Escaped-radial nematic configuration in submicrometer-size cylindrical cavities: Deuterium nuclear-magnetic-resonance study

Abstract

Deuterium nuclear magnetic resonance ${(}^{2}$H NMR) is used to extend studies of confined nematic structures to submicrometer-size cavities. Spectral patterns reveal the escaped-radial configuration in untreated cylindrical cavities of Nuclepore filters. This configuration is found to survive in pore sizes as small as 0.2 \ensuremath{\mu}m in radius. Singular point defects are found to be present along the escape axis with the density of the defects being determined from the $^{2}\mathrm{H}$ NMR spectra. This density is found to be unaffected by cycling between the nematic and isotropic phases with or without the presence of an applied magnetic field.