Surfactant adsorption dynamics

Advances in techniques for investigating dynamic adsorption of surfactants at the air-water interface are discussed. Of particular interest are the ma ximum-bubble-pressure method. and the interrogation of adsorption layers on an overflowing cylinder (OFC) cell using ellipsometry, surface-light scatt ering, laser Doppler velocimetry and neutron reflection. Recent studies des cribed here, with a model di-chain anionic fluorocarbon surfactant sodium b is(1H, 1H-nonafluoro-n-pentyl) sulphosuccinate (di-CF4) demonstrate that th e OFC presents an ideal flexible platform for investigating dynamics of ads orption from solutions. Under certain conditions the behaviour is consisten t with an activated-diffusion mechanism, as has been found previously fur s imple alcohols and various other non-ionic and ionic surfactants.