Exploring Diffusiophoretic Micromotors in Self-Organizing Reaction-Diffusion Systems

About This Grant

With support from the Chemical Structure and Dynamics (CSD) program in the Division of Chemistry, Professor Oliver Steinbock at Florida State University is investigating the mechanisms by which the motion of nano- and micro-particles driven by concentration gradients of solutes (known as diffusiophoresis) is influenced and controlled by self-organizing reaction-diffusion patterns far from equilibrium. In many biological systems, steep gradients and active transport processes reinforce one another to enable highly organized behaviors. In contrast, this nonequilibrium coupling remains largely unexplored in chemistry, limiting opportunities for developing self-regulating materials and understanding transport phenomena in synthetic media. Professor Steinbock and his students will develop experimental model systems that combine synthetic micromotors with pattern-forming chemical reactions, such as oscillatory and Turing systems, to investigate scenarios in which particle motion and chemical self-organization coexist, disrupt each other, or give rise to emergent order. Their studies could provide important experimental insights into novel types of complex systems involving new forms of chemical self-organization, which would also inform the analysis of similar phenomena in living systems. Educational and outreach components include hands-on research opportunities for students, public science lectures for adult learners, social media engagement through art-in-STEM content, and participation in local science festivals. The proposed research will combine chemically powered Janus particles with classical oscillatory reactions such as the Landolt and Briggs-Rauscher systems, both of which rely on hydrogen peroxide as a key reactant. These particles will catalyze local decomposition reactions that create chemical gradients and drive self-propulsion. Their behavior will be studied in environments that feature large-scale, dynamic concentration structures, including traveling waves, rotating spirals, and stationary Turing patterns produced by the Belousov-Zhabotinsky and chlorite-iodide-malonic acid reactions. Polymer microbeads will be used to probe passive diffusiophoresis and its modulation by chemical structures. The research will further explore the dynamics of mixed particle populations to investigate clustering, segregation, and mobile inhibitory domains, as well as the possibility of particles triggering or suppressing wave formation. These systems represent new forms of active matter with feedback between motion and chemical reactivity. The experimental studies will be guided by simplified kinetic models and numerical simulations to identify key mechanisms and regimes of behavior. The overall goal is to reveal fundamental principles governing particle-pattern interactions in chemically driven, self-organizing systems, and to lay the groundwork for future applications in autonomous materials, microscale transport control, and soft robotics. 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.