Adsorption of alkyl polyglucosides on the solid/water interface: Equilibrium effects of alkyl chain length and head group polymerization
2004 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 20, p. 4051-4058Article in journal (Refereed)
Abstract [en]
The equilibrium adsorption behavior of two n-alkyl-b-D-glucosides (octyl, C8G1 and decyl, C10G1) and four n-alkyl-β-D-maltosides (octyl, C8G2, decyl, C10G2, dodecyl, C12G2 and tetradecyl, C14G2) from aqueous solution on a titania surface, as measured by ellipsometry, has been investigated. The main focus has been on the effect of changes in the alkyl chain length and head group polymerization, but a comparison with their adsorption on the silica/water and air/water interface is also presented. Some comparison with the corresponding adsorption of ethylene oxide surfactants, in particular C10E6 and C12E6 is given as well. For all alkyl polyglucosides, the maximum adsorbed amount on titania is reached slightly below cmc where it levels off to a plateau and the amount adsorbed corresponds roughly to a bilayer. However, there is no evidence that this is the actual conformation of the surfactant assemblies on the surface, but the surfactants could also be arranged in a micellar network. On hydrophilic silica, the adsorbed amount is a magnitude lower than on titania, corresponding roughly to a layer of surfactants lying flat on the surface. A change in the alkyl chain length does not result in any change in the plateau molar adsorbed amount at equilibrium, however the isotherm slope for the alkyl maltosides increases with increasing chain length. Head group polymerization on the other hand affects the adsorbed amount. The alkyl glucosides start adsorbing at lower bulk concentrations than the maltosides and equilibrate at higher adsorbed amounts above cmc. When compared with the ethylene oxide surfactants, it is confirmed that the EO-surfactants hardly adsorb on titania, since the measured changes in the ellipsometric angles are within the noise level. They do, however, adsorb strongly on silica
Place, publisher, year, edition, pages
2004. Vol. 20, p. 4051-4058
Keywords [en]
Adsorption, alkyl polyglucoside, oxide, titania, silica, non-ionic surfactant, ellipsometry, sugar based surfactant
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-27178OAI: oai:DiVA.org:ri-27178DiVA, id: diva2:1054182
Note
A1669
2016-12-082016-12-082020-12-01Bibliographically approved