The role of added surfactant in a biomimetic in situ synthesis of inorganic/polymer composites in which the inorganic phase displays uniformity of size, morphology, phase, and crystallographic orientation is discussed. Addition of a surfactant, AOT, to the synthetic system induces nucleation and orientation of CdS crystals within a poly(ethylene oxide) film. Interaction of the AOT with polymer-bound Cd2+ ions determines the nucleation and orientation of the resulting crystals. Other surfactants, with different structures and headgroups, produced different results, ranging from inhibition of mineral growth to extraction of the cations from the film. The use of other metals in place of Cd2+ results in different interactions and produces a change in the order of the product. (c) 2005 Elsevier B.V. All rights reserved.