Droplet size effect on the memory-mode operating temperature of smectic-A holographic polymer dispersed liquid crystal

The memory-mode operation of a polymer dispersed liquid crystal (PDLC), which depends on the stiffness of the layer structure in the smectic-A phase, has been analysed by comparing ordinary PDLC and holographic PDLC (HPDLC). Although both PDLC films were fabricated from the same material, the temperature range of the memory-mode operation was lower in the HPDLC than in the ordinary PDLC. In calorimetric analysis, the differential scanning calorimeter curves of the ordinary and holographic PDLC films were the same. Therefore, the liquid-crystal phase does not depend on the structural difference. This suggests that the force exerted against the layer structure of the smectic phase is greater in HPDLC because the droplet size is smaller and the ratio of the surface to volume is higher.