Hydronium and hydroxide at the interface between water and hydrophobic media.
The behavior of hydronium and hydroxide ions at the water/alkane, water/vapor, and water/rigid wall interfaces was investigated by means of molecular dynamics simulations. All these interfaces exhibit a strong affinity for hydronium, which is in agreement with spectroscopic and low pH zeta-potential measurements. Except for the water/rigid wall interface, which strongly structures water and weakly attracts OH(-), none of the other investigated interfaces shows an appreciable accumulation of hydroxide. This computational result is at odds with the interpretation of higher pH zeta-potential and titration experiments, however, it is supported by surface selective spectroscopies of the surface of water and hydroxide solutions.
Vácha
Robert
R
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, Prague 6, Czech Republic.
Horinek
Dominik
D
Berkowitz
Max L
ML
Jungwirth
Pavel
P