Controlling Surface of Rods with Entrained Particle as Asperities

Abstract

Changing the surface properties (i.e., roughness or friction) can be instrumental for many applications but can be a complex and resources intensive process. In this paper, we demonstrate a novel process of controlling the friction of a continuous rod by delivering inorganic micro-particles. A standardized continuous particle transfer protocol has been developed in our laboratory for depositing particles from a liquid carrier system to the cylindrical rod substrate. The particle transfer process can produce controllable and tunable surface properties. Polymeric binder is used to deliver the particles as asperities over the rod substrate and by controlling their size, shape and distribution, the coefficient of friction of the rod is determined. Tabletop experiments are designed and performed to measure the friction coefficient following the Capstan equation. The entrained particles on the substrate will create a size and shape-based asperities which will alter the surface morphology toward desired direction. Both oblique and direct quantitative measurements are performed at different particles and binder concentrations. A systematic variation in the friction coefficient is observed and reported in the result section. It is observed from the capstan experiment that adding only 1% irregular shaped particles in the suspension changes the friction coefficient of the rods by almost 115%. The proposed friction control technique is a simple to scale up, low-cost, low-waste, and low energy manufacturing method for controlling the surface morphology.