Phase‐Separated Dielectric Gels Based on Christiansen Effect

Abstract Phase separation is a trivial phenomenon but a mature strategy in materials science. The flexible materials are provided toughness and strength by phase separation, yet there are few applications in optics and electronics industry. A novel phase‐separated dielectric gel (PSDG) with a strong Christiansen effect is prepared via radical polymerization using hydroxyethyl methacrylate as a monomer, 4‐cyano‐4′‐pentylbiphenyl and tributyl citrate as mixed solvents, and polyethylene glycol as a softener. The solvent ratios and ambient conditions can efficiently change the color of PSDG which makes it strongly selective for the wavelength of transmitted light. Besides, it has a high dielectric constant (10 at 1 kHz), sensitively responding to the electric field. The phase separation degree of PSDG varies with applied electric field, which will induce its transmittance alteration accordingly. The current field sensitive PSDG provides a novel idea for “smart windows”. Additionally, varying the size and shape of the electrodes can precisely control the phase separation in PSDG and also enables the function of free writing on flexible materials. Therefore, the designed PSDG has great application potential for flexible touch and interesting interactions.