Gradient measurement technique to identify phase transitions in nano-dispersed liquid crystalline compounds

Abstract

Characterization and phase transitions in pure and 0.5% BaTiO₃ nano-dispersed liquid crystalline (LC) N-(p-n-heptyloxybenzylidene)-p-n-nonyloxy aniline, 7O.O9, com-pounds are carried out using a polarizing microscope attached with hot stage and camera. We observed that when any of these images are distorted, different local structures suffer from various degradations in a gradient magnitude. So, we examined the pixel-wise gradient magnitude similarity between the reference and distorted images combined with a novel pooling strategy – the standard deviation of the GMS map – to determine the overall phase transition variations. In this regard, MATLAB software is used for gradient measurement technique to identify the phase transitions and transition temperature of the pure and nano-dispersed LC compounds. The image analysis of this method proposed is in good agreement with the standard methods like polarizing microscope (POM) and differential scanning calorimeter (DSC). 0.5% BaTiO₃ nano-dispersed 7O.O9 compound induces cholesteric phase quenching the nematic phase, which the pure compound exhibits.

Keywords:

• differential scanning calorimeter (DSC)
• gradient measurement (GMS)
• gradient magnitude similarity deviation (GMSD)
• MATLAB
• nano-dispersion
• polarizing microscope (POM)

Acknowledgements

Authors like to express their deep gratitude towards the department of ECE, K L University, Vaddeswaram and The Hindu College, Machilipatnam, for their continuous support and encouragement during this work. Dr R.K.N.R. Manepalli thanks UGC for the grant 42-784/2013 (SR).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Dr RKNR Manepalli thanks UGC for the grant [grant number 42-784/2013 (SR)].