Comparison of the thermo- and electro-optical properties of doped and un-doped MOM based PDLCs

Experiments on the thermo- and electro-optical behavior of pure polymer dispersed liquid crystal (NOA-PDLC) film and new type of metallomesogen based PDLC (MOM-PDLC) film are presented. The NOA-PDLC film and the MOM-PDLC film consisted of the droplets of nematic LC (E7) up to a 40% weight fraction in a NOA resin matrix, respectively. The samples were prepared by putting the PDLC solutions into the Indium Tin Oxide (ITO)-coated glass cells and U-V-curing process. The electro-optical properties of the NOA-PDLC films and MOM-PDLC films were studied under the conditions of an externally applied square wave electric field (2-11 V/mum) and a film thickness (30-50 mum) with an argon laser (wavelength 514 nm), respectively. The experimental results are compared for two kinds of PDLC films. The electro-optical effects showed promising switching times with a rise time of 1 ms and a decay time of 3 ms and an exceptionally high contrast ratio up to 800 for MOM-PDLC sample. These results demonstrate the validity of employing this new type of MOM-PDLC in electro-optical devices. (C) 2003 Elsevier B.V. All rights reserved.