Effect of electrolytes on the rate of surface tension lowering; the rate of surface equilibrium attainment as a factor in detergency

Abstract

1. 1. The effect of electrolytes on the initial time rate of surface tension lowering of anionic surface-active agents has been investigated. The increase in rate observed is largely determined by the charge of the added positive ion. In the case of cationic surface-active agents the increase in rate is largely determined by the charge of the added negative ion. 2. 2. An increase in temperature results in an increase in rate of surface tension lowering for sodium laurate. 3. 3. Detergent power and initial time rate of surface equilibrium attainment can, in most cases, be correlated where data are available, if it is assumed that any variable which affects the rate of surface tension lowering at the solution-air interface will have the same effect at the interface between the solution and any second phase. 4. 4. This correlation is reasonable if one assumes that most soils are oily in nature and that the first step in detergency is the removal of oil from the fiber by preferential wetting under nonequilibrium conditions.