HydroCat · Understanding the Collective Behaviour of Catalytically-Driven, Self-Propelled Colloids: From Fine-Grained Hydrodynamic Simulations to Effective Field-Theoretical Descriptions

Understanding the Collective Behaviour of Catalytically-Driven, Self-Propelled Colloids: From Fine-Grained Hydrodynamic Simulations to Effective Field-Theoretical Descriptions

Microscopic particles have been used to achieve many industrial goals. For example, they form the basis for cosmetics, and cement. In addition, investigating such particles has a strong biomedical relevance, think blood. Suspensions of passive particles obey the laws of statistical physics, which have been successfully applied to describe a wide range of equilibrium phenomena. However, when taken out of equilibrium, there is an unprecedented richness of dynamics, e.g., the patterns formed by flocks of birds or growing bacterial colonies. Researchers strive to incorporate the richness of living dynamics into traditional equilibrium systems to create new products. Of technological interest is the enhanced microfluidic mixing that can be achieved by the incorporation of motile (self-propelled) components. Central to the implementation of such features is the development of artificial self-propelled particles. These achieve motion by generating chemical gradients through catalytic surface reactions. Artificial swimmers are preferred over biological ones, because they do not bring any evolutionary baggage into the mix. Yet, despite artificial self-propelled particles being around since the mid 2000’s, many aspects of the way they achieve motion are poorly understood. This is problematic from an implementation perspective, as better understanding of these particle’s propulsion mechanism will enable the exploration of new propulsion routes that employ non-toxic fuels. Currently, hydrogen peroxide is widely used to fuel the motion of these particles, but this chemical is not biocompatible. Attempts to produce swimmers powered by less harmful chemical fuels have been unsuccessful, thus far. Finally, full understanding of the nature of the propulsion mechanism of man-made swimmers will facilitate their use as simple model systems to understand out-of-equilibrium systems. Physicist wish to use these particles to study the origin of the complex dynamics observed in living systems, without having the added complications that biological functions such as reproduction and decision-making skills bring about. Artificial swimmers seem ideally suited for the task, as they only self-propel. However, to truly understand the dynamics in these systems one must disentangle the various contributions that are present: fluid flow, chemical fields, contact interactions, etc. Since the presence of chemical gradients is intimately linked with their motion, one must understand the latter fully to be able to extract how the former influences the collective motion of such particles.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз