Surface interactions during polyelectrolyte multilayer buildup. 1. Interactions and layer structure in dilute electrolyte solutions
2004 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 20, no 13, 5432-5438 p.Article in journal (Refereed) Published
We report the investigation of surface forces between polyelectrolyte multilayers of poly(allylamine hydrochloride) (PAH) and poly(styrenesulfonate sodium salt) (PSS) assembled on mica surfaces during film buildup using a surface force apparatus. Up to four polyelectrolyte layers were prepared on each surface ex situ, and the surface interactions were measured in 10(-4) M KBr solutions. The film thickness under high compressive loads (above 2000 muN/m) increased linearly with the number of deposited layers. In all cases, the interaction between identical surfaces at large separations (> 100 Angstrom from contact) was dominated by electrostatic double-layer repulsion. By fitting DLVO theory to the experimental force curves, the apparent double-layer potential of the interacting surfaces was calculated. At shorter separations, an additional non-DLVO repulsion was present due to polyelectrolyte chains extending some distance from the surface into solution, thus generating an electrosteric type of repulsion. Forces between dissimilar multilayers (i.e., one of the multilayers terminated with PSS and the other with PAH) were attractive at large separations (30-400 Angstrom) owing to a combination of electrostatic attraction and polyelectrolyte bridging.
Place, publisher, year, edition, pages
2004. Vol. 20, no 13, 5432-5438 p.
self-assembly process, cationic bipolar amphiphiles, mica surfaces, charged surfaces, consecutive adsorption, force measurements, hydration forces, films, particles, salt
IdentifiersURN: urn:nbn:se:kth:diva-23519DOI: 10.1021/la049636kISI: 000222174800043ScopusID: 2-s2.0-3042680433OAI: oai:DiVA.org:kth-23519DiVA: diva2:342217
QC 20100525, QC 201110172010-08-102010-08-102012-03-21Bibliographically approved