Polyelectrolyte adsorption onto planar surfaces: A study by electrokinetic measurements

This paper presents the results of the investigations on the adsorption phenomenon of polyelectrolytes on model surfaces like Langmuir-Blodgett (LB) layer. The adsorption process of polyelectrolytes from aqueous solution is a very complex phenomenon and depends on different adsorption factors like concentration, time, pH, surface nature, etc. The characterisation of the polyelectrolyte-covered surfaces was made by streaming potential measurements. Measurements of the electrokinetic (or zeta) potential give information about (i) the existence of acidic or basic molecular groups on the solid surface, (ii) the interaction between the components of the electrolyte solution and the solid surface, (iii) swelling phenomena, and (iv) stability of adsorbed layer in the solid-aqueous electrolyte system. The results demonstrate clearly, through the electrokinetic analyses, that planar substrates are an ideal model surface, here LB layer, for an optimised adsorption as function of solution concentration and time.