Dielectric dynamics and optical behaviour of surfactant free LC/silicone oil based non-aqueous emulsions

We are presenting the non-aqueous emulsions comprising of liquid crystal 8CB (4 '-Octyl-4-biphenylcarbonitrile) and silicone oil in varying ratios (5:95, 10:90, 25:75 and 50:50 wt./wt.%). Emulsions are self-stabilised via dipolar interactions, alignment and anchoring without the use of any surfactant. The formation of distinct defects geometries over the studied concentration range of silicone oil in the liquid crystal matrix has been discussed. The dielectric dynamics of the non-aqueous emulsions have been studied in the smectic (30 degrees C) and nematic (38 degrees C) phases over the continuous broadband of frequency 50Hz-1MHz. In both cases (smectic and nematic regions), dielectric permittivity decreases with a rise in the content of the silicone oil in the emulsion systems. The proposed mechanism for such dielectric behaviour has been discussed considering charge/defects boundary interactions and decrement of resultant dipole moment. A relaxation mode in the lower frequency range has been observed for all the emulsion systems. In addition, the emulsion systems have shown significant optical transmission behaviour. A significant enhancement in optical transmission about 82% has been noticed for 25 wt% comparing to 5 wt% emulsion system. Such self-stabilised systems could pave a way to develop dual-frequency LCs systems for progressive technological applications, tunable polarisation filters, and adaptive optics.