Effect of cooling rate on temperature range of blue phases in chiral nematic liquid crystals

Arshdeep Singh and Praveen Malik*

* Liquid Crystal Research Laboratory, Department of Physics, Dr. B. R. Ambedkar National Institute of Technology Jalandhar, Punjab, India

E-mail: pmalik100@yahoo.com

Blue phase liquid crystals are of immense research interest due to large number of potential applications.	They posses several advantages such as absence of alignment layer, wide viewing angle and response time in submillisecond. We investigated the effect of rate of cooling on temperature range of blue phases of Cholesteryl nonanoate/N-(4-ethoxybenzylidene)-4-butylaniline mixture. Both liquid crystals were mixed in ratio 50:50 wt.% and filled in an ITO coated glass cell of 10 µm thickness at isotropic temperature. Polarizing optical microscopy studies of blue phases were performed at different rates of cooling 0.1°C, 0.2°C, 0.3°C, 0.5°C, 1°C, 2°C and 5°C per minute. An increase in blue phase temperature range with increase in cooling rate is observed. The increased blue phase range may be due to supercooling tendency of blue phases.

Keywords: biquid crystal, Blue phases

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