Association of anionic surfactant and physisorbed branched brush layers probed by neutron and optical reflectometry
2015 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 440, 245-252 p.Article in journal (Refereed) Published
Pre-adsorbed branched brush layers were formed on silica surfaces by adsorption of a diblock copolymer consisting of a linear cationic block and an uncharged bottle-brush block. The charge of the silica surface was found to affect the adsorption, with lower amounts of the cationic polyelectrolyte depositing on less charged silica. Cleaning under basic conditions rendered surfaces more negatively charged (more negative zeta-potential) than acid cleaning and was therefore used to increase polyelectrolyte adsorption. The structure of adsorbed layers of the diblock copolymer was as determined by neutron reflectometry found to be about 70 nm thick and very water rich (97%). Interactions between the anionic surfactant sodium dodecylsulfate (SDS) and such pre-adsorbed diblock polymer layers were studied by neutron reflectometry and by optical reflectometry. Optical reflectometry was also used for deducing interactions between the individual blocks of the diblock copolymer and SDS at the silica/aqueous interface. We find that SDS is readily incorporated in the diblock copolymer layer at low SDS concentrations, and preferentially co-localized with the cationic block of the polymer next to the silica surface. At higher SDS concentrations some desorption of polyelectrolyte/surfactant complexes takes place.
Place, publisher, year, edition, pages
2015. Vol. 440, 245-252 p.
Polymer brush layer, Diblock copolymer, SDS, Adsorption, Polyelectrolyte-surfactant complex, Optical reflectometry, Neutron reflectivity
IdentifiersURN: urn:nbn:se:kth:diva-157337DOI: 10.1016/j.jcis.2014.11.002ISI: 000346461100031ScopusID: 2-s2.0-84911423822OAI: oai:DiVA.org:kth-157337DiVA: diva2:769732
FunderSwedish Research CouncilVINNOVAEU, FP7, Seventh Framework Programme, 290251
QC 20150220. Updated from manuscript to published article.2014-12-092014-12-092015-02-20Bibliographically approved