PERMEABILITY OF COMMON BLACK FOAM FILMS TO GAS .2.

The film permeability coefficients K for permeation of air through com mon black films (CBF) have been experimentally measured using the stat ionary bubble method described earlier (R. Krustev, D. Platikanov and M. Nedyalkov, Colloids Surfaces A: Physicochem. Eng. Aspects, 79 (1992 ), 129.) The dependence of K on LiCl concentration and temperature T h ave been studied for CBF from sodium dodecyl sulfate (SDS) + LiCl aque ous solutions. The K(T) dependence for the system SDS + NaCl has also been studied. The results prove our hypothesis that the film permeabil ity is determined mainly by the monolayer permeability K-ml of the ads orption layers. The K-ml values increase with increasing distance betw een the monolayers (i.e. the film thickness) and tend to a constant va lue. K-ml and K depend on the specific adsorption of the counterions i n the dodecyl sulfate monolayer. The CBF with Li+ ions are essentially more permeable than those with Na+ ions, which are more strongly adso rbed.