Using Ion Beam Analysis to study the surfactant distribution in cross-linked colloidal polymer films - poster

T. Palmer1, M. Duewel2, K. Greiner2, R.W. Smith3, H.M. van der Kooji4, J. Sprakel4, J.L. Keddie1

1University of Surrey, Guildford, UK
2Synthomer Germany GmbH, Marl, Germany
3Surrey Ion Beam Centre, Guildford, UK
4Wageningen University, Wageningen, The Netherlands

The distribution of surfactant in waterborne colloidal polymer films such as adhesives and coatings is of significant interest for scientific understanding and industrial applications, with a general desire to prevent surfactant accumulation at the surfaces of films. We have studied the direct impact of particle deformation on surfactant migration during film formation, using a model poly (butyl acrylate) system synthesised with deuterated Sodium Dodecyl Sulphate. The particle deformation has been controlled via cross-linking of the polymer chains at differing amounts, from 0 mol% to 35 mol%. Ion Beam Analysis has been used to probe dried films, providing information on the surfactant’s depth distribution close to the top surface. It has been seen in the first instance, that for low and high cross-linking densities, surfactant is not found to accumulate at the surfaces of the films. At intermediate levels, surfactant is seen to accumulate strongly at the surface of the dried films, giving a ~10nm thick enriched layer. The observed results have been explained using a simple model that considers known theory about particle deformation and skin formation and the effect that cross-linked chains will have on these processes. The ability to exert control over surfactant distribution in drying films will aid in the design of new high-performance adhesives.