Influence of chain length of prepolymers in permanent memory effect of PDLC assessed by solid-state NMR

The relationship between linear chain (ethylene oxide units) length of polymerisable monomers with morphology, electro-optical properties and C-13 nuclear magnetic resonance (NMR) spectroscopy of the corresponding polymer-dispersed liquid crystal (PDLC) films was investigated. The preferred liquid crystal molecule alignment and permanent memory effect of PDLC were greatly influenced by the length of the molecular chain of prepolymers to be incorporated as a polymer matrix. By increasing the number of ethylene oxide in prepolymer chain and maintaining the number of functionalities (polymerisable groups in each monomer molecule), the permanent memory effect of PDLC increased, as proved by solid-state C-13 NMR spectroscopy.