Characteristic two-step phase transitions in chloro(dimethyl)(octadecyl)silane monolayers following Ostwald’s step rule
説明
For fundamental understanding of spread monolayers of chloro(dimethyl)(octadecyl)silane (CDMOS), the effects of temperature and of compression strain rate on the properties and morphologies of the monolayers have been systematically studied with Brewster angle microscope (BAM). π-A isotherms and BAM images clearly demonstrate that the CDMOS monolayers undergo characteristic two-step phase transitions during compression at a very narrow temperature range around 20.0°C, but above and below that temperature range only one-step phase transitions appear. This unusual two-step phase transition is explained by the well known Ostwald’s step rule. When the compression strain rate becomes ten times slower, so-called solid film regions on the isotherms disappear, indicating that the shape of the π-A isotherms are determined by the balance between the relaxation times of the molecular processes in the monolayers during compression and the times of observation (tob). Change of condensed phase domain size is considered in relation to the degree of supersaturation during compression.
収録刊行物
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- Colloids and Surfaces A: Physicochemical and Engineering Aspects
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Colloids and Surfaces A: Physicochemical and Engineering Aspects 156 281-290, 1999-10-01
Elsevier BV
