ChBE Seminar: Engineering directed Transport and Collective Dynamics of Charged Colloids
Speaker: Carlos A. Silvera Batista, Assistant Professor, Department of Chemical & Biomolecular Engineering, Vanderbilt University
Title: Engineering directed Transport and Collective Dynamics of Charged Colloids under Electric Fields
Gradients in electrical potential (electric fields), along with gradients in concentration of ionic species, are a principal way to control the motion of colloids. The surface and body forces that electric fields exert on anisotropic colloids have opened new applications in self-propulsion, transport of cargo, dynamic assembly, and directed assembly. This talk focuses on the long-range transport of charged colloids, as well as on the dynamic assembly of anisotropic and active colloids. In the first part, Dr. Batista will present a study of the dynamics of charged colloids under direct currents and gradients of chemical species (electrodiffusiophoresis). In this approach, he developed a method to simultaneously visualize the progression of concentration polarization and the ensuing dynamics of charged colloids near electrodes. With the aid of confocal microscopy, his research group showed that the passage of current through water induce the focusing and aggregation of charged colloids away from both electrodes. Preliminary experiments show that this phenomenon can potentially be useful to perform focusing, trapping and separation operations in lab-on-a-chip devices. In the second part, he'll discuss strategies to tailor the propulsion and collective dynamics of Janus particles (JPs) under electric fields. He engineered the relaxation time of JPs by controlling the properties of the medium and the particles. The insights from this study provide helpful quantitative information for the design of colloidal machines with targeted propulsion, interparticle interactions and collective dynamics. In addition, our results provide the experimental basis for the design of non-equilibrium strategies for materials fabrication.
Dr. Carlos A. Silvera Batista initiated undergraduate studies in chemical engineering at the Universidad de San Buenaventura (Cartagena, Colombia) and subsequently obtained a bachelor’s degree from the City College of New York (CCNY). Dr. Silvera began his research trajectory as a LSAMP scholar under the guidance of Prof. Ilona Kretzschmar (CCNY). After earning a PhD in chemical engineering from the University of Florida, Dr. Silvera held postdoctoral positions at the National Institute of Standards and Technology and at the University of Michigan, where he received the President’s Postdoctoral Fellowship. Currently, as an assistant professor at Vanderbilt University, his research interest is on the electrokinetics and directed assembly of colloidal systems. His research work has resulted in over 20 peer-reviewed publications in high-impact scientific journals, such as JACS, ACS Nano, Langmuir and Science. During his spare time, Dr. Silvera enjoys watching basketball, gardening, and the cooking of BBQ recipes from all over the world.