Molecular modeling of glucose diffusivity in silica nanochannels.

The diffusivity of glucose was studied in confined environment of a 10 nm silica nanochannel to evaluate the influence of the interface on glucose transport at a nano-scale range. Molecular dynamics studies revealed that glucose forms a weakly adsorbed layer at the silica interface. The calculated diffusion coefficients were overestimated by up to 30% compared to the experimental ones, though they follow the same dependence on concentration. Close to the interface, radial diffusivity was observed to be lower than lateral, while diffusivities were affected by the interface up to 3 nm from it. This slowdown of glucose diffusivity is found to be related to the decrease in the probability of longer random walk jumps. It is also observed that the dynamics on the interface is characterized by adsorption-desorption processes. These results clearly suggest that glucose transport is affected by the interface in 10 nm nano-confinement.