PVA film is widely used as a non-toxic water soluble polymer. This proposal relates to its use in unit dose detergent pouches where plasticised PVA film stores a concentrated mixture of surfactants. We wish to understand the ageing and failure mechanisms of these films and in particular the extent to which small molecules within PVA film can migrate to the surface and modify the surface properties. Following our recently published NR and ion beam study, we now proposed to exploit the unique ability of NR to study the surfactant migration under realistic atmospheric conditions in which the humidity is controlled. The influence of humidity is known to be significant to the shelf-life of commercial systems, and determining the influence of this parameter on some well defined model systems if of both fundamental and practical significance.