The morphology and the electro-optical properties of PDLCs cured in the presence of electric fields

Polymer dispersed liquid crystals, PDLCs, are composite materials generally formed by spherical liquid crystal droplets embedded in a polymer matrix. Reports of PDLCs with different droplet shape are not widespread. In this work, epoxy/LC mixtures in different weight ratios were polymerised in the presence of an external AC electric field with increasing strengths. The morphology and the electro-optical properties of the obtained PDLCs were found to be dependent from the strength of the electric field applied during the curing process. Common PDLCs with spherical droplets were obtained from samples polymerised under the action of low strength electric fields, but PDLCs with elongated droplets and memory states were found for polymerisation performed in the presence of intermediate electric fields. For larger electric fields, PDLCs were characterised by a morphology with long cylindrical channels and large memory states.