Control homogeneous alignment of chiral nematic liquid crystal with smectic-like short-range order by thermal treatment

This study indicated that the smectic-like short-range order (SSO) provided an opportunity to improve the planar orientation of chiral nematic liquid crystal (N*-LC) molecules while increasing the light transmittance of the N*-LC cells. The SSO formed between N*-smectic A (SmA) transition was first introduced into N*-LC compositions and then applied a specific thermal process at the temperature of SSO (TSSO). Finally, the uniform alignment of the N*-LC molecules was obtained. Decreasing the heating rate and extending the holding time at TSSO were effective at reducing the oily streak and perfecting the planar texture of the N*-LC cells. And this method was also resultful for N*-LC composites exhibited different pitches.