The PDLC film (Polymer-Dispersed Liquid Crystal) technology combines polymers and liquid crystal materials, creating a base for a new generation of window displays.
PDLC has the properties to become transparent when an electric current is supplied to it, allowing you to turn the film from transparent to opaque with simple controls.
Unlike other PDLC films, Rayno's uses an innovative sponge construction to bring more flexibility in design and application.
http://www.smartglassproject.com/pdlc-film/