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Abstract. The electro-optical performances of polymer dispersed liquid crystal (PDLC) were investigated in the presence of organically modified clays. With the addition and increasing amount of modified clay, driving voltage and memory effect, viz. transparent state of the film after the electricity is off simultaneously increased due most likely to the increased viscosity. Among the two types of modifier, 4-(4-aminophenyl) benzonitrile having greater chemical affinity with LC than hexylamine, gave finer dispersion of clay in liquid crystal, greater viscosity, larger driving voltage and response time, and greater memory effect.

Abstract. Morphology, grating formation dynamics and electro-optical performance of transflective multiplexing with holographic polymer dispersed liquid crystal (HPDLC) were investigated in the presence of silica nanoparticles (Aerosil R812 (RS) and modified Aerosil 200 (MS)) and silicon monomer (vinyltrimethoxy silane (VTMS)) by using three coherent laser beams. The addition of Si additive significantly augmented the diffraction efficiencies of transmission and reflection gratings due to the enhanced phase separation with large LC channels. The film was driven only with Si additives which are enriched at the polymer-LC interfaces. As the additive content increased, driving voltage decreased to a minimum of 30 V at 2.0 wt% VTMS. It was found that the interface modification and large droplet size are crucial to operate the film. Among the three types of Si additive, VTMS showed the highest electro-optical performance due to its low viscosity and high reactivity.

The morphology and electro‐optical performance of holographic polymer dispersed liquid crystal (HPDLC) were investigated with the addition of multiwalled carbon nanotube (CNT), both pristine and chemically modified one (CNT‐CC). With the addition of CNT, the diffraction efficiency increased and showed a maximum at 0.6% while nucleation was delayed due to the increased mixture viscosity. Film was driven only with CNT due to the induced local electric field of polymer to overcome the threshold resistance. Among the two types of CNT, chemically modified one gave finer CNT dispersion, lower mixture viscosity, larger liquid crystal (LC) droplet, higher diffraction efficiency, and shorter response time while the pristine CNT decreased the driving voltage. Copyright © 2010 John Wiley & Sons, Ltd.

Films were made by incorporating various quantities of fluoroalkyl acrylate (FA) into the chain termini of polyurethane acrylate oligomer of polymer stabilized cholesteric liquid crystals (PSCLCs). The effects of switching voltage, scanning electron and polarized optical microscope morphologies, texture transition and reversibility, and contact angle of the films were then studied. It was found that the switching voltage of the film decreased with the addition of FA up to 0.8 wt%, beyond which it increased. The decrease and increase were respectively explained in terms of decreased interface energy as noted from the contact angle of the LC on polymer surface, and too small droplet size as noted from the SEM. Copyright © 2008 John Wiley & Sons, Ltd.