Rubber Substrate Research Articles

Graphene nanoplatelets on recycled rubber: an experimental study of material properties and mechanical improvements.

This study presents an experimental investigation of the mechanical behaviour of recycled rubber pads coated with graphene nanoplatelets. The investigation is part of an effort to develop a novel rubber-based composite that aims to reroute rubber from end-of-life tyres from illegal landfills and incineration back into the market in the form of a novel composite for vibration isolation. Graphene nanoplatelets were deposited on rubber pads via ultrasonic spray coating. The pads were made of a combination of recycled rubber (from tyres) and virgin rubber. A comprehensive analysis of the structural and chemical properties of the graphene coating, ensuring its integrity on the rubber substrate, was performed by combining surface topography, Raman and Fourier-transform infrared (FTIR) spectroscopy. Stacked coated pads were cured and tested dynamically in compression and shear under cyclic loading. Results showed promising improvements in the mechanical properties, in particular, in compressive stiffness and damping of the coated specimens with respect to their uncoated counterparts, laying the foundation for using graphene-enhanced recycled rubber as a novel composite.This article is part of the theme issue 'Celebrating the 15th anniversary of the Royal Society Newton International Fellowship'.

Robust and Lubricating Interface Semi-Interpenetrating Network on Inert Polymer Substrates Enabled by Subsurface-Initiated Polymerization.

Lubricating hydrogel coatings on inert rubber and plastic surfaces significantly reduce friction and wear, thus enhancing material durability and lifespan. However, achieving optimal hydration lubrication typically requires a porous polymer network, which unfortunately reduces their mechanical strength and limits their applicability where robust durability and wear-resistance are essential. In the research, a hydrogel coating with remarkable wear resistance and surface stability is developed by forming a semi-interpenetrating polymer network with polymer substrate at the interface. By employing a good solvent swelling method, monomers, and photoinitiators are embedded within the substrates' subsurface, followed by in situ polymerization under ultraviolet light, creating a robust semi-interpenetrating and entangled network structure. This approach, offering a thicker energy-dissipating layer, outperforms traditional surface modifications in wear resistance while preserving anti-fatigue, hydrophilicity, oleophobicity, and other properties. Adaptable to various rubber and plastic substrates by using suitable solvents, this method provides an efficient solution for creating durable, lubricating surfaces, broadening the potential applications in multiple industries.

ЗАВИСИМОСТЬ УДАРНО-АБРАЗИВНОЙ ИЗНОСОСТОЙКОСТИ СЛОИСТЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ ОТ ДЕФОРМИРОВАННОГО СОСТОЯНИЯ РЕЗИНОВОЙ ПРОСЛОЙКИ

It is established that during impact-abrasive testing of layered composite materials made of 40X, P40X and rubber steels, the amount of absorbed energy depends not only on the physical and mechanical properties of the materials, but also on the geometric parameters of the elastic-dissipative layer. The impact and abrasive wear resistance of layered composite materials is 1.5-2 times greater than when using wear-resistant steels. A method for determining the deformed state of a rubber elastic-dissipative substrate of layered composite materials is proposed and the effect of stress and strain intensity on the dissipation operation when testing structural steels for impact and abrasive wear resistance is shown. The influence of the heat treatment regime of the 40X steel working layer on the impact and abrasive wear of the SCM is investigated. The mechanism of destruction of the surface of sintered structural steels during impact and abrasive wear has been revealed.

Design and preparation of durable intelligent haze removal and self-cleaning protective coatings

Conventional superhydrophobic coatings lose effectiveness over due to degradation from ultraviolet (UV) radiation, contaminants, and abrasion. Moreover, external cleaning methods are often needed to maintain self-cleaning performance in the presence of oils and organic contaminants. This study develops an organic-inorganic hybrid coating comprising polymethylhydrosiloxane (PMHS)-modified diatomaceous earth (DE) loaded with titanium dioxide (TiO2) on a room-temperature vulcanized rubber (RTV) substrate. The PMHS-DE-TiO2 coating achieves a synergistic effect, combining superhydrophobicity and photocatalysis. Notably, it exhibits a water contact angle (WCA) of 162.2°, a sliding angle (SA) of 5°, and achieves complete degradation of methylene blue (MB). It maintains hydrophobicity, integrity and functionality under UV radiation, prolonged abrasion, and acidic/alkaline salt solution immersion. The coating also degrades NO at 73.09 % maximum rate. Integration with a negative air ion generator further harnesses the timely superhydrophobic self-cleaning and photocatalysis to significantly enhance dust and fog removal efficiency beyond conventional commercial ion generators. Aligning with green low-carbon principles, this multifunctional coating provides an innovative solution for environmentally-friendly construction materials suitable for long-lasting exterior and interior usage. It resists pollution while mitigating airborne hazards, meeting growing demands for healthy buildings.

Nitrogen-Doped Diamond-like Carbon Buffer Layer Enhances the Mechanical and Tribological Properties of Diamond-like Carbon Films Deposited on Nitrile Rubber Substrate

The poor adhesion between the DLC film and rubber restricts its application of seals. Introducing a suitable interlayer can bolster the adhesion of the coating or film. In this study, nitrogen-doped diamond-like carbon (N-DLC) emerged as the optimal intermediate layer between rubber and DLC. A series of N-DLC/DLC multilayer films were fabricated via DC magnetron sputtering on nitrile rubber (NBR) substrates, varying the substrate bias voltage (0 V, 100 V, 200 V). A scanning electron microscopy analysis revealed that the composite film surface was smoother than the DLC film alone. The results of Raman spectroscopy and X-ray photoelectron spectroscopy indicated a robust bond between nitrogen and carbon atoms in the composite film, with nitrogen facilitating the conversion of sp3C-C bonds into sp2C=C. Mechanical tests demonstrated that the N-DLC interlayer improved film adhesion and reduced the CoF of the composite film to 0.2–0.3. Specifically, the CoF of the N-DLC/DLC film prepared at 100 V was as low as 0.20, with a wear amount of 1.13 mg. Consequently, the inclusion of the N-DLC interlayer substantially enhanced the mechanical and tribological properties of DLC-coated NBR, rendering this coating highly advantageous for various applications.

Optimized Tribological Performance of Nitrogen-Doped Diamond-like Carbon Films on NBR: Influence of Bias Voltage of DC Magnetron Sputtering.

In this research, nitrogen-doped diamond-like carbon (N-DLC) coatings were deposited on Nitrile Butadiene Rubber (NBR) substrates using direct current magnetron sputtering (DC-MS) under varying bias voltages. This study aimed to explore environmentally friendly, low-wear, and non-lubricating seal coatings to enhance the durability of rubber sealing products, which predominantly operate under dynamic sliding conditions. By reducing the coefficient of friction (CoF), the friction and wear on rubber products can be significantly minimized, extending their lifespan. This investigation thoroughly examined the microstructure, mechanical properties, and tribological behavior of the N-DLC films. Among the coatings, the one produced at a bias voltage of -50 V demonstrated superior hardness, elastic modulus, and the lowest CoF in comparison to those prepared with 0, -100, and -200 bias voltages. This optimal combination of properties resulted in an exceptionally low wear rate of 10-9 for the film deposited at -50 V, indicating its outstanding wear resistance.

Bioinspired superhydrophobic surfaces with silver and nitric oxide-releasing capabilities to prevent device-associated infections and thrombosis

Bacteria-associated infections and thrombus formation are the two major complications plaguing the application of blood-contacting medical devices. Therefore, functionalized surfaces and drug delivery for passive and active antifouling strategies have been employed. Herein, we report the novel integration of bio-inspired superhydrophobicity with nitric oxide release to obtain a functional polymeric material with anti-thrombogenic and antimicrobial characteristics. The nitric oxide release acts as an antimicrobial agent and platelet inhibitor, while the superhydrophobic components prevent non-specific biofouling. Widely used medical-grade silicone rubber (SR) substrates that are known to be susceptible to biofilm and thrombus formation were dip-coated with fluorinated silicon dioxide (SiO2) and silver (Ag) nanoparticles (NPs) using an adhesive polymer as a binder. Thereafter, the resulting superhydrophobic (SH) SR substrates were impregnated with S-nitroso-N-acetylpenicillamine (SNAP, an NO donor) to obtain a superhydrophobic, Ag-bound, NO-releasing (SH-SiAgNO) surface. The SH-SiAgNO surfaces had the lowest amount of viable adhered E. coli (> 99.9 % reduction), S. aureus (> 99.8 % reduction), and platelets (> 96.1 % reduction) as compared to controls while demonstrating no cytotoxic effects on fibroblast cells. Thus, this innovative approach is the first to combine SNAP with an antifouling SH polymer surface that possesses the immense potential to minimize medical device-associated complications without using conventional systemic anticoagulation and antibiotic treatments.

Double‐Helical Carbon Nanotube‐Wrapped Elastomeric Mandrel for Electrical Shortage‐Free, One‐Body Multifunctional Fiber Systems

AbstractSoft and elastic fiber‐based electronic devices exhibiting high electromechanical stability are highly desirable for sustainable and continuous utilization in various applications. However, effectively assembling the cathode and anode in a single body without unwanted interconnections and realizing an intimate contact interface between the electrode and substrate remain challenging. Here, an electrical shortage‐free one‐body fiber system with double‐helix buckle electrodes created by torsion‐ and strain‐mismatch between carbon nanotube (CNT) ribbons and a rubber substrate is reported. The as‐used CNT ribbons serve as the strain‐insensitive electrode, while the rubber mandrel‐core fiber acts as the key matrix in the following three aspects: as an elastic substrate that ensures reversible structural changes during mechanical deformations; as a dielectric layer for capacitive strain sensing; and as an electrothermal expansion element for tensile contraction. Moreover, because of the mismatch‐induced torque‐balance structure, the helically wrapped CNT buckle electrodes can effectively absorb the applied stresses without noticeable delamination and electrical conductance loss. Consequently, the double‐helix buckle fiber system can reliably provide multiple functions, viz. detection of various deformations (e.g., stretching, twisting, and pressing), electrochemical energy storage with excellent strain tolerance, and reversible electrothermal tensile actuation.

Defect‐Induced Rashba Effect in Metal Halide Perovskite Thin Films Deposited on a Flexible Substrate

AbstractMetal halide perovskites (MHPs) exhibit strong spin‐orbit coupling and structural inversion asymmetry, making them ideal for testbeds of Rashba effects and for use in spin‐related optoelectronic and spintronic applications. However, the Rashba band splitting is mainly observed in bulk MHPs so far and is rarely observed in thin films. In this study, a direct observation of Rashba band splitting in MHP thin films at room temperature is reported. By employing a silicone rubber substrate with a high thermal expansion coefficient, the out‐of‐plane tensile strain significantly reduces the activation energy of ion migration in these thin films and leads to a considerable amount of point defects. These point defects disrupt the inversion symmetry and ultimately give rise to the Rashba band splitting. These findings open up new possibilities for manipulating Rashba effects in MHP thin films through device engineering.

An accurate respiratory rate estimation algorithm for a rubber fiber respiratory sensor

Respiratory measurement is a crucial indicator for assessing health status; however, current methods for measuring respiratory rate and frequency are passive and not intuitive. This study investigates peak detection algorithms using a resistive strain sensor integrated into a garment for respiratory rate monitoring. The sensor, constructed with CNT material and a flexible rubber substrate, exhibits high conformity to the body’s contours. Designed for respiration measurement, the sensor maintains a low 6% strain for optimal sensitivity, demonstrating a 4% decrease after 800 repetitions of 10% elongation. Garment design emphasizes cohesion between the sensor and fabric, achieved through a piping technique. Respiratory measurement relies on a resistive sensor principle, where abdominal volume changes induce tension, altering resistance. Three peak detection algorithms are evaluated: the window size algorithm, low-pass filter, and FIR filter. The window size algorithm shows a 93% matching rate for normal breathing but requires manual adjustments based on breathing speed. The low-pass filter reduces noise but introduces lag, challenging peak matching. The FIR filter effectively detects peaks at increased speeds, achieving a matching rate exceeding 98%. The study concludes that the choice of algorithm depends on respiratory scenarios, with the window size algorithm suitable for regular cycles, the low-pass filter for real-time monitoring, and the FIR filter for accelerated respiratory rates. The study primarily explores static situations, indicating the need for future research on dynamic respiratory movements to enhance algorithm versatility.

Fabrication of robust superhydrophobic surface on silicone rubber

Robust superhydrophobic surfaces with periodic array structures composed of circular silica islands on silicone rubber substrates were fabricated using a combination of multi-laser exposure and chemical modification. Abrasion tests with sandpaper demonstrate that hard silica regions on the surface can protect the silicone rubber region from external damage, resulting in long-lasting superhydrophobicity. Moreover, with an increase in area fraction and a decrease in array hole radius, the wear of the filled superhydrophobic silica is slowed while the protection for the silicone rubber region is enhanced. Particularly, the optimum surface geometry had an area fraction of 35 % and array hole radius of 100 μm retaining its hydrophobicity up to 63 times of abrasion, eight times more than that of the superhydrophobic surface processed by lasers alone. The results of a sand impact test confirmed the resulting surface's resilience in an aeolian sand environment. This research demonstrated the feasibility of producing robust, superhydrophobic surfaces on flexible silicone rubber substrates and providing a foundation for improving and innovating related products.

Designing polymeric coating with low coefficient of friction for natural rubber glove application

A layer of polymeric coating with low coefficient of friction (COF) on rubber glove surface is necessary for quick and easy donning. The current study elucidates the effect of varying the composition of soft and hard monomers in novel styrene-butyl acrylate-isoprene (St-BA-Iso) terpolymer on the properties of emulsion and its coating performance on rubber glove substrate. Styrene contributed to the terpolymer’s overall strength and smooth surface. Butyl acrylate, as a soft monomer, imparted flexibility and lower the glass transition temperatures of the coating. Isoprene, another soft monomer, further contributed to the coating’s flexibility and, when combined with butyl acrylate, played a role in maintaining coating adhesiveness. Terpolymers with higher loading of BA and Iso was found to produce films of relatively low glass transition temperature, Tg and higher COF. Meanwhile, high loading of St in the terpolymer resulted with smooth coating surface but exhibited severe delamination from the substrate when stretched due to the high rigidity and poor coating adhesion. St-40 terpolymer with 4 St: 3 BA: 3 Iso composition was able to produce a coating with well-balanced properties, producing smooth film (COF < 0.1) with moderately high Tg (24 °C), while retaining good coating adhesion on the rubber substrate.

Low friction and wear of Nitrogen-doped diamond-like carbon films deposited on NBR with different flows of N2 by DC-MS

Utilizing a diamond-like carbon (DLC) coating on rubber surfaces is an innovative approach to improve the wear resistance and tribological characteristics of rubber. In this paper, a series of N-doped diamond-like thin films (N-DLC) were deposited on the surface of nitrile butadiene rubber (NBR) substrate by varying the flow rate of nitrogen using direct current magnetron sputtering (DC-MS) technology, and the effects of nitrogen flow rate on the surface morphology, structure, surface energy and tribological properties of N-DLC films were systematically investigated. The results show that the friction coefficients of the N-DLC films are all smaller than those of the undoped DLC films, and most importantly, the samples maintain a stable, ultra-low coefficient of friction of about 0.057 and a low wear rate of the order of 10−9 in the tribological tests at a nitrogen flow rate of 3 sccm, exhibiting excellent tribological performance. This is attributed to several key factors: higher hardness, better film-base bonding, lower surface roughness, and lower friction interface adhesion. This recognition provides insight into the preparation of N-DLC films on rubber to achieve low frictional wear.

Ceramic coating on rubber by aerosol deposition with cryogenic substrate cooling

Aerosol deposition (AD) is a non-thermal ceramic coating process based on the impact consolidation of ceramic particles upon impact with the substrate. AD forms dense, thick ceramic films on a variety of hard substrates. However, because the substrate must be hard to form a ceramic film by AD, the process does not work on flexible materials, especially rubber, where non-thermal ceramic coating is required. In this study, we fabricate dense, thick ceramic coatings on soft rubber substrates by cooling the rubber substrate below its glass transition temperature during deposition. The ceramic coating on rubber shows optical transparency, mechanical properties, and microstructure comparable to the ceramic film formed by AD on a hard substrate.

Preparation of Bi2O3@PCPA‐KH590/chloroprene composites with good mechanical properties under high‐filling

AbstractAs a “green” radiation protection material with the potential to replace lead oxide, bismuth oxide has more research applications in the field of γ protection. However, due to their different surface properties, there are compatibility and interaction problems between metal oxides and rubber. To enhance the performance of bismuth oxide in neoprene, Bi2O3@PCPA‐KH590 was prepared by coating bismuth oxide with polyphenol/polyamine and grafting KH590 on the surface of bismuth oxide. This allows for creating more active sites with the help of polyphenol/polyamine, enabling KH590 to be grafted onto bismuth oxide particles. The S functional group on the silane coupling agent is then cross‐linked with the rubber substrate, enhancing the dispersibility of the bismuth oxide powder. This improvement not only improves the dispersibility of the bismuth oxide powder but also enhances the mechanical properties of the rubber composite material. Compared with pure CR, the mechanical properties of 60 wt% filler‐modified powder composites can still be maintained at a high level, with the tensile strength reaching 12.83 Mpa. In sum, the proposed method appears feasible for preparing highly filled radiation protection rubber‐based materials.

Armadillo-inspired ultra-sensitive flexible sensor for wearable electronics

Flexible sensors are receiving growing attention as a valuable technology in application areas such as wearable electronics, soft robotics and e-skin. Unfortunately, most flexible sensors generally suffer from low sensitivity, narrow application range and single detection function. Herein, we present an uneven deformation strategy inspired by armadillo skin to construct ultra-sensitive flexible sensors. ASR-CLNS sensor consists of a silicone rubber substrate imitating the armadillo skin (ASR) and a continuously laminated conductive network (CLN). Mechanical deformation-induced stress concentration substantially contributes to ultra-high sensitivity. Noteworthily, the non-uniform substrates have specific stress concentration responses in different tensile directions, and the stretch sensitivity can be easily adjusted by microstructure customization or simply changing the sensor placement angle, which enables it to meet the detection requirements of more scenarios. Simultaneously, the laminated structure of the CLN endows the sensor pressure sensitivity, which allows sensors to be used to detect small pressures such as human breathing. Additionally, CLN demonstrated fast heat transfer capability, which can effectively improve the thermal management properties of composites. In short, this work provides an unexplored strategy to develop tunable/ultra-high sensitivity and multifunctional flexible sensor devices.

Commercial scale production of Yamabushitake mushroom (Hericium erinaceus (Bull.) Pers. 1797) using rubber and bamboo sawdust substrates in tropical regions

Yamabushitake (Hericium erinaceus) is one of the most sought out mushrooms that is widely used for both direct consumption and medicinal purposes. While its demand increases worldwide, cultivation of the mushroom is limited to temperate areas and its production in tropical regions has never been explored. The aim of this study was to test the utilization of rubber and bamboo sawdust, alone or as a substrate mixture, for industrial scale Yamabushitake mushroom production. Five substrate treatments with various ratios of the two sawdust were compared for their physicochemical properties in relation to mushroom productivity. The highest mushroom fresh and dry (113.22 and 23.25 g, respectively), biological efficiency (42.61%), and cap size (9.53 cm) were obtained from the substrates containing 100% rubber sawdust, with the mushroom yield decreasing proportional to the ratio of bamboo sawdust. The 100% rubber sawdust substrate provided a higher initial organic matter and carbon content together with C:N ratio at 63.2%, 36.7% and 65.48, respectively, whereas the 100% bamboo sawdust provided higher nitrogen content (1.03%), which was associated with lower mushroom yield but higher number of fruiting bodies. As in the 100% rubber sawdust substrate, a comparable mushroom yield and growth attributes were also obtained in the 3:1 rubber-bamboo sawdust mixture substrate. Principle component analysis of the measured variables indicated a strong influence of substrate C:N ratio before spawning and the change in substrate electrical conductivity and N content after cultivation to the variation in mushroom productivity among the treatments. The results demonstrate the applicability of rubber sawdust and its combination with up to 25% of bamboo sawdust for Yamabushitake mushroom cultivation and provide the basis for substrate optimization in the tropical Yamabushitake mushroom industry through a circular economy framework.

Abstract P1121: Substrate Rigidity And Mybpc3 Genotype Regulate Development Of Hypertrophic Cardiomyopathy Structural And Functional Phenotypes In Human Ipsc-derived Micro-heart Muscle Arrays

Introduction: We hypothesized that mechanical loading is a key factor in the early stages of hypertrophic remodeling associated with pathogenesis of hypertrophic cardiomyopathy (HCM). We tested this hypothesis in vitro with human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM) bearing heterozygous loss-of-function mutations in Myosin Binding Protein C (MYBPC3). Cardiomyocytes were cultured in engineered micro-heart muscle arrays that were loaded by changing substrate rigidity. Methods: Isogenic control and MYBPC3 +/- hiPSC-CM were seeded into dogbone-shaped molds to form micro-heart muscle atop silicone rubber substrates with rigidity levels ranging from levels of embryonic (0.4 kPa) to fibrotic adult heart (114 kPa). Spontaneously contracting micro-tissues formed within 48 hours. 10 days after formation, tissues were monitored for action potentials (voltage sensitive dye, BeRST-1), Ca 2+ transients (GCaMP6f reporter), and contractility (substrate deflection). Cell and tissue architecture were assessed in 8 μm cryosections, and RNA transcription via qRT-PCR. Results: MYBPC3 +/- and control cardiomyocytes had similar physiology and morphology in 2D monolayers. However, MYBPC3 +/- tissues exhibited marked changes in Ca 2+ handling, which were exacerbated when substrate stiffness increased to the level of healthy heart muscle (15 kPa). This was concurrent with hypertrophy of MYBPC3 +/- cardiomyocytes at 15 kPa. MYBPC3 +/- tissue Ca 2+ handling abnormalities were linked to enhanced Ca 2+ intake rather than SERCA deficiency or excessive myofilament buffering. MYBPC3 +/- tissues exhibited mis-regulation of cardiac troponins on the RNA and protein localization levels, which may underlie the observed structural and physiological changes. Conclusions: Changes in the rigidity of the substrate, mimicking changes in heart muscle caused by blood pressure, pushed hiPSC-cardiac micro-tissues with MYBPC3 mutations to recapitulate key structural and electrophysiological characteristics of HCM. In contrast, control tissues exhibited hypertrophy and abnormal calcium handling, but only at extreme values of substrate stiffness. This suggests that HCM mutations may exaggerate load-dependent hypertrophic remodeling.

Effect of local pressure difference caused by argon flow on properties of DLC films on rubber

The application of a diamondlike carbon (DLC) coating on rubber surfaces is a promising method to enhance the tribological properties of rubber and alleviate its poor wear resistance. However, in the preparation of DLC films, accurate pressure detection in the sputtering region is challenging due to the single detection position in common sputtering systems. In this paper, the direct current magnetic sputtering method was used to prepare DLC films on nitrile butadiene rubber (NBR). A set of Faraday beam detection device (FBDD) was employed to monitor the current density in the sputtering region. It was found that even if the pressure at the detection position of the vacuum gauge is consistent, the actual pressure in the sputtering region may be different under different rates of argon flow based on the detection results from the FBDD. The surface energy of DLC films was also calculated and researched. According to the results of FBDD, a series of analytical characterization methods were selected to explore the influence mechanism of changing the Ar flow rate on the properties of DLC films on NBR when the initial sputtering pressure remained consistent. The results of FBDD show that the density of the beam in the sputtering region increases with the increase in the Ar flow rate introduced into the vacuum chamber. The surface energy of DLC films was also calculated and evaluated by a contact angle tester. Raman and x-ray photoelectron spectroscopy results indicate that the increase in the Ar flow rate leads to an increase in pressure, which is conducive to the formation of sp3 in DLC films, and the increase in sp3 improves the surface energy of DLC films. The highest sp3 content and surface energy among as-prepared DLC films are observed when the argon flow rate was 40 SCCM. Ball-on disk friction experiment was used to characterize the tribological performance of DLC films on NBR rubber and the adhesion between DLC films and NBR rubber was evaluated by a nanoscratching test. Combining the results of tribology and nanoscratching testing, it can be inferred that the Ar flow rate plays an important role in improving the mechanical properties of DLC films on NBR rubber. Furthermore, the results of scanning electron microscopy confirmed that the sputtering atoms can effectively fill in the grooves of the rubber substrate. This finding is of significance for controlling the sputtering process of preparing DLC on rubber and improving the frictional properties of rubber.

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.