High Frequency Surface Viscoelastic Characterization of Polymer Gels
Abstract
Recent studies indicate that the quartz crystal microbalance (QCM) has relevant uses in the field of soft material contact mechanics. The QCM consists of a thin, quartz crystal disk that has metal electrodes deposited on both faces of the crystal. When a load is applied to either of the electrode surfaces, the change in resonant frequency and change in HWHM of the resonance are predicted based on the contact area and mechanical properties of the loading material. In our experiments, hemispherical polymer gels are formed using a physically crosslinked triblock copolymer. Contact experiments in which the gels are brought in and out of contact with the QCM allow the high frequency viscosity of the gels to be calculated. It is found that reduced viscosity increases exponentially with polymer concentration, a result that is consistent with published data on the high frequency rheological behavior of dilute polymer solutions. It should also be noted that the QCM is sensitive only to a depth of around 1 micron, which may be useful in determining if there is a solvent layer at the surface of the gels.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MARH21007N