(463a) Engineering the Dispersant Phase to Enhance Control of Electron Transport in Conductive Particle Suspension

Understanding how to formulate suspensions of electronically conductive particles to tune their performance in response to flow is important for engineering the next generation of advanced electronics and energy storage devices. Unfortunately, we only have an incomplete framework to describe the influence of particle motion and microstructure on the electron hopping phenomenon that governs the macroscopic conductivity of these suspensions. Building upon prior work assessing the role of dynamic clusters in non-Brownian fluid suspensions, I highlight how tuning the mechanical properties of a suspension’s continuous phase can alter the particle microstructure to achieve a desired electrical performance in both the quiescent state and with an applied shear intensity. By utilizing rheo-electric measurements that simultaneously acquire the electrical properties and rheological data of soft materials, variations in electrical transport were observed for composites containing model silver-coated nano- and micro- particles dispersed in silicone oils and organogel. To elucidate the fundamental physics governing these differences, I illustrate how Brownian and shear-driven self-diffusion affect the measured conductivity, collected in alternating current frequency sweeps for shear rates ranging from 750 s^-1 to 0 s^-1. Furthermore, I describe how these composites exhibit an anisotropic electrical response depending on the orientation of the applied electric field relative to the direction of flow. Using a custom-built printed electrode geometry, I demonstrate how electron transport can be enhanced by orienting the electric field parallel to the flow direction. Our results indicate the complex interplay particle loading, applied shear rate, and dispersant mechanical properties on the suspension’s ability to facilitate electron transport. Armed with a new understanding of advanced suspension formulation strategies, we believe that this insight will provide new design rules for optimizing the performance of slurries with conductive particles.