Zinc Oleate Nanorod-Induced Vertical Alignment of Nematic Liquid Crystal

Nanocomposite zinc oxide nanorods capped with oleic acid (ZOR) with positive dielectric anisotropy liquid crystal (LC) 4 '-octyl-4-biphenylcarbonitrile (8CB) filled in unaligned cells exhibit homeotropic alignment of host LC molecules. Further, systematic investigation of the textural, dielectric, and conductivity properties of nanocomposites filled in planar cells is performed with increasing concentration of nanorods. At a nanorod concentration <= 0.2 wt % in 8CB, the order parameter of nanocomposite samples is found to be increasing and ionic conductivity is found to be decreasing as compared to pure LC. Beyond 0.3 wt % concentration of nanorods in 8CB, vertical alignment (VA) of host LC is observed even in a planar aligned cell. The VA of LC molecules in ZOR nanocomposites is confirmed through attenuated total reflection-Fourier transform infrared absorption spectra studies.

Automated summary

The study shows that as the concentration of ZOR nanorods increases, the order parameter of LC nanocomposites increases while the ionic conductivity decreases. Beyond 0.3 wt % concentration of nanorods, vertical alignment of host LC is observed even in planar aligned cells.