An analysis of carrier‐facilitated transport

Abstract
The physical and mathematical characteristics of carrier‐facilitated transport in a liquid film are examined for a reaction scheme of the form A + BAB, in which A is the permeating species and B and AB are diffusable species which are constrained not to leave the film. For thin films, a solution is developed as a perturbation from purely physical diffusion and is expressed as a second‐order power series. For thick films, a solution is developed as a perturbation from a state in which the species concentrations at any one point within the film are related by an equilibrium constraint. This development utilizes the techniques of matched asymptotic analysis. Taken together, these solutions provide an excellent estimate of the facilitation for a film of any thickness, as shown by comparison with numerical results.