Conformation of preadsorbed Polyelectrolyte Layers on Silica studied by secondary Adsorption of Colloidal Silica
2008 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 325, no 1, 84-92 p.Article in journal (Refereed) Published
The conformation of cationic polyelectrolytes preadsorbed on macroscopic silica surfaces was studied before and after addition of colloidal silica (CS) and compared to the fixation capacity of CS. The Study included two polyelectrolytes of equal charge density, cationic polyacrylamide and cationic dextran. Adsorbed amounts were determined with stagnation point adsorption reflectometry (SPAR) and quartz crystal microgravimetry (QCM). Unsaturated layers of polyelectrolyte were formed in SPAR by stopping the adsorption at a fractional coverage relative to saturation adsorption. These layers were probed by secondary saturation adsorption of colloidal silica (CS). At low salt concentrations a high fractional coverage of polyelectrolyte was required to attain adsorption of CS, while significant adsorption of CS was found also for low fractional coverages of polyelectrolyte at salt concentrations above 10 mM NaCl. Saturation adsorption of cationic polyacrylamide (CPAM) and cationic dextran (Cdextran) onto the silica surface was found to be similar, while the secondary adsorption of CS was significantly higher onto preadsorbed CPAM compared with Cdextran. The QCM and SPAR data together indicated that the adsorbed layer of Cdextran was thinner than CPAM, and that a loose, expanded layer was formed after adsorption of CS on CPAM but not on Cdextran.
Place, publisher, year, edition, pages
2008. Vol. 325, no 1, 84-92 p.
polyelectrolyte adsorption; conformation; cationic polyacrylamide; cationic dextran; colloidal silica; nanoparticles; reflectometry; quartz crystal microbalance
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-6015DOI: 10.1016/j.jcis.2008.05.023ISI: 000258791800010ScopusID: 2-s2.0-47749100395OAI: oai:DiVA.org:kth-6015DiVA: diva2:10586
QC 20100720. Uppdaterad från manuskript till artikel (20100720).2006-06-212006-06-212011-07-06Bibliographically approved