title: Effect of alcaline cations in zeolites on their dielectric properties.
abstract: The effect on dielectric properties of alkaline cations Li+, Na+ and K+ incorporated in a zeolite Faujasite structure X or Y, has been investigated. Two major phenomena have been proved to occur: ionic conductivity and rotational polarization of the water molecules adsorbed. The polarizability of the cation which is directly linked to its radius, affects ionic conductivity as well as rotational polarization. Li cations are more strongly Linked to the framework than K+ and Na+ and induce a lower ionic conductivity. K+ is weakly fixed and induces a ionic conductivity even at low solvation level. At low water content, the cation nature and number mainly control the free rotation of the water molecules and affect the relaxation frequency. Close to saturation, the water molecules are mainly linked together by H bonds: the cation nature and number do not really affect the global dielectric properties anymore.
authors.affiliation: Laboratoire de Sécurité des Procédés Chimiques (LSPC) INSA de Rouen, Saint Etienne du Rouvray, France.
authors.forename: Benoît
authors.initials: B
authors.lastname: Legras
authors.affiliation: Laboratoire de Sécurité des Procédés Chimiques (LSPC) INSA de Rouen, Saint Etienne du Rouvray, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Polaert
authors.affiliation: Laboratoire de Sécurité des Procédés Chimiques (LSPC) INSA de Rouen, Saint Etienne du Rouvray, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Estel
authors.affiliation: Direction Catalyse et Séparation IFP Energies Nouvelles - Lyon, Solaize, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Thomas
mesh_terms: D000468:Alkalies / Q000737:chemistry* / Q000528:radiation effects; D002412:Cations / Q000737:chemistry* / Q000528:radiation effects; D017097:Electric Impedance; D008422:Materials Testing; D008872:Microwaves; D014867:Water / Q000737:chemistry*; D017641:Zeolites / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D000468:Alkalies; D002412:Cations; D014867:Water; D017641:Zeolites