We have found the new types of photonic liquid crystal, SmBP_<Iso> Phase, which shows the uniform isotropic iridescent color strongly dependent on the concentration, chirality and temperature for the first time. SmBP_<Iso> has both the finite local order parameter of the helix of the orientation and the smectic layer simultaneously, but spontaneously achieves complete isotropic nature in optical wave-length without any discontinuity in mesoscopic length scales. It was confirmed by visco-elastic measurement that the SmBP_<Iso> should be originated from the anomalous softening of the smectic layers due to the freezing effect on the molecular fluctuation induced by the introduction of the connection of the molecules. We expected that the random distribution of the distinct helix in 3-dimensional space can be stabilized by the apparent elastic long-range interaction "field" produced by the deformation of the smectic order. We have also first recognized two different types of thermodynamic phase transitions among SmBP phases, order-disorder transition for the spatial arrangement of the helix and the transition of the connectivity of smectic layers, which are attributed to the transition of the spatial distribution of the both orders, not belong to the order parameters themselves.
1 0 0 0 OA 3C14 フォトニック液晶-液晶秩序の欠陥が作る秩序(生体関連・リオトロピック液晶)
- 著者
- 山本 潤 西山 伊佐 横山 浩
- 出版者
- 一般社団法人 日本液晶学会
- 雑誌
- 日本液晶学会討論会講演予稿集 2003年 日本液晶学会討論会 (ISSN:18803490)
- 巻号頁・発行日
- pp.283-284, 2003-10-14 (Released:2017-01-10)
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.