Metal oxide alumina nanowire-induced polymer-dispersed liquid crystal composites for low power consumption smart windows

Abstract

Herein, polymer dispersed liquid crystals (PDLCs) based smart windows are proposed using a host thiol-ene-based UV curable photopolymer and nematic liquid crystals (E7). The proposed PDLC was prepared by polymerization-induced phase separation technique. PDLCs were doped with alumina nanowires (ANWs) in different concentrations and investigated their dispersion effect on various physical properties. An increase in nematic to isotropic transition temperature was observed in ANWs doped PDLC nanocomposite. Reduction in threshold and saturation voltages by 62.5% (1.5 V) and 56.57% (16.5 V), at 1.0 and 0.25 wt.% of doped ANWs respectively in PDLC was noticed. This reduction could be attributed to an increased electric field caused by lowering medium resistivity and increased cell capacitance. A decrease in dielectric anisotropy with temperature and ANWs doping in all samples was also observed. The maximum absorbance for 0.5 wt.% ANWs doping in PDLC at a wavelength of 511 nm were observed. The electric field-induced results indicate that the proposed ANWs doped PDLC composite film can operate at a much lower voltage (19.5 V) and show improved transparency. These findings may assist to develop fast-switching smart windows and other energy-saving devices.