Water-based Lubricant Research Articles

Effect of bionic shield texture on friction behavior of Silicon Carbide under water lubrication condition

Abstract Reasonable texture parameters can effectively generate local dynamic pressure effects and promote the formation of lubrication film. The synergistic friction reduction mechanism of the shield-shaped texture on the Silicon Carbide (SiC) surface under water-based lubrication conditions between the flow pressure effect and the "rolling ball" effect is investigated by combining simulation analysis and friction experiments. The effects of shield textured surface on the friction and wear characteristics of SiC surface and the characteristics of interfacial polarization electric field under different rotational speeds and different load conditions were analyzed. The results display that synergistic texture lubrication has a beneficial effect on improving tribological properties. The surface with 6% texture area occupancy showed the best tribological characteristics. The surface with a textured area occupancy of 6% displays the optimal tribological properties. Moreover, the friction reduction mechanisms under different working conditions are discussed, with the textured uniformly arranged surfaces being more suitable for high-speed and heavy load (140 N, 2000 rpm) conditions and the textured non-uniformly arranged surfaces being more suitable for low-speed and light load (40 N, 400 rpm) conditions.

Enhancing Water Lubrication in UHMWPE Using Mesoporous Polydopamine Nanoparticles: A Strategy to Mitigate Frictional Vibration.

Establishing a persistent lubrication mechanism and a durable tribo-film on contact surfaces is identified as crucial for improving the tribology and vibration characteristics of polymer materials under water-lubricated conditions. This study focuses on enhancing tribological performance and reducing frictional vibrations in ultrahigh molecular weight polyethylene (UHMWPE) through the incorporation of mesoporous polydopamine (MPDA) nanoparticles. In the experiments, MPDA nanoparticles were synthesized and blended with UHMWPE to create UHMWPE/MPDA composites. The interactions between these composites and zirconia (ZrO2) ceramic balls under water lubrication were examined. The results show that when the MPDA content of the composite is 1.5 wt %, the coefficient of friction and wear rate are reduced by 40% and 52% compared with those of pure UHMWPE, respectively. This notable enhancement helped to mitigate friction-induced vibrations, particularly those caused by intermittent sticking and slipping motions. MPDA nanoparticles were shown to act as reservoirs for water, releasing and replenishing water based on the loading conditions, which sustained continuous water-based lubrication at the composite surfaces. Additionally, the surface deformation behavior of the composite material is significantly weakened, which provides a more stable friction surface. This work introduces a novel approach to enhance the interface stability of polymers in water-lubricated environments, offering guidance for developing advanced materials and reducing friction and wear in engineering applications.

Fabrication of Surface-carbonated Boron Nitride Nanosheets and Their Application as Water-based Lubrication Additives

As a typical two-dimensional layered material, hexagonal boron nitride nanosheets (BNNSs) have high mechanical strength, good conductivity, and excellent lubrication performance, which have great potential as solid nano lubricant additives in tribology. When BNNS is used as a water-based or oil-based lubricant additive, its inherent chemical inertness and poor dispersion stability make it difficult to achieve optimal anti-friction and anti-wear performance. In this paper, a simple and efficient preparation method for obtaining hexagonal boron nitride nanosheets (C-HPC-BNNSs) with surface carbonization modification and excellent dispersion stability in water-based lubricants was proposed. Using hydroxypropyl cellulose (HPC) as a modifier, a wet ball milling process combined with high-temperature carbonization treatment effectively reduced the thickness of BNNSs while uniformly modifying N-doped carbon layers on the surface of the nanosheets. Benefit from the smaller layer thickness of C-HPC-BNNSs, they exhibit excellent dispersion stability in the water-glycol solution and can maintain no significant agglomeration behavior for up to 30 days, which is the basis for the excellent lubrication performance of lubricant systems. In addition, the N-doped carbon layer modified on the surface is beneficial for enhancing the hydrophilicity of BNNSs and synergistically enhances the tribological properties of the material with BNNSs. The test results of the four-ball friction tester show that compared with the pure water-glycol solution and the water-glycol system with added C-HPC-BNNSs, the friction coefficient (COF) and wear volume of the system with added C-HPC-BNNSs could be as low as 0.095 and 1.99 × 10-4 mm3, respectively. This work has positive significance for the preparation, surface modification, and tribological application expansion of two-dimensional layered material BNNSs, which is conducive to further understanding the relationship between.

248 - Evaluation of bacterial displacement by intermittent catheters with gel- or water-based lubricants using an in vitro urethral agar channel model

248 - Evaluation of bacterial displacement by intermittent catheters with gel- or water-based lubricants using an in vitro urethral agar channel model

Mucus-inspired biomass-derived carbon dots-based solvent-free nanofluid with polyelectrolytes networks toward excellent green lubrication

Mechanical friction and wear account for 23 % of global energy, highlighting a need for eco-friendly lubricants. Drawing inspiration from marine organisms' adsorption proteins, we have developed carbon dots-based solvent-free nanofluid. Incorporating hydrophilic polyelectrolytes, the nanofluid forms three-dimensional adsorption-lubrication networks, leveraging carbon dots' strong chelating affinity, synergistically enhancing lubrication. Using the UMT-3 TriboLab and a 3D optical profilometer, we assessed the tribological performance of nanofluid and remarkably reduced the friction coefficient by 47.3 % and wear rate by 90.8 % compared to PEG 200 (Polyethylene Glycol with an average molecular weight of 200). Additionally, the infrared camera detected that nanofluid as water additives, significantly reduce wear and heat generation, decreasing temperature rise by 4.7 times. This biomimetic approach paves the way for green, oil-free, and high-performance water-based lubrication technologies.

Tribological properties of the P and S-free protic ionic liquids as water-based lubricants

Three kinds of P and S-free 1,8-Diazabicyclo[5.4.0] undec-7-ene water-soluble protic ionic liquids (PILs) were successfully synthesized and applied as additives in water-1,2-Propylene glycol (PG). The physicochemical properties of PILs and the anti-friction, anti-wear and anti-corrosion properties were investigated. Research results demonstrated that the addition PILs lubricant additive could greatly improve the tribological properties of water-1,2-PG. The addition of 5 wt% PILs with long alkyl chain will result in the reduction of friction coefficient and wear volume by about 45 % and 95 %, respectively. Meanwhile, the PILs with long-chain show more effect lubrication behavior than the short one. In addition, the obtained PILs also possess excellent anti-corrosion properties as water-based lubrication additives. The elemental analysis of the contact area showed that the PILs would generate a chemical reaction film during the friction process, and the carboxylate anion could form a chemical and physical adsorption film on the surface of contact area, which would provide better anti-friction and anti-wear properties.

Unravelling molecular origins of improved tribological properties of amino acid ionic liquid water-based lubricants

In the quest for sustainable lubrication, this study explores the potential of water-based lubricants (WBLs) with amino acid ionic liquid (AAIL) additives. The research combines experimental and reactive molecular dynamics (MD) simulations to assess the tribological and rheological enhancements provided by AAILs. Specifically, tetrabutylphosphonium (P4444) cations paired with Serine (Ser) and Tryptophan (Trp) anions were mixed into water to create AAIL WBLs. The introduction of AAILs significantly improved the lubricants’ rheological properties and reduced the coefficient of friction by up to 34 %. This reduction is attributed to the formation of hydration shells around the amino acid anions, which create a chemically adsorbed tribofilm on iron oxide surfaces, and P4444 cations that establish a load-bearing layer in the middle regions of the lubricant. This dual-layer structure, supported by hydration lubrication, effectively maintains lubricant fluidity while bearing substantial loads. Among the AAIL WBLs tested, those with a thicker, more stable, hydrated amino acid tribofilm demonstrated more significant friction reduction. These insights into the molecular mechanisms behind AAIL WBLs’ tribological behaviour underscore their promise as eco-friendly lubricants, contributing to advancing a circular economy in industries reliant on lubrication.

The In Vivo Effect of Water-Based Lubricants on the Vaginal Microbiome of Women from Varying Age Groups: Exploratory Analysis of a Randomized Controlled Trial.

Vaginal mucosa undergoes physiological changes across the lifespan, such as increased pH and reduced natural lubrication which are known to impact vaginal commensal microorganisms, hence increasing the chances of vaginal infections. An improved understanding of vaginal microbiome composition in different age groups and the effect of social behaviors, such as the use of personal lubricants, could facilitate the development of new strategies to maintain good vaginal health. The objective of this study was to assess the effect of water-based lubricants on the human vaginal microbiome. Fifty females from three age groups (18-29, 30-44, and 45-65 years) with mild-to-moderate vaginal dryness were randomized to one of five lubricants (four of which were formulated to meet expert guidance on osmolality and pH). Subjects entered the study at tolerance or treatment phase (vaginal intercourse minimum once a week using assigned lubricant). Four vaginal swabs per participant were sampled during pre-("baseline"), post-first ("2 h", "24 h") and post-last ("4 weeks") lubricant application to assess bacterial and fungal diversity via amplicon sequencing. Vaginal pH and relative humidity were measured at baseline, 2 h, and 24 h post-lubricant application. Relative bacteriome abundance was statistically compared between timepoints for each lubricant group. Vaginal moisture, age, BMI, and pH were correlated with bacteriome relative abundance. Lactobacilli and Gardnerella sp. Were predominant across participants. Repeated lubricant application did not significantly alter the vaginal bacteriome during 4 weeks of product use (p > 0.05) when measured by relative abundance and alpha-diversity index. Bacteriome diversity and abundance differed significantly between age groups at baseline whereas lactobacilli relative abundance was negatively associated with age and vaginal pH.

Correlation between preparation techniques and frictional properties of cellulose nanocrystals as additives in water-based lubricants

To explore the tribological characteristics of cellulose nanocrystals derived through various preparation techniques when utilized as additives in water-based lubricants, two types of cellulose nanocrystals (S-CNC and C-CNC) were chosen. These were produced via sulfuric acid hydrolysis and oxidation methods. The morphology and structural features were assessed through techniques such as Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), laser confocal Raman spectroscopy, elemental analysis, scanning electron microscopy (SEM), and laser particle size analysis. According to thermogravimetric analysis (TGA), the thermal stability of S-CNC is slightly superior to that of C-CNC. S-CNC exhibits liquid crystallinity when the concentration exceeds 0.5 %, whereas C-CNC does not display liquid crystallinity at any concentration tested. Further investigation was conducted on the frictional properties of the two types of CNCs using a UMT reciprocating friction tester. The results indicate that both types of CNC exhibit significant friction reduction properties at various additive concentrations, provided the addition does not exceed w=1 %. When below their respective liquid crystalline phase concentrations, the friction reduction performance of S-CNC is slightly inferior to that of C-CNC; however, when above the liquid crystalline phase concentration, the friction reduction performance of S-CNC surpasses that of C-CNC. The addition of w=0.5 % S-CNC leads to a relative reduction of 63.4 % in the friction coefficient compared to the base system. Analysis of the steel plate surface contact angle and post-wear surface suggests that the lubrication mechanism of CNC involves the adsorption of polar functional groups such as hydroxyl or carboxyl groups from the CNC structure onto the friction pair surface, forming a lubricating protective film to varying degrees. Additionally, the liquid crystalline structure of S-CNC facilitates the formation of an ordered lubricating film, further enhancing the frictional properties. These findings provide valuable insights into the application of nanocellulose crystals as lubricant additives.

Development of a biomimetic water-based lubricant: Nanoencapsulation of stearic acid using liposomes

Water-based lubricants are abundant in nature; however, they perform poorly in mechanical systems. Based on research into synovial fluid lubrication a water-based liposomal lubricant was developed using a phospholipid (DSPC) and stearic acid (SA). Compared to pure water the liposomal DSPC lubricant improved wear and friction performance, although it underperforms a low viscosity oil such as hexadecane. The inclusion of SA encapsulated within the liposome further improves the performance to a level comparable to hexadecane. Improved performance is achieved due to the following factors: a) DSPC-SA lubricant forms a growing multi bilayer structure in the contact region thereby decreasing wear b) the electrostatic charge associated with the structure allows for retention of the film within the contact area thereby decreasing friction and wear c) liposomes allow for utilisation of insoluble additives within water-based lubricants. The optimal liposomal lubricant tested demonstrates a 63 % reduction of the coefficient of friction and a 99 % reduction in resulting wear compared to DI water alone, thereby providing an avenue for effective utilisation of water in mechanical systems.

Bottle-brush polyurethane as water-based lubricant additive for hydrophobic interfaces

Water-based lubricants were limited on chemically inert and hydrophobic interfaces due to the difficulty in forming an effective boundary lubrication layer. In this study, a bottle-brush polyurethane (BBP) lubricant additive was designed to address the issue through the establishment of multiple non-covalent interactions. 1H NMR, FTIR and molecular dynamics (MD) simulation revealed that the backbone and side chains of BBP provided multiple hydrogen bond interactions. QCM-D verified that BBP was capable of constructing a denser interfacial adsorption layer than linear macromolecules. The as-prepared BBP lubricant exhibited outstanding lubrication performance across various hydrophobic interfaces and was better than oleophilic, hydrophilic and amphiphilic lubricants. Meanwhile, BBP lubricant presented extremely low toxicity to cells and earthworms, indicating potential in medical and industrial fields.

Study on ultra-low friction performance of PTFE film combined with water-based ionic liquid lubrication at electrical contact interfaces

By polytetrafluoroethylene (PTFE) films on the surface of steel disc and using water-based ionic liquids as lubricants, the solid-liquid synergistic effect of PTFE films and water-based ionic liquids was systematically investigated. The results showed that PTFE films exhibited excellent tribological performance and maintained good insulation capabilities under electrical conditions in the sliding electrical contact interface. When using water-based lactate Ionic liquids as lubricants, the PTFE film achieved a COF of less than 0.01 under a load of 2 N, realizing ultra-low friction. The analysis of the lubrication mechanism revealed that two types of protective films were formed on the PTFE film and steel friction pair surfaces. These protective films effectively prevented direct contact between the friction pairs, significantly enhancing tribological performance.

Investigation on the lubrication performance of different carbon nanoparticles for titanium alloy

PurposeThis study aims to develop a high-performance nanofluid that can be used in titanium alloys machining. Titanium alloys are difficult-to-cut materials and difficult to be lubricated. This study explored the lubrication performance of various carbon nanoparticles in water-based lubricants for titanium alloys.Design/methodology/approachThe lubricating and antiwear properties of the developed cutting fluid were tested by a tribo-tester. The lubricant performance was evaluated through friction coefficient, wear volume and surface quality. The lubrication mechanism was analyzed through surface morphology, wettability and bonding analysis.FindingsThe lubricating performance of four kinds of carbon nanoparticles on titanium alloys was tested and the results showed that single-layer graphene had the smallest COF and wear volume. The interaction between nanoparticles and debris was an important factor that influenced the lubrication performance of nanoparticles for titanium alloy. Moreover, the hybrid nanofluid with graphene and spherical graphite in a ratio of 1:2 achieved a balance between lubricating performance and price, making it the optimal choice.Practical implicationsThe developed lubricant containing carbon nanoparticles that can lubricate titanium alloys effectively has great potential in machining titanium alloy as a high-performance cutting fluid in the future.Originality/valueThis paper fulfills an identified need for water-based lubricant for titanium alloys considering the bad tribological properties.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0124/

Preparation and Tribological Behavior of γ-AlOOH/Hexagonal Boron Nitride Composites as Additives in Water-Based Lubricant

Preparation and Tribological Behavior of γ-AlOOH/Hexagonal Boron Nitride Composites as Additives in Water-Based Lubricant

Tribological and Anticorrosion Properties of N-Heterocyclic-Organophosphonic Acid Ionic Liquids as Water-Based Lubricant Additives

Four ionic liquids (ILs) were synthesized by a simple neutralization reaction using 1,8-diazabicyclo[5.4.0]undecane-7-ene as the cation and organophosphonic acids with different carbon chain lengths as the anion. The obtained ILs had an excellent water-soluble property and the tribological performance was studied by a four-ball friction tester. The results showed that the longer carbon chains, the better tribological properties of the ILs. Compared with the blank, only 0.05 wt% of ILs addition resulted in the decrease of friction coefficient and wear volume about 30% and 60%, respectively. The adsorption state of the ionic liquid on the steel surface was also investigated by molecular dynamics simulation. It is believed that the good tribological performance and corrosion inhibition was attributed to the effective physical adsorption due to the polarity of the organophosphonate, which can form an effective adsorption film and prevent the steel surface from corrosion.

High performances of cellulose nanocrystal based bicomponent supramolecular hydrogel lubricant

To improve the limitations of water-based lubricants, a novel cellulose nanocrystal based supramolecular hydrogel (CNC/x-DG/y) was prepared by mixing cellulose nanocrystal (CNC) and diglycerol (DG) into deionized water (DW). The hydrogel was characterized to determine its material ratio and gelation mechanism. When DW was fixed at 1 mL, CNC content should be no <2.4 wt% and DG content 0.1–1.3 mL. The gelification was driven by the multiple H-bond network between CNC and DG, which immobilized water molecules. The rheological performances, the anti-rust property and the volatilization behaviour of the hydrogel were further studied. The results showed that the hydrogel had satisfactory viscoelasticity, excellent thermal stability, strong creep recovery, high anti-rust performance and low volatilization rate, which were exactly its advantages for use as lubricant. A typical representative of the hydrogel, namely CNC/2.4-DG/0.1, was selected to evaluate the tribological performances, and the resulting worn surfaces were analyzed. CNC/2.4-DG/0.1 exhibited a lower friction coefficient of 0.059 and a smaller wear volume of 0.81 × 10−3 mm3, compared to DW(1 mL) + CNC(2.4 wt%) and DW(1 mL) + DG(0.1 mL). The outstanding tribological performances of CNC/2.4-DG/0.1 were reasonably attributed to the synergistic mending effect of CNC and DG and the dissipative effect of H-bonds between the two.

Natural Surfactant Stabilized Aqueous MoS2 Nano-Lubricants for Reducing Friction and Wear

From the outlook of energy saving and environmental protection, the development of eco-friendly and green lubricants without compromising their lubrication performance has become a global agenda. Nevertheless, water-based lubricants suffer from low lubricity and weak load-bearing capacity, making them unsuitable for various industrial applications. Herein, using liquid-phase exfoliation, bulk MoS2 layers are delaminated into atomically thin nanosheets and stabilized in a water medium by a natural surfactant, Sapindius Mukrossi (SM). A natural SM surfactant consisting of 10 % –12 % saponin molecules has a hydrophobic tail aglycone and hydrophilic head glycone molecules that provide steric repulsive forces against the aggregation of exfoliated MoS2 nanosheets. Optimization of the surfactant concentration in water led to highly concentrated MoS2 nanosheets (∼1.23 mg/ml in a single step) with an average lateral length (<L>) and number of layers (<N>) of ∼ 150 nm and ∼ 8 layers, respectively. Owing to its high concentration and few-layers, MoS2 nanosheets based aqueous dispersion was directly tested for aqueous lubricant applications. Compared to pure water, MoS2 nanosheets (0.1 wt%) in water led to effective reductions in the coefficient of friction and wear scar diameter of ∼ 75 % and ∼ 65 %, respectively. Wear depth ∼ 15 µm on SS ball is reduced to ∼ 1 µm when 0.1 wt% of MoS2 nanosheets-SM surfactant dispersion under similar testing conditions. Post-mortem analysis suggested that the stable formation of protective tribo-film on the worn surfaces of steel surface that were tested at different intervals (1-210-400 Days) leads to an effective sliding under load. To demonstrate the practicality of this dispersion, SM surfactant stabilized MoS2 nanosheets was used as a dielectric lubricant fluid in a wire EDM for advanced metal-cutting fluid applications.

Superdispersed spherical fullerenol and lamellar graphene oxide synergize to enhance the antiwear properties of water-based lubricants: Mathematical model and mechanism investigation

The development of high-performance water-based lubricating additives with excellent properties has been the focus of research recently. Herein, carbon-based nanomaterials made of spherical fullerenol and lamellar graphene oxide (GO) were explored as water-based lubricating additives to enhance tribological properties via the response surface method systematically. The antiwear mechanisms of the carbon-based nanomaterials were revealed through simultaneous wear surface characterizations and molecular dynamics simulations. Results showed that the spherical fullerenol and lamellar GO had superdispersion stability in the water-based lubricants. Fullerenol and GO could play a superior synergistic role to considerably enhance the antiwear properties of the water-based lubricants. Particularly, the wear rate decreased by almost 93 % when the water-based lubricant was supplemented with fullerenol and GO (0.1 wt% each) at the load of 1.5 N and sliding speed of 30 mm/s. The antiwear mechanisms indicated that an excellent antiwear effect was produced by the stable tribofilms containing GO and fullerenol, which combined with hydration layers synergistically exerting a bearing capacity.

Tribological Effects of Quaternary Ammonium-Functionalized Montmorillonite as Water-Based Additives.

In this study, a water-soluble quaternary ammonium salt (QAS)-functionalized montmorillonite (MMT) was fabricated using a mechanochemical method as a high-performance water lubrication additive. The intercalation of QAS into the MMT layer expands the layer spacing of MMT, but does not affect the hydrophilicity of MMT. The ultrathin layer QAS-functionalized montmorillonite (QAS-MMT) demonstrated excellent water-stable dispersion and can be used as a water-based lubrication additive. Only 0.1% addition can reduce the friction coefficient by more than 71.4% and the wear volume by about 58.8% when compared to water, demonstrating its excellent friction reduction and antiwear performance. The frictional mechanism indicates that the physical adsorption film, together with the chemical reaction film, endows the QAS-MMT additives with outstanding tribological performance, provides excellent lubrication for the contact of steel/steel pairs, and prevents the steel surface from being further worn.

A study of sexually transmitted infections among men who have sex with men (MSM) in a coastal city Mangaluru, Karnataka

BackgroundSTI (Sexually Transmitted Infections) is common among ‘high-risk groups’ in India, a term used by the National AIDS Control Organization (NACO) which includes men who have sex with men (MSM) and others. Sexual transmission of HIV, most prominent STI between men could be a major cause for concern in most parts of India. HIV infection among MSM has been increasing in recent years round the world, particularly in Asia. Objectives1. To determine the sociodemographic characteristics of men who have sex with men. 2. To estimate the magnitude of sexually transmitted infections (STI) in men who have sex with men. MethodsA cross sectional study was carried out using structured, pretested questionnaire at Hind Kusht Nivaran Sangh, Mangaluru. Face to face interviews of the selected participants was done and data were recorded after obtaining their consent. ResultsA total of 102 MSM were interviewed and the data was collected. The common presenting symptoms were pain while urinating (33.33 %) and least common was bleeding while defecating (1.9 %). The most common morbidity of study population was urinary tract infection (38.23 %) and proctitis (25.4 %) and 3.92 % subjects had HIV/AIDS. ConclusionHealth sector should include safe access to information and education about HIV and other STIs, condoms, water-based lubricants, HIV testing and counselling, and STI services.