Nanoarchitectonics of a cation-exchangeable layered Mg-silicate and its direct crystallization on synthetic fluorophlogopite mica particles

This study aimed to prepare a hybrid of cation-exchangeable stevensite-like magnesium-layered silicate and a synthetic mica (fluorophlogopite). The magnesium-layered silicate was synthesized via the reaction of magnesium chloride with colloidal silica in the presence of urea under hydrothermal conditions (100 °C or 140 °C for 2 d). The cation-exchange capacity of the stevensite-like silicate was influenced by the operating temperature; specifically, a higher capacity was achieved at a higher temperature (0.42 meq/g stevensite at 140 °C and 0.36 meq/g at 100 °C). The capacity was also affected by the solution pH, which was directly related to the growth rates of the octahedral and tetrahedral sheets. Upon addition of fluorophlogopite into the starting mixture, direct crystallization of the stevensite-like layered silicate occurred on the fluorophlogopite particles via hydrothermal treatment for possible applications as a cosmetic pigment.