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Author
Bernett, M. K. | Halper, L. A. | Jarvis, N. L. | Thomas, T. M.
Title
Effect of Adsorbed Monomolecular Films on the Evaporation of Volatile Organic Liquids.
Coporate
Naval Research Laboratory, Washington, DC
Report
NRL Report 6931, July 9, 1969, 18 p.
Distribution
Available from National Technical Information Service
Keywords
organic liquids | light water | evaporation
Identifiers
surface active agents; monomolecular films; surface chemistry; organic liquid/air interfaces; light water fire fighting foams
Abstract
An investigation was made of the effect of adsorbed surface-active films on the rate of evaporation of volatile organic liquids. A series of partially fluorinated compounds were studied either as monolayers adsorbed from solution or as insoluble films spread at the liquid/vapor interface. In no instance was the rate of evaporation significantly reduced by the presence of a monomolecular film. Insoluble multimolecular films of polydimethylsiloxanes, however, were found to reduce effectively the rate of evaporation, provided the film thickness was sufficient to decrease the rate of diffusion of the solvent molecules through the film to a value below their rate of diffusion through the saturated, nonturbulent vapor layer overlying the surface.