Effect of Smectic Layers on Thermal Diffusivity of Side-Chain Polymer Liquid Crystals
Effect of Smectic Layers on Thermal Diffusivity of Side-Chain Polymer Liquid Crystals
复制标题
近晶层对侧链聚合物液晶热扩散率的影响
DOI：
10.1021/acs.macromol.1c02222
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发表时间：
2022
期刊：
影响因子：
5.5
通讯作者：
Tokita Masatoshi
中科院分区：
文献类型：
--
作者：
Harada Hirofumi;Saito Takeshi;Tokita Masatoshi
聚合物的热导率（TC）是已知的有效提高的液体结晶度。液晶（lc）在取向方向上表现出较大的各向异性TC。然而，除了取向顺序外，其他LC结构（如近晶层结构）对TC的影响尚未得到很好的研究。本研究利用一系列在侧链中含有偶氮苯的LC PMnMA聚甲基丙烯酸酯研究了LC结构与热扩散率之间的关系。PMnMA形成向列相(N)、近晶A相（SmA）和近晶C相（SmC）。这些LC通过磁场或大振幅振荡剪切排列，在面内或面外方向上产生具有介观长轴的玻璃状LC膜。这些玻璃状LC在LC取向方向上的热扩散系数随着LC取向程度的增加而增加，而N和SmC LC的值小于SmA LC。这些结果表明，近晶层可以提高其法向的热扩散系数。
The thermal conductivity (TC) of polymers is known to be effectively enhanced by liquid crystallinity. Liquid crystals (LCs) exhibit anisotropic TC with a greater magnitude in the orientation direction. However, the effects of other LC structures than the orientational order, such as smectic layer structures, on TC have not been well studied. This study investigated the correlation between LC structures and thermal diffusivity using a series of LC PMnMA polymethacrylates having azobenzene mesogens in the side chains. PMnMA formed nematic (N), smectic A (SmA), and smectic C (SmC) phases. These LCs were aligned by a magnetic field or large-amplitude oscillatory shear, yielding glassy LC films with mesogen long axes in the in-plane or out-of-plane direction. These glassy LCs increased thermal diffusivities in the LC orientation direction with the degree of LC orientation, whereas N and SmC LCs had smaller values than SmA LCs. These results demonstrated that smectic layers can enhance thermal diffusivity in their normal direction.