Structural transitions at solid-liquid interfaces

✍ Scribed by Ravi K. Ballamudi; Ioannis A. Bitsanis

• Book ID: 104632299
• Publisher: Springer
• Year: 1996
• Tongue: English
• Weight: 594 KB
• Volume: 2
• Category: Article
• ISSN: 0929-5607
• DOI: 10.1007/bf00127100

✦ Synopsis

In this paper we present the findings of our investigations using molecular dynamics, on molecularly thin films of n-octane confined between topographically smooth solid surfaces. We focus on the effect of increasing solid surface-methylene unit energetic affinity and the effect of increasing pressure (normal load) of the film in inducing liquid-solid phase transitions. We observed an abrupt transition in the structural features of the film at a critical value of the characteristic energy that quantified the affinity between solid surfaces and methylene units. This energetically driven transition was evident from the discontinuous increase of intermolecular order, a precipitous extension of the octane molecules and freezing of molecular migration and rotation. Increasing pressure had a similar effect in inducing a liquid-solid phase transition. The characteristics of the transition showed that it is a mild first order transition from a highly ordered liquid to a poorly organized solid. These findings demonstrate that the solidification of nanoscopically thin films of linear alkanes is a general phenomenon (driven either energetically or by increasing pressure), and does not require the aid of commensurate surface topography.