Molecular dynamics simulations of mixed deep eutectic solvents and their interaction with nanomaterials

The nanoscopic level properties of a mixed deep eutectic solvent composed by choline chloride as hydrogen bond acceptor and urea plus ethylene glycol plus glycerol as hydrogen bond donor are studied using classical molecular dynamics simulations. Local heterogeneities are inferred by the development of prevailing hydrogen bonding for some of the involved hydrogen bond donors. Interfacial behaviour at vacuum is also characterized by different regions across the interface. In the case of liquid-liquid interfaces, the presence of a common type of hydrogen bond acceptor leads to minor structuring across the interfaces. The results of the behaviour of mixed deep eutectic on 2D surfaces show strong adsorption when graphene and boron nitride are considered and minor layering for MoS2, but adsorbed layers on these materials are also heterogeneous. Likewise, the behaviour of carbon nano tubes is also analysed, confirmed preferential confinement of one of the considered hydrogen bond donors (ethylene glycol) and nanotube solvation characterized by large adsorption of the considered hydrogen bond acceptor. The reported results show heterogeneities at the nanoscopic level in the mixed deep eutectic solvent induced by the developed preferential hydrogen bonding, which are proposed to control deep eutectic solvents properties through composition. (C) 2019 Elsevier B.V. All rights reserved.