The effect of doping sulphhydryl-functionalised silica with different diameters on the electro-optical properties of PDLC

In this study, we synthesised two kinds of spherical SiO2-SH particles with uniform and non-uniform morphologies, and investigated their effects on the electro-optical properties of PDLC. Compared with uniform SiO2-SH nanoparticles, we found that the samples doped with non-uniform SiO2-SH regulate the electro-optical properties of PDLC better. The electro-optical properties test results demonstrated that doping a small amount of SiO2-SH with different sizes significantly reduced the driving voltage of PDLC and maintained a high contrast ratio. SEM results indicated that the size of the polymer meshes was broadened with increasing SiO2-SH doping. This phenomenon can be attributed to the larger specific surface area and higher concentration of sulphhydryl groups in SiO2-SH particles of different sizes. These characteristics enable SiO2-SH to better react with acrylate monomers, thereby improving modulation effects on the electro-optical properties of PDLC. However, when the doping amount exceeded a certain value, the driving voltage of PDLC began to rise, and its electro-optical properties deteriorated because of the agglomeration of nanoparticles at higher doping levels. This study demonstrated that doping SiO2-SH particles of different sizes can optimise the properties of PDLC, which provided new ideas and directions for doping PDLC with nanomaterials.