Continuous Nematic-Isotropic Transition in Submicron-Size Liquid-Crystal Droplets

Abstract

Deuterium NMR of nematic droplets in a polymer matrix reveals the effect of confinement on molecular orientational ordering near the nematic-isotropic ($N\ensuremath{-}I$) phase transition. For large droplets of 0.35 \ensuremath{\mu}m in diameter, the $N\ensuremath{-}I$ transition is first order. For droplets of less than 0.035 \ensuremath{\mu}m in diameter, the isotropic phase shows a paranematic order and the $N\ensuremath{-}I$ transition is replaced by a continual evolvement from paranematic to nematic order. This result provides the first demonstration of Sheng's prediction that the $N\ensuremath{-}I$ coexistence curve terminates at a critical enclosure size.