From Transport Phenomena to Systems Chemistry: Chemohydrodynamic Oscillations in A+B→C Systems

Can simple chemistry drive the emergence of self-organised complex behaviours? Addressing this big-picture question crucially impacts the comprehension of fundamental mechanisms at the basis of stationary and dynamical spatio-temporal chemical patterns which represent an integral part of Origin of Life studies and morphogenesis. This is also of paramount importance in cutting-edge approaches for the design and control of bio-inspired self-organised functional materials as well as for understanding how complex biological networks work. So far, spontaneous chemical self-organisation has constituted the realm of Nonlinear Chemistry. Oscillations, waves, Turing structures have been typically obtained in systems characterised by a complex network of nonlinear reactions activated on appropriate relative timescales. Here we revisit the emergence of oscillatory dynamics in systems characterised by a kinetics as simple and general as a bimolecular process, provided that it is actively coupled with transport phenomena, in the absence of any nonlinear or external kinetic feedback. We also present new numerical experiments to substantiate and clarify the minimal ingredients underlying these complex dynamics. The objective of this paper is to discuss chemo-hydrodynamics as a possible mechanism for activating self-organised structures and functional behaviours in contexts characterised by a minimal chemistry like prebiotic conditions. In this view, we also highlight the necessity to include convective phenomena in the paradigm of Systems Chemistry.