The need to engineer friction at the microscale is increasingly important in technologies as diverse as soft robotics, geosciences, and consumer products. In this seminar, I will describe our journey from the classical field of particulate suspensions to the futuristic applications of tactile engineering. The first part of the talk will focus on the role of particle roughness in the rheology, structure, and dynamics of dense colloidal suspensions. We find that shear thickening, exemplified by the ability to run on cornstarch pools, is a strong function of the particle shape and jamming distance. The second part of the talk will discuss our recent work on linking soft tribology to haptics. We develop a universal scaling law governing the elastohydrodynamic lubrication friction for patterned surfaces of many tribopairs, such as elastomers, thermosets, and hydrogels in lubricated sliding conditions. The data are in statistical agreement with that collected from a bioinspired robotic fingertip and human fingers. This framework provides a foundation that informs the engineering of manufactured surfaces, robotic grippers, and haptic materials with the desired friction coefficient.
