Determination of Solubility Limits of Photocured PDLC Systems Using Infrared Microspectroscopy

Abstract
Infrared microspectroscopy is used to determine the solubility limits of a UV-curable polymer-dispersed liquid crystal (PDLC) system comprised of a low-molecular-weight liquid crystal (E7) and a photocurable monomer (NOA65). The LC is allowed to diffuse into the monomer by the contact method, and then the sample is subjected to curing. The morphology of the system after polymerizaton exhibits several distinct spatial regions, and the associated concentration gradients are measured. At an irradiation temperature of 30 °C, the concentration of LC in the matrix is found to be 27 ± 3%, and at a temperature of 100 °C, it is 65 ± 3%.