{"title":"Dielectric studies of polyacrylamide hydrogels","authors":"A. Konsta, D. Daoukaki, A. Kyritis, P. Pissis","doi":"10.1109/ISE.1996.578205","DOIUrl":null,"url":null,"abstract":"The dielectric properties of polyacrylamide/water hydrogels, as a function of water content and temperature, are investigated using ac dielectric relaxation spectroscopy (DRS) in the frequency range 5 Hz-13 MHz and thermally stimulated depolarization currents (TSDC) in the temperature range 77-300 K. TSDC spectra reveal three peaks, the first two being attributed to the reorientation of free and loosely bound water molecules respectively, whereas the third one is a manifestation of the glass transition in the hydrogel constituents. DRS spectra display a dielectric dispersion which shifts gradually to lower frequencies with decreasing T. The water crystallization at T<0 /spl deg/C, as well as the non-reversibility of the freezing-thawing process, are clearly demonstrated from the evolution of ac conductivity spectra with temperature.","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"3 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"9th International Symposium on Electrets (ISE 9) Proceedings","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/ISE.1996.578205","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The dielectric properties of polyacrylamide/water hydrogels, as a function of water content and temperature, are investigated using ac dielectric relaxation spectroscopy (DRS) in the frequency range 5 Hz-13 MHz and thermally stimulated depolarization currents (TSDC) in the temperature range 77-300 K. TSDC spectra reveal three peaks, the first two being attributed to the reorientation of free and loosely bound water molecules respectively, whereas the third one is a manifestation of the glass transition in the hydrogel constituents. DRS spectra display a dielectric dispersion which shifts gradually to lower frequencies with decreasing T. The water crystallization at T<0 /spl deg/C, as well as the non-reversibility of the freezing-thawing process, are clearly demonstrated from the evolution of ac conductivity spectra with temperature.