A CA MODEL OF SPONTANEOUS FORMATION OF CONCENTRATION GRADIENTS

It is shown that a two-compartment isolated fluid system,where a chemical reaction takes place close to the surfaces of the semipermeableseparating membrane, can spontaneously develop a transient concentrationdifference across the membrane. If the system is open to theflow of chemicals, the difference can persist in the steady state. Thisallows concentrating chemicals in a single compartment, which may beuseful for chemical engineering purposes, and which is particular interestingin the study of the dynamics of vesicles and protocells. The phenomenonis investigated and demonstrated here with a CA model: it isalso shown that, in the limiting case of infinitely fast diffusion, the resultsare coherent with those of a homogeneous model.