Advancements and Applications of Liquid Crystal/Polymer Composite Films

Liquid crystals (LCs) possess some typical liquid properties, such as fluidity, the inability to support shear, and the formation and coalescence of droplets, which exhibit optical, electrical, and magnetic anisotropic properties, and give materials various physical properties. Composite films composed of LCs and polymers have provided a new field of LC science and technology and have attracted great attention over the past years due to their applications in displays, light shutters, fiber-optic communications, switchable windows, photonic crystals, and augmented reality/virtual reality devices. These composite films, such as polymer-dispersed liquid crystals (PDLCs), polymer-stabilized liquid crystals (PSLCs), and polymer-dispersed and polymer-stabilized liquid crystals (PD&PSLCs), are fabricated by phase separation methods as well as electrospinning and microfluidic techniques. The combination of LCs and polymers will yield a variety of novel characteristics such as switchable optical transmittance, broadband optical reflectivity, excellent optical diffusivity in diffusers for backlight units of liquid-crystal displays, high sensitivity to electric field, magnetic field, and chemical stimulation, and high ion transport speeds for smart windows, microlenses, sensors, actuators, and energy storage devices such as dielectric capacitors, dye-sensitized solar cells, thermoelectric devices, and solid batteries. This Review gives new insights and understanding about LC/polymer composite films that are particularly suitable for large-area electrically switchable windows and multiple related fields.