Synthesis of monodisperse Zn-smectite

The preparation of ultra-thin clay mineral films promises to open novel applications for more sensitive sensors, stronger plastics and other unexpected functionalities. However, most natural and synthetic clay particles necessarily need often tedious preparation procedures to remove crystalline impurities and to obtain completely exfoliated forms. Furthermore, the wide range of particle sizes characteristic of commonly available synthetic and natural clays can lead to variable properties and unexpected reactions. Here we report the synthesis of a homogenous monolayer-thick Zn-smectite that will benefit specific applications requiring ultra-thin and monodispersed layered nanomaterials. Furthermore, the fast and easy preparation overcomes the problems associated with the processing of both currently available synthetic and natural smectites. XRD, FE-SEM, and TEM analyses show the synthetic Zn-smectites to be relatively impurity free. Electron microscopy imaging illustrates its nanometer-sized dimension and very thin sheet-like morphology. Based on light scattering and small angle X-ray scattering measurements, it has a narrow size distribution (ave.similar to 70 nm) and a molecular-level thickness (similar to 0.7 nm), respectively. This nanostructure combined with the interesting properties of Zn is anticipated to yield novel applications as a clay-based nanomaterial. (C) 2009 Elsevier B.V. All rights reserved.