@article{cite-key,

title = {A Multi-scale Interfacial Investigation of Organic Friction Modifiers in Hydrocarbon},

author = {David Burgess and Peter J. Fryer and Ian McRobbie and Jacqueline Reid and Zhenyu Jason Zhang},

url = {https://doi.org/10.1007/s11249-026-02137-w},

doi = {10.1007/s11249-026-02137-w},

isbn = {1573-2711},

year  = {2026},

date = {2026-04-06},

journal = {Tribology Letters},

volume = {74},

number = {2},

pages = {41},

abstract = {To link molecular characteristics and lubrication performance of Organic Friction Modifiers (OFMs), a multi-scale study was carried out to investigate the effects of functional groups and solvents on the tribological properties of two model OFMs, namely palmitic acid and pentadecylamine. It was observed that the solvent composition has a profound effect on the surface adsorption and the interfacial adhesion force of the OFMs, showing vastly different values of adsorption kinetics and surface coverage. It must be highlighted that the presence of water within the hydrocarbon has a considerable impact on the lubrication performance of OFMs. We were able to quantitatively correlate the molecular properties such as binding force and adsorption kinetics of the OFM with their macroscopic testing results satisfactorily, suggesting that the static Coefficient of Friction (COF) is governed by the properties of the film formed in a thermodynamic equilibrium, whilst the dynamic COF is related to the interfacial forces at the surface during sliding, and finally the wear on the solid surface is related to ability of the OFMs to rapidly re-adsorb on the solid substrate once removed.},

keywords = {Coefficient of friction (COF), Nanotribology, openQCM Q-1, Organic friction modifiers, QCM-D, Quartz Crystal Microbalance, Tribology},

pubstate = {published},

tppubtype = {article}

}

@article{GAMANIEL2025110688,

title = {Influence of plant-based compounds on the structural stability of mucous boundary layers in tribological contact},

author = {Samuel S. Gamaniel and Erik G. Vries and R. Hans Tromp and Els H. A. Hoog and Rob Vreeker and David T. A. Matthews and Emile Heide},

url = {https://www.sciencedirect.com/science/article/pii/S0301679X25001835},

doi = {https://doi.org/10.1016/j.triboint.2025.110688},

issn = {0301-679X},

year  = {2025},

date = {2025-09-01},

urldate = {2025-01-01},

journal = {Tribology International},

volume = {209},

pages = {110688},

abstract = {This study presents a new methodology for understanding the molecular interactions of plant-based compounds on lubricating boundary layers in oral contacts. The methodology was used to investigate the impact of a plant protein (fava bean protein isolate) and a phenolic compound (tannic acid) on the structure and lubricating property of mucous boundary layers. Tribological experiments, coupled with quartz crystal microbalance with dissipation monitoring measurements and fluorescence microscopy imaging, were used to elucidate the mechanism of boundary film disruption and lubrication losses. It was found that even at concentrations up to 5 % w/v, fava bean proteins bind to mucins and hydrophobic polydimethylsiloxane (PDMS) surfaces, forming a hydrated, hydrophilic layer that sustains lubrication. Conversely, even at concentrations lower than 0.5 % w/v, tannic acid interacts strongly with mucins via hydrophobic interactions and/or hydrogen bonding, leading to protein aggregation, interrupting mucin binding onto PDMS, and increasing friction due to the disruption of the lubricating boundary layer. Fluorescent microscopy images revealed that the tannic acid-bovine submaxillary mucin interaction impairs the stability of the mucous boundary film, facilitating mucous protein detachment during a single sliding experiment of a PDMS probe. Results from these investigations provide critical insights into the molecular-level mechanisms influencing oral lubrication, particularly for the development of polyphenol-rich foods, and emphasize the importance of tribological assessment as a research tool in the development of plant-based protein alternatives.},

keywords = {Astringency, Fava bean protein isolate, Mucous boundary lubrication, openQCM Q-1, Polyphenols, QCM-D, Quartz Crystal Microbalance, Tannic Acid, Tribology},

pubstate = {published},

tppubtype = {article}

}