International audienceTert-butanol is the molecular archetype of a variety of H-bonded systems that form micelle-like supermolecular clusters in the liquid state. This self-association process is characterized by a prepeak in the static structure factor. Recently, it has been shown by neutron scattering that this prepeak is totally suppressed in a nanoconfined geometry [Morineau, D.; Alba-Simionesco, C. J. Phys. Chem. Lett. 2010, 1, 7155.]. The authors have shown that excluded volume effects was one main ingredient of this suppression, but the question of the survival of H-bonded self-association in nanochannels has remained unresolved experimentally. From molecular dynamics simulations, we prove that self-association survives under confinement despite the absence of the prepeak. Furthermore, we show that its apparent suppression is due to a negative contribution arising from the liquid-porous solid correlations, which cannot be disentangled experimentally. Strikingly, the stability of micelle-like clusters surpasses the putative formation of interfacial H-bonds with surface silanols, leading to an unexpected hydrophobic interaction of tert-butanol with surface silica. This work highlights the foremost interest of combining neutron scattering and molecular simulations with a careful account of the complex situation encountered under confinement to better understand the molecular microstructure of H-bonded liquids

From hydrogen bonds, tert-butanol molecules self-organize in micelle-like supermolecular clusters in the liquid state. While these nanoclusters have been largely investigated in the bulk phase, the confined situation remains seldom. However, from a relevant combination of neutron scattering and molecular simulation, it has been shown that these clusters persisted under hydrophilic cylindrical confinement [