Hybrid materials: Intricate structures guiding complex dynamics.

The structure and certain properties of Class {I} and Class {II} nanocomposites based on silica-poly(ethylene)oxide blends are described herein. The detailed structure of the silica framework of Class {I} materials is depicted by combining Si-29 NMR and X-Ray diffractometry, while the properties of the polymer phase are obtained from C-13 NMR and thermal analysis (DSC). These experiments demonstrate the significant influence of the catalyst on the silica structure (compositional and positional disordering). Moreover, the dynamic properties of the polymer phase are greatly effected by the silica morphologies (silica surface area and degree of phase interpenetration). Class {II} materials were also studied. They have rubbery properties and can be used as a matrix to absorb large quantities of solvents. Hence, combining uniaxial anisotropy (through unidirectionnal strain) with deuterated molecules enabled the study of these materials by quadrupolar NMR. This technique is very sensitive to the local anisotropy of the samples used and leads to a better understanding of supramolecular interactions between probe and host polymer.