KES3-1347
Photonic Reflections from Janus Cholesteric Liquid Crystal Droplets
Topic
S3. Processing / Fabrications (Emerging Horizons in Polymer Processing and Fabrication)
When and Where
Sep 30, 2026
10:20 - 10:45
Room 104
Session Chairs
Sungmin PARK
Presenter(s)
Sooyoung Park (Kyungpook National University)
Co-Author(s)
Abstract
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 (CLCsolid) 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 CLCsolid 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.
