Double-hydrophilic block copolymers consisting of a long poly(ethylene oxide) block and a short poly(methacrylic acid) block, modified by partial alkylation with dodecylamine (PEO-b-PMAA-C 12 ) were employed as dispersed templates for the controlled precipitation of calcium phosphate from aqueous solution at different pH values. Two new and nontrivial superstructures of an organized inorganic/organic hybrid material were characterized by ultracentrifugation, small-and wide-angle X-ray analysis, and electron microscopy. At pH 3.5 and 4.0, and pH 4.5, 5.0, and 6.3, two different types of discrete nested structures are obtained which consist of hybrid nanofilaments arranged to give an unusual neuronlike morphology. The fibers originate from a core of similar size to the primary polymer aggregates, suggesting that cooperative interactions at a local level between dissolving calcium phosphate clusters and disassembling polymer units could be responsible for the highly anisotropic nature of the secondary growth process.Aging of the nanofilaments grown in acidic solution results in a second hybrid morphology, consisting of compact aggregates with a diameter of about 130 nm, which show the interlocked layer structure of an ordered inorganic/ organic mesophase with a repeat period of about 3 nm. Such calcium phosphate/ polymer nanohybrids with complex morphologies are interesting from the viewpoint of prebiotic structure formation, and might also be useful as novel ceramics precursors, reinforcing fillers, or biomedical implants.

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There are a number of strategies available for extending the length scale of structural organization in inorganic materials. Those that involve the assembly of inorganic nanoparticles into materials with higher-order architecture are collectively termed nanotectonics. In this review, we highlight one possible approach that involves the template-directed assembly of preformed nanoparticle building blocks. The inspiration for the use of preformed particles arises in part from studies of certain biomineral structures, some general aspects of which are summarized. Several synthetic examples of the use of template-directed approaches in nanotectonics are described in detail.