材料期刊网

液晶作为功能材料在显示、信息存储、防伪等领域应用广泛。综述了液晶分子在平行板、圆柱形和球形等微孔道介质、聚合物及凝胶介质等物理空间受限条件下的液晶相行为。液晶在微孔道介质中的液晶相行为主要受微孔道尺寸、液晶分子在介质表面的界面效应的影响。当微孔道尺寸大于某个临界值时,液晶相到各向同性的转变为典型的一级相变;当微孔道尺寸小于某个临界值时,液晶相转变表现为二级相变,表面诱导取向有利于液晶相的稳定。在聚合物/液晶复合体系中,当聚合物含量较大时,往往会出现相分离现象。随着体系中液晶含量的增加,液晶相变温度和结晶温度呈增高的趋势,与之伴随的是液晶对聚合物链段运动的增塑效应导致聚合物玻璃化温度的降低;而聚合物含量较小时,聚合物网络有利于稳定液晶相,尤其是蓝相液晶。此外,超分子液晶凝胶可有效调控液晶的相态结构及其性能。

Liquid crystals（LCs） as functional materials have wide applications in display,information storage,anti-counterfeit,etc.The review summarized the researching progress on phase behaviors of LCs under physical confinements such as micro-channels,polymer matrixes and supermolecular gels.Under confinement of micro-channels,the phase transition of LC molecules depends on the size of micro-channels and interface interaction between LC and the wall of micro-channels.When the size of micro-channels is larger than the critical value,the liquid crystal-isotropic transition was first order.However,when the size of micro-channels was smaller than the critical value,the liquid crystal-isotropic transition was second order,and the surface-induced orientation improves the stability of LC phases.For polymer/LC composites,there exists an obvious phase separation between LCs and polymer at high content of polymer,and the phase transition and crystallization temperatures of LC tend to increase with the content of LCs,and the glass transition temperature of polymer matrix decreases due to plasticization effect of LCs;at low content of polymer in composites,the polymer networks improve the stability of LC phases,especially blue phase LCs.And supermolecular gels could adjust the phase structure and properties of LCs.