Self-oscillations in chemoresponsive gels: A theoretical approach

Some gels can swell or shrink in function of the concentration of the solutes contained in the solvent. We develop and discuss an algorithm based on Stefan-Maxwell equations to study the dynamics of a sphere of chemoresponsive gel immersed in a medium kept far from equilibrium. We show that the coupling of the reaction with these volume changes creates some feedback that can lead to chemomechanical instabilities. As a result, a reaction that is not oscillatory in homogeneous conditions or in a nonresponsive gel can induce self-oscillations of volume and concentrations in a responsive gel. We also show that chemical oscillations related to long range activation can be strongly modified in such gels, even when the changes of volume are small. (C) 2005 American Institute of Physics.