Adsorption of Anionic or Cationic Surfactants in Polyanionic Brushes and Its Effect on Brush Swelling and Fouling Resistance during Emulsion Filtration

Zhefei Yang, Volodymyr V. Tarabara, Merlin L. Bruening

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Atom transfer radical polymerization of ionic monomers from membrane surfaces yields polyelectrolyte brushes that swell in water and repel oil droplets to resist fouling during filtration of oil-in-water emulsions. However, surfactant adsorption to polyelectrolyte brushes may overcome this fouling resistance. This work examines adsorption of cationic and anionic surfactants in polyanionic brushes and the effect of these surfactants on emulsion filtration. In situ ellipsometry with films on flat surfaces shows that brushes composed of poly(3-sulfopropyl methacrylate salts) (pSPMK) swell 280% in water and do not adsorb sodium dodecyl sulfate (SDS). pSPMK-modified microfiltration membranes reject >99.9% of the oil from SDS-stabilized submicron emulsions, and the specific flux through these modified membranes is comparable to that through NF270 nanofiltration membranes. Moreover, the brush-modified membranes show no decline in flux over a 12 h filtration, whereas the flux through NF270 membranes decreases by 98.7%. In contrast, pSPMK brushes adsorb large quantities of cetyltrimethylammonium bromide (CTAB), and at low chain densities the brushes collapse in the presence of this cationic surfactant. Filtration of CTAB-stabilized emulsions through pSPMK-modified membranes gives minimal oil rejection, presumably due to the brush collapse. Thus, the fouling resistance of polyelectrolyte brush-modified membranes clearly depends on the surfactant composition in a particular emulsion.

Original languageEnglish
Pages (from-to)11790-11799
Number of pages10
JournalLangmuir
Volume31
Issue number43
DOIs
StatePublished - Oct 6 2015
Externally publishedYes

Funding

FundersFunder number
National Science FoundationIIA-1243433
U.S. Environmental Protection AgencyRC-83518301
National Science Foundation1243433

    Fingerprint

    Dive into the research topics of 'Adsorption of Anionic or Cationic Surfactants in Polyanionic Brushes and Its Effect on Brush Swelling and Fouling Resistance during Emulsion Filtration'. Together they form a unique fingerprint.

    Cite this