Excellent Lubrication Research Articles

Fabrication of carbon dots@2D CuCo-MOF composites as lubricating additives in pentaerythritol ester for enhanced tribological properties at elevated temperatures

In this study, we successfully synthesized CD@CuCo-MOF composites, which are composed of ultrathin two-dimensional (2D) nanosheets of metal-organic framework (MOF) doped with carbon dots (CDs). The synthesis process involved hydrothermal and ultrasonically assisted self-assembly with a proper solvent ratio. The composites were then dispersed into pentaerythritol ester (PETE) with the aid of ultrasonic treatment. We thoroughly evaluated the physicochemical features and tribological properties of the CD@CuCo-MOF composites using advanced testing and characterization techniques including XRD, Raman, FTIR, TG, XPS, FIB-TEM and so on. The results demonstrated that the addition of CD@CuCo-MOF resulted in a 61.1 % reduction in the coefficient of friction (COF) at a concentration of 0.1 wt% when compared to the base oil at room temperature. With the rise in temperature, CD@CuCo-MOF exhibited excellent lubricating properties due to its hybrid inorganic-organic structure and interlayer sliding effect. This led to a reduction of 59.2 % and 42.9 % in the mean COF compared to PETE oil at temperatures of 100 °C and 200 °C. This enhancement in the tribological performance of CD@CuCo-MOF could be attributed to several factors, including its superior dispersion stability, excellent lubricating properties, and involvement in the formation of a tribofilm. The tribofilm formed from a combination of CDs, CuCo-MOF, metal oxides, carbides, and nitrides promoted the rearrangement of the contact surface, thereby minimizing the friction and wear between the rubbing surfaces. These findings hold significant guiding implications for advancing the development of potential-controlled lubrication using MOFs doped with CDs across a wide temperature range.

Functional nano drug delivery system with dual lubrication and immune escape for treating osteoarthritis

Local drug delivery via inter-articular injection offers a promising scenario to treat the most common joint disease, osteoarthritis (OA), which is closely associated with the increased friction or cartilage degeneration and the inflammatory syndrome of synovium. Therefore, it is quite necessary to improve the retention of drug delivery system within synovial joint, simultaneously restore the lubrication of degraded cartilage and meanwhile alleviate the inflammation. In this study, we propose a hydrophilic coating modified nano-liposome drug carrier (PMPC-Lipo) to achieve these functions. A modified chain transfer agent was utilized to polymerize 2-methacryloyloxyethyl phosphorylcholine (MPC), the obtained polymer, combined with lecithin and cholesterol, formed a liposome (PMPC-Lipo) where poly (MPC) acted as hydrophilic coating. PMPC-Lipo was found to restore the lubrication of mechanically damage cartilage (mimicking OA conditions) to the level like healthy cartilage due to the hydration lubrication. Additionally, due to the presence of poly (MPC), we also found PMPC-Lipo avoid the recognition of macrophage and thus escape from the phagocytosis to prolong its retention in synovial joint. Furthermore, after encapsulating gallic acid (GA) into PMPC-Lipo, the obtained GA-PMPC-Lipo can effectively scavenge reactive oxygen species and restore the imbalance of matrix secretion in inflammatory chondrocytes. Collectively, the proposed GA-PMPC-Lipo may provide a new idea for osteoarthritis treatment by providing both long-term effective drug action and excellent lubrication properties.

Bio‐inspired low wear and durable lubrication interfacial system based on thixotropic hydrogel for artificial joints

AbstractInspired by the excellent wear resistance and lubrication of articular joints, a novel bionic interfacial system was proposed by combining thixotropic hydrogel with surface porous Ultrahigh Molecular Weight Polyethylene (UHMWPE). Thixotropic hydrogel, synthesised by gelatin, alginate sodium, tannic acid and weak crosslinking by Ca2+ (Gel‐TA‐Alg@Ca2+), was used as a lubricant due to its shear‐thinning when loaded, then the recovery viscosity to be benefitted for reserving in surface pores on UHMWPE when unloaded. Surface porous UHMWPE was fabricated by using hydroxyapatite particles as porogen to control its porosity, pore size, surface roughness and surface energy (PE‐HA). Gel‐TA‐Alg@Ca2+ significantly reduced average coefficients of friction and wear factors compared to those under normal saline and calf serum solution lubricating after reciprocating tribological testing. Notably, Gel‐TA‐Alg@Ca2+ still maintained thixotropy and was stored in surface pores of UHMWPE even after tribological testing for 7200 min. Thus, durable lubrication could be realised due to the synergistic effect of surface porous structure and thixotropy. Stribeck curves showed the characterisations of mixed, elastohydrodynamic and hydrodynamic, but without boundary lubrications for PE‐30HA under three lubricants. The present results might provide the potential application to construct the durable lubrication bionic articular joint interfacial system for artificial joints.

Refractory high-entropy aluminized coating with excellent oxidation resistance and lubricating property prepared by pack cementation method

Refractory high-entropy alloys (RHEAs) exhibit superior mechanical properties at high temperatures compared to that of conventional high-temperature alloys. However, some refractory metallic elements are highly susceptible to oxygen absorption at room temperature and the resulting oxide films are not protective, resulting in catastrophic oxidation before they can exhibit excellent mechanical properties. Therefore, it is essential for them to improve the high-temperature oxidation properties of RHEAs. The pack cementation method can be used to prepare the aluminized coatings on the surface of RHEAs to improve their high-temperature oxidation resistance. In the present work, the aluminized high-entropy coatings were prepared on the surface of as-cast Ta25Nb25W25V25 RHEAs. The diffusion activation energy required for aluminization was experimentally calculated to be 137.667 kJ/mol, thus the growth kinetics of the coating was constructed. Aluminized coatings with the thickness of ∼75 μm and Vickers hardness of ∼680 HV0.01 obtained by holding at 1100 °C for 9 h were selected for the study. The oxidation activation energy of the aluminized coating at 800–1000 °C was 96.981 kJ/mol, while that of as-cast RHEAs was only 48.816 kJ/mol, so the oxidation resistance of the specimen was greatly improved. At 20–600 °C, the aluminized coatings also exhibited excellent wear resistance and lubrication properties. In particular, the average coefficients of friction were reduced by 0.13–0.24 compared to that of as-cast RHEAs, which can be attributed to the AlW intermetallic compound particles formed within the aluminized coating acting as self-lubricating particles.

Lubricity Performance of Ethylene Glycol Ester from Soybean Oil as a Lubricity Enhancer Bio-Additive for Low-Sulfur Diesel Fuel

The present study aims to show the tribological properties of soybean oil's ethylene glycol ester (SOEGE) and its effect on low-sulfur diesel fuel lubrication. The SOEGE or 2-hydroxyethyl ester was synthesized by a transesterification reaction of soybean oil and ethylene glycol with a potassium carbonate catalyst. The product was characterized using Gas Chromatography-Mass Spectrometry (GC-MS). Then, the lubricity of commercial diesel fuel (Pertadex) and SOEGE were tested alone using the High-Frequency Reciprocating Rig (HFRR) machine. Its mixture form with various product doses in Pertadex (0.2, 0.4, 0.6, 0.8, and 1% v/v) was also tested with the same apparatus. This study showed that the product's coefficient of friction and Wear Scar Diameters (WSD) were 0.057 and 154.4 m, respectively. This value is lower than Pertadex and Fatty Acids Methyl Ester (FAME) of Soybean oil from the literature. Furthermore, adding products into Pertadex can reduce the coefficient of friction and WSD of Pertadex. The Pertadex coefficient of friction was reduced from 0.161 to 0.135 after the addition of 0.8% product. At a concentration of 1% product, WSD Pertadex was successfully reduced by 39.42%. These phenomena imply that ester ethylene glycol has an excellent lubricating effect on low-sulfur diesel. This work's findings open opportunities for other researchers to develop alternative lubricating bio-additives for low-sulfur diesel through the in-depth study of tribochemistry or tribosurface.

Macroscale Superlubricity of Hydrated Anions in the Boundary Lubrication Regime.

Cations can achieve excellent hydration lubrication at smooth interfaces under both microscale and macroscale conditions due to the boundary layer composed of hydration shells surrounding charges, but what about anions? Commonly used friction pairs are negatively charged at the solid/solution interface. Achieving anionic adsorption through constructing positively charged surfaces is a prerequisite for studying the hydration lubrication of anions. Here we report the hydration layer composed of anions adsorbed on the positively charged polymer/sapphire interface at acidic electrolyte solutions with pH below the isoelectric point, which contributes to the hydration lubrication of anions. Strongly hydrated anions (for the case of SO42-) exhibit stable superlubricity comparable to cations, with strikingly low boundary friction coefficient of 0.003-0.007 under contact pressures above 15 MPa without a running-in period. The hydration lubrication performance of anions is determined by both the ionic hydration strength and ion adsorption density based on the surface potential and tribological experiments. The results shed light on the role of anions in superlubricity and hydration lubrication, which may be relevant for understanding the lubrication mechanism and improving lubrication performance in acidic environments, for example, in acid pumps, sealing rings of compressors for handling acidic media, and processing devices of nuclear waste.

A promising high temperature self-lubricating Cu-based superalloy with coherent cuboidal L12-γʹ phases

High temperature self-lubricating materials including composites or coatings exhibit remarkable tribological property but typically suffer from poor ductility. Therefore, striking a fine balance between these two properties is a great challenge. In this work, series of high-temperature self-lubricating Cu100-x(Ni3Al1)(x/4) superalloys were obtained, and it possesses both good tensile strength at room temperature or high temperature and appreciable elongation value (its elongation can reach up to 3%). Compared with other high temperature self-lubricating materials, it has already made great progress in the aspect of mechanical property. The results showed that the source for remarkable high temperature tribological properties derives from the synergistic effect of naturally formed oxide scale and high temperature bearing capacity. In the naturally formed oxide scale, the CuO layer provides excellent lubrication action due to those unique advantages, such as easy to shear, formation of twinning and brittle-ductile transition at high temperature. Additionally, the existence of substantial coherent interfaces hinders the crack initiation. The dense and continuous γ-Al2O3 protective layer can hinder the diffusion of the oxygen anions and metal cations, which is beneficial to inhibit the further oxidation of the alloy. The work provides a novel strategy for the design and preparation of high temperature self-lubricating materials.

Effects of Ni-5 wt% Al/Bi2O3 addition and heat treatment on mechanical and tribological properties of atmospheric plasma sprayed Al2O3 coating

To solve the problem of high friction and wear of the plasma sprayed Al2O3 coating in a wide temperature range, two Al2O3-based composite coatings, namely Al2O3-(NiAl-Bi2O3) coating and Al2O3-(NiAl-Bi2O3)-H coating (heat treatment), were prepared by involving Ni-5 wt% Al and Bi2O3, and applying a simple heat treatment. Compared to the Al2O3 coating, two Al2O3-based composite coatings attained increased toughness and adhesive strength. In particular, heat treatment endowed Al2O3-(NiAl-Bi2O3)-H coating with improved compositional homogeneity and more NiBi intermetallic compound and α-Al2O3 phases. In terms of tribological behavior, when subjected to rubbing against the counterpart Al2O3 ball, Bi2O3 and NiBi were shown to have good lubricating properties, and they exerted friction-reducing and anti-wear effects in both Al2O3-based composite coatings at 25 and 400 °C, respectively. At 800 °C, under the action of thermo-mechanical coupling, a tribo-oxide layer composed of multiple oxides (Al2O3, Bi2O3, NiO and Bi2Al4O9) was generated on the worn surface of the two composite coatings, achieving the excellent lubrication and wear-resistance.

Facile Synthesis of Lignin-Castor Oil-Based Oleogels as Green Lubricating Greases with Excellent Lubricating and Antioxidation Properties

Facile Synthesis of Lignin-Castor Oil-Based Oleogels as Green Lubricating Greases with Excellent Lubricating and Antioxidation Properties

Design of an anticorrosion/bactericidal dual functional organic coating based on the slippery liquid-infused porous surface

In this work, a long-lasting slippery liquid-infused porous surface (SLIPS) was fabricated on an organic coating to achieve both anticorrosion and antibacterial functions. Phenyl-modified etched basalt (PEB) scales were produced to construct micro-nano capillary structures and generate π electrons, which facilitated the retention of lubricant on the surface when assembled onto an epoxy resin layer. Plant oil was selected as a lubricant to introduce numerous –COOH, and was robustly trapped on the surface by π-COOH interactions, which enhanced the durability of the SLIPS coating. Based on the electrochemical tests, the coating displayed superior anticorrosion performance with |Z|0.01Hz values of 1.99 × 1010 Ω·cm2 after 14 days of immersion, which benefited from excellent barrier effect and liquid repellency. The zeta potential result proved that the corrosion resistance of SLIPS coating was further improved by the electrostatic repulsion. In addition, the antibacterial experiment results demonstrated only 0.32% of biofilm coverage and no live bacteria after 3 days of immersion, which implied the dual mechanisms of SLIPS coating in killing bacteria and inhibiting bacterial adhesion. The SLIPS coating with excellent lubricant retention and promising anticorrosion/bactericidal performance possesses tremendous application potential in marine protection.

Synthesis and characterization of polyvalent high-performance synthetic base oil for drilling operations in recalcitrant and unconventional oil and gas reservoirs

Synthetic ester fluid is one of the most widely recommended drilling fluids for unconventional and recalcitrant reservoirs owing to its numerous technical advantages, high sustainability, non-toxic and inherently biodegradable. However, there are serious concerns about its thermal and hydrolytic stability at high temperatures and pressures (HTHP) as well as its viscosity and flow characteristics in low temperature climates such as deep-water wells. Hence, its inability to maintain stable borehole and flat rheology characteristics may invariably threaten its application under these aforementioned scenarios.In this study, a high-performance ternary mixture of synthetic ethyl esters of plants oil (SEEP mixture) fluid was synthesized by a non-catalyzed supercritical ethanol transesterification process using coconut, castor seed and linseed oil as starting materials. The nature, chemistry and fluid particle interactions of the individual components that make up the synthetic ester fluid were critically studied. The process equipment consists of a continuous flow reactor equipped with a PID controlled furnace as heat source to the reactor and a high- pressure transducer. The conversion efficiency was monitored by an Agilent 5500a FTIR machine with attenuated total reflectance (ATR) system while a GC-EIMSD system was used for fatty acid ester compositional analysis. The oil was extracted by a Soxhlet apparatus mechanism. The extracted Plant oil and the synthetic esters were characterized under standard recommended laboratory procedures by API, ASTM and the European Union (EN) standard protocols. Also, fluid's toxicity and biodegradability tests were conducted according to OECD recommended practices. The results were compared with existing synthetic hydrocarbon fluids (SHFs) for HTHP and deep-water wells.The conversion efficiency of the non-catalyzed transesterification process was 96.50%. The amount of oil yield from the plant oil after Soxhlet extraction is commendable. Hence, synthetic ester fluid raw materials are readily available in large quantities and in a sustainable manner. The GC-MS analysis shows that the coconut oil contains 92% saturated fatty acid. Whereas, the castor seed oil contains 98.31% unsaturated fatty acid with 89.75% of mono-unsaturated ricin-oleic acid (D-12-hydroxyoctadec-cis-9-enoic acid). The linseed oil has high content of linolenic acid with 89.60% unsaturated fatty acid. The designed fluid has excellent lubricity characteristics, extremely low cloud and pour point temperatures, higher oxidative stability, low peroxide value, lower copper strip corrosion value and lower kinematic viscosity and density variations with temperatures which signals flat rheology when used to form a synthetic based mud. Also, its flash point and auto-ignition temperatures are high and thus forestall possible fire hazard in high temperature zones. Finally, the fluid is non-toxic and inherently biodegradable.

In-situ exfoliation of large sized h-BNNS by esterified nanocellulose to build aqueous lubricants that can switch between liquid and gel states

The development of cellulose-based aqueous dispersions provides new ideas for the preparation of green lubricants. Herein, an esterified cellulose-assisted in-situ exfoliation (ECAIE) method was used to produce large lateral sized 2D materials in cellulose dispersions which with excellent dispersion stability. Taking h-BN as an example, the ECAIE method produces NC@h-BNNS aqueous dispersion with lateral size of h-BNNS reaching 1200 nm, exhibiting excellent lubrication properties. The obtained aqueous lubricants show the ability to switch between liquid (oscillation) and gel (resting) states. This method was also extended to the production of aqueous dispersions of various other cellulose/2D materials, and the efficient lubrication of the resulting dispersions on engineered steel surfaces has been demonstrated, indicating their great potential in the field of lubrication.

The tribological performance analysis of palm olein-based grease lubricants containing copper nanoparticle additive

Mineral oil-based lubricants have been widely used for their beneficial properties. However, their environmental impact and toxicity have raised concerns, resulting in a search for sustainable and environmentally friendly alternatives. This study investigates the tribological behavior of palm olein-based grease with copper nanoparticles additive concentrations of 0.25 and 0.50 wt%. The friction and wear tests were conducted using a four-ball tribometer to evaluate the performance of the formulated grease and compare it with commercial mineral grease. The results showed that the palm olein-based grease with a 0.25 wt% copper nanoparticle additive concentration had excellent lubricant performance, with low friction and wear prevention characteristics. This concentration of Cu nanoparticles led to a 35.05% reduction in average friction coefficient (COF), a 32.56% reduction in wear scar diameter (WSD), and a 48.02% reduction in wear volume compared to pure palm olein-based grease.

The Synthesis of Cu-Coated Ti2SnC Ceramic and Its Tribological Behaviors as a Lubricant Additive

Lubricant additive plays an important role in reducing the friction and wear for base oil. MAX phase ceramics may have superior advantages for additive application due to their unique nanolayered structure. In this paper, Ti2SnC ceramic is prepared by sintering the elemental mixtures at 1250 °C. In addition, Cu-coated Ti2SnC ceramic is successfully prepared using a chemical plating method for the first time. It is confirmed that the Ti2SnC ceramic has good self-catalytic activity, and a layer of stacking Cu nano-particles can be deposited on the Ti2SnC surface without pretreatment. When the Cu-coated Ti2SnC ceramic powder is doped into PAO10 base oil, the oil can exhibit excellent lubrication properties, where the friction coefficient is as low as 0.095. A layer of tribo-film can be formed during the sliding process when the Cu-coated Ti2SnC ceramic is incorporated into PAO10 base oil, which can reduce the friction coefficient. The superior lubrication properties can be attributed to the synergistic lubrication effect of Ti2SnC ceramic and Cu nano-particles.

Superlow friction and wear enabled by nanodiamond and hexagonal boron nitride on a-C:H films surfaces in dry nitrogen

Hydrogen-deficient amorphous carbon (a-C:H) is subjected to abnormally high friction in an inert environment, and the possibility of maintaining ultra-low friction is still a great challenge. Here, nanodiamond and hexagonal boron nitride are used to improve the tribological properties of a-C:H films. Particularly, an excellent synergistic lubrication effect was obtained after surface treatment using a solution droplet of nanodiamond + h-BN mixture with a mass ratio of 1:1 and a concentration of 0.1 mg/mL, and concurrently vacuum heated at 80 °C. The COF also decreased sharply to be below 0.001, about two orders of magnitude lower than the case without surface treatment. Correspondingly, the wear rate of steel ball was also decreased by ∼97%. The dominant factor to obtain ultra-low friction is the incommensurate contact between the tribolayer formed by nanodiamond + hexagonal boron nitride and the hydrogen passivation layer. Meanwhile, the incommensurate contact of mismatched h-BN nanoflakes promotes the formation of ultra-low friction. Besides, low shear slip at the interface formed by the in-situ growth of h-BN layered shear band and ND + h-BN nano-composited shear band, respectively, rubbing against the upper ND + h-BN mixed tribolayer also makes a contribution. The ultra-low friction is achieved under the joint action of these factors. These findings can enrich the understanding of the surface modification of a-C:H films by low-dimensional nano-lubricants. It is helpful to develop solid carbon films with more adaptability and robustness under extreme working conditions and provide important scientific and technical guidance.

Spectroscopic Evaluation of Surface Chemical Processes Occurring in MoS2 upon Aging.

Molybdenum disulfide (MoS2) coatings have attracted widespread industrial interest owing to their excellent lubricating properties under vacuum and inert conditions. Unfortunately, the increase in MoS2 interfacial shear strength following prolonged exposure to ambient conditions (a process referred to as "aging") has resulted in reliability issues when MoS2 is employed as solid lubricant. While aging of MoS2 is generally attributed to physical and chemical changes caused by adsorbed water and/or oxygen, a mechanistic understanding of the relative role of these two gaseous species in the evolution of the surface chemistry of MoS2 is still elusive. Additionally, remarkably little is known about the effect of thermally- and tribologically-induced microstructural variations in MoS2 on the aging processes occurring in the near-surface region of the coating. Here, we employed three analytical techniques, namely, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and grazing-incidence X-ray diffraction (GIXRD), to gain insights into the aging phenomena occurring in sputtered MoS2 coatings before and after tribological testing, while also evaluating the impact of thermally-induced variations in the coating structure on aging. The outcomes of XPS analyses provide evidence that a substantial surface oxidation of MoS2 only takes place under humid conditions. Furthermore, the correlation of XPS, ToF-SIMS, and GIXRD results allowed for the development of a qualitative model for the impact of shear-induced microstructural variations in MoS2 on the transport of water in the near-surface region of this material and on the extent of surface oxidation. These results add significantly to our understanding of the aging mechanisms of MoS2 coatings used in tribological applications and their dependence on environmental conditions.

Self-Adaptive Macroscale Superlubricity Based on the Tribocatalytic Properties of Partially Oxidized Black Phosphorus.

The high-flash heat generated by direct contact at asperity tips under high contact stress and shear significantly promotes the tribocatalytic reaction between a lubricating medium and a friction interface. Macroscale superlubricity can be achieved by using additives with good lubrication properties to promote the decomposition and transformation of a lubricating medium to form an ultralow shear interface during the friction process. This paper proposed a way to achieve self-adaptive oil-based macroscale superlubricity on different tribopairs, including steel-steel and steel-DLC (diamond-like carbon), which is based on the excellent lubricating performance of black phosphorus with active oxidation and the catalytic cleavage behavior of oil molecules on the surface of oBP. This work potentially expands the industrial application of superlubricity.

A comprehensive ab-initio insights into the pressure dependent mechanical, phonon, bonding, electronic, optical, and thermal properties of CsV3Sb5 Kagome compound

In this paper, we have presented a comprehensive study of the physical properties of Kagome superconductor CsV3Sb5 using the density functional theory (DFT) methodology. The structural, mechanical, electronic properties (band structure, electronic energy density of states, Fermi surface, and charge density distribution), atomic bonding, hardness, thermodynamics, optical properties, and their pressure dependences have been investigated systematically at different pressures. The calculated ground state lattice parameters and volume are in excellent agreement with available experimental results. The estimated single-crystal elastic constants ensured the mechanical stability of the compound, whereas phonon spectra endorse dynamical stability at zero pressure. The electronic band structure, density of states, and optical properties confirmed the metallic feature. The Pugh ratio and Poisson’s ratio of the compound under study revealed the softness/ductility. The hardness of CsV3Sb5, estimated using several formulae, is quite low while the machinability index predicted good machinability with excellent lubricating properties. The compound shows tendency towards structural instability at a pressure around 18 GPa. The optical constants have also been studied to correlate them with electronic properties (band structure) and predict the possible applications of this compound. Both the mechanical and optical properties show directional anisotropy. CsV3Sb5 is predicted to be an efficient absorber of ultraviolet radiation. The compound is also an efficient reflector of visible light. The superconducting transition in CsV3Sb5 has been revisited following prior studies.

Partially Oxidized Violet Phosphorus as an Excellent Lubricant Additive for Tribological Applications.

As a novel two-dimensional material, violet phosphorus (VP) has attracted a considerable amount of attention due to its high carrier mobility, anisotropy, wide band gap, stability, and easy stripping properties. In this work, the microtribological properties of partially oxidized VP (oVP) and the mechanism of reducing friction and wear as additives in oleic acid (OA) oil were studied systematically. When adding oVP to OA, the coefficient of friction (COF) decreased from 0.084 to 0.014 with the steel-to-steel pair, and the ultralow shearing strength tribofilm consisting of amorphous carbon and phosphorus oxides that formed resulted in the reductions of COF and wear rate individually by 83.3% and 53.9%, respectively, compared with those of pure OA. The results extended the application scenarios for VP in the design of lubricant additives.

Preparation and Performance Evaluation of Polyacrylamide Hydrogel Coating on the Surface of Silicone Rubber Nasogastric Tube

To prepare the hydrogel coating on the surfaces of nasogastric tubes and to evaluate its effect on the insertion of nasogastric tubes in a rabbit model. The polyacrylamide (PAAm) hydrogel coating was prepared by UV-induced free radical polymerization. The morphology of the PAAm coating and its interfacial bonding with the silicone rubber substrates of nasogastric tubes were observed with scanning electron microscope. The composition of the coating was analyzed by Fourier transform infrared (FTIR) spectrometer and X-ray photoelectron spectrometer (XPS). The water absorption power and stability of the coating were measured by the weighing method. Water contact angle meter was used to measure the wettability of the coating and tribometer was used to determine the friction coefficient of the silicone rubber substrates before and after the modification. The cytotoxicity of the coating on L929 murine fibroblast cell line was explored with CCK-8 assay after 24-h coculturing of the L929 cell line with silicone rubber substrates before and after modification. An animal model of nasogastric tube insertion in New Zealand rabbits was used to evaluate the effect of the lubrication coating by assessing the insertion time and nasal damage. In this study, PAAm hydrogel coating was prepared and constructed on the surface of silicone rubber nasogastric tubes. The coating, with a three-dimensional network structure, showed strong interfacial bonding with silicone rubber substrates. The appearance of amino and carbonyl groups indicated that the PAAm hydrogel coating was grafted on the surfaces of nasogastric tubes. Before the modification, the silicone rubber substrate essentially did not absorb much water, whereas, after the modification, the silicone rubber substrate showed significant improvement of as much as 2.9% in water absorption. After sonication for 90 min, the weight loss rate was only 0.15%. Compared with pristine nasogastric tubes, the water contact angle of the modified nasogastric tubes was reduced from 111.9°±2.2° to 58.9°±1.5° ( t=22.59, P<0.05). In addition, the friction coefficient of silicone rubber nasogastric tubes decreased by 69.3% from 0.378±0.05 to 0.116±0.004 ( t=42.80, P<0.05) after modification. Moreover, there was no significant difference in the cytocompatibility between L929 cells cocultured with pristine nasogastric tube and those cocultured with modified nasogastric tube. The animal experiment of nasogastric tube insertion showed that the insertion time of the modified nasogastric tubes was reduced from (41.6±7.8) s to (12.4±2.9) s ( t=8.509, P<0.05). Laryngoscopy revealed that the PAAm hydrogel coating significantly reduced the mucosal damage caused by the insertion of nasogastric tubes. In this study, PAAm hydrogel coating with strong interfacial bonding was prepared on the surface of silicone rubber nasogastric tubes. The coating has excellent hydrophilic lubrication property and cytocompatibility, effectively shortens the insertion time, and reduces the damage caused by nasogastric tube insertion.