5-{[(4′-正戊基氧-4-联苯基基)羰基]氧}-1-戊炔的相转变与相结构

Phase Transitions and Structures of 5-{[(4'-Pentyloxy-4-biphenylyl) carbonyl]oxy}-1-pentyne

采用差示扫描量热(DSC)、一维(1D)广角X射线衍射(WAXD)、热台偏光显微镜(PLM-hotstage)等研究手段对含联苯液晶基元的侧链液晶聚炔单体5-{[(4′-正戊基氧-4-联苯基基)羰基]氧}-1-戊炔(A3EO5)的本体相转变和相结构进行了研究.DSC和1D-WAXD实验结果表明,A3EO5在升温和降温过程中均呈现四个相转变过程,形成双向性液晶.样品从各向同性态降温至室温过程中,首先形成近晶A相,随后进入层内排列具有准长程有序的近晶B相,继续降温将形成层内为正交排列的近晶E相,在此之后样品进入晶相.PLM结果指出样品在各向同性态降温过程中分别形成球状织构、角锥织构和同心圆弧织构.

Phase transitions and structures of the monomer of side-chain liquid crystalline polyacetylene containing biphenyl mesogen,namely,5-{[（4＇-pentyloxy-4-biphenylyl）carbonyl]oxy}-1-pentyne （A3EO5） were investigated by differential scanning calorimetry （DSC）,one dimensional （1D） wide angle X-ray diffraction （WAXD）,and polarized light microscopy equipped with hot-stage （PLM-hot stage）.DSC and 1D-WAXD results show that A3EO5 forms an enantiotropic liquid crystal and displays four transitions during the cooling and subsequent heating processes.Upon cooling from isotropic phase to room temperature,the sample forms smectic A phase and then leads to smectic B phase with pseudo long-range orientation within the layer structure,further lowering the temperature,A3EO5 forms smectic E phase with orthorhombic packing within the smectic layer and enters crystal phase.PLM results show that the sample forms spherulitic texture,focal conic texture and concentric arcs texture during the cooling process.