Improved Dielectric Model for Polyvinyl Alcohol-Water Hydrogel at Microwave Frequencies
You Kok Yeow, Zulkifly Abbas, Kaida Khalid and Mohamad Zaki Abdul Rahman
DOI : 10.3844/ajassp.2010.270.276
American Journal of Applied Sciences
Volume 7, Issue 2
Problem statement: The study described rigorous dielectric modeling for Polyvinyl Alcohol (PVA)-water hydrogel mixture at microwave frequencies. Approach: A commercial open-ended coaxial sensor was used to measure the dielectric constant, loss factor and ionic conductivity, ? of PVA-water hydrogel mixture ranging concentration of 80-100% water content. Results: The sensor was operating between 0.13 and 20 GHz at and above of room temperature (25±1)°C. Indirectly, the relaxation time, ?, activation energy, Q and entropy change, ?S of the hydrogel mixtures are determined based on linear fitting of measured data using Debye and Arrhenius approaches. Conclusion/Recommendations: Two main relaxation processes were found ranging 2-10 and 10-20 GHz, respectively. Dielectric dispersion is suggested to describe by combination of Cole-Davidson (CD) and Debye (Dy) processes. The results are discussed qualitatively based on bound states of water in hydrogel mixtures.
© 2010 You Kok Yeow, Zulkifly Abbas, Kaida Khalid and Mohamad Zaki Abdul Rahman. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.