Effects of surface properties on the tribocharging characteristics of polymer powder as applied to industrial processes

Experiments performed on different powders of different size distributions tribocharged with stainless steel beads, showed the charge acquired by the powder can be correlated with the actual work function difference between the powder and stainless steel and particle size. The charge acquired increased with particle size, but the charge distribution was generally bi-polar. Ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS) were performed on a selection of materials, and showed the work function increased with surface contamination and oxidation, and the difference narrowed for metals and polymers. Such a small difference in work function may contribute to bi-polar charging, suggesting for tribocharging, minimization of oxidation and contamination and relative humidity control are needed.