Thin liquid film structure and stability: The role of depletion and surface-induced structural forces

Journal Article · Sun Oct 15 04:00:00 EDT 1995 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.470395· OSTI ID:165722

Chu, X L; Nikolov, A D; Wasan, D T ^[1]

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1. Department of Chemical Engineering, Illinois Institute of Technology, Chicago, Illinois 60616 (United States)

Film stability and structure formation inside a liquid film containing colloidal particles are investigated by Monte Carlo (MC) numerical simulations and by analytical methods. The effective pair interaction between particles is calculated from the Ornstein--Zernike theory with Percus--Yevick closure. Consistent with the recent experimental observations and theoretical studies, these MC simulations reveal the phenomena of internal particle layering as well as inlayer structure formation. In particular, an ordered two-dimensional hexagonal structure is observed at a particle concentration of 37 vol% (instead of 43 vol% for the hard-sphere potential) when the effective pair interaction between particles is taken into account. Furthermore, the particles inside a layer ``condense`` due to the attractive depletion force which leads to the formation of voids. The formation of such void structures results in the formation of ``dark spots`` which have been observed in film thinning experiments. The calculated film structural disjoining pressure, created by the particles inside the film, is found to be in agreement with the experimentally measured force-distance curves using the surface force apparatus. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

• OSTI ID: 165722
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 15 Vol. 103; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COLLOIDS
LIQUIDS
MONTE CARLO METHOD
SIMULATION
STABILITY
STRUCTURE FACTORS
SURFACE FORCES
THICKNESS
THIN FILMS