Improved dielectric model for polyvinyl alcohol-water hydrogel at microwave frequencies

• Main Authors: You, Kok Yeow, Z., Abbas, K., Khalid, M. Z. A., Rahman
• Format: Article
• Language: English
• Published: Science Publications 2010
• Subjects: TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.utm.my/id/eprint/26161/1/YouKokYeow2010_ImprovedDielectricModelforPolyvinylAlcoholWater.pdf; http://eprints.utm.my/id/eprint/26161/; https://www.thescipub.com/abstract/10.3844/ajassp.2010.270.276
• Institution: Universiti Teknologi Malaysia

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, s 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, t, 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.