Complex dynamics of interacting fronts in a simpleA+B→Creaction-diffusion system

Abstract

Pattern interaction has so far been restricted to systems with relatively complex reaction schemes, such as activator-inhibitor systems, that lead to rich spatio-temporal dynamics. Surprisingly, a simple second-order chemical reaction is capable of generating similar complex phenomena, such as attractive or repulsive interaction modes between the localized reaction zones (or fronts). We illustrate the latter statement both analytically and numerically with two initially separated A + B → C reaction-diffusion fronts when the solution of B is initially confined between two solutions of A. The nature of the front-front interaction changes from an attractive type to a repulsive one above a critical distance separating the two fronts initially. The complexity of the pattern dynamics emerges here due to finite-size effects. A scaling law relating the critical distance d c above which the repulsion occurs and kinetic parameters gives insights into (i) extracting those parameters from experiments for bimolecular reactions and (ii) the control strategy of periodic patterns.

On-Chip Control over Polyelectrolyte–Surfactant Complexation in Nonequilibrium Microfluidic Confinement

“…This model considers two dimensions (length and width) without the height of the main channel and neglects the wall interaction effects. A 2D approach was successfully applied in multiple works on microfluidic diffusion and reaction systems [ 42 , 44 , 46 , 54 , 55 , 56 ]. The laminar flows of the reacting solutions in such systems are strictly parallel to the “x” axis in the main channel due to a very low Reynolds number.…”

Marangoni-vs.buoyancy-driven flows: competition for spatio-temporal oscillations in A + B → C systems

“…27,28 It was shown that these simple structures can evolve to unexpected behaviors, for example, when one reactant is sandwiched between two pools of the other one, two A + B -C fronts can interact together in the form of attractive or repulsive collective dynamics, depending on the initial distance between the fronts. 29 It was recently shown that simple A + B -C reactions can also exhibit spatiotemporal oscillations, provided that the reaction combines with hydrodynamics. [30][31][32][33] In reactive fluids, natural convection can indeed arise spontaneously from changes in the composition/temperature of the system, further inducing in situ local gradients in the physical properties (i.e.…”

“…It was shown that these simple structures can evolve to unexpected behaviors, for example, when one reactant is sandwiched between two pools of the other one, two A + B → C fronts can interact together in the form of attractive or repulsive collective dynamics, depending on the initial distance between the fronts. 29…”