Directed nucleation of calcite at a crystal-imprinted polymer surface

The finely tuned properties of natural biominerals and composites reflect t he remarkable level of control that is exercised over the size, shape and o rganization of the constituent crystals(1-4). Achieving this degree of cont rol over synthetic materials might therefore lead to superior material prop erties. Organic small molecules, polymers or surfactant mesophases have bee n used to guide the growth and morphology of inorganic materials via steric constraints or structure-directing interactions(5-16). Here we show that s ynthetic polymers can be imprinted with motifs of crystal surfaces so as to template the growth of specific crystal phases. Our polymers, imprinted wi th calcite, are able to induce the nucleation of calcite under conditions f avouring the growth of aragonite (another polymorph of calcium carbonate). The synthesis of the polymers, based on the principles of molecular imprint ing(17-20), involves the adsorption of functional monomers to a calcite sur face, followed by co-polymerization with a cross-linker to create an imprin t of the crystal surface. Subsequent removal of the calcite template yields a polymer matrix with a surface functionality mirroring the crystal face a nd able to promote the nucleation of calcite. We expect that the molecular- imprinting approach to directed nucleation can be applied to crystals other than calcite.