Characteristics of selective reflection of chiral nematic liquid crystalline gels with a nonuniform pitch distribution

The particles of photopolymerizable monomer/chiral dopant composites with a crystalline (Cr)-chiral nematic (N*) phase transition were prepared. By mixing the particles with different pitches of the N* phase together with the Cr phase and making the liquid crystal (LC) monomer molecules cross-linked by photopolymerization in the planarly oriented N* phase, a chiral nematic liquid crystal (N*-LC) gel film with a nonuniform pitch distribution was obtained. The bandwidth of the reflection spectrum and the location of reflection band of the gel film can be controlled accurately by controlling the pitch lengths of the N* phase of the particles.