Measurements of tribological properties of poly(pyrrole) thin film bearings

• Published in: Tribology international 1998-06, Vol.31 (6), p.313-323
• Main Authors: Liu, X., Chetwynd, D.G., Gardner, J.W., Bartlett, P.N., Beriet, C.
• Format: Article
• Language: English
• Subjects: Applied sciences; capacitive sensing; conductive polymer; Exact sciences and technology; friction testing; Friction, wear, lubrication; Machine components; Mechanical engineering. Machine design; Organic polymers; Physicochemistry of polymers; polypyrrole films; precision bearing; Properties and characterization; surface characterisation; Surface properties
• ISSN: 0301-679X; 1879-2464
• DOI: 10.1016/S0301-679X(98)00040-1

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 electrochemically deposited onto gold electrodes on the plano-convex glass substrates and studied extensively. The measuring apparatus has been greatly improved from that reported earlier and now provides simultaneous monitoring of frictional force and wear. High precision capacitive gauging is employed to provide high resolutions of frictional force of better than 100 μN and height variation (wear) of 2 nm. A large number of specimens of poly(pyrrole) grown from five different counter-ions were prepared and their performances evaluated. The film morphology of each type of film was examined by atomic force microscopy (AFM) for control of the variability of film formation. Results are presented for the friction coefficients and wear rates observed for the films typically 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 are also discussed with a load range of 0.2–5 N and a sliding speed up to 30 mm s −1.