Adhesion, friction and lubrication of nano- and micro-structured surface coatings

Abstract

Event Abstract Back to Event Adhesion, friction and lubrication of nano- and micro-structured surface coatings Suzanne Giasson1, 2 and Lucie Giraud1 1 University of Montreal, Faculty of Pharmacy, Canada 2 University of Montreal, Chemistry Department, Canada Self-lubricating surfaces or water-based lubricants are highly in demand for biomedical applications that require friction and wear control. Numerous tribological studies of lubricant coated-surfaces in aqueous media have been reported. However, the role of surface structure and elasticity on surface properties remains highly contentious because of the lack of consistent control of these parameters. We investigated the effect of both parameters (structure and elasticity) on adhesion and friction properties using soft and hard nano- and micro-particles covalently attached on silica-based substrates. Silica spheres were used as hard particles and pH sensitive polymer particles containing poly(acrylic acid) as soft ones. All particles were self-assembled from solution giving rise to a monolayer of particles with heterogeneous coverage but equivalent surface patterns. The adhesion and friction forces as function of applied load between two identically structured surfaces in aqueous media were determined using the Surface Forces Apparatus (SFA) Our results show that all structured surfaces exhibit friction coefficient similar or even lower than that measured on smooth coated surfaces under significantly higher applied loads. The lowest friction coefficient was measured between hard structured surfaces. This most probably arises from the effect of asperities on reducing the real contact area which is most evidenced with non-deformable hard structures. In addition, the elastic contribution to friction for hard structures is negligible resulting in constant dissipation energy between the surfaces leading to very low friction coefficient (10-3<µ<10-2). The friction coefficient measured with the nanoparticles was larger than that between micron- sized ones. Adhesion was observed only for the first compression of the surfaces during which irreversible rearrangements of hard particles occurred. Subsequent compressions and surface separations were reproducible and purely repulsive. The friction behaviour of the soft patterned surfaces was quite different than that of hard structured ones mainly because the soft polymeric structures provide elastic effects that can be tuned via changes in environmental conditions (pH, ionic strength). Increasing pH of the aqueous media gave rise to a swelling of the immobilized soft particles due to an increase in the degree of ionization of the polymer. The friction coefficient decreased with increasing the pH and swelling (µ varying from 1 to 10-2 for pH 4 to 10). No adhesion was measured between the highly charged and swollen soft structured surfaces. The variety of surface interactions arising from such structured surfaces is promising for the development of new coatings for surfaces immersed in aqueous media and subjected to high loads and shear rates, such as those of artificial implants where friction and wear should be minimized. Keywords: self-assembly, surface property, Microfriction, Nano/micro particle Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Interfacial phenomena Citation: Giasson S and Giraud L (2016). Adhesion, friction and lubrication of nano- and micro-structured surface coatings. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02219 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Suzanne Giasson Lucie Giraud Google Suzanne Giasson Lucie Giraud Google Scholar Suzanne Giasson Lucie Giraud PubMed Suzanne Giasson Lucie Giraud Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.