Kwong-Yu Chan, Professor in the Department of Chemistry, the University of Hong Kong, presented the following seminar at the Pacific Rim Conference in Nanoscience (7-11 September 2004). The seminar is available for viewing and discussion through the internanotech Community at http://internanotech.net/
Electrolytes in Nanopores: Molecular Simulations and Related Applications
Before presenting molecular simulations of electrolytes confined in nanopores, an overview and examples will be given for applications and experiments related to transport of electrolytes in nanostructures. The operation of a small room temperature liquid fuel cell will be demonstrated. The modification of the nanopores of Nafion, a solid polymer electrolyte, to change its proton, water and methanol permeability will be reported. Improvement of the membrane performance in a methanol fuel cell is probably due to the change of hydrophobicity of furfuryl alcohol during its polymerization within the nanopores of the membrane. Syntheses of porous carbon electrode materials with long and well-defined mesopores will be presented. The loading of mixed metal nanoparticles into these structures and the electrochemical performance will also be discussed as an example of the applications of nanostructured electrodes.
Equilibrium and non-equilibrium molecular dynamics simulations (EMD & NEMD) are applied to several models of electrolytes, including the extended simple point charge (SPC/E) model for water. Confinement by the nanopore affects the solvation of ions, hydrogen bonding, ion-ion interaction, and the mobility of ions and water. The presence of an external field in NEMD allows the direct observation of a current and net flow of ions. Comparisons of the EMD and NEMD results are made and the validity of the Nernst-Einstein relation is discussed. In addition, the application of an alternating electric field allows investigations of frequency dependent conductivity and relaxation phenomena. In the narrowest channel, severe confinement leads to more ion pairing, less solvation, less hydrogen bonding, and also a capacitor character.
internanotech Community: internanotech.net
Blog On Nanotechnology - Nanomosis: http://barryhardy.blogs.com/nanomosis/