Nematic to smectic-A phase transition in mixture of liquid crystal and nonmesogenic impurities: existence of tricritical point
Nematic to smectic-A phase transition in mixture of liquid crystal and nonmesogenic impurities: existence of tricritical point
复制标题
液晶和非介晶杂质混合物中向列相到近晶相的转变：三临界点的存在
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Bhaskar Chandra Khan
中科院分区：
文献类型：
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作者：
P. Mukherjee;Bhaskar Chandra Khan
对液晶和非介晶杂质混合物的实验表明，非介晶杂质在向列相-近晶相-A相变中起着重要作用。利用Flory-Huggins各向同性混合理论和Landau-de Gennes理论，我们提出了一个唯象理论，讨论了这种杂质在近晶液晶和非介晶杂质混合物中对向列相-近晶相-A相变的作用。我们讨论了非介晶杂质对向列相-近晶相-A相变的有序参数、Frank弹性常数(张开和弯曲)和转变温度的影响。我们的理论结果表明，随着非介晶溶质浓度的增加，存在一个三临界点，在该点上，二级向列相-近晶相-A相变为一级相变。我们发现理论结果和实验结果有很好的一致性。图形摘要
ABSTRACT Experiments on the mixture of liquid crystals and nonmesogenic impurities showed the significant role of nonmesogenic impurities on the nematic–smectic-A phase transition. Using both Flory–Huggins theory of isotropic mixing and Landau–de Gennes theory, we present a phenomenological theory that discusses the role of such impurities on the nematic–smectic-A phase transition in a mixture of smectic liquid crystal and nonmesogenic impurities. We discuss the impact of nonmesogenic impurities on the order parameters, Frank elastic constants (splay and bend) and transition temperature of the nematic–smectic-A phase transition. Our theoretical results show that there exists a tricritical point for which the second-order nematic–smectic-A phase transition becomes first order at a tricritical point by increasing the concentration of nonmesogenic solute. We find a remarkable agreement between theoretical and experimental results. Graphical Abstract