title: Liquid ethanol simulated on crystalline alpha alumina.
abstract: Equilibrium molecular dynamics simulations were employed to investigate the structural properties of interfacial liquid ethanol on two alumina surfaces-the (0001) and the (11[overline]02) terminations of α-Al2O3-both described using the CLAYFF force field. The resultant atomic density profiles show that ethanol molecules in the first monolayer are well ordered and that their distribution depends on the surface OH groups. A pronounced dipolar orientation is found for the ethanol molecules in the first layer and also, although to a smaller extent, among the ethanol molecules in the second molecular layer. The orientational distribution predicted for the methyl group of ethanol on α-Al2O3 (11[overline]02) is consistent with that observed experimentally by Shen and co-workers. The orientation of molecules in the second layer is opposite compared to that found in the first adsorbed molecular layer. Our simulations show long residence times and slowly decaying reorientation autocorrelation functions for ethanol molecules in the first adsorbed layer, suggesting that within the first adsorbed layer ethanol molecules are strongly coordinated with both α-Al2O3 (0001) and α-Al2O3 (11[overline]02) surfaces. Analysis of the hydrogen bond network confirms that preferential surface-ethanol interactions are responsible for such observations.
authors.affiliation: School of Chemical, Biological, and Materials Engineering, University of Oklahoma, Norman, Oklahoma 73019, USA.
authors.forename: Anh
authors.initials: A
authors.lastname: Phan
authors.forename: David R
authors.initials: DR
authors.lastname: Cole
authors.forename: Alberto
authors.initials: A
authors.lastname: Striolo
mesh_terms: D000465:Algorithms; D000537:Aluminum Oxide / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry*; D006860:Hydrogen Bonding; D056004:Molecular Dynamics Simulation; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D000431:Ethanol; D000537:Aluminum Oxide