A major influence on particles and amphiphile adsorption, particularly for charged materials is the surface potential. Recent experiments have shown that this can be manipulated artificially by applying electric potentials to e.g. silicon/silica/solution interfaces. Surprising irreversible binding of an anionic surfactant was observed and the origin of this phenomenon will be determined by exploring behaviour of different surfactants using neutron reflectivity. In particular we will explore the removal of cationic surfactants by applying a positive potential and changes in the adsorption isotherm when the 'natural' negative potential is increased. This work will develop an understanding of the influence of applied fields and allow means to control modification of interfaces that will be of wide importance in many applications.