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Journal of Sensors
Volume 2014 (2014), Article ID 373528, 8 pages
http://dx.doi.org/10.1155/2014/373528
Research Article

Effect of a Non-Newtonian Load on Signature for Quartz Crystal Microbalance Measurements

1School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
2Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive, Singapore 637553
3Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
4School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459

Received 12 July 2014; Accepted 27 October 2014; Published 13 November 2014

Academic Editor: Ignacio R. Matias

Copyright © 2014 Jae-Hyeok Choi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The quartz crystal microbalance (QCM) is increasingly used for monitoring the interfacial interaction between surfaces and macromolecules such as biomaterials, polymers, and metals. Recent QCM applications deal with several types of liquids with various viscous macromolecule compounds, which behave differently from Newtonian liquids. To properly monitor such interactions, it is crucial to understand the influence of the non-Newtonian fluid on the QCM measurement response. As a quantitative indicator of non-Newtonian behavior, we used the quartz resonator signature, , of the QCM measurement response, which has a consistent value for Newtonian fluids. We then modified De Kee’s non-Newtonian three-parameter model to apply it to our prediction of values for non-Newtonian liquids. As a model, we chose polyethylene glycol (PEG400) with the titration of its volume concentration in deionized water. As the volume concentration of PEG400 increased, the value decreased, confirming that the modified De Kee’s three-parameter model can predict the change in value. Collectively, the findings presented herein enable the application of the quartz resonator signature, , to verify QCM measurement analysis in relation to a wide range of experimental subjects that may exhibit non-Newtonian behavior, including polymers and biomaterials.