Effect of Temperature on the Columnar Tilt of Discotic Liquid Crystals

The effect of temperature on the tilt of discotic columns in a columnar phase has been studied. The homogenous alignment of discotic columns is achieved by applying a mechanical shearing. In the columnar phase, the tilt of the discotic columns at substrate surface is found to change with temperature. A decrease in the temperature of the substrates causes an increase in the pretilt of the discotic columns. The phenomenon is explained based on the consideration of surface free energy at the interface of the substrate.