Two-Step Smectic CA Phase Formation from Isotropic Liquid upon Supercooling in Main-Chain Liquid-Crystalline BB-5(1-Me) Polyester
Two-Step Smectic CA Phase Formation from Isotropic Liquid upon Supercooling in Main-Chain Liquid-Crystalline BB-5(1-Me) Polyester
复制标题
主链液晶 BB-5(1-Me) 聚酯过冷时各向同性液体两步形成近晶 CA 相
DOI：
10.1002/macp.201000398
复制
发表时间：
2011
影响因子：
2.5
通讯作者：
& Watanabe J.
中科院分区：
文献类型：
--
作者：
Ishige R.;Tokita M.;Funaoka S.;Kang S.;& Watanabe J.
利用DSC、WAXD和光学显微镜研究了主链BB-5（1-Me）聚酯在过冷各向同性液体状态下的中间相形成过程。过冷各向同性液体遵循两个不同的SmCA形成过程。在85 °C以上，它形成预期的SmCA相。下面，它产生了一个亚稳态SmA相，显示层间距几乎是SmCA相的两倍。SmA相的发展从一个均匀的成核，然后由3D生长，然后转化为SmCA相。这种两步SmCA形成涉及聚合物链构型的变化：首先，链在每两个单元中折叠以形成SmA相，然后它们拉伸以实现SmCA相中介晶的特征性锯齿形排列。
The mesophase formation process of a main‐chain BB‐5(1‐Me) polyester in the supercooled isotropic‐liquid state has been studied using DSC, WAXD, and optical microscopy. The supercooled isotropic liquid follows two different SmCA formation processes. Above 85 °C, it forms the expected SmCA phase. Below, it yields a metastable SmA phase that displays a layer spacing almost twice the one of the SmCA phase. The SmA phase develops from a homogeneous nucleation followed by 3D growth and thereafter transforms to the SmCA phase. This two‐step SmCA formation involves a change in polymer chain configuration: first, the chains are folded in each two units to form the SmA phase and then they stretch to achieve the characteristic zigzag arrangement of the mesogens in the SmCA phase.