Control of helical-axis orientation of chiral liquid crystals in monodispersed polymer particles

In the chiral-liquid-crystal (LC*) phase, calamitic molecules are aligned helically; hence, the refractive indices of the materials are altered periodically along the helical axis. The LC* materials have unique optical properties, such as selective reflection, that arise from the periodic structure of the refractive index. Here, we report a simple method for preparing monodispersed microparticles of LC* polymers. Optimizing polymerization conditions, monodispersed LC* polymer microparticles were obtained. In these particles, we could three-dimensionally control the helical-axis orientation of molecules. Based on the helical alignment, each single particle selectively reflected visible light. Because of the monodispersity, the microparticles showed no photonic cross-communication; namely, a clear reflection color without any optical degradation was observed, suggesting that LC* materials have potential for optical application in holographic coatings and omni-directional lasing.