Tribological behaviors of a novel trilayer nanofilm: the influence of outer chain length and interlayer thickness

Abstract

Polydopamine (coded as PDA) is reported to be very adhesive and reactive due to the attached functional groups, such as amine and hydroxyl groups. In this work, taking advantage of the condensation between Si-OH of the hydroxylated alkyltrichlorosilane (ATS) and C-OH on PDA surface, ATS molecules with different chain carbon number of 10, 14 and 18 were grafted onto the 3-aminopropyl triethoxysilane (APTES)-PDA dual-layer film, which was composed of PDA outerlayer and APTES underlayer, on Si substrate. Thus, hydrophobic trilayer films coded as APTES-PDA-ATS were prepared successfully. In order to reveal the dependence of the tribological behaviors upon the microstructures of the film, tribological experiments were conducted on an atomic force microscope and a ball-on-plate tribometer. Experimental results showed that the (micro-) friction reducing (characterized by a parameter of relative friction coefficient or friction coefficient, RFC or FC) and macro-wear resisting (characterized by anti-wear life) behaviors were related with the chain length of outerlayer and the PDA thickness. Specifically, on one hand, as the chain length increases, RFC/FC decreased and macro anti-wear life lengthened; on the other hand, as PDA gets thicker, RFC increased and the anti-wear life enhanced.

Ultrastable Lubricating Properties of Robust Self-Repairing Tribofilms Enabled by in Situ-Assembled Polydopamine Nanoparticles

“…Inspired by mussels, polydopamine (PDA) has excellent film-forming properties in water, and it has been found that PDA films show good lubrication properties under various friction conditions. − Especially, PDA nanoparticles (PDA-NPs) can be continually self-assembled on friction interfaces due to its strong chemical bonding with metal substrates . Thus, it proposes a new method for achieving self-repairing PDA tribofilms enabled by PDA-NPs as aqueous lubricant additives without the general tedious process of surface pretreatment and film formation .…”

Self-assembly and tribological properties of a novel organic–inorganic nanocomposite film on silicon using polydopamine as the adhesion layer

“…26 Meanwhile, polydopamine provides a platform as connection layer for self-assembly, which has stronger binding forces than APS, and consequently endue assembled multi-layer lms the high interface strength. Polydopamine as the connection liner for the assembled graphene oxide (GO) 16,27 and aliphatic chloride 28,29 to enhance the tribological properties has been reported. Unfortunately, no work has been reported on tribological performance of the self-assembled metallic oxide nanoparticles with polydopamine as the adhesive layer so far.…”