Published online by Cambridge University Press: 09 July 2018
Dans le cadre de l'étude de l'interaction eau-kaolinite, des mesures de conductivité (pertes diélectriques) et de permittivités réelles ont été entreprises à fréquence variable (103–107 Hz) et en fonction de la température (27–80°C). La conductivité croît avec la fréquence et la température de mesures. L'utilisation d'un modèle de conduction par déplacement de protons par sauts discrets entre sites localisés est applicable. La loi σ′(ω) ∼ Aωs est vérifiée. L'évolution du paramètre s en fonction de la pression de vapeur d'eau permet de déterminer le mécanisme d'établissement de la monocouche d'eau sur le solide. La permittivité réelle décroît avec la fréquence. C'est une fonction croissante de la pression de vapeur d'eau. Un calcul simple permet de retrouver la loi expérimentale relative à la permittivité ɛ′ ∼ exp(K√P).
Measurements of conductivity (dielectric losses) and real part of permittivity were performed, at variable frequency (103–107 Hz) and as a function of temperature (27–80°C), in order to study the interaction between water vapour and kaolinite. The conductivity increased with frequency and temperature. The use of a conduction model involving proton hops between localized sites proved suitable. The law σ′(ω) = Aωs was verified. The development of parameter s as a function of water vapour pressure allowed determination of the mechanism of adsorption of water during monolayer formation on a solid. The real part of the permittivity decreased with frequency and increased with the water vapour pressure. A simple calculation led to the experimental law ɛ′ ∼ exp(K√P).
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