The hydrophobic hydration in a series of hydrocarbons is probed using molecular dynamics simulations. The solutes considered range from methane to octane. Examination of the shapes of the hydration shell suggests that there is not a stable clatharate-like structure for these solutes. The time a given water molecule spends in the hydration shell is relatively short implying that there is a free exchange of hydrogen bonds between the interface region and the bulk. Although few discrete water molecules penetrate the hydration shell, the structure of the water molecules around the solute is not significantly perturbed, even for octane. The hydrogen bond network is essentially preserved. The solutes are accommodated in the voids of the tetrahedral network of water in such a way as to leave the local environment almost intact. The hydrophobic hydration arises not only due to the small size of water molecule as demonstrated earlier but also due to the plasticity of the hydrogen bond network. Even for octane we find very little evidence for water mediated interactions between non-bonded carbon atoms leading us to suggest that the transition to globular conformations can only occur for very long hydrocarbon chains.
Workshop on Hydrogen Bonds at High Pressure
August 21-23, 1998
National Academy of Sciences of the United States of America
alkanes, hydrogen bonds, hydrophobic hydration, molecular dynamics, solvation, water
and Thirumalai, D.
Hydration for a Series of Hydrocarbons, Workshop on Hydrogen Bonds at High Pressure, Gifu, JA
(Accessed February 27, 2024)