Equilibrium measurements of oscillatory disjoining pressures in aqueous foam films

Journal Article · Tue Dec 01 04:00:00 EST 1992 · Langmuir; (United States)

DOI:https://doi.org/10.1021/la00048a028· OSTI ID:5834112

Bergeron, V; Radke, C J ^[1]

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1. Lawrence Berkeley Lab., CA (United States) Univ. of California, Berkeley (United States)

Disjoining pressure isotherms are measured for single, isolated foam films stabilized with sodium dodecyl sulfate above the critical micelle concentration (cmc). The measured isotherms exhibit an equilibrium oscillatory component that extends out to film thicknesses as large as 50 nm. The oscillations originate from surfactant structuring within the film and are responsible for the multiple black films extensively studied by Perrin in 1918. We find that as film thickness decreases, the slopes and peak heights of the oscillations increase for each subsequent black film encountered. The discrete changes in film thickness observed at each black film transition range from 6 to 10 nm and are a function of the ionic strength and surfactant concentration. Pressures required to rupture the multiple black films are several orders of magnitude lower than the final film-rupture pressure. Finally, the oscillatory form of the disjoining pressure permits quantitative interpretation of stepwise thinning behavior observed in films containing surfactant above the cmc. 50 refs., 13 figs.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5834112
• Journal Information: Langmuir; (United States), Journal Name: Langmuir; (United States) Vol. 8:12; ISSN LANGD5; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
661000 -- General Physics-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COLLOIDS
DISPERSIONS
EQUILIBRIUM
FILMS
FOAMS
MATHEMATICAL MODELS
MICELLAR SYSTEMS
PRESSURE MEASUREMENT
STABILIZATION
SURFACTANTS
THIN FILMS