Thermotropic Behavior of Syndiotactic Polymethylenes with ω-[4-(trans-4-Pentylcyclohexyl)phenoxy]alkyloxycarbonyl Side Chains
Thermotropic Behavior of Syndiotactic Polymethylenes with ω-[4-(trans-4-Pentylcyclohexyl)phenoxy]alkyloxycarbonyl Side Chains
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DOI：
10.1021/acs.macromol.5b00743
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发表时间：
2015-06-09
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：
Koshimizu, Noboru;Aizawa, Yosuke;Tokita, Masatoshi
以4-（反式-4-戊基环己基）苯氧基通过烷氧羰基间隔基连接到主链碳原子上，合成了一系列间规P5 CP（n）聚亚甲基，研究了其热致性.除了P5 CP 2外，P5 CPn形成近晶相，其中棒状聚亚甲基主链排列在矩形晶格中，侧链介晶基元聚集成平行于矩形晶格短边的层。随着温度的降低，介晶的堆积从类近晶C转变为类近晶I（SmI-like）（n = 4-8），从类近晶A转变为类SmI-like（n = 10-14）。在SmI样相，每个液晶基元沿着主链轴连接到每六个骨架碳原子，揭示了包装的液晶基元和主链构象的3/2螺旋之间的相关性。相反，P5 CP 2形成近晶相，主链排列成行，并且由于短间隔子，介晶基元几乎不聚集成层。
A series of syndiotatic P5CP(n) polymethylenes was prepared with 4-(trans-4-pentylcyclohexyl)phenoxy moieties linked to each backbone carbon atom via an alkyloxycarbonyl spacer and with even numbers of alkyl carbons n ranging from 2 to 14, and their thermotropic behaviors were investigated. The P5CPn, except P5CP2, formed smectic phases in which the rod-like polymethylene backbones were arranged in rectangular lattices, and the side-chain mesogens were aggregated into layers parallel to the shorter sides of the rectangular lattices. The packing of the mesogens changed with decreasing temperature from smectic C-like to smectic I-like (SmI-like) for n = 4-8 and from smectic A-like to SmI-like for n = 10-14. In the SmI-like phases, each mesogen along the main-chain axis was connected to every sixth backbone carbon atom, revealing a correlation between the packing of the mesogens and the main-chain conformation of a 3/2 helix. Conversely, P5CP2 formed a smectic phase with the main chains arranged in rows and with the mesogens barely aggregated into layers due to the short spacers.