Taking the desirable attributes of CVD and aqueous plating techniques while minimizing the disadvantages of each, supercritical fluid chemical deposition (SFCD) demonstrates itself to be a promising process alternative to enable the fabrication of nanostructured devices. This paper gives information about the SFCD process for metal deposition as an alternative to CVD through various examples of inorganic deposition (films or nanostructures). In particular, the use of SFCD will be demonstrated for the surface modification of carbon nanotubes (CNTs) and their decoration with palladium nanoparticles.

Polymer swelling by scCO2 was mainly studied to understand many industrial processes, especially in the field of pharmacy for drug delivery (impregnation) and also polymer processing by CO2-assisted extrusion. We have studied here another application of polymer swelling by scCO2 for the synthesis of nanocomposites. The selected model system was the direct synthesis of copper nanoparticles in a poly(ethylene glycol) matrix (PEG). The study of the formation of nanostructures in polymer matrix is constituted of three main steps: i) thermodynamical behaviour of the polymer/CO2 system, ii) viscosity of the polymer/CO2 system and iii) nucleation and growth of copper nanoparticles. First, the thermodynamical behaviour of the PEG/CO2 system was studied by in situ IR spectroscopy. This method gives accurate values of the polymer swelling by scCO2 but also of the CO2 sorption in the polymer. For example, at 40°C-15MPa, the swelling of PEG is equal to 35% for a CO2 solubility of 23 wt%. Secondly, we have developed an original falling ball viscometer for the determination of PEG viscosity as a function of CO2 density. A good knowledge of the polymer/CO2 system is finally used for the control of formation of copper nanoparticles. This formation was followed by in situ UV - visible spectroscopy and characterized by transmission electron microscopy.