Effects of flows in auto-organization, self-assembly, and emergence of chirality

Abstract

The motion of molecular species in solution, in stagnant, and under simple stirring conditions is dominated by Brownian dynamics. However, when the hydrodynamic forces of laminar flows (imperfect mixing conditions) are such that can align chemical species, these may show a different chemical behaviour to that under conditions of Brownian dynamics (stagnant and uniform mixing conditions). Supra- and macro-molecular species show sizes and shapes that may cause alignment in common laminar flows and thus, within these flows, a different behaviour to that under uniform mixing conditions can be expected. Experimental evidence on this has been reported on the growth of J-aggregates of amphiphilic porphyrins, where diastereoselective and enantioselective effects by consequence of laminar flows have been detected. Furthermore, the hydrodynamic torque originated by a vortex stirring may select the chiral sign in the spontaneous mirror symmetry breaking that occurs during the auto-organization processes of these systems. In consequence, mechanical torques must be considered to form part of the specific group of chiral fields capable of determining the chiral sign outcome in bifurcation scenarios of spontaneous mirror symmetry breaking, as those that we can imagine that may have taken place in the route from chemical evolution to biological evolution.