Competitive adsorption of polymers and surfactants at the solid/liquid interface

The competitive adsorption of three cationic polymers (JR polymers) and a cationic surfactant (CTAB) onto a silica surface from a low ionic strength medium has been investigated. Competition between polymers showed that smaller molecules were adsorbed initially, preventing the subsequent adsorption of larger polymers. Adsorption from combined polymer and surfactant systems showed that the smallest polymer (JR 125) was excluded from the surface, the intermediate molecular mass polymer (JR 400) was almost unaffected by the surfactant and the largest molecular mass polymer (JR 30M) was partially excluded from the surface. These experiments showed the importance of having sufficient bonding groups on the polymer and the relative rates of diffusion to the surface.