How particle size, shape and zeta potential influence suspension rheology. Many products are suspensions or dispersions of particles in a liquid medium. Examples range from adhesives, ceramics, paints and inks through to foods, drinks, personal care products and medicines. The physical properties of the dispersed particles in such systems, including particle size, particle size distribution, concentration, electric charge (zeta potential), and even particle shape, can all strongly influence the overall (bulk) rheological properties of a suspension, thereby defining product behavior and functionality. Understanding these interactions is crucial when it comes to achieving desirable product performance, whether it be a stable paint or medicine, workable cement, or a visually appealing shower gel or drink. This white paper examines the impact of particle properties on suspension viscosity, and more broadly on rheological behavior. It looks in some detail at how particle size, shape and zeta potential influence critical aspects of suspension performance such as viscosity and stability and how these properties can be manipulated to tailor this behavior.