Journal article
Quartz Crystal Microbalance with Dissipation (QCM-D) studies of the viscoelastic response from a continuously growing grafted polyelectrolyte layer
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, Δf, and dissipation, ΔD, in order to extract information on layer thickness, shear elasticity, μ, and shear viscosity, η, of the growing film.
The increasing rate of changes in Δf and ΔD 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 Δf and ΔD 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. © 2013 Elsevier Inc.
Language: | English |
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Year: | 2013 |
Pages: | 229-234 |
ISSN: | 10957103 and 00219797 |
Types: | Journal article |
DOI: | 10.1016/j.jcis.2013.07.008 |
ORCIDs: | Thormann, Esben |
Biomaterials Carboxylic acids Colloid and Surface Chemistry Elasticity Electrolytes Electronic, Optical and Magnetic Materials Film growth Grafting (chemical) Grafting from Iniferter Iniferters Models Photopolymerization Poly(acrylic acid ) Poly(acrylic acid) Polyethylenes Polymerization Polymers QCM-D Quartz Crystal Microbalance Quartz crystal microbalance Quartz crystal microbalances Surfaces, Coatings and Films Thick films Viscoelastic model Viscoelastic modeling Viscoelasticity Viscosity Voigt model alcohol article elasticity film measurement polyacrylic acid polyelectrolyte polymerization prediction priority journal quartz crystal microbalance sensor thickness viscoelasticity viscosity water