Accession Number:

AD0625344

Title:

TRANSFER OF AIR THROUGH ADSORBED SURFACE FILMS AS A FACTOR IN FOAM STABILITY.

Descriptive Note:

Technical rept.,

Corporate Author:

STANFORD RESEARCH INST MENLO PARK CALIF

Personal Author(s):

• Brown,A. G.
• Thuman,W. C.
• McBain,J. W.

Report Date:

1949-10-01

Pagination or Media Count:

22.0

Abstract:

A method was developed for the direct determination of the rate with which single bubbles, floating at the surface of detergent solutions, lose air to the atmosphere because of the pressure gradient set up in the film by the higher pressure of the air in the bubble. The rate of decrease of bubble radius with time may be used as a direct measure of the permeability of the surface film to air, or a permeability constant may be calculated. Low permeability is associated with high stability foams, whereas solutions yielding foams of poor stability show very high permeability to air for the adsorbed surface film. Factors affecting the interpretation of the permeability data are discussed. Both permeability and surface viscosity appear to depend on the coherence developed in the surface film, but the quantitative dependence appears to be different in the two cases. Author

Descriptors:

• *CLEANING COMPOUNDS
• *BUBBLES
• STABILITY
• FOAM
• PERMEABILITY
• SURFACE ACTIVE SUBSTANCES
• FILMS
• ADSORPTION
• VISCOSITY
• SURFACE TENSION
• VOLUME

Subject Categories:

• Physical Chemistry
• Solvents, Cleaners and Abrasives

Distribution Statement:

APPROVED FOR PUBLIC RELEASE