Polymer stabilized liquid crystal (PSLC) devices can be used as smart privacy windows that switch between transparent and opaque states. The polyimide alignment layer of a PSLC device is usually obtained by the treatment of polyamide acid (PAA) with temperatures over 200 °C. This hinders the fabrication of PSLC devices on flexible substrates, which melt at these high temperatures. In this work, the fabrication of a PSLC alignment layer using a lower temperature that is compatible with most flexible substrates, is demonstrated. It was found that the treatment of PAA at 150 °C could generate the same alignment for liquid crystals. Based on this, a PSLC device was successfully fabricated on a flexible polyethylene terephthalate (PET) substrate, demonstrating excellent electro-optic performances.
Keywords: PAA; PSLC; alignment layer; flexible substrate; smart window.