Assessment of electric-field-induced lubricant film activation in electrorheological biolubricants by optical interferometry

This study investigates the activation of lubricant films in electrorheological (ER) biolubricants under an applied electric field. ER biolubricants based on castor oil and Cloisite 15A nanoclay were analyzed using colorimetric interferometry on a modified PCS EHD 1 tribometer–interferometer. Results show a rapid increase in film thickness upon electric activation, followed by stabilization. Film enhancement was more pronounced at low entrainment speeds, where dielectrophoretic forces dominate hydrodynamic ones. These findings demonstrate the feasibility of electrically controlled lubrication, contributing to sustainable and adaptive tribotronic systems.