TY  - JOUR
AU  - Yeow, You Kok 
AU  - Abbas, Zulkifly 
AU  - Khalid, Kaida 
AU  - Rahman, Mohamad Zaki Abdul 
PY  - 2010
TI  - Improved Dielectric Model for Polyvinyl Alcohol-Water Hydrogel at Microwave Frequencies
JF  - American Journal of Applied Sciences
VL  - 7
IS  - 2
DO  - 10.3844/ajassp.2010.270.276
UR  - https://thescipub.com/abstract/ajassp.2010.270.276
AB  - 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, σ 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, τ, activation energy, Q and entropy change, ΔS 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.