Interplay between Nanoparticle-Induced and Substrate-Induced Ionic Effects in Molecular Liquid Crystals

The future progress of liquid crystal science and technology relies on the development of new liquid crystal materials exhibiting advanced properties. A promising way to produce tunable multifunctional materials involves the dispersion of nanoparticles in molecular liquid crystals. As a rule, an electric field induced reorientation of liquid crystals is used to control the properties of such materials. This reorientation can be altered by ions present in molecular liquid crystals in minute quantities. Because ions can interact with both nanoparticles and substrates of a liquid crystal cell, it is important to understand how such interactions can affect the electrical properties of liquid crystals. This report presents a discussion of ionic effects induced by nanoparticles and substrates in molecular liquid crystal. Both experimental and theoretical results are presented. Substrate-induced ionic effects dominate if relatively thin samples are used to measure the electrical properties of molecular liquid crystals doped with nanoparticles. Nanoparticle-enabled ionic phenomena become more pronounced if thicker samples are utilized. In any real situation, the combined effect of substrates and nanoparticles on the behavior of ions in molecular liquid crystals should be considered.