PDLC films prepared by electron beam and ultraviolet curing: influence of curing conditions on the electro-optical properties

Polymer dispersed liquid crystal (PDLC) films were prepared by polymerizati on-induced phase separation processes using ultraviolet (UV) and electron b eam (EB) radiation. A mixture of the nematic LC material E7, an aromatic po lyester acrylate, and additional monomeric acrylates was exposed to the EB radiation. A photoinitiator was included in the initial mixture in the case of UV exposure. The electro-optical behaviour of the PDLC films obtained h as been investigated as a function of the chosen radiation. The transmissio n versus voltage curves strongly depend on the curing conditions, and are h ighly reproducible. Threshold and saturation voltages continuously increase with increasing dose values for UV-cured films, whereas plateau values wer e reached for EB-cured samples. A small memory effect has been observed for UV-cured systems.