Self-assembled, optically responsive nematic liquid crystal/polymer core-shell fibers: Formation and characterization
Self-assembled, optically responsive nematic liquid crystal/polymer core-shell fibers: Formation and characterization
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DOI：
10.1016/j.polymer.2010.08.011
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发表时间：
2010-10-01
期刊：
影响因子：
4.6
通讯作者：
West, John L.
中科院分区：
文献类型：
--
作者：
Buyuktanir, Ebru A.;Frey, Margaret W.;West, John L.
我们在这里报告的形成和结构表征的光学响应，高双折射电纺双折射液晶（LC）微纤维。LC微纤维由聚乳酸（PLA）和低分子量4-戊基-4-氰基联苯（5CB）在氯仿/丙酮溶剂中的溶液电纺而成。在静电纺丝过程中，低分子量的5CB相分离并自组装以在PLA壳内形成平面排列的聚乳酸核。用液晶和聚合物组分的相变曲线测定了5CB在PLA中的溶解极限和5CB/PLA芯/皮纤维中液晶的相分离程度。结构分析表明，纤维中的LC核和溶解的LC促进了PLA晶体的α-形式的形成，并将5CB/PLA纤维中PLA壳的结晶度从6.6%增加到52%。5CB液滴形成和PLA纤维形成之间的竞争被观察到作为纺丝溶液组合物和施加的静电纺丝电压的函数。通过偏光显微镜证实PLA核内5CB的对齐。(C)2010爱思唯尔有限公司版权所有。
We report here the formation and structural characterization of optically responsive, highly birefringent electrospun nematic liquid crystal (LC) microfibers. The LC microfibers are electrospun from a solution of polylactic acid (PLA) and low molecular weight 4-pentyl-4-cyanobiphenyl (5CB) in chloroform/acetone solvent. In the electrospinning process, the low molecular weight 5CB phase-separates and self-assembles to form a planarly aligned nematic core within a PLA shell. The solubility limit of 5CB in PLA and the degree of phase separation of LC in the 5CB/PLA core/sheath fibers is determined using the phase transition enthalpies associated with LC and polymer components. Structural analysis revealed that the LC core and dissolved LC in the fibers promote the formation of the alpha-form of PLA crystals and increase the degree of crystallinity of the PLA shell in 5CB/PLA fibers from 6.6% to 52%. Competition between 5CB droplet formation and PLA fiber formation is observed as a function of spinning solution composition and applied electrospinning voltage. Alignment of the 5CB within the PLA core is confirmed by polarizing optical microscopy. (C) 2010 Elsevier Ltd. All rights reserved.