Anionic surfactant induced desorption of a cationic surfactant from mica.

The adsorption and desorption of a cationic surfactant, didodecyldimethy- lammonium bromide, from water onto a mica surface has been investigated using neutron reflectivity. The surfactant was observed to adsorb strongly as a bilayer that was tenacious to a sustained water wash, but on the addition of an anionic surfactant, sodium dodecyl sulfate, at its critical micelle concentration complete desorption was observed.We thank BP PLC for funding (RG8620), and specifically Stephanie Houston and Isabella Stocker for their input. We also thank ISIS (RB 1710119, DOI:10.5286/ISIS.E.86389514) and the beamtime committee for the allocation of beamtime, as well as the beamline scientists for their invaluable support