(379c) Directed Motion and Programmed Assembly of Actively Rotating Colloids

Authors: 
Bharti, B., Louisiana State University
Lee, J. G., Louisiana State University
Active particles offer new opportunities to design materials where the excess energy stored in the building blocks can be utilized for on-demand structural reconfiguration. In nature, similar non-equilibrium dynamic matter exists in the form of motor proteins, bacteria and other swimming microorganisms. To translate artificial active particles into next generation of out-of-equilibrium materials, there is an immediate need to develop a fundamental scientific knowledge that goes beyond the collective behavior and allows to direct the assembly of active particles. Here, we present an experimental approach to direct the assembly of a new class of bioinspired active colloids that have both translational and rotational kinetic energy. The model active colloids used are polymeric microspheres with a triangular metal patch on their surfaces. In presence of alternating current (AC)-electric field the spherical colloids strongly interact with neighboring particles via dipole-dipole pair potential and allow assembly of actively rotating and spatially translating clusters and crystals. We will present the influence of applied field and particle characteristics on the assembly and reconfiguration of supracolloidal domains formed by rotating active particles. Our study introduces a new class of high energy colloidal structures, where the individual building block has potential energy and rotational kinetic energy and allows for dynamic reconfiguration of assembled domains into various metastable states. The principle presented here may enable new design rules for directed assembly of self-healing and defect-correcting structures highly desirable for future technology development.