Association of anionic surfactant and physisorbed branched brush layers probed by neutron and optical reflectometry.

Research output: Contribution to journalArticle

Abstract

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 70nm 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.

Details

Authors
  • Xiaoyan Liu
  • Andra Dedinaite
  • Tommy Nylander
  • Aleksandra Dabkowska
  • Maximilian Skoda
  • Ricardas Makuska
  • Per M Claesson
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry
  • Nano Technology
Original languageEnglish
Pages (from-to)245-252
JournalJournal of Colloid and Interface Science
Volume440
Publication statusPublished - 2015
Publication categoryResearch
Peer-reviewedYes