Heteroatom-Terminated Acrylate-Based Polymer-Dispersed Liquid Crystal Composite Films with High Contrast Ratio and Low Driving Voltage.

A series of polymer-dispersed liquid crystal (PDLC) films were prepared by using acrylate monomers containing heteroatom-terminated groups. The microscopic morphology and electro-optical properties reveal that these monomers effectively reduce the switching voltage and improve the contrast ratio at the same time. The saturation voltage of the best sample was reduced by 47%, and the contrast ratio was improved by 74%. In addition, the introduction of various heteroatoms endows the PDLC films with a variety of functionalities. Sulfur atoms effectively increase the refractive index of the polymer matrix (n_p). By adjustment of the match between n_p and the ordinary refractive index of the LC, films with large contrast ratio and diminutive switching voltage were manufactured for display applications. Besides, chlorine atoms can help reduce the surface anchoring energy of the polymer matrix to LCs and reduce the impedance. Meanwhile, the abundant C-H, C-O, C═O, and C-Cl groups endow the films with solar modulation functions.