This research combines Prof. Córdova-Figueroa’s expertise in low Reynolds number hydrodynamics and colloidal suspensions to study the emerging field of complex fluids based on ‘two-faced’ Janus particles—particles which have two distinct sides—that depending on their surface functionality could lead to novel material properties and aggregation/self-ordering abilities or to autonomous behaviors using on-board chemical motors operating far from equilibrium. This NSF CAREER proposal presents research and educational activities designed to elucidate important aspects of reconfigurable complex fluids—active materials that could change and relax their structure with minimum or no external intervention using as precursors Janus and catalytically-driven colloidal particles. The research efforts are divided in two main tasks. The first one focuses in studying the motion, rheology, and structural organization of Janus particle suspensions guided by a combination of fluid flows and external forces. Different behaviors are expected depending on the interparticle force between the ‘Janus’ faces of the particles (e.g., hard sphere, attractive, soft). The second research task aims at understanding collective motion of catalytically-driven Janus particle suspensions. A simple ‘colloidal’ approach to autonomous motion via chemical reactions will be used and implemented based on classic multicomponent diffusion and depletion flocculation theory. Simple elementary dynamic units operating with specific rules and exploiting chemotaxis will be proposed as ‘elements’ for future reconfigurable materials. These efforts will be accomplished by Brownian/Stokesian dynamics simulations and experiments with collaborating partners.