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Physical Chemistry

Lund University

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Phase separation, adsorption behavior and delivery capacity of polyelectrolytes and oppositely charged surfactants at surfaces

An enhanced surface adsorption is typically obtained from dilute mixtures of a polyelectrolyte and an oppositely charged surfactant under conditions when there is a bulk associative phase separation in the mixture. This phenomenon is used in everyday products (e.g., shampoos, laundry detergents) that are specifically designed to produce deposited surface layers. Often the phase-separation and enhanced deposition can be obtained by a simple dilution process. The same process can also be used to deliver some additional substance to the surface together with the polyion-surfactant ion complexes. As an example, the co-deposition of emulgated silicone oil droplets onto hydrophilic and hydrophobic surfaces has been studied for formulations containing anionic surfactant and cationic polymers of varying hydrophobicity. The aim of the present project is to provide fundamental understanding of the kinetics of this process by combining models of kinetics with experimental data by obtained by using surface techniques such as neutron reflectometry and ellipsometry as well as scattering techniques to reveal the changes in composition at the interface versus time. 

 

People: James Holdaway, Tommy Nylander, Lennart Piculell; E. Johnson, P. Ellingson, B. Schubert (Procter & Gamble, Cincinnati).

Contact persons: Tommy Nylander and Lennart Piculell