Three in one: Mesogenic aromatic acid as a liquid crystal matrix, a chiral dopant in liquid crystals and a stabilizer for nanoparticles

Abstract

Studies of thermodynamics of the N*-I phase transitions and optical properties of the new liquid crystal - (R)-2-[4″-(trans-4-butylcyclohexyl)-2′-chloro-p-terphenyl-4-oxy] propanoic acid are carried out. The aim of these studies is to analyze the capabilities of that liquid crystal to simultaneously serve as a matrix for inorganic semiconductor nanoparticles (NP) as well as a chiral dopant for liquid crystals and a chiral ligand stabilizing the surface of CdSe NPs. The chiral doping of a nematic liquid crystal was proven by the measurements of selective transmittance of the visible light. The embedding of NPs in a nematic liquid crystal leads to the increase in TN⁎I, which is explained by the shape anisotropy of the NPs. The anisotropy of the ligand shell may result from the interaction between the ligand and LC matrix inducing the change of the spherical shape of the shell toward the ellipsoidal one. TN⁎I of the liquid crystal matrix of (R)-2-[4″-(trans-4-butylcyclohexyl)-2′-chloro-p-terphenyl-4-oxy] propanoic acid (R-MPA) decreases with the embedding of NPs stabilized by the same ligands, which is in a good agreement with prior experimental results and theory, but there exists a considerable quantitative difference.