Synchronization and Dynamic Properties of Active Polymer Brushes

FRANCISCO BEZZECCHI; CLAUDIO PASTORINO

Los Polvorines, Gral. Sarimiento, Pcia. Buenos Aires

Workshop; Transport Phenomena and Non-Equilibrium Processes; 2018

UNGS

In this work, we studied the evolution of a system composed of activated end-grafted polymer chains, by computer simulations. These self-sustained oscillating polymers, which describe a pendular movementaround their equilibrium position, were studied with two types of local interactions. One of them is the direct interaction between neighboring polymer chains. The degree of interaction was controlled by tuningthe grafting density of the polymers fixed to the substrate. Alternatively, we also implemmented a harmonic potential among first neighbors chains, to couple the chains elastically. In this case, the behavior ofthe system is controlled with the stiffness (elastic constant) of the inter-chain springs. For both types of polymer coupling, gradual changes of the system towards synchronous-oscillating states are observed, asthe degree of interaction between chains is increased. This collective behavior is quantified with the so-called Kuramoto order parameter (also known as order or coherence), defined in the literature for a typicalmodel system of self-sustained and globally coupled oscillators, which exhibit synchronization effects. The gradual increase of the order parameter stops abruptly from certain interaction values, in which thesystem presents propagating waves and therefore, low coherence. Through studies of the spatial correlations of the system it is concluded that certain particular states are characteristic modes imposed by theperiodic boundary conditions, because the typical wavelength of these propagating waves is in principle greater than, or, of the order of the size of the simulated system. Larger systems were also simulated tostudy finite-size effects and to observe the propagation of these waves in different conditions.