NSF Award
2314405
Janus particles are small particles that are measured in micrometers and have a non-uniform surface chemistry. They have the potential to revolutionize many technologies, including defense applications, understanding microorganisms' behavior in nature, and improving human health by serving as micrometer scale cargo carriers. The primary challenge this award aims to address is understanding how Janus particles interact with boundaries, which is relevant to each of these applications. To achieve this goal, the project team plans to use a unique microscope to study these interactions. Additionally, the team will investigate how Janus particles use chemical signals to navigate when they are near a boundary. Further, they aim to standardize and disseminate educational modules based on colloidal and interfacial phenomena, which is a fundamental concept explored during this work.<br/><br/>Over the past decade, Janus particles have emerged as a promising type of anisotropic particle with potential applications in various technological fields. The main goal of this award is to accurately measure the non-uniform surface interactions of both active and non-active Janus particles near a boundary. To achieve this objective, the proposed work will leverage a recently developed tool called Scattering Morphology Resolved Total Internal Reflection Microscopy (SMR-TIRM) to investigate the interactions and dynamics of Janus particles. The approach involves mapping the scattering from Janus particles at different azimuthal angles and then using this information to track the position and orientation of a mobile Janus particle. Despite recent progress in understanding these complex materials, significant questions remain about their dynamics. This award aims to address two of these questions related to the non-uniform interactions experienced by a Janus particle in the presence and absence of self-propulsion. To answer these questions, it is crucial to monitor the Janus particle dynamics and infer the surface forces that the particle experiences. In particular, the project team will conduct these measurements in the presence and absence of chemical fuel, which a catalytic Janus particle uses to generate a mechanical force.<br/><br/>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.
