Integrated sensing from the synergetic color change of the center/brush of cholesteric liquid crystal particles

Cholesteric liquid crystal (CLC) particles can adaptively respond to constant changes in external stimuli and thus are widely used in solvent-sensing, pattern fabrication, and anti-counterfeiting. Previous studies discussed the color change at the center of the particles for various applications. However, few studies analyzed the color change of the brush structure of particles in response to various applications because of the complicated birefringence effect. In this paper, we present a novel integrated sensing system based on the synergetic color change from the center and the brush structure of CLC particles. This system provides abundant and additional sensing information relative to the traditional system. CLC particles are prepared by mixing reactive mesogens, a reactive chiral dopant, a non-reactive LC molecule, and a photoinitiator by using a microfluidic device and subsequent photopolymerization. The CLC particles exhibit gorgeous color at the center and brush structure upon various solvent stimuli because of the Bragg reflection and the birefringence effect, which is explained by the possible color-changing mechanism introduced in this paper. For proof-of-concept applications, such color-changing polymer particles are demonstrated in multi-solvent-sensing detection and pattern display. This study provides new insights into the development of stimuli-responsive advanced functional materials with tailorable nanostructures toward technological applications ranging from sensing to display.

Automated summary

This paper presents a novel integrated sensing system based on the synergetic color change from the center and the brush structure of CLC particles. By mixing reactive mesogens, a reactive chiral dopant, a non-reactive LC molecule, and a photoinitiator, CLC particles are prepared and exhibit gorgeous color at the center and brush structure upon various solvent stimuli.