含氟侧链棒状液晶的合成及介晶性

Synthesis and Mesomorphism of Liquid Crystals Containing Longer Perfluoroalkyl Chains

合成了两个系列含氟侧链和碳氢脂肪链的液晶化合物,其结构通式C_3H_7-C_6H_(10)-C_6H_4-OOC-R(系列Ⅰ)和C_3H_7-C_6H_4-C_6H_4-OOC-R(系列Ⅱ),R=C_6H_4-C_6X_(13),C_6H_4-O(CH_2)_3C_6X_(13),(CH_2)_2C_6X_(13),X=F或H。POM和DSC对其介晶性研究发现:末端基为碳氢脂肪链时,化合物主要出现向列相;末端基为含氟碳链时,化合物呈现近晶相态。含氟液晶与相同碳原子数的脂肪链液晶相比,具有更高清亮点和宽的液晶相范围。

Two series of liquid crystals containing longer hydrocarbon and perfluoroalkyl chains, with structure of C3H7-C6H10-C6H4-OOC-R （series one） and C3Hv-C6H4-C6H4-OOC-R （series two）, R = C6XI3-C6H4. C6XI3（CH2）3O-C6H4, C6XL3-（CH2）2, X = F or H,were prepared and their mesomorphic properties were studied though DSC and POM. The results have showed that molecules with hydrocarbon chains lead to nematic phase, the molecules containing longer fluorocarbon segments present smectic phase. Moreover, the liquid crystals with perfluorinated terminal chains have higher clearing points and a much broader range mesophase than these with hydrocarbon chains.