CAREER: Design Rules for Electrical Transport in Suspensions of Conductive Particles

Northwestern University, Evanston IL

Investigators

Abstract

Soft materials consist of microscopic buildings blocks whose nanoscale interactions can be engineered to yield radically different material behaviors. Suspensions are one class of soft material that contain solid particles dispersed in a fluid. The development of new electrochemical energy storage technologies has generated renewed interest in understanding the properties of suspensions containing electrically conductive nano- and micro- particles, especially for applications requiring suspensions that exhibit low viscosity and high electrical conductivity. While the rheology of dense suspensions has a firm theoretical and experimental basis, the electrical properties are less well understood. This knowledge gap presents a unique challenge and opportunity to design suspensions with optimal properties. This project will address this challenge by combining new synthesis techniques with advanced structural and electrical characterization methods to bridge the current gap in understanding electron transport in fluid suspensions of conducting particles. This project will also prepare the future workforce with foundational knowledge in the properties of soft materials and their potential application to emerging and contemporary societal challenges. Motivated by recent rheo-electric measurements of suspensions of carbon black in polar and non-polar solvents, this project will test the hypothesis that particle dynamics play a significant and underappreciated role in mediating electron transport in fluid suspensions of conducting particles. The objective will be to test this hypothesis with three novel approaches. New synthetic approaches will control the size, shape, and interactions between conductive nano- and micro-particles, while new rheo-electric characterization techniques will allow for direct quantification of electrical transport characteristics. These new synthetic and characterization approaches will be augmented by microstructural measurements using small angle scattering techniques. The combination of these three approaches will result in the development of design rules that can be used to engineer the electrical properties of suspensions for electrochemical energy storage technologies and other useful purposes. 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.