Résumé:
Polymer thin films are efficient matrices to stabilize nanoparticles; however, their potential utility as active matrices for the fabrication and utilization of metallic and molecular nanoparticles has not been extensively exploited. Polymer-metal nanocomposite thin films combine the unique characteristics of the components as well as manifest mutualistic effects. We will describe a soft chemistry within polymer thin films that facilitates the in situ generation of noble metal nanoparticles, crystal-to-crystal transformation at the nanoscale, the fabrication of unusual materials like mercury nanodrops and nanocrystals (A) and the range of applications of the nanocomposite thin films from nonlinear optics to sensing and catalysis.
Development of simple protocols to tune molecular assembly and hence the materials responses can open up new avenues in the field of molecular materials; the amorphous phase offers a new dimension of exploration in this context. As an illustrative case, we consider diaminodicyanoquinodimethanes (DADQ) which show strong fluorescence enhancement from the solution to the crystalline solid state. The amorphous-to-crystalline transformation of DADQ nanoparticles (B) partially confined by fixing in a polymer thin film demonstrates the induction and control of molecular assembly at the nanoscale with significant consequences for fluorescence emission responses. Relevance of the amorphous phase to fundamental nucleation theories will be highlighted.

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