Binding of sodium dodecyl sulfate to polyethylene oxide at the silica—water interface

Abstract

The effect of preadsorbed polethylene oxide (PEO) on silica on the subsequent adsorption of sodium dodecyl sulfate (SDS) on the silica was investigated in this study. Even though SDS does not normally adsorb on the similarly charged silica, it is shown that anionic SDS can be made to adsorb on it in the presence of preadsorbed PEO. The role of polymer molecular weight and the mode of addition of SDS were also investigated. The amount of SDS bound to PEO preadsorbed on silica was not affected by the polymer molecular weight. Interestingly, adsorption of SDS determined from its mixtures with PEO in solution is lower than that found on preadsorbed PEO on silica. It is also shown that interactions between PEO and SDS at the silica—water interface are stronger than the interactions between them in bulk solution.