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Full-Text Articles in Physics

Surface Elastic And Molecular-Anchoring Properties Of Nematic Liquid-Crystals Confined To Cylindrical Cavities, G. P. Crawford, David W. Allender, J. W. Doane Jun 1992

Surface Elastic And Molecular-Anchoring Properties Of Nematic Liquid-Crystals Confined To Cylindrical Cavities, G. P. Crawford, David W. Allender, J. W. Doane

Physics Publications

The measurement of the saddle-splay surface elastic constant K24 in a nematic liquid crystal is reported based on two independent deuterium nuclear-magnetic-resonance (2H-NMR) experiments. Fifty years after the pioneering work of Oseen and Zocher, these measurements were made from observations of nematic director-field configurations and a configuration transition discovered in submicrometer-sized cylindrical cavities of Nuclepore membranes under selected surface preparations and wall curvatures. The experimental difficulties in separating the effect of anchoring energy from surface elastic energy (inherent in small confining volumes) were overcome by a unique use of NMR and the ability to predict stable nematic structures with ...


Determination Of The Liquid-Crystal Surface Elastic-Constant K24, David W. Allender, G. P. Crawford, J. W. Doane Sep 1991

Determination Of The Liquid-Crystal Surface Elastic-Constant K24, David W. Allender, G. P. Crawford, J. W. Doane

Physics Publications

Analysis of the Frank free energy for nematics confined to cylindrical regions indicates that the director pattern is dependent on the surface elastic constant K24 if there is weak normal anchoring and escape along the cylinder axis. Using deuterium nuclear-magnetic-resonance techniques on samples of submicrometer-size cavities in Nuclepore membranes, we report the first measurement of K24.