Chemical characterization of Titan's tholins: solubility, morphology and molecular structure revisited
Résumé
In this work Titan's atmospheric chemistry is simulated using a capacitively coupled plasma radio frequency discharge in a N2−CH4 stationnary flux. Samples of Titan's tholins are produced in gaseous mixtures containing either 2 or 10% methane before the plasma discharge, covering the methane concentration range measured in Titan's atmosphere. We study their solubility and associated morphology, their infrared spectroscopy signature and the mass distribution of the soluble fraction by mass spectrometry. An important result is to highlight that the previous Titan's tholin solubility studies are inappropriate to fully characterize such a heterogeneous organic matter and we develop a new protocol to evaluate quantitatively tholins solubility