无机-有机杂化树枝状香蕉形液晶化合物的合成与表征  

SYNTHESIS AND CHARACTERIZATION OF AN INORGANIC-ORGANIC HYBRID BENT-CORE LIQUID CRYSTAL WITH A CUBIC SILSESQUIOXANE CORE

作　　者：潘其维[1] 陈小芳[1] 沈志豪[1] 范星河[1] 周其凤[1] 

机构地区：[1]北京分子科学国家实验室高分子化学与物理教育部重点实验室北京大学化学与分子工程学院,北京100871

出　　处：《高分子学报》2008年第7期703-707,共5页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号20634010;20574002;20504002)资助项目

摘　　要：利用硅氢加成反应制备得到8个香蕉形液晶基元尾接于六面体倍半硅氧烷的8个顶点之上的杂化树枝状香蕉形液晶化合物.此化合物的化学结构通过核磁、红外、元素分析和GPC表征.一维和二维X-射线衍射研究表明,该化合物具有两个双层近晶C相;对样品施加三角波电压后显示该化合物具有反铁电性.An organic-inorganic hybrid bent-core liquid crystal （BCLC） with eight bent-core mesogens end-attached to inorganic polyhedral oligomeric silsesquioxanes （POSS） cores was synthesized and characterized to study how the inorganic cubic core may affect the liquid crystalline phase behavior and electro-optical properties of the BCLC. POSS-SBC was successfully synthesized by hydrosilylation reaction of Q8M8^H and 3＇-[4-（4-dodecyloxybenzoyloxy）- benzoyloxy]-4-（10-undecen-l-yloxy） benzoyloxybiphenyl with Pt （dvs） as catalyst in high yield. Well-defined chemical structure of POSS-SBC was confirmed by NMR, IR, elemental analysis, and GPC. Liquid crystalline phase behavior of this compound was investigated by differential scanning calorimetry, 1D and 2D wide-angle X-ray diffractions, and small-angle X-ray scattering. Meanwhile, electro-optical characterization was carried out by applying a triangular wave electric field. Response current was measured, and texture change under the electric field was observed. Two bilayer antiferroelectric SmC phases can be confirmed for POSS-SBC. In the higher temperature LC phase,the arrangement of POSS cores in the layer is not ordered. It is a conventional SmCA2 PA phase with layer thickness of 8.0 nm. In the lower temperature LC phase, layer thickness decreases to 7.7 nm. POSS cores from a two-dimensionally ordered structure between two bilayers. It is a bilayer SmCAPA phase with inorganic nano-size mesophase dispersed in it. To our best knowledge, it is the first antiferroelectric LC phase with inorganic nano-size mesophase dispersed in it.

关 键 词：六面体倍半硅氧烷 香蕉形液晶 无机-有机杂化 

分 类 号：O753.2[理学—晶体学]