Adsorption and lubricating properties of HFBII hydrophobins and diblock copolymer poly(methyl methacrylate-b-sodium acrylate) additives in water-lubricated copper vs. a-C:H contacts

Publication year: 2015
Authors: Hakala TJ1, Metsäjoki J1, Granqvist N2, Milani R1, Szilvay GR1, Elomaa O3, Deng M4, Zhang J4, Li F3
Affiliations:

1 VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, FI-02044, Finland
Bionavis Ltd, Elopellontie 3C, FI-33470 Ylöjärvi, Finland
Aalto University, School of Chemical Technology, Department of Materials Science and Engineering, Vuorimiehentie 2A, FI-02150 Espoo, Finland
Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, China

Published in: Tribology International, Volume 90, October 2015, Pages 60–66
doi: 10.1016/j.triboint.2015.04.006

In a metal forming process the adhesion between the workpiece and the tool needs to be minimised, which can be achieved by use of lubricants and coatings. Here adsorption and lubrication properties of HFBII hydrophobins and diblock copolymer poly(methyl methacrylate-b-sodium acrylate) in water-lubricated copper vs. a-C:H coating contacts were studied by Surface Plasmon Resonance (SPR) and by a pin-on-disc (POD) tribometer. Hydrophobins formed a dense monolayer film on a-C:H surface and reduced friction by 13–30% but increased the wear of copper compared to pure water lubrication. Poly(methyl methacrylate-b-sodium acrylate) formed a sparse lubricating layer compared to HFBII lubricated contacts, but the friction coefficient was lower. HFBII molecules prevented copper oxide tribofilm formation on the copper pin.

 


MP-SPR keywords: coating thickness, Copper surface, diamond like carbon (DLC), hydrogenated amorphous carbon, hydrophobin interaction, LayerSolver, polymer interaction