Induzione e controllo di dinamiche complesse in sistemi meccanochimici

Mechanochemistry studies chemical processes in far-from-equilibrium conditions driven by the transfer of mechanical energy from a milling body to a reactive substrate. The objective of this Thesis is to explore how such mechanical forcing induces and controls the onset of complex dynamics and self-organized chemical patterns. To this aim we develop a numerical model able to simulate the kinematics of one or more milling bodies within a mechanochemical reactor. We show that, depending upon the elasticity of the collisions and the mechanical forcing, a milling body can undergo a transition from periodic to chaotic behaviours. By characterizing the set of collisions between the milling body and the reactor walls, we point out a strong spatial heterogeneity of the collision distributions (and, accordingly, of the kinetic energy dissipation) consistent with a multifractal topology. We finally propose a new mechanochemical mechanism for promoting collective behaviours in an ensemble of coupled chemical oscillators, in which the chemical information is transferred non-locally through a milling body and the chemical oscillators are placed at the reactor walls. Our analysis reveals the crucial role played by the spatio-temporal dynamics of the signal carrier in the global chemical coupling. A switch from synchronized to desynchronized scenarios can thus be controlled by tuning the mechanical properties of the device.