approaches. Many methods for altering the color of CLCs have been proposed in the past, including applying an electric field, changing the viewing angle, adjusting temperature, changing the polarization state, loading zinc ions and photofluorochromic spiropyran into CLC, and so on. − These approaches have been used in many applications because they make it simple to change the structural color of CLCs. On the other hand, these conventional methods demand intricate experimental equipment including voltage generators and heat controllers.…”