Liquid Crystals

Liquid crystals are highly structured liquids, with the orientational (nematic, cholesteric) and positional (smectic) order of constituent molecules. The type of molecular order is controlled by the shape and chirality of liquid crystal molecules, with over one hundred known liquid crystal phases. Molecular alignment in liquid crystal films results in optical properties (e.g. refractive index, reflectivity, transmission) that can vary with wavelength (color) and polarization of incident light. 

Liquid crystals are stimuli-responsive materials. Their molecular order is sensitive to their environment, e.g. temperature, electric and magnetic fields, or adsorption of chemicals. Due to the two key attributes of liquid crystals, liquid-like behavior and optical anisotropy, liquid crystals are primarily used in switchable displays and optoelectronic devices. Liquid crystalline polymer networks and elastomers are promising stimuli-responsive materials under close investigation by academic, governmental, and industrial researchers for potential applications in soft robotics, ruggedized electronics, and the health sciences.