Electro-optics of PDLC films doped with WO3 nanoparticles

We have studied the voltage-dependent optical transmittance (V-Tr) of thin (25 µm) films of polymer-dispersed liquid crystals (PDLCs) doped with nanoparticles of WO3 with sizes <100 nm, at concentration of 1 wt.%. The PDLC films were produced by photopolymerization-induced phase separation of nematic liquid crystal E7 and photo-curable pre-polymer NOA65, mixed at the ratio 50:50 wt.%. In order to estimate the effect from WO3 nanodopants, the V-Tr characteristics of WO3-doped PDLCs were compared to those of PDLC films prepared upon the same photo curing and from the same starting materials (E7 and NOA65), but with no WO3. The WO3 nanodoped E7/NOA65 PDLCs exhibited electro-optic (EO) switching voltages that are close to those of the typical nanoscale PDLCs. The produced nanocomposite PDLCs are of interest for various EO devices driven by alternating-current electric field (e.g., efficient EO shutters, attenuators and filters).