Influence of Temperature on the Frictional Properties of  Water-Lubricated Surfaces

Lee, Sang M.; Røn, Troels

doi:10.3390/lubricants2040177

Cited by 9 publications

(6 citation statements)

References 37 publications

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“…Meanwhile, friction forces can be easily measured and the application of the soft EHL model to the contacts in this study can be Given that the mechanical properties (contact pressure) of the steel-PDMS and PDMS-PDMS tribopairs are similar (Table 1), drastically different lubricating properties of the model mucus fluids for the two interfaces can be attributed to the different surface hydrophilicity of steel vs PDMS pins. This has been well described in a number of previous tribological studies involving aqueous solutions, 43 and is also clearly manifested in much more effective lubrication of PBS-0 at steel-PDMS (FIG. 5a) than at PDMS-PDMS interfaces (FIG.…”

Section: B-1 Modelled Lubrication Thickness and Friction Coefficientssupporting

confidence: 69%

“…Nevertheless, it should be emphasized that this was observed for both thin films as well as flooded lubrication in the case of PGM:b-PEI.Several differences were observed for the PDMS-PDMS interface compared to the steel-PDMS interface. Firstly, for the PDMS-PDMS interface, µ was high at low speeds but was decreasing with increasing speed for the flooded lubrication with PBS-0, which is typical behavior of aqueous lubrication for hydrophobic interfaces without surface-adsorbing additives, highlighting the importance of surface hydrophilization for effective lubrication with water 42,43. Secondly, flooded lubrication of the PDMS-PDMS interface with PGM:b-PEI displayed µ ≤ 0.02 throughout the entire speed range (similar to the steel-PDMS contact).…”

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confidence: 96%

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Gastric mucus and mucuslike hydrogels: Thin film lubricating properties at soft interfaces

et al. 2017

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Mucus is a viscous slime that plays a vital role in protecting and lubricating biological tissues, in particular, soft epithelium interfaces such as in the stomach, intestines, and esophagus. Previous attempts to generate mucus models that mimick or simulate its characteristics have been predominantly focused on the rheological properties. This study investigates both rheological and tribological shear properties of thin films of gastric mucus from a porcine source and its mimics at compliant soft interfaces. The lubricating efficacy of biological mucus and its mimics was observed to be superior at hydrophilic tribological interfaces compared to hydrophobic ones. Facile spreading of all mucus samples at hydrophilic steel-polydimethylsiloxane (PDMS) interfaces allowed for the retainment of the lubricating films over a wide range of speed, slide/roll ratio, and external load. In contrast, poor wetting at hydrophobic PDMS-PDMS interfaces led to depletion of the mucus samples from the interface with increasing speed. Among the different mucus models investigated in this study, fluid mixtures of commercially available porcine gastric mucin (PGM) and polyacrylic acid (PAA) displayed the most persistent lubricating effects under various tribological experimental conditions. A mixture of PGM and PAA holds a high potential as mucus mimic, not only for its rheological similarity, but also for its excellent lubricity in soft compliant and hydrophilic contacts.

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Section: B-1 Modelled Lubrication Thickness and Friction Coefficientssupporting

confidence: 69%

mentioning

confidence: 96%

Gastric mucus and mucuslike hydrogels: Thin film lubricating properties at soft interfaces

et al. 2017

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“…100%. While this effect is also observed from the lubrication with water, 56 the reduction in l values in high-speed regime by the lubrication with the mucilage is an order of magnitude larger. Considering that the contact pressure of steel-glass interface is even higher than that of HDPE-HDPE interface (Table I), relatively more feasible lubrication of hydrophilic steel-glass pair than hydrophobic HDPE-HDPE pair by the mucilage can be attributed to its superior wettability.…”

Section: Wetting Interfacesmentioning

confidence: 80%

“…The outstanding lubricating properties exhibited by T. baccata mucilage particularly at soft hydrophilic interface (including halfhydrophilic interface) suggests that it has a high potential as fluid lubricant for biomedical applications such as endoscopes, catheters, or as personal lubricants, where the contact characteristic is basically soft and hydrophilic. 56,57 Further in vitro lubrication studies of T. baccata mucilage as well as biocompatibility studies would be necessary to facilitate the application of mucilage as a hydrogel fluid lubricant for biomedical devices.…”

Section: Discussionmentioning

confidence: 99%

Slippery when sticky: Lubricating properties of thin films of Taxus baccata aril mucilage

et al. 2016

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Mucilage is hydrogel produced from succulent plants and microorganisms displaying unique adhesiveness and slipperiness simultaneously. The objective of this study is to establish an understanding on the lubricating mechanisms of the mucilage from Taxus baccata aril as thin, viscous lubricant films. Oscillation and flow rheological studies revealed that T. baccata mucilage is shear-thinning, thixotropic, and weak hydrogel that is highly stretchable under shear stress due to its high density physical crosslinking characteristics. In addition, T. baccata mucilage showed a distinct Weissenberg effect, i.e., increasing normal force with increasing shear rate, and thus it contributes to deplete the lubricant from tribological interfaces. Lubrication studies with a number of tribopairs with varying mechanical properties and surface wettability have shown that the lubricity of T. baccata mucilage is most effectively manifested at soft, hydrophilic, and rolling tribological contacts. Based on tenacious spreading on highly wetting surfaces, slip plane can be formed within mucilage hydrogel network even when the lubricating films cannot completely separate the opposing surfaces. Moreover, highly stretchable characteristics of mucilage under high shear enhance smooth shearing of two opposing surfaces as lubricating film.

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“…The advantages of water for use as a liquid lubricant are its high cooling capacity, good fire-resistance, and low cost [2,3]. However, there is a problem that the viscosity of water is too low to provide lubricating films between contact surfaces [4] . For this reason, several studies on additives to water to enable it to function as a lubricant have been carried out to address the problem [3,[5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Dependence of pH level on tribological effect of graphene oxide as an additive in water lubrication

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Kinoshita²,

Nishina³

et al. 2022

Int. J. Automot. Mech. Eng.

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A study of the effectiveness of graphene oxides (GO) dispersed in water as a lubricant additive between tungsten carbide (WC) pin against stainless steel (SUS304) plate was carried out. A 0.1 wt.% GO was prepared and used as a lubricant under an applied load of 3 N for 20,000 friction cycles of reciprocating tribological testing. The results show that a GO dispersion with pH 3 provided the lowest friction coefficient, which was approximately 0.05. Worn areas on the wear track of the SUS304 flat plate and WC ball surface were also small. The increasing pH obviously affected the tribological properties, where the friction coefficient increased to approximately 0.10-0.20 in the steady state for pH 5, pH 7 and pH 9. Meanwhile, a GO dispersion with pH 10 was not able to provide good tribological properties for the tested materials. The observations on microscopic images revealed the formation of tribofilms on the wear tracks for low pH. The tribofilms caused reduction of the friction force and protected the plates from severe wear during the sliding tests.

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Influence of Temperature on the Frictional Properties of Water-Lubricated Surfaces

Cited by 9 publications

References 37 publications

Gastric mucus and mucuslike hydrogels: Thin film lubricating properties at soft interfaces

Gastric mucus and mucuslike hydrogels: Thin film lubricating properties at soft interfaces

Slippery when sticky: Lubricating properties of thin films of Taxus baccata aril mucilage

Dependence of pH level on tribological effect of graphene oxide as an additive in water lubrication

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