Mesomorphism and Shape-Memory Behavior of Main-Chain Liquid-Crystalline Co-Elastomers: Modulation by the Chemical Composition
作者:Alfonso Ramon García-Márquez、Benoît Heinrich、Nicolas Beyer、Daniel Guillon、Bertrand Donnio
DOI:10.1021/ma501164u
日期:2014.8.12
two sets of alternated, linear copolymers with disiloxane or trisiloxane chain extender, respectively, were investigated. They either exhibit both smectic C (SmC) and nematic (N) phases or a single SmC phase, the nature of which being dictated by the length of the inserted siloxane moieties, and the temperatures ranges regulated by the composition of the mesogenic mixture (mesogens ratio). As anticipated
报告了两种具有组成可调的转变温度和中间相结构的主链液晶共弹性体(MC-LCEs)的两个同源系列的同构行为,形变和形状记忆类型。通过硅氧烷低聚物(线性间隔基和网状点分子)与液晶二元混合物之间的通用铂催化氢化硅烷化反应,一步一步制备弱交联的大分子,液晶二元混合物由确定比例的二乙烯基单体液晶元组成。首先,研究了分别与二硅氧烷或三硅氧烷扩链剂的两组交替的线性共聚物。它们要么同时表现出近晶C(SmC)和向列相(N)相,要么表现出单一SmC相,其性质取决于所插入的硅氧烷基团的长度,温度范围取决于介晶混合物的组成(介晶比)。正如预期的那样,相应的共弹性体的热行为不受网状结构(小于5%w / w)的强烈影响,网状结构的过渡温度(从环境温度到大约100°C)和中间相类型(SmC和N)是从聚合物中复制而来的,大多数仍然由组成成分(介晶比,硅氧烷和共聚单体)的混合决定。此外,这些MC-LCE表现出两种类型的形状