Résumé:

Nanotubes can be obtained from top down (Carbon nanotubes) or bottom up approaches (Organogels, self-structured bridged silsesquioxane…). In most cases the nature of the nanotubes determines the vibrational spectroscopy technique best suited for the study of the physical properties of the nanomaterial. In this presentation, some examples are discussed where the coupling of Raman and/or infrared spectroscopies with ab initio calculations has given new insights into both structural properties and self-assembling mechanisms of the nanomaterials. In the case of the encapsulation of foreign species in the hollow core of carbon nanotubes, resonant Raman spectroscopy allows studying the relation between size of the nano container and physical properties of the molecules under confinement (figure). Vibrational experiments were carried out under extreme conditions (diamond anvil cell technique for high pressure vibrational investigations). The pressure dependence of the Raman spectra allows assessing charge transfer properties between nanotube and encapsulated species under confinement. Infrared spectroscopy is a very powerful technique for the study of organogels of nanotubes and self-structured bridged silsesquioxane nanomaterials. The local and long range order structuring resulting from sol-gel reaction of organic or hybrid precursors have been investigated in situ using macro and micro spectroscopies in the middle and far infrared. The significant contribution of synchrotron radiation for infrared studies of hybrid nanomaterials under extreme conditions is reported. The infrared spectroscopy experiments are combined with density functional theory simulations allowing the study of the self-assembling properties of the materials.