The Structure of Water-Methanol Mixtures Under an Electric Field: Ab Initio Molecular Dynamics Simulations
Abstract
Liquid methanol and water are examples of hydrogen-bonded systems which exhibit abnormal high proton conductivity.[1][2] Their mixture is of fundamental interest due to the rich and complex structure and topology of the hydrogen-bonded network in the solution. Previous studies suggest that the water-methanol mixtures exist in form of ice-like water cages surrounding the hydrophobic groups of the methanol molecules.[3] Recent experimental and theoretical studies proposed a new picture that, at low methanol concentrations, the mixture is consist of two separate percolating hydrogen-bonded networks.[4][5] Ab-Initio Molecular Dynamics (AIMD) simulations were performed using the VASP code[6] to understand the local hydrophobic structures in water-methanol mixtures, especially under the influence of electric field. Simulations of the water-methanol mixtures were performed at five concentrations: pure water, XM = 0.25 (20 H2O and 7 CH3OH molecules), XM = 0.50 (13 H2O and 14 CH3OH), XM = 0.75 (7 H2O and 20 CH3OH), and pure methanol in a supercell of length 12.22 Å. The finite electric field applied is between 0.25 and 0.75 V/Å.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 01, 2014
- Source ID
- 10.1149/ma2014-01/24/1071
Entities
People
- Jun He
- Stephen J Paddison
- Vito Di Noto