Photonic Reflections from Compartmentalized Janus Cholesteric Liquid Crystal Droplets Prepared via Microfluidics and Phase Separation

Compartmentalized Janus photonic droplets were fabricated via phase separation of monodisperse droplets generated from a reactive cholesteric liquid crystal (CLC)/silicone oil (SO) mixture in dichloromethane using microfluidics. Subsequent phase separation followed by UV curing stabilized the CLC/SO Janus morphology, yielding solid‐state CLC (CLC solid ) menisci. The inner concave surface of the CLC meniscus displayed multiple photonic reflections, including central retroreflection (CR), diffuse egg‐like reflection (ER), and two internal reflections (IR1 and IR2), whereas the outer concave surface generated a geometry‐dependent total internal reflection (TIR) at the periphery. ER/CR and IR1/IR2 arose from Bragg reflection at 0° and 45° incidence, respectively, whereas IR1/ER and IR2/CR originated from photonic layers near the inner and outer surfaces, respectively. TIR appeared exclusively in dish‐like menisci at low CLC content, where the incident angle exceeded the critical angle at the periphery. UV–vis spectroscopy confirmed mixed right‐ and left‐handed circular polarizations for IR1 and IR2 due to oblique Fresnel reflections, whereas CR remained exclusively right‐handed. The orientation of the CLC/SO droplets and CLC solid particles significantly influenced the resulting photonic patterns, which were further differentiated using circular polarizing filters. The coexistence of distinct circular polarizations and orientation‐dependent photonic patterns within a single droplet highlights its potential for advanced anticounterfeiting applications.