Kinetics and mechanism of proton transport across membrane nanopores.
We use computer simulations to study the kinetics and mechanism of proton passage through a narrow-pore carbon-nanotube membrane separating reservoirs of liquid water. Free energy and rate constant calculations show that protons move across the membrane diffusively along single-file chains of hydrogen-bonded water molecules. Proton passage through the membrane is opposed by a high barrier in the effective potential, reflecting the large electrostatic penalty for desolvation and reminiscent of charge exclusion in biological water channels. At neutral pH, we estimate a translocation rate of about 1 proton per hour and tube.
Dellago
Christoph
C
Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
Hummer
Gerhard
G
D003198:Computer Simulation; D004058:Diffusion; D006860:Hydrogen Bonding; D007700:Kinetics; D008567:Membranes, Artificial; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011522:Protons; D014867:Water / Q000737:chemistry
D008567:Membranes, Artificial; D037742:Nanotubes, Carbon; D011522:Protons; D014867:Water