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Mica powders with ultrahigh specific surface areas (ca. 100 m2/g) were treated with aqueous solutions of peroxide radical initiators bearing a single cationic group to exchange the mica surface ions with initiator cations. The stability of the initiators, the adsorption isotherms on the mica, and the adsorption equilibrium constants were measured. The resulting materials initiate the polymerization of styrene at various conditions, forming bound polymer chains in amounts up to ca. 30 wt % polymer (ca. 55 vol %) with respect to the mica. The bound chains could be removed from the surface by extraction with good solvents for poly(styrene) only when the solvent contained ions for ion exchange. On the basis of kinetic evidence, the mechanism of grafting appears to be propagation of free radicals from the surface into the monomer solution, i.e., “growth from the surface”. The results differ strongly from those previously obtained with a dicationic surface-bound azo initiator, where grafting was shown to occur by “growth to the surface”.

A novel synthetic concept is presented which allows, for the first time, the preparation of soluble, constitutionally well-defined transition-metal coordination polymers of considerable molecular weights from kinetically unstable, pseudotetrahedral copper(1)-and silver(1)-phenanthroline complexes. It is demonstrated that rigorous exclusion of all molecules that might act as competitive ligands for the metal ions of the polymer constitutes the central requirement for obtaining solutions of "proper" coordination polymers, i.e., polymers having a constant number of repeating units per individual chain. Tetrachloroethane was found to be an appropriate solvent for this purpose. Solubility of the copper(1) and silver(1) coordination polymers -which are polyelectrolytes -in this rather apolar solvent was achieved by the attachment of two hexyl side chains to each polymer repeating unit. It was thus possible to prove the defect-free constitution of the obtained coordination polymers and to show their excellent stability in solution with the aid of 'H and I3C NMR spectroscopy. Moreover, formation of coordination polymers of considerable chain lengths is supported by the complete disappearance of end-group absorptions in the 'H NMR spectra and the results of viscosimetric investigations.

Cation-bearing peroxide free-radical initiators were attached to mica surfaces via ion exchange and used to polymerize styrene. Polystyrene chains grafted to the mica by growth from the surface resulted. Scanning electron microscopy showed distinct droplets on the surface. The droplets appear, from their size, to each consist of a single polymer chain molecule. The density of the droplets on the surface could be varied by varying the polymerization time. The droplets could be made to coalesce into thin films by increasing the grafting density, by heating, or by solvent treatment. Upon heating, the droplets appeared to spread on the surface at temperatures well below the normal glass transition temperature of polystyrene.

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