Adsorption of Low charge Density Polyelectrolyte Containing Poly(ethylene oxide) Side chains on Silica: Effects of Ionic strength and pH
2005 (English)In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 38, no 14, 6152-6160 p.Article in journal (Refereed) Published
Adsorption characteristics of a random copolymer of poly(ethylene oxide) monomethyl ether methacrylate and methacryloxyethyl trimethylammonium chloride (PEOMENIA:METAC) on silica were studied using stagnation point adsorption reflectometry (SPAR), quartz crystal microbalance with dissipation (QCM-D), and contact angle techniques. The PEOMEMA:METAC copolymer used in this study is a low charge density polyelectrolyte, with 2% of the monomer units carrying permanent positive charges and 98% containing poly(ethylene oxide) side chains that are approximately 45 repeating units long. The surface excess was determined as a function of pH and concentration of indifferent electrolyte. It was found that the presence of a small amount of 1: 1 electrolyte decreases the adsorbed amount significantly. Further, increasing the pH at a constant ionic strength, 10 mM, results in decreasing surface excess. It is suggested that the adsorption is realized via a combination of non-Coulomb interactions between the poly(ethylene oxide), PEO, grafts and protonated silanol groups at the silica-solution interface and an electrostatic interaction between the charged segments and the oppositely charged surface. Increasing pH and/or salt concentration results in progressive charging of the silica surface with the consequent decrease in affinity between silica and PEO, explaining the decrease in the adsorbed amount of the polymer.
Place, publisher, year, edition, pages
2005. Vol. 38, no 14, 6152-6160 p.
Adsorption; Ammonium compounds; Contact angle; Copolymers; Electric charge; Ionic strength; pH effects; Polyethylene oxides; Quartz; Reflectometers; Silica; Charge density; Low charge density polyelectrolytes; Quartz crystal microbalance with dissipation (QCM-D); Stagnation point adsorption reflectometry (SPAR)
IdentifiersURN: urn:nbn:se:kth:diva-8143DOI: 10.1021/ma050851xISI: 000230376400041ScopusID: 2-s2.0-22944446391OAI: oai:DiVA.org:kth-8143DiVA: diva2:13388
QC 201008132008-03-272008-03-272010-08-13Bibliographically approved