Unveiling Spatiotemporal Diffusion of Hot Carriers Influenced by Spatial Nonuniform Hot Phonon Bottleneck Effect in Monolayer MoS2.

The exceptional semiconducting properties of two-dimensional (2D) transition metal dichalcogenides (TMDs) have made them highly promising for the development of future electronic and optoelectronic devices. Extensive studies of TMDs are partly associated with their ability to generate 2D-confined hot carriers above the conduction band edges, enabling potential applications that rely on such transient excited states. In this work, room-temperature spatiotemporal hot carrier dynamics in monolayer MoS2 is studied by transient absorption microscopy (TAM), featuring an initial ultrafast expansion followed by a rapid negative diffusion, and ultimately a slow long-term expansion of the band edge C-excitons. We provide direct experimental evidence to identify the abnormal negative diffusion process as a spatial contraction of the hot carriers resulting from spatial variation in the hot phonon bottleneck effect due to the Gaussian intensity distribution of the pump laser beam.

Dynamic Directional Ultrasonically In Situ-Generated N,S-Codoped Carbon Dots in Poly(ethylene glycol) for Improved Tribological Performance.

The dispersion stability of nanomaterials in lubricants significantly influences tribological performance, yet their addition as lubricant additives often presents challenges in secondary dispersion. Here, we present a straightforward method for in situ preparation of N,S-codoped CDs (N,S-CDs)-based lubricants using heterocyclic aromatic hydrocarbons containing N/S elements in poly(ethylene glycol) (PEG) base oil by a directional ultrasound strategy. Two types of N,S-CDs were successfully prepared via the directional ultrasound treatment of PEG with benzothiazole (BTA) and benzothiadiazole (BTH) separately. The resultant N,S-CDs have a uniform distribution of N and S elements and maintain good colloidal dispersion stability in PEG even after 9 months of storage. The N,S-CDs can enter the surface gap of the friction pairs and then induce a tribochemical reaction. Benefiting from the synergistic effect of N and S activating elements, a robust and stable protective film consisting of iron sulfides, iron oxides, carbon nitrides, and amorphous carbonaceous compounds is formed, thus endowing N,S-CDs-based lubricants with improved antiwear and friction-reducing performance. Compared with pure PEG, the coefficient of friction (COF) of the N,S-CDs(BTH)-based lubricant decreased to 0.108 from 0.292, accompanied by a 91.2% reduction in wear volume, and the maximum load carrying capacity increased to 450 from 150 N.

Experimental and Theoretical Studies on Long Alkyl Chain-Bearing Dibenzotriazole Ionic Liquids as Eco-friendly Corrosion Inhibitors in Aqueous Hydrochloride Acid.

Three long alkyl chain-bearing dibenzotriazole ionic liquids (BTA-R-BTA, R = 8, 12, and 16) were synthesized with high yield (>98%) through a simple and eco-friendly process. Their anticorrosion performance for Q235 carbon steel in 6 M hydrochloride acid was comprehensively evaluated by weight loss tests, electrochemical methods (potentiodynamic polarization and electrochemical impedance spectroscopy), and surface analysis techniques. As the length of the alkyl chain increased, the maximum corrosion inhibition efficiency enhanced from 55.02% (for BTA-8-BTA at 1.2 mM) to 97.10% (for BTA-12-BTA at 0.3 mM) and 98.84% (for BTA-16-BTA at 0.3 mM). Density functional theory calculation indicated that the alkyl chain length had little influence on the inhibitors' electronic structures, while molecular dynamics simulations revealed that the thickness, surface coverage, and compactness of adsorption films formed at the metal-electrolyte interface increased with the elongated alkyl chain. Corrosion inhibition efficiency is strongly correlated with the structures of the adsorption film.

Low-Friction Soft Robots for Targeted Bacterial Infection Treatment in Gastrointestinal Tract.

Untethered and self-transformable miniature robots are capable of performing reconfigurable deformation and on-demand locomotion, which aid the traversal toward various lumens, and bring revolutionary changes for targeted delivery in gastrointestinal (GI) tract. However, the viscous non-Newtonian liquid environment and plicae gastricae obstacles severely hamper high-precision actuation and payload delivery. Here, we developed a low-friction soft robot by assembly of densely arranged cone structures and grafting of hydrophobic monolayers. The magnetic orientation encoded robot can move in multiple modes, with a substantially reduced drag, terrain adaptability, and improved motion velocity across the non-Newtonian liquids. Notably, the robot stiffness can be reversibly controlled with magnetically induced hardening, enabling on-site scratching and destruction of antibiotic-ineradicable polymeric matrix in biofilms with a low-frequency magnetic field. Furthermore, the magnetocaloric effect can be utilized to eradicate the bacteria by magnetocaloric effect under high-frequency alternating field. To verify the potential applications inside the body, the clinical imaging-guided actuation platforms were developed for vision-based control and delivery of the robots. The developed low-friction robots and clinical imaging-guided actuation platforms show their high potential to perform bacterial infection therapy in various lumens inside the body.

A General Strategy for Enhanced Photodynamic Antimicrobial Therapy with Perylenequinonoid Photosensitizers Using a Macrocyclic Supramolecular Carrier.

Perylenequinonoid natural products are a class of photosensitizers (PSs) that exhibit high reactive oxygen species (ROS) generation and excellent activity for Type I/Type II dual photodynamic therapy. However, their limited activity against gram-negative bacteria and poor water solubility significantly restrict their potential in broad-spectrum photodynamic antimicrobial therapy (PDAT). Herein, a general approach to overcome the limitations of perylenequinonoid photosensitizers (PQPSs) in PDAT by utilizing a macrocyclic supramolecular carrier is presented. Specifically, AnBox·4Cl, a water-soluble cationic cyclophane, is identified as a universal macrocyclic host for PQPSs such as elsinochrome C, hypocrellin A, hypocrellin B, and hypericin, forming 1:1 host-guest complexes with high binding constants (≈107 m -1) in aqueous solutions. Each AnBox·4Cl molecule carries four positive charges that promote strong binding with the membrane of gram-negative bacteria. As a result, the AnBox·4Cl-PQPS complexes can effectively anchor on the surfaces of gram-negative bacteria, while the PQPSs alone cannot. In vitro and in vivo experiments demonstrate that these supramolecular PSs have excellent water solubility and high ROS generation, with broad-spectrum PDAT effect against both gram-negative and gram-positive bacteria. This work paves a new path to enhance PDAT by showcasing an efficient approach to improve PQPSs' water solubility and killing efficacy for gram-negative bacteria.

A biomimetic lubricating nanosystem for synergistic therapy of osteoarthritis.

Failure of articular cartilage lubrication and inflammation are the main causes of osteoarthritis (OA), and integrated treatment realizing joint lubrication and anti-inflammation is becoming the most effective treat model. Inspired by low friction of human synovial fluid and adhesive chemical effect of mussels, our work reports a biomimetic lubricating system that realizes long-time lubrication, photothermal responsiveness and anti-inflammation property. To build the system, a dopamine-mediated strategy is developed to controllably graft hyaluronic acid on the surface of metal organic framework. The design constructs a biomimetic core-shell structure that has good dispersity and stability in water with a high drug loading ratio of 99%. Temperature of the solution rapidly increases to 55 °C under near-infrared light, and the hard-soft lubricating system well adheres to wear surfaces, and greatly reduces frictional coefficient by 75% for more than 7200 times without failure. Cell experiments show that the nanosystem enters cells by endocytosis, and releases medication in a sustained manner. The anti-inflammatory outcomes validate that the nanosystem prevents the progression of OA by down-regulating catabolic proteases and pain-related genes and up-regulating genes that are anabolic in cartilage. The study provides a bioinspired strategy to employ metal organic framework with controlled surface and structure for friction reduction and anti-inflammation, and develops a new concept of OA synergistic therapy model for practical applications.

Fabrication of Poly(ionic liquid) Hydrogels Incorporating Liquid Metal Microgels for Enhanced Synergistic Antifouling Applications.

Hydrogels are ideal for antifouling materials due to their high hydrophilicity and low adhesion properties. Herein, poly(ionic liquid) hydrogels integrated with zwitterionic copolymer-functionalized gallium-based liquid metal (PMPC-GLM) microgels were successfully prepared by a one-pot reaction. Poly(ionic liquid) hydrogels (IL-Gel) were obtained by chemical cross-linking the copolymer of ionic liquid, acrylic acid, and acrylamide, and the introduction of ionic liquid (IL) significantly increased the cross-linking density; this approach consequently enhanced the mechanical and antiswelling properties of the hydrogels. The swelling ratio of IL-Gel decreased eight times compared to the original hydrogels. PMPC-GLM microgels were prepared through grafting the zwitterionic polymer PMPC onto the GLM nanodroplet surface, which exhibited efficient antifouling performance attributed to the bactericidal effect of Ga3+ and the antibacterial effect of the zwitterionic polymer layer PMPC. Based on the synergistic effect of PMPC-GLM microgels and IL, the composite hydrogels PMPC-GLM@IL-Gel not only exhibited excellent mechanical and antiswelling properties but also showed outstanding antibacterial and antifouling properties. Consequently, PMPC-GLM@IL-Gel hydrogels achieved inhibition rates of over 90% against bacteria and more than 85% against microalgae.

Photothermal COFs with donor-acceptor structure for friction reduction and antiwear.

For the first time, a novel donor-acceptor structured COF with excellent photothermal conversion and mono-dispersity in various oils without any further modification is reported; it realized responsive friction reduction, excellent antiwear and long-time lubrication.

Investigation of ultrafast intermediate states during singlet fission in lycopene H-aggregate using femtosecond stimulated Raman spectroscopy.

The singlet fission process involves the conversion of one singlet excited state into two triplet states, which has significant potential for enhancing the energy utilization efficiency of solar cells. Carotenoid, a typical π conjugated chromophore, exhibits specific aggregate morphologies known to display singlet fission behavior. In this study, we investigate the singlet fission process in lycopene H-aggregates using femtosecond stimulated Raman spectroscopy aided by quantum chemical calculation. The experimental results reveal two reaction pathways that effectively relax the S2 (11Bu+) state populations in lycopene H-aggregates: a monomer-like singlet excited state relaxation pathway through S2 (11Bu+) → 11Bu- → S1 (21Ag-) and a dominant sequential singlet fission reaction pathway involving the S2 (11Bu+) state, followed by S* state, a triplet pair state [1(TT)], eventually leading to a long lifetime triplet state T1. Importantly, the presence of both anionic and cationic fingerprint Raman peaks in the S* state is indicative of a substantial charge-transfer character.

Charge Transfer in Graphene-MoS2 Vertical Heterostructures Tuned by Stacking Order and Substrate-Introduced Electric Field.

Vertical van der Waals heterostructures composed of graphene (Gr) and transition metal dichalcogenides (TMDs) have created a fascinating platform for exploring optical and electronic properties in the two-dimensional limit. Numerous studies have focused on Gr/TMDs heterostructures to elucidate the underlying mechanisms of charge-energy transfer, quasiparticle formation, and relaxation following optical excitation. Nevertheless, a comprehensive understanding of interfacial charge separation and subsequent dynamics in graphene-based heterostructures remains elusive. Here, we have investigated the carrier dynamics of Gr-MoS2 heterostructures (including Gr/MoS2 and MoS2/Gr stacking sequences) grown on a fused silica substrate under varying photoexcitation energies by comprehensive ultrafast means, including time-resolved terahertz (THz) spectroscopy, THz emission spectroscopy, and transient absorption spectroscopy. Our findings highlight the impact of the substrate electric field on the efficiency of modulating the interfacial charge transfer (CT). Specifically, the optical excitation in Gr/MoS2 generates thermal electron injection from the graphene layer into the MoS2 layer with photon energy well below A-exciton of MoS2, whereas the interfacial CT in the MoS2/Gr is blocked by the electric field of the substrate. In turn, photoexcitation of the A exciton above leads to hole transfer from MoS2 to graphene, which occurs for both Gr-MoS2 heterostructures with opposite stacking orders, resulting in the opposite orientations of the interfacial photocurrent, as directly demonstrated by the out-of-phase THz emission. Moreover, we demonstrate that the recombination time of interfacial exciton is approximately ∼18 ps, whereas the defect-assisted interfacial recombination occurs on a time scale of ∼ns. This study provides valuable insights into the interplay between interfacial CT, substrate effects, and defect engineering in Gr-TMDs heterostructures, thereby facilitating the development of next-generation optoelectronic devices.

Fault Diagnosis for Reducers Based on a Digital Twin.

A new method based on a digital twin is proposed for fault diagnosis, in order to compensate for the shortcomings of the existing methods for fault diagnosis modeling, including the single fault type, low similarity, and poor visual effect of state monitoring. First, a fault diagnosis test platform is established to analyze faults under constant and variable speed conditions. Then, the obtained data are integrated into the Unity3D platform to realize online diagnosis and updated with real-time working status data. Finally, an industrial test of the digital twin model is conducted, allowing for its comparison with other advanced methods in order to verify its accuracy and application feasibility. It was found that the accuracy of the proposed method for the entire reducer was 99.5%, higher than that of other methods based on individual components (e.g., 93.5% for bearings, 96.3% for gear shafts, and 92.6% for shells).

Separation and purification of polyprenols from Ginkgo biloba leaves by silver ion anchored on imidazole-based ionic liquid functionalized mesoporous MCM-41 sorbent.

Polyprenols (PPs) are compounds with excellent biological activities and are applied in food, pharmaceutical, and cosmetic industries. However, its strong non-polar nature makes it difficult to separate with many saturated impurities (such as saturated fatty acids) extracted together. Complexation extraction is an effective method for separating saturated and polyunsaturated compounds. In this study, mesoporous silica MCM-41 was modified by imidazole-based ionic liquids (IL) followed by coating these MCM-41-supported IL compounds with silver salt to construct π-complexing adsorbent (AgBF4/IL•MCM-41) to enrich PPs from Ginkgo biloba leaves (GBL) extract. The mesoporous π-complexing sorbent was characterized by small-angle X-ray scattering (SAXS), FTIR, and nitrogen adsorption-desorption. The effect of the ratio of silver salt to IL•MCM-41 on the adsorption capacity of polyprenols from GBL was compared, and the dosage of AgBF4 was determined to be 1.5 mmol/g IL•MCM-41. Adsorption isotherms and kinetics indicate that the π-complexing adsorbent has excellent PPs adsorption performance (153 mg/g at 30 °C) and a fast adsorption rate (the time to reach adsorption equilibrium is 210 s). The PPs were separated using the fixed bed after treatment for only one cycle with AgBF4/IL•MCM-41, and the content of PPs in the product was increased from 38.54% to 70.2%, with a recovery rate of 86.6%. The π-complexing adsorbent showed excellent reusability for ≥3 adsorption-desorption cycles.

A dual-responsive microemulsion with macroscale superlubricity and largely switchable friction.

Although stimuli-responsive microemulsions (MEMs) consisting of water, oil and surfactants have found extensive potential applications in industrial fields, a responsive MEM exhibiting either macroscale superlubricity or two friction states where its coefficient of friction (CoF) can be switched by more than one order of magnitude has not yet been reported. Moreover, although traditional liquid superlubricants can provide ultralow friction and wear, effective control over the friction between two contacting surfaces is crucial for both achieving accurate control of the operation of an instrument and fabricating smart devices. Here we create a thermo- and magneto-responsive MEM capable of providing superlubrication for metallic materials in a broad temperature range from -30 to 20 °C using n-hexane, water, surfactant DDACe ((C12H25)2N+(CH3)2[CeCl4]-) and ethylene glycol. The MEM can abruptly and dramatically switch its CoF by approximately 25 fold based on a thermally reversible MEM-emulsion (EM) transition. Its anti-freezing performance allows it to provide effective lubrication even when the surrounding temperature attains as low as -60 °C. Together with its facile preparation, ultrahigh colloidal stability and magnetically controlled migration, such a novel smart MEM is envisioned to find widespread applications in materials science.

Carbon Dots with Spatially-Mediated-N/S-Co-Doping Enabling One-Year Stable Lubricant with Oil Leakage Detection Capability.

The dispersion stability of nano-lubricating additives is crucial for the shelf life of lubricant and its practical applications. Nitrogen-sulfur co-doped carbon dots (N,S@CDs) via a one-step hydrothermal method with nitropyrene and thiourea as raw materials are hereby presented. The N and S elements are selectively distributed throughout the entire carbon skeleton with a doping amount of 22.6 at%. The as-synthesized N,S@CDs exhibit excellent dispersion stability in PEG200 and maintain stability for over one year. The experiment results indicate that N,S@CDs significantly improve the anti-wear and friction reduction properties of PEG200, while the friction coefficient is reduced from 0.25 to 0.09 with 1.5 wt% N,S@CDs addition, and the wear volume, depth, and width are reduced by 68%, 52%, and 57%, respectively. The good lubrication performance is attributed to N,S@CDs excellent dispersion stability, enhanced filling and polishing effects, and complex tribochemical reactions caused by heteroatom doping to form a stable protective film on the worn surface. Furthermore, the as-prepared N,S@CDs exhibit intrinsic fluorescence intensity in PEG200 with the photoluminescence quantum yield (PLQY) of 12.5% and remain fluorescent stable during the long-term friction process, therefore the N,S@CDs have a potential application prospect in non-destructive detection of oil leakage via fluorescence labeling method.

Pulsed Laser Manufactured Heteroatom Doped Carbon Dots via Heterocyclic Aromatic Hydrocarbons for Improved Tribology Performance.

Traditional laser-assisted method (top-down synthesis strategy) is applied in the preparation of carbon dots (CDs) by cutting larger carbon materials, which requires harsh conditions, and the size distribution of the CDs is seldom monodisperse. In this work, heteroatom-doped CDs, represented by N,S co-doped CDs (N,S-CDs), can be prepared successfully by pulsed laser irradiation of heterocyclic aromatic hydrocarbons-based small molecule compound solution. The friction coefficient (COF) of base oil PAO decreases from 0.650 to 0.093, and the wear volume reduces by 92.0% accompanied by 1 wt.% N,S-CDs addition, while the load-bearing capacity is improved from 100 to 950 N. The excellent lubrication performance is mainly attributed to the formation of a robust tribofilm via a tribochemical reaction between N,S-CDs and friction pairs, and the N,S-CDs can play a mending effect and polishing effect for worn surfaces. Furthermore, the lubricant containing heteroatom doped CDs are capable of being prepared in situ via pulsed laser irradiation of heterocyclic aromatic hydrocarbons in base oil, which can avoid the redispersed problem of nano-additive in base oil to maintain long-term dispersion, with COF of 0.103 and low wear volume ≈1.99 × 105 µm3 (76.9% reduction) even after standing for 9 months.

Effect of deep learning image reconstruction with high-definition standard scan mode on image quality of coronary stents and arteries.

Background: The high-definition standard (HD-standard) scan mode has been proven to display stents better than the standard (STND) scan mode but with more image noise. Deep learning image reconstruction (DLIR) is capable of reducing image noise. This study examined the impact of HD-standard scan mode with DLIR algorithms on stent and coronary artery image quality in coronary computed tomography angiography (CCTA) via a comparison with conventional STND scan mode and adaptive statistical iterative reconstruction-Veo (ASIR-V) algorithms. Methods: The data of 121 patients who underwent HD-standard mode scans (group A: N=47, with coronary stent) or STND mode scans (group B: N=74, without coronary stent) were retrospectively collected. All images were reconstructed with ASIR-V at a level of 50% (ASIR-V50%) and a level of 80% (ASIR-V80%) and with DLIR at medium (DLIR-M) and high (DLIR-H) levels. The noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), artifact index (AI), and in-stent diameter were measured as objective evaluation parameters. Subjective assessment involved a 5-point scale for overall image quality, image noise, stent appearance, stent artifacts, vascular sharpness, and diagnostic confidence. Diagnostic confidence was evaluated based on the presence or absence of significant stenosis (≥50% lumen reduction). Both subjective and objective evaluations were conducted by two radiologists independently, with kappa and intraclass correlation statistics being used to test the interobserver agreement. Results: There were 76 evaluable stents in group A, and the DLIR-H algorithm significantly outperformed other algorithms, demonstrating the lowest noise (41.6±7.1/41.3±7.2) and AI (32.4±8.9/31.2±10.1), the highest SNR (14.6±3.5/15.0±3.5) and CNR (13.6±3.8/13.9±3.8), and the largest in-stent diameter (2.18±0.61/2.19±0.61) in representing true stent diameter (all P values <0.01), as well as the highest score in each subjective evaluation parameter. In group B, a total of 296 coronary arteries were evaluated, and the DLIR-H algorithm provided the best objective image quality, with statistically superior noise, SNR, and CNR compared with the other algorithms (all P values <0.05). Moreover, the HD-standard mode scan with DLIR provided better image quality and a lower radiation dose than did the STND mode scan with ASIR-V (P<0.01). Conclusions: HD-standard scan mode with DLIR-H improves image quality of both stents and coronary arteries on CCTA under a lower radiation dose.

Hybrid Carbon Nanospheres with Encapsulated (Bi)Metallic Nanocrystals as Lubricant Additives for Antiwear and Friction Reduction.

Herein, the novel core-shell organo-inorganic hybrid carbon nanospheres with encapsulated ultrafine bimetal nanocrystals were successfully prepared by a one-pot domino drive synthesis combined with postcarbonization. The excellent properties of the metals such as high strength and thermal conductivity are retained, and the poor dispersion of the metal in the oil could be improved by encapsulating the metal in organic-inorganic hybrid carbon nanospheres. The vanadium and wolframium nanocrystals embedded in nitrogen-doped carbon nanospheres (V/W@NCNs) manifested remarkable oil dispersity on account of the lipophilic organic phase of the carbon shell. It is worth noting that the as-obtained V/W@NCNs display better tribological properties compared with the base oil, such as a higher extreme pressure of 1250 N, a lower friction coefficient of about 0.09, and a significant reduction in wear volume of 91.5%, which are attributed to the robust protective film that was formed on the surface of the friction pair through mechanical deposition and physical and tribochemical reaction during the friction process.

Versatile MXene Gels Assisted by Brief and Low-Strength Centrifugation.

Due to the mutual repulsion between their hydrophilic surface terminations and the high surface energy facilitating their random restacking, 2D MXene nanosheets usually cannot self-assemble into 3D macroscopic gels with various applications in the absence of proper linking agents. In this work, a rapid spontaneous gelation of Ti3C2Tx MXene with a very low dispersion concentration of 0.5 mg mL-1 into multifunctional architectures under moderate centrifugation is illustrated. The as-prepared MXene gels exhibit reconfigurable internal structures and tunable rheological, tribological, electrochemical, infrared-emissive and photothermal-conversion properties based on the pH-induced changes in the surface chemistry of Ti3C2Tx nanosheets. By adopting a gel with optimized pH value, high lubrication, exceptional specific capacitances (~ 635 and ~ 408 F g-1 at 5 and 100 mV s-1, respectively), long-term capacitance retention (~ 96.7% after 10,000 cycles) and high-precision screen- or extrusion-printing into different high-resolution anticounterfeiting patterns can be achieved, thus displaying extensive potential applications in the fields of semi-solid lubrication, controllable devices, supercapacitors, information encryption and infrared camouflaging.

Wear-resistant CoCrNi multi-principal element alloy at cryogenic temperature.

Traditional high strength engineering alloys suffer from serious surface brittleness and inferior wear performance when servicing under sliding contact at cryogenic temperature. Here, we report that the recently emerging CoCrNi multi-principal element alloy defies this trend and presents dramatically enhanced wear resistance when temperature decreases from 273 to 153 K, surpassing those of cryogenic austenitic steels. The temperature-dependent structure characteristics and deformation mechanisms influencing the cryogenic wear resistance of CoCrNi are clarified through microscopic observation and atomistic simulation. It is found that sliding-induced subsurface structures show distinct scenarios at different deformation temperatures. At cryogenic condition, significant grain refinement and a deep plastic zone give rise to an extended microstructural gradient below the surface, which can accommodate massive sliding deformation, in direct contrast to the strain localization and delamination at 273 K. Meanwhile, the temperature-dependent cryogenic deformation mechanisms (stacking fault networks and phase transformation) also provide additional strengthening and toughening of the subsurface material. These features make the CoCrNi alloy particularly wear resistant at cryogenic conditions and an excellent candidate for safety-critical applications.

Towards outstanding lubricity performance of proton-type ionic liquids or synergistic effects with friction modifiers used as oil additives at the steel/steel interface.

Anti-wear (AW) additives and friction modifiers (FMs) and their interactions in lubricants are critical to tribological performance. This research investigates the compatibility and synergism of three oil-soluble alkylamine-phosphate ionic liquids with friction modifiers, organomolybdenum compounds. Three proton-based ionic liquids (PILs) were synthesized using a simple, low-cost, and unadulterated procedure as well as the chain lengths of the PILs affected the effectiveness of friction reduction and anti-wear. For example, the effect of a short-chain PIL alone as an additive on friction and wear behavior was not significant, whereas a long-chain PIL was more effective. In addition, PILs appeared to be able to coexist with organic molybdenum compounds and worked synergistically with dialkyl dithiophosphate oxygen molybdenum (MoDDP) to produce a sustained low coefficient of boundary friction (the coefficient of friction approaching 0.042). We proposed a three-stage tribochemical process to explain this interaction of PILs + MoDDP with contact surfaces to form physically adsorbed friction-reducing films and chemically reactive wear-protective films. This study reveals the compatibility and synergistic effects of two common lubricant components, which can be used to guide lubricant development in the future.