Abstract
Chiral TWIN molecules are consists of two equivalent monomer liquid crystal molecules connected by hydrocarbon spacers. In case that the spacer length is just twice as side-chain length of the monomer, the mixture of chiral twin/monomer system has complete spatial commensurability. We have found for the first time that the mixing of the small amount of the TWIN molecules strongly destabilize the smectic phase of the monomer and induce new types of TGB modulated phases, because the TWIN molecules strongly freeze the fluctuation motions of the monomer molecules, which is the origin of the excluded volume interaction to stabilize the smectic layers themselves. Spatial commensurability and strong lateral attractive interaction play important roles to the fluctuation freezing effect. We have investigated the chiral twin/monomer by polarizing microscope, X-ray diffraction, viscoelastic measurement and dynamic light scattering.
