Molecular dynamics of the interfacial properties of partially fluorinated polymer dispersed liquid crystal gratings

Abstract

The interfacial properties of polymer dispersed liquid crystal (PDLC) gratings influenced by partial matrix fluorination are studied through molecular dynamics methods. The miscibility between the fluorine-substituted monomer and other materials in the prepolymer mixture is evaluated by using the solubility parameters of molecules. The interfacial effect of different fluorination levels is analysed theoretically. The results indicate that most fluorine-substituted monomers are distributed on the interface between the monomer and the LC. The interaction energy on the interface decreases with increasing fluorination, which can improve the electro-optical tunable performance of such gratings. However, it should also be noted that excessive fluorination may lead to penetration of fluorine-substituted monomers into the LC medium. Such a result will block the normal diffusion of LC during the photo-initiated polymerization-induced phase separation process. Through calculation of the radial distribution function, a reasonable alignment structure for LCs near the interface is given. The calculation of the order parameter shows that fluorination causes disorder of their orientation.