Structure and thermal behavior of layered silver perfluorocarboxylates

Abstract

The structure and thermal behavior of silver perfluorocarboxylates (AgCO2(CF3)(n)CF3, n = 10, 12, 14, and 16) have been investigated by using various analytical tools. The X-ray diffraction patterns were composed of a series of peaks that could be indexed to (0k0) reflections of a layered structure. The adjacent layers were presumed to overlap by as much as 94% of the terminal CF3 groups. Diffuse, reflectance infrared Fourier transform spectroscopy revealed that the binding state of the carboxylate group to silver was a bridging one. The thermal analyses indicated that a chain melting process commenced at similar to560 K without any interim premelting event but the thermal decomposition reaction was followed immediately after the chain melting process. More importantly, the temperature at which the structural collapse occurred was found to be similar to100 K higher than that in silver hydroalkanecarboxylate such as silver stearate. The enhanced thermal stability seemed to be associated with the high rigidity of the fluorocarbon chains. Perfluorocarbons are thus expected to be a promising organic moiety, endowing the organic/inorganic hybrid materials with high thermal stability.