Nano-droplet formation in polymer dispersed liquid crystals

Abstract

In this work we analyse the fabrication of Polymer Dispersed Liquid Crystals (PDLCs) using SU8-2002-2007 photoresist and 5CB and E7 Liquid Crystals. Also we report the nonlinear optical behaviour for these materials and for Polymer Dispersed Liquid Crystals with a Twisted Cell (T-PDLC). We found that depending of several parameters, the droplets size varies from nano to micro dimensions. We report for first time, to our best knowledge, the synthesis of a SU8 Polymer Dispersed Liquid Crystal (PDLC) by using the polymer SU8 photoresist and liquid crystals (LC) and also the nonlinear behaviour of T-PDLC. We have characterized the droplets formation from nano to micron size depending of the different variables in the synthesis. We have used this PDLC in microfabrication as planar waveguides of different thickness over Si wafers. Our results also show that PDLCs present low NL optical Kerr coefficient (n₂ about 10^-9cm²/W) and that it is three orders of magnitude larger in T-PDLC. Nevertheless, the fabrication processes of T-PDLCs make impossible their use in microfabrication.