Quartz Crystal Microbalance with Dissipation (QCM-D) studies of the viscoelastic response from a continuously growing grafted polyelectrolyte layer
2013 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 408, 229-234 p.Article in journal (Refereed) Published
Poly(acrylic acid) was grown from substrates by photopolymerization, and the grafting process was monitored in situ by Quartz Crystal Microbalance with Dissipation (QCM-D) measurements in a 1:1 v/v mixture of water/ethanol. The polymerization process was monitored into the thick film region, where the change in frequency and dissipation with increasing film mass changes sign as predicted by the Voigt viscoelastic model. Our experimental data are compared with predictions of this model, and satisfactory agreement is found for low overtone numbers. The Voigt model was applied to analyze the measured changes in frequency, Delta f, and dissipation, Delta D, in order to extract information on layer thickness, shear elasticity, mu, and shear viscosity, eta, of the growing film. The increasing rate of changes in Delta f and Delta D observed after about 150 s of polymerization was found to correlate with an increasing growth rate of the film thickness. For longer polymerization times a close to linear increase in thickness with time was observed. The sensitivity, defined as the derivatives of Delta f and Delta D with respect to thickness, depends on overtone number and is different for the frequency and dissipation signals - facts that should be considered when investigating small changes in thick films used in e.g. sensor applications.
Place, publisher, year, edition, pages
2013. Vol. 408, 229-234 p.
Quartz Crystal Microbalance, QCM-D, Viscoelastic model, Voigt model, Grafting from, Iniferter, Poly(acrylic acid)
IdentifiersURN: urn:nbn:se:kth:diva-129436DOI: 10.1016/j.jcis.2013.07.008ISI: 000323989900033ScopusID: 2-s2.0-84885182597OAI: oai:DiVA.org:kth-129436DiVA: diva2:652964
FunderSwedish Foundation for Strategic Research Vinnova, P38574-1
QC 201310022013-10-022013-09-302013-10-02Bibliographically approved