8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P7.38Thu 811:10-14:00Hydrogen-bond-induced supermolecular assemblies in ananoconfined tertiary alcoholAziz Ghoufi, 1 Denis Morineau, 1 Ronan Lefort, 1 and Ivanne Hureau 11 Institut of physics, University of Rennes, IPR, 263 general Leclerc, Beaulieu 32500,Rennes, FranceTert-butanol is the molecular archetype of a variety of H-bonded systems that form micelle-like supermolecularclusters in the liquid state. This self-association process is characterized by a prepeakin the static structure factor, Recently, it has been shown by neutron scatteriong that this prepeakis totally suppressed in nanoconfined geometry [D. Morineau and C. Alba-Simionesco, J. Phys.Chem. Letter, 1, 7155 (2010)]. The authors have shown that excluded volume effects was onemain ingredient of this suppression, but the question of the survival of H-bonded self-associationin nanochannels has remained unresolved experimentally. From Molecular Dynamics simulationswe prove that self-association survive under confinement despite the absence of the prepeak. Weshow that its apparent suppression is furthermore due to a negative contribution arising from theliquid-porous solid correlations, which can not be disentangled experimentally. Strikingly, the stabilityof micelle-like clusters surpasses the putative formation of interfacial H-bonds with surfacesilanols leading to an unexpected hydrophobic interaction of tert-butanol with surface silica. Thiswork highlights the foremost interest to combine neutron scattering and molecular simulations witha careful account for the complex situation encountered under confinement to better understandingthe molecular microstructure of H-bonded liquids.38