Marcoule Institute for Separative Chemistry

The main objective of the laboratory of sonochemistry in complex fluids (LSFC) consists in fundamental studies of the mechanisms of sonochemical reactions in homogeneous solutions and in heterogeneous systems. Studied systems are bound to research performed for the next generation of nuclear reactors, which aim at a sustainable development. Sonochemistry, i.e. the chemical effects of ultrasound, originates in acoustic cavitation: nucleation, growth and implosion of gas bubbles in liquids submitted to an ultrasonic field. The implosion occurs on the microsecond time scale and the collapse induces extreme local conditions of temperature and pressure (~5000 K, several 100 bar) and cooling rates of the order of 1010 K s^-1. This local concentration of energy constitutes the origin of the light emission by the cavitation bubbles (the sonoluminescence), of the chemical activity in the bulk and of the evolution of heterogeneous systems. Each cavitation bubble, having a resonance size of ~150 μm at 20 kHz, can be considered as a high-temperature microreactor that does not need specific reactants to be added and that does not generate additional waste, hence adhering to the "green chemistry" principles.

The main tasks of the LSFC are to study:

• (i) "single-bubble" and "multi-bubble" sonoluminescence,
• (ii) the mechanisms of sonochemical synthesis of nanoparticles and the interaction of nanoparticles with the cavitation bubbles,
• (iii) the sonochemical reactivity at the solid-liquid interface.