Showing papers by "Gerard C. L. Wong published in 1997"

Thermal Fluctuations of Freely Suspended Smectic-A Films from Mesoscopic to Molecular Length Scales

Abstract: Smectic-A (SmA) liquid crystals are uniaxial systems possessing long-range orientational order In addition, the molecules are on average arranged in equidistant layers, while the translational order is liquidlike in the other two directions The positional order along the uniaxial direction is not truly long range but decays algebraically with position as r 2h This absence of true long-range

Critical examination of prewetting and surface melting on caprolactam

Abstract: In a previous study, surface melting on the (001) surface of caprolactam (${\mathrm{C}}_{6}$ ${\mathrm{H}}_{11}$ ON) was reported to proceed in a series of layering transitions, followed by a prewetting transition. We have reproduced the original results and shown that they can be better explained by the wetting of hydrated caprolactam (with ${\mathrm{H}}_{2}$ O molecules at bridging sites between the caprolactam dimers) on caprolactam, and that such hydration is most likely caused by ${\mathrm{H}}_{2}$ O microinclusions in the crystals grown from solution. In agreement with this interpretation, we have also shown that the reported effects are absent on 'dry' surfaces.

Orientational Wetting in Hybrid Liquid Crystalline Block Copolymers

Abstract: The wetting behavior of hybrid isotropicysmectic block copolymers is examined. For symmetric diblocks, the generic parallel ordering of the lamellae is suppressed, and the copolymer wets the surface with the lamellae perpendicular to the surface. The parallel ordering, however, can be restored in asymmetric lamellar diblocks. We propose an explanation in terms of block-specific interface wetting, and configurational frustration induced by the incommensurability between the smectic spacing and the smectic block size defined by the diblock lamellar period. [S0031-9007(96)01913-8]