DissolutionRate of theMonolayer of1-Monolaurinat ConstantArea

Abstract

Dissolution rate of the monolayer of 1-monolaurin at constant area was obtained by measuring the decrease of surface pressure. Surface pressure of a monolayer, which had been compressed rapidly and held at a constant area, decreased linearly with the square root of elapsed time. Surface pressure-area curve of the spread monolayer of 1-monolaurin was obtained from the initial pressure obtained by the extrapolation to time zero. It was found that a monolayer of 1- monolaurin was in state a of liquid expanded film. Surface concen-tration corresponding to each surface pressure was calculated from the state equation of liquid expanded film of Jura and Harkins. Logarithm of surface concentration varied linearly with the square root of elapsed time. Adsorption isotherm was calculated by thetheory of Ter Minassian- Saraga for the dissolution rate of a monolayer.
It has been concluded that the spread monolayer of 1- monolaurin isequilibrated immedi- ately with the sublayer and then 1- monolaurin dissolved in the sublayer is transfered to bulk liquid by diffusion.