Neutron reflectometry of anionic surfactants on sapphire: A strong maximum in the adsorption near the critical micelle concentration
2016 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 471, 81-88 p.Article in journal (Refereed) PublishedText
The adsorption of the anionic surfactants, lithium, sodium and cesium dodecylsulfates, and sodium decylsulfonate, on the positively charged C-plane (0001) of sapphire (alumina) has been measured using neutron reflection. For each of the four surfactants there is a strong maximum in the adsorption at about the critical micelle concentration. The maximum becomes more marked from lithium to cesium. The measurements were reproduced over a range of different physical conditions and could not be accounted for in terms of impurities. The maximum is explained quantitatively by using the combination of a mass action model to calculate the mean activity of the surfactant, and a cooperative model of the adsorption (Frumkin), in which saturation of the layer is not attained until well above the critical micelle concentration.
Place, publisher, year, edition, pages
2016. Vol. 471, 81-88 p.
Surfactant adsorption, Solid-liquid interface, Adsorption maximum, Sodium dodecylsulfate, Neutron reflection, Adsorption isotherm, Charged surface
IdentifiersURN: urn:nbn:se:uu:diva-297770DOI: 10.1016/j.jcis.2016.03.014ISI: 000374511900011PubMedID: 26990955OAI: oai:DiVA.org:uu-297770DiVA: diva2:943665