Formation of aqueous colloidal dispersions of exfoliated γ-zirconium phosphate by intercalation of short alkylamines

A good exfoliation of layered gamma-zirconium phosphate in aqueous medium at room temperature has been obtained by intercalation of short alkylamines such as methyl-, dimethyl- and ethyl-amine. No appreciable exfoliation was observed when butylamine or longer alkylamines were intercalated, while intermediate behavior was obtained with the intercalation of propylamine. Since a good exfoliation of this layered compound is an essential step for its functionalization by topochemical reactions with phosphonic or phosphinic acids, the amine intercalation compounds and the various steps of the intercalation processes were investigated in order to obtain information on the mechanism of the exfoliation and a model of this mechanism is proposed. The use of the colloidal dispersion of exfoliated lamellae for the preparation of auto-consistent and flexible membranes as well as thin supported films of gamma-zirconium phosphate is described.