نبذة مختصرة : International audience ; Aerosol evolution is a major challenge in climatology. Many questions remain unanswered, especially in the field of cloud microphysics. The aerosols studied here consist of micrometric water droplets formed from a mixture of water-saturated air and HFE7100, and are studied using a set-up that combines optical microtomography and Fourier transform infrared spectrophotometry (FT-IR). Parabolic flight experiments were performed with different concentrations of HFE. About 500 droplets are tracked over time. During the microgravity phase (about 22 s), as they move slowly, a high degree of coherence is achieved between successive microtomographic images. This makes it possible to follow each individual droplet and thus to study the overall dynamics of evaporation. FT-IR analysis provides a time-resolved measurement of the evolution of the chemical composition of the gas phase. This work demonstrates the possibility of analyzing aerosols under microgravity conditions using optical microtomography and FT-IR analysis simultaneously. The combination of these two techniques provides access to both the chemical composition and the size distribution of the droplets, opening up interesting prospects for the description of droplet nucleation and evaporation in gas mixtures
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