@article {10.3844/ajassp.2010.270.276, article_type = {journal}, title = {Improved Dielectric Model for Polyvinyl Alcohol-Water Hydrogel at Microwave Frequencies}, author = {Yeow, You Kok and Abbas, Zulkifly and Khalid, Kaida and Rahman, Mohamad Zaki Abdul}, volume = {7}, year = {2010}, month = {Feb}, pages = {270-276}, doi = {10.3844/ajassp.2010.270.276}, url = {https://thescipub.com/abstract/ajassp.2010.270.276}, abstract = {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.}, journal = {American Journal of Applied Sciences}, publisher = {Science Publications} }