MEASUREMENTS OF TRIBOLOGICAL PROPERTIES OF POLY(PYRROLE) THIN-FILM BEARINGS

We report the results of a recent study on the tribological properties of electropolymerised thin films at light loads and low speeds. Poly( pyrrole) films incorporating different counter-ions have been electroc hemically deposited onto gold electrodes on the piano-convex glass sub strates and studied extensively. The measuring apparatus has been grea tly improved from that reported earlier and now provides simultaneous monitoring of frictional force and wear. High precision capacitive gau ging is employed to provide high resolutions of frictional force of be tter than 100 mu N and height variation (wear) of 2 nm. A large number of specimens of poly(pyrrole) grown from five different counterions w ere prepared and their performances evaluated. The film morphology of each type of film was examined by atomic force microscopy (AFM) for co ntrol of the variability of film formation. Results are presented for the friction coefficients and wear rates observed for the films typica lly at a load of 2 N and a sliding speed of 5 mm s(-1). The effects of normal loading force and sliding speed on the friction coefficient ar e also discussed with a load range of 0.2-5 N and a sliding speed up t o 30 mm s(-1). (C) 1998 Elsevier Science Ltd. All rights reserved.