Phase Separation and Image Recording in UV Laser Cured PDLC

Optical properties of Polymer Dispersed Liquid Crystals (PDLC) are determined by the used polymerisation method. We have previously performed a systematic study on UV curable mixtures in order to obtain a correlation between the characteristics of the UV irradiation i.e. intensity and exposure time, and the optical properties of PDLC samples. Here we report the results of a detailed investigation performed by using the UV lines of an Ar ion laser as light source to cure the standard mixture NOA65-E7. We observe that, due to the high intensity in a narrow wavelength region (333-363 nm), fast curing can be obtained leading to peculiar morphologies. We also demonstrate how is possible to exploit the laser curing technique to write switchable images in these materials.