Unifying interfacial self-assembly and surface freezing

• Published in: Physical review letters Vol. 106; no. 13; p. 137801
• Main Authors: Ocko, B M, Hlaing, H, Jepsen, P N, Kewalramani, S, Tkachenko, A, Pontoni, D, Reichert, H, Deutsch, M
• Format: Journal Article
• Language: English
• Published: United States 30-03-2011
• Subjects: 08 HYDROGEN; Alcohols - chemistry; Aluminum Oxide - chemistry; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ELASTICITY; FREEZING; HYDROGEN; nanoscale structures; SAPPHIRE; self-assembly; SUBSTRATES; surface freezing; Surface Properties; Temperature; THERMODYNAMIC MODEL
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/physrevlett.106.137801

X-ray investigations reveal that the monolayers formed at the bulk alkanol-sapphire interface are densely packed with the surface-normal molecules hydrogen bound to the sapphire. About 30-35 °C above the bulk, these monolayers both melt reversibly and partially desorb. This system exhibits balanced intermolecular and molecule-substrate interactions which are intermediate between self-assembled and surface-frozen monolayers, each dominated by one interaction. The phase behavior is rationalized within a thermodynamic model comprising interfacial interactions, elasticity, and entropic effects. Separating the substrate from the melt leaves the monolayer structurally intact.