Multiwalled carbon nanotube induced improvements in the electro-optical and dielectric properties of polymer dispersed liquid crystals

This study explores the augmentation of electro-optical and morphological properties of polymer-dispersed liquid crystal (PDLC) films by incorporating multiwalled carbon nanotubes (MWCNT). The characteristics of PDLC films fabricated using the polymerisation-induced phase separation (PIPS) technique with a combination of nematic liquid crystal (QYPDLC-036B) and polymer (NOA65) were significantly enhanced by the incorporation of MWCNT. The effect of MWCNT concentration on the morphology of PDLC films was examined using polarising optical microscopy and scanning electron microscopy. The addition of 0.0078 wt% MWCNT to the nematic liquid crystal improved the contrast ratio from 453 (undoped) to 892, lowered the threshold voltage from 34 V to 24 V, and reduced the response time from 4.058 ms to 2.908 ms. A precision impedance analyser was used to study the dielectric behaviour of these films, and the relaxation time and distribution parameters were calculated using the Debye and Cole-Cole models. Non-zero distribution parameter indicates non-Debye-type relaxation behaviour for all the films. Such advancements hold significant promise for applications in electro-optical systems such as smart windows, optical switches and modulators.