CAREER: Biomimetic Swarm of Active Colloids with Off-Center Interaction Sites

University Of Akron, Akron OH

Investigators

Abstract

The field of microrobotics is growing rapidly and holds great promise for engineering applications such as targeted therapeutics, environmental remediation, and microscale cargo delivery. Similar to microorganisms, microrobots harvest energy from their environment and self-propel in fluids to perform tasks at the microscale. Microrobots are too small to host electronic units to be programmed or be able to communicate with each other. Instead, their structures and interactions are engineered to exploit physical inter-particle communication and to perform or facilitate decision making. Inspired by the dynamics of schools of fish, herds of deer, and flocks of birds, the objective of this award is to perform the foundational research necessary to establish a new class of microrobots as a platform for transformative functionalities that mimic biology. Similar to the animals, these microparticles can avoid aggregation and orient themselves in a group such that they generate controlled directional motions. Thus, they overcome barriers that currently impede the exploitation of microrobot swarms for transport and engineering applications enabled by cooperative behavior. In the proposed system of microrobots with off-center repulsive interaction sites, new interactions emerge from the coupling of active self-propulsion with passive torques about the particle centers. These active-passive hybrid interactions lead to biomimetic collective motion of microrobots, even in the regime of negligible hydrodynamic interactions. To build a foundational framework and study the emergent biomimetic phenomena far from boundaries and under confinement, continuum kinetic models will be developed to study large-scale systems, linear stability analysis will be used to study phase transitions, and agent-based active Brownian simulations are employed to analyze the relative arrangement of particles and elucidate the emergence of motile-crystal and liquid-like states. Educational studies will measure the contrasts between the impacts of the hands-on experiments and augmented reality approaches on learning outcomes and self-efficacy of high school students in exploring scientific ideas about microrobotics and low Reynolds hydrodynamics. An interactive research-oriented undergraduate course on biomimicry and microrobotics will be offered and its intended impact on the career pathway selection of the students will be examined. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.