Adsorption of polymer and surfactant from their binary mixtures on alumina

Thee adsorption of water-soluble polymers and surfactants on positively charged alumina has been investigated. In the case of same charged adsorbates, such as sodium poly (styrenesulfonate) (PSS) and sodium dodecylsulfate (SDS), the competitive adsorption between PSS and SDS on alumina occurs, where the adsorption strength of SDS is much greater than that of PSS. The adsorption from opposite charged adsorbates of PSS and hexadecyltrimetlyiammonium chloride (HTAC) shows enhancement of HTAC adsorption by PSS due to a formation of their complexes on alumina surface, which provides a lower micropolarity compared with those of respective adsorbates. In the case of neutral polymer and anionic surfactants, such as poly(vinylpyrrolidone) (PVP) and lithium dodecyl sulfate (LiDS), lithium perfluorooctanesulfonate (LiFOS), and sodium bis (2-ethylhexyl)sulfosuccinate(AOT), the adsorption of anionic surfactants enhances remarkably the adsorption of PVP at low surfactant concentrations due to a formation of PVP-surfactant complexes. However, at high surfactant concentrations, the adsorption of PVP decreases where the magnitude in the adsorption of PVP is still higher than that in the absence of the surfactants. In particular, the adsorption of PVP is most enhanced by the adsorption of-AOT. In addition, the conformation of PVP adsorbed on alumina takes predominantly as train segments even in a wide range of PVP adsorption: the PVP-LiFOS system shows a larger train portion for PW conformation in comparison with PVP-LiDS and PVP-AOT systems.