INORGANIC ORGANIC HOST-GUEST MATERIALS - SURFACE AND INTERCLAY REACTIONS OF STYRENE WITH COPPER(II)-EXCHANGED HECTORITE/

Many important layered silicate-polymer nanocomposite materials may be synthesized using an in-situ polymerization process. Using this techn ique, organic monomers are intercalated into the interlayer regions of the hosts, where subsequent polymerization may then occur. In this pa per, we report on the in-situ polymerization of styrene in Cu(II)-exch anged hectorite thin films. Scanning force microscopy (SFM) images of the polymer surface reveal that the surface polystyrene is generally a ggregated into groups of elongated strands. SFM imaging of the intercl ay regions, in conjunction with X-ray diffraction (XRD) and electron s pin resonance (ESR) data, indicates that approximately 20-30% of these regions contain polystyrene, with minimal reduction in the majority o f Cu2+ sites observed. XRD data shows little or no intercalation of th e monomer into the true intergallery regions. Instead, the polymer lik ely forms in intercrystallite or planar defect regions. In addition, t wo distinct phases of polymeric material are found within these defect regions, a highly polymerized polystyrene in addition to a polystyren e form exhibiting greater material stiffness. (C) 1998 John Wiley & So ns, Inc.