Highly improved dielectric behaviour of ferronematic nanocomposite for display application Jessy P. J, Radha S., Nainesh Patel Liquid Crystals, 2019 We report the investigation of influence of nickel zinc ferrite magnetic nanoparticles (NZFO (Ni0.5Zn0.5Fe2O4)) on phase transition, optical and dielectric properties in a nematic liquid crystal (NLC). The interaction of NZFO nanoparticles with NLC was confirmed by the formation of ferronematic droplets due to the transfer of magnetic orientational effect onto the underlying NLC matrix. The doping results in shift of nematic to isotropic transition to low-temperature region. An enhancement in the value of refractive index is observed in the nematic region after the addition of NZFO nanoparticles. The dielectric constant of NLC was remarkably enhanced by 10 times after doping, which is found to be maximum at 0.1 wt% concentration of NZFO nanoparticles. The decrease in the value of dissipation factor in low-frequency region shows that the magnetic nanoparticles are able to trap ionic impurities effectively. The obtained results suggest that the optimum amount of doping concentration is 0.1 wt% of NZFO nanoparticles in NLC due to high dielectric constant with low dissipation factor and high refractive index with high dispersive power at room temperature. Graphical Abstract
Phase behavior of thermotropic chiral liquid crystal with wide blue phase P. J. Jessy, S. Radha, Patel Nainesh Aip Conference Proceedings, 2018 We modified the phase transitions of a thermotropic chiral nematic liquid crystal system with various concentrations of chiral component and investigated their phase behavior and optical properties. The study shows that coupling between chirality and nematicity of liquid crystals lead to changes in phase morphology with extended temperature window of blue phase including human body temperatures and enhanced thermochromism performance. The temperature dependent refractive index analysis in the visible spectral region reveals that the optical modulation due to pitch variation of helical pattern results in the creation of new mesophases and more pronounced chirality in mixtures leading to blue phase which can be controlled by the chiral concentration. The appearance of extended blue phases with primary colors will pave way for the development of new photonic devices.We modified the phase transitions of a thermotropic chiral nematic liquid crystal system with various concentrations of chiral component and investigated their phase behavior and optical properties. The study shows that coupling between chirality and nematicity of liquid crystals lead to changes in phase morphology with extended temperature window of blue phase including human body temperatures and enhanced thermochromism performance. The temperature dependent refractive index analysis in the visible spectral region reveals that the optical modulation due to pitch variation of helical pattern results in the creation of new mesophases and more pronounced chirality in mixtures leading to blue phase which can be controlled by the chiral concentration. The appearance of extended blue phases with primary colors will pave way for the development of new photonic devices.
Thermo optical study of nematic liquid crystal doped with ferrofluid Jessy P. J., M. Shalini, Nainesh Patel, Pradip Sarawade, Radha S. Aip Conference Proceedings, 2017 Liquid crystal composite materials with tunable physical properties are of great scientific interest because of optoelectronic and biomedical applications. We report our study of modified optical properties of 5CB Nematic Liquid Crystal (NLC) by doping with ferrofluid at low concentrations of 0.1% by the investigation of thermo optic behaviour. The observed sensitivity of optical response in ferrofluid doped NLC is expected to pave way for several thermo-optic applications.
Study of the optical, thermal, and mechanical properties of nematic liquid crystal elastomers Santosh A. Mani, Sameer U. Hadkar, P. J. Jessy, Suman Lal, Patrick Keller, Samriti Khosla, Nitin Sood, Pradip Sarawade Journal of Information Display, 2016 In the present study, the optical, thermal, and mechanical properties of liquid crystal elastomers (LCEs) were investigated using various techniques. The presence of functional groups in LCE was studied using Fourier transform infrared spectroscopy. The phase transition temperatures were confirmed via polarizing optical microscopy and Fabry–Perot scattering studies. The differential thermal analysis was used for investigating the thermal behavior. A dynamic mechanical analysis was used to study the mechanical properties of LCE. The significant mechanical changes with a considerable reversible effect were observed for this soft material. The changes in the mechanical shape with the temperature are attributed to the change in the phase of the LCE material.
Effect of CNT on Liquid Crystal Elastomer Santosh A. Mani, Jessy P.J., Suman Lal, S. K. Tripathi, Samriti Khosla, Rita A. Gharde, Pradip B. Sarawade 12th IEEE International Conference Electronics Energy Environment Communication Computer Control E3 C3 Indicon 2015, 2016 Dispersion of Carbon Nanotube (CNT) into Liquid Crystal Elastomers (LCE) provides simple and effective means of controlling physical properties at macroscopic scale. In this paper, we doped LCE with small amount of carbon nanotube and characterizations were performed by various techniques like Polarizing Microscopy Study (PMS), Fabry Perot Scattering Studies (FPSS), Fourier Transform Infrared (FTIR) Spectroscopy, Data Thermal Analysis (DTA) and Mechanical Study. The experimental results reveal that optical, thermal and mechanical properties are function of doped CNT material, which reflected strong agglomeration and rearrangement of nanotubes in LCE. Therefore, a small amount of CNT enhances existing properties which can be optimized for various applications.
Thermo-elastic behaviour of liquid crystal elastomer Jessy P. J, Santosh A. Mani, Jyoti R. Amare, Rita A. Gharde Aip Conference Proceedings, 2015 The effect of temperature on Liquid Crystal Elastomer was studied to understand thermo-elastic behaviour of these fantastic soft materials. The investigations were performed using Polarizing Microscopy Studies (PMS) and Differential Thermal Analysis (DTA). The relative length shows hysteresis as function of temperature. As temperature increases, the length shrinks, while it returns to original shape on cooling.
Spectroscopic and thermo-mechanical studies of Liquid Crystal Elastomer Rita A. Gharde, Santosh A. Mani, P.J. Jessy, Jyoti R. Amare, Patrick Keller Key Engineering Materials, 2015 The structure and influence of temperature on mechanical deformation of Liquid Crystal Elastomers (LCEs) were studied using various techniques like Raman Spectroscopy (RS), Fourier Transform Infrared (FTIR) Spectroscopy and Polarizing Microscopy Studies (PMS) etc. The spectroscopic studies confirmed the presence of functional group attached to the sample. The shrinkage in length was observed while heating whereas material returns to its original length on cooling which revealed the correlation of mechanical behavior of Liquid Crystal Elastomers with temperature. This spontaneous shape changing property indicates that LCE material plays an important role in biological applications.
