Effects of polyhedral oligomeric silsesquioxane and silicon microstructure on the electric-optical performance of polymer dispersed liquid crystals

Abstract

In this work, two silicon nanomaterials are doped into polymer/liquid crystal composites by a facile method. SEM and FT-IR characterizations indicate that SiO2-SH and synthesized thiol polyhedral oligomeric silsesquioxane (POSS-SH) have been successfully implanted into PDLCs successfully. The electro-optical tests imply that the electro-optical performance of PDLC films can be greatly enhanced by doping proper amounts of SiO2-SH nanoparticles and nanostructured POSS-SH into the polymer matrix. The driving voltage can be reduced by nearly 78.2% if the concentration of SiO2-SH is 4 wt%; whereas only nearly 60% driving voltage is reduced when 4 wt% POSS-SH is doped into system, indicating better electric-optical performance regulation effect of SiO2. The lower driving voltage of SiO2-SH doped PDLC samples may be due to the existence of high content –SH on the surface of nanoparticles, which can conduct click reactions with acrylate bond under the effect of initiator.