Control of the molecular pretilt angle in liquid crystal devices by using a low-density localized polymer network

We developed a method to fabricate liquid crystal (LC) devices with variable pretilt angle (2–90°) which involves voltage application during the UV-light-induced polymerization of a photo-reactive monomer added in concentrations below 1%. Polymerization follows the application of the high voltage, which facilitates the motion of the monomer to the cell substrates. Control of the pretilt angle is accomplished through the formation of a thin polymer layer near the cell substrates, which stabilizes the LC orientation. The pretilt angle can be controlled over a small area of the sample, which allows for the fabrication of LC lenses and prisms.