Determination of kinetics of adsorption and layer thickness of lamellar gel surfactant films deposited onto silica

The phase behaviour of aqueous surfactant systems and in particular the transition between a gel (Lb) and liquid crystalline (La) phase can be influenced by some low molecular weight additives. We have developed surfactant formulations which self-assemble into a lamellar phase in water, that can be switch between the Lb phase and the La phase not only depending on the temperature, but also by including water-soluble additives. The effect of deposition of these lamellar structures can be monitored, and the adsorbed amount, refractive index and layer thickness have been determined using ellipsometry, but only after dilution and removing aggregates from the solution. The present study aims to take advantage of neutrons and monitor the deposition of deuterated DODAC mixtures and thus study the adsorption processes onto the silica surface.