The light switching characteristics induced by a thermal smectic A (SMA) ↔ chiral nematic (N*) phase transition were studied for homeotropically aligned [smectic A liquid crystal (SmA-LC)/nematic liquid crystal (N-LC)/chiral dopant] and [side chain type smectic A liquid crystalline polymer (SmA-LCP)/N-LC/chiral dopant] composites. A drastic change from a transparent SmA phase to a light-scattering N* phase occurred in both composites upon heating. In the case of the heat-induced N* phase for the (SmA-LC/N-LC/chiral dopant) composite, the N* phase exhibited weak light scattering due to formation of a scroll texture. On the other hand, in the case of the heat-induced N* phase for the (SmA-LCP/N-LC/chiral dopant) composite, the N* phase showed strong light scattering due to formation of a focalconic texture. The existence of a SmA-LCP was responsible for a higher contrast ratio between the transparent SmA phase and the light scattering N* phase for the (SmA-LCP/N-LC/chiral dopant) composite than for the (SA-LCN/N-LC/chiral dopant) composite.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics