Advanced thermal interface materials based on ultra-thin and ultra-strong metal-gel

Advanced thermal interface materials based on ultra-thin and ultra-strong metal-gel | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Advanced thermal interface materials based on ultra-thin and ultra-strong metal-gel Qiang Fu, Zilong Xie, Hui Zhou, Runlai Li, Xizhi Chen, Zirui Wang, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7376124/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Liquid metal-based thermal interface materials offer exceptional thermal conductivity and conformability, yet their low strength and stabilities remain huge challenges, which largely limits their applications under working conditions of dynamic loading. Here, we utilize an ultrathin nanofiber polymer film as a structural scaffold, which features a robust network essential for effectively confining liquid metal, resulting in unique interpenetrating metal-gel. Surface modification of polymer film with sputtered metals enhances compatibility, enabling uniform infiltration and stabilization of liquid metal. The obtained metal-gels exhibit a remarkable tensile strength of 117 MPa, the highest reported for thermal interface materials, while maintaining good flexibility. They can be fabricated as ultrathin films (≤ 2 µm), delivering an ultralow bond line thickness and interfacial thermal resistance (7.7 mm²·K·W⁻¹). With impressive stability against pressure, folding, solvent exposure, and cooling cycling, this work overcomes key reliability issues of liquid metal, offering promise for advanced cooling applications. Physical sciences/Materials science/Structural materials/Composites Physical sciences/Materials science/Soft materials/Gels and hydrogels thermal interface materials liquid metal gel polymer composites strengthen thermal conductive composites Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Thermal interface materials based on liquid metal (TIM-LMs) have garnered significant attention due to their exceptional thermal conductivity and conformability 1 , 2 , 3 , 4 , 5 . These advantages reduce the interfacial thermal resistance ( R eff ) between heat sources and heat sinks, thereby significantly enhance the cooling performance of high-power electronic modules, like high-power microwave, radar, laser, and AI 3 , 6 , 7 , 8 , 9 . However, the upsurge of applications under the working condition of dynamic load, such as, electric vehicles, electric drones, and hypersonic missile, poses new challenges for TIM-LMs 10 , 11 . The associated electronic systems are subjected to extreme conditions including high accelerations (30–700 m s − 2 ), high vibrations, and high rates (75-1500 m s − 1 ) 12, 13 . There is an urgent need for TIM-LMs capable of stable operation for a long time without affecting its performance Due to long-range disordered amorphous structure, LM is intrinsically flowable and easy to leak, lacking structure stability 14 , 15 , 16 , 17 . Preparing LM-polymer composites is a simple and effective solution 18 , 19 . In such composites, a high filling amount is always required to achieve a low R eff 20 , 21 , 22 , 23 . But when the LM content is over-high (>60 wt%), the composites become very brittle, accompanied by serious interfacial problems between the polymer and LM, leading low mechanical strengths (typically lower than 3 MPa) 24 , 25 , 26 . Such composites can hardly resist the extremely high dynamic stress in realistic applications. How can LM become strong and stable at high content in LM-polymer composites? Hydrogel give us a good example 27 , 28 , in which water is confined and fixed via polymer network. With high liquid contents (>90 wt%), hydrogels show exceptional mechanical performances 29 , 30 . Hydrogels could be strengthened via a series of intelligent strategies, such as entanglements, networks, alignments, and composite 31 , 32 , 33 . One of the keys is to construct highly ordered and robust network, along with good interfacial interactions 29 . Drawing inspiration from fiber networks of bio-tissues, like collagen and tendon, researchers devised oriented fiber-reinforced network, leading gel strengths up to 10 ~ 80 MPa 34 , 35 . Analogous to hydrogels, transforming LM into metal-gels requires a robust, highly compatible network structure with uniformly distributed nanopores below 100 nm to effectively confine and stabilize LM. In our recent work, we developed an ultra-high molecular weight polyethylene (UPE) porous film through a multi-step stretching process, resulting in a nanofiber network with pore sizes between 40–60 nm and thickness as low as a few micrometers or even tens of nanometers 36 , 37 . This porous film exhibits outstanding mechanical properties (strengths up to 1.7 GPa) 36 , 37 , and is well-suited as a scaffold for LM immobilization. To enhance compatibility between UPE and LM, we sputter Au particles onto UPE surface, forming an alloyed interface to facilitate the wetting and infiltration of LM. As a result, a large amount (up to 95 wt%) of gallium-indium-tin LM could be easily infiltrated and tightly confined in nanofiber network to form metal-gels. These gels do not leak even under a pressure of 4.5 tons, and are stable over complex conditions, like folding, ultrasonication, solvent erosion, and cooling cycle. Owing to the high thermal conductivity and deformability of LM and the low bond line thickness (≤ 2 µm) of the UPE film, the R eff remains very low (7.7 mm²·K·W⁻¹). The fabrication process of gel only involves three simple steps (sputtering, coating, and pressing), that can be readily integrated with continuous industrial production to make large-area products, showing promise as advanced LM-TIMs in the working conditions of dynamic loading. Results Network design in LM gel fabrication. In the fabrication of LM gel, UPE film is selected as framework due to its advantageous mechanical and thermal properties: an iron-like strengthen (≤ 1.7 GPa), flexibility, and high thermal conductivity (≤ 65 W m − 1 K − 1 ) 36, 38 , 39 , 40 . These merits are expected to impart the LM gel with high strength, good conformability and low thermal resistance. A critical challenge in preparing LM gels is how to make the high-surface-energy LM wet and immerse in the network, as well as resolve the interface problem between LM and polymer. We overcome this by introducing an Au interface layer. Au can be stably integrated on UPE through a common ion sputtering method. It offers a metal-metal interaction between Au-UPE and LM to promote wetting 41 , 42 , 43 . At the same time, Au has a high thermal conductivity (> 300 W m − 1 K − 1 ) to suppress the phonon scattering at the polymer-LM interface. After sputtering Au, coating LM and pressing film, LM can be fully immersed in Au-UPE film to form a metal-gel film (Fig. 1 a). Figure 1 b displays the scalable fabrication and the micro-structure of LM gel film. By large-area UPE matrix and the continuous coating, we successfully obtained LM gel film with lengthen more than 50 cm and thickness around 1.5 µm, demonstrating the practical scalability of metal-gels. Considering that UPE films are already widely available as industrial raw materials, and that metal sputtering, coating, and pressing are well-established industrial processes, the LM/Au-UPE gel films hold strong potential for rapid industrial scale-up and production. Corresponding scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) elemental mapping images reveal the atoms distribution of LM in Au-UPE, suggesting the fully wetting and immersion of LM. As shown in Fig. 1 c, LM gels integrated with ultra-strong fiber networks exhibit order-of-magnitude improvement in mechanical strength (up to 117 MPa, increased from 10 0 MPa class to 10 2 MPa class) as compared to other types of TIMs (LM-based composites, polymer-based thermal grease/pad, and carbon-based vertically arranged materials), representing the highest strength reported among TIMs to date (Fig. 1 c, Supplementary Table 1) 3 , 24 , 25 , 26 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 . The R eff (7.7 mm²·K·W⁻¹) of LM gels is still left behind that of some state-of-the-art LM-based TIMs, but is obviously prior to that of polymer-based and carbon-based TIMs, demonstrating the special adaptability of cooling under high-stress conditions (Fig. 1 c, Supplementary Table 1). Characteristics of the network structure in gels. Atomic force microscopy (AFM) images and SEM images reveal that a uniform gold coating, approximately 20 nm in width, forms on the Au-UPE fiber network surface after sputtering (Fig. 2 a-I, II, Supplementary Fig. 1). Correspondingly, SEM images and contact angle measurements show a significant decrease in the LM contact angle, which allows the LM to spread flat and fully infiltrate the network (Fig. 2 a-IV). In contrast, on pristine UPE film, the LM exhibits a large contact angle, with droplets aggregating into spheres that fail to wet the surface (Fig. 2 a-III), highlighting the remarkable effect of the Au layer in improving wettability and interfacial interactions. We find that LM gels are distinct from common hydrogels or organic gels. In those gels, the continuous phase is water or an organic solvent, and wettability can be enhanced by decorating the fiber network with chemical groups. In LM gels, however, the continuous phase is metallic. Conventional surface modifications, such as silane, dopamine functionalization, etc, do not significantly reduce the LM contact angle (contact angle > 120°, Supplementary Fig. 2); only by decorating the UPE fiber network with a metal layer (Au layer) is the wettability improved (contact angle < 60°). Further calculation results for the surface energy ( σ ) of differently modified UPE films confirm that only the metal-treated films exhibit a significant increase of σ from 42 mN m − 1 of pristine UPE to 51 mN m − 1 of Au-UPE (Supplementary Fig. 3). The enhancement of σ makes the surface properties of metallized film more closely match the high surface tension of the LM, thereby promoting the wetting at the interface. We demonstrate that this metallization-based wetting mechanism is universal to other metals; sputtering either Pt or Ag onto the UPE surface also reduces the LM contact angle to as low as 64° and 53° (Supplementary Fig. 4). Considering the balance of chemical stability and thermal conductivity, Au is solely selected as the metal layer. A more fundamental factor promoting the wetting between UPE and LM is the alloyed interface interaction formed between Au particles and the LM (Fig. 2 b). On one hand, Au can form an alloy with the LM. On the other hand, the oxide layer on the LM surface is a metastable and active layer that may interact with Au. The appearance of small peaks at (111), (200), and (220) in the X-ray diffraction (XRD) analysis confirms that the filling of LM in Au-UPE leads to the generation of a small amount of AuGa₂ alloy (Fig. 2 c). The X-ray photoelectron spectroscopy (XPS) spectra also confirm the formation of an Au-Ga alloy: an additional new peak appears in the Au 4 f orbital of LM/Au-UPE at 84.8 eV (Fig. 2 d), and another new peak appears in the Ga 3 d orbital at 20.6 eV (Fig. 2 e). In addition, a new peak also emerges in the O 1 s spectra of LM/Au-UPE at 533.7 eV. Given that Au is difficult to oxidize, this indicates that the active oxide layer of LM has formed a certain interaction with Au. The wettability of LM on Au-UPE shows a positive correlation with the gold content: as the sputtering time increases from 0 s to 20 s, the contact angle drops from 84° to 54° (Fig. 2 f), and the σ increases gradually from 40.5 mN m − 1 to 50.1 mN m − 1 (Supplementary Fig. 5), verifying the key role of Au in influencing the interface. A 20 s sputtering time is chosen as the standard parameter for Au layer fabrication in subsequent studies, as shorter times result in insufficient wettability, while longer times cause excessive metal content and film rupture due to the high heat from sputtering. These tests confirm the favorable alloying interaction between Au and the LM. The network structure characteristics of the LM gel was investigated using rheological analysis. Oscillatory strain sweeps reveal that at low strains, the storage modulus (G') consistently exceeds the loss modulus (G''), confirming the stable and semi-solid gel structure of LM/Au-UPE, which is analogous to that of conventional PVA hydrogels (Fig. 2 g). At higher strains, a crossover of G' and G'' occurs, indicating that LM/Au-UPE also undergoes a gel transition characteristic of conventional gels. Notably, for the same liquid content, the gel transition for LM/Au-UPE occurs at a much higher oscillation strain (472% strain) compared to that for conventional hydrogel (40% strain, H₂O/PVA), representing a nearly tenfold increase in the yield strain (Fig. 2 g). This demonstrates that the fiber network architecture imparts superior mechanical stability, allowing the gel to withstand large dynamic shear strains under which conventional polymer networks fail. Such network stability is further evidenced by frequency sweep tests (Supplementary Fig. 6). The modulus (G' and G'') of the LM/Au-UPE gel exhibit markedly weaker frequency dependence than those of the H₂O/PVA gel, a hallmark of a robust and stable network (Supplementary Fig. 6). As illustrated in Fig. 2 h, this is mainly because the fiber network structure is composed of rigid and highly crystalline fibers. Their response to external force under strain is small, and they always maintain the structure of fibrous junctions, thus retaining better stability under high shear strain. In contrast, the conventional molecular chain network has low crystallinity and high flexibility. Although there are some cross-linking points, the chain segments between them can be disturbed by dynamic strain, causing entanglement and disentanglement of the molecular chains, which leads to poorer shear stability. Mechanical stability and thermal resistance of LM gels. To examine the effect of fiber network in mechanical stabilization, we fabricated a series of LM/Au-UPE gels with varied LM contents (0 to 100 wt%) and assessed their tensile strength (Fig. 3 a, Supplementary Fig. 7). The strength shows a progressive degradation with increasing LM content, dropping from 148 MPa for pristine Au-UPE (0 wt% LM) to 0 MPa for pure LM (100 wt%). Remarkably, the strength of LM/Au-UPE persists at robust levels (≥ 117 MPa) for LM fractions from 0–90 wt%, underscoring the excellent mechanical reinforcement introduced by the fiber network. And a decline in strength is observed when the LM content exceeds 90 wt%, likely due to the network being fully infiltrated, and the additional LM only forming a mechanically irrelevant, zero-strength liquid layer on the surface (Fig. 3 c). The R eff of the LM/Au-UPE gels was measured at 40 psi using a steady-state heat flow method. As shown in Fig. 3 b, with increasing LM content, R eff decreases from 1305 mm² K W⁻¹ for 0 wt% LM (pristine Au-UPE) to 6.0 mm² K W⁻¹ for 100 wt% LM (pure LM). A sharp decline in R eff emerged as the LM content surpassed 70 wt%, eventually stabilizing at exceptionally low values (≤ 7.7 mm²·K·W⁻¹) above 90 wt%. This can be attributed to incomplete filling of the fiber network at LM contents below 70 wt%; sufficient infiltration and filling of the Au-UPE fiber network by LM occurs only at higher LM loadings (Fig. 3 c, Supplementary Fig. 8). This complete infiltration is crucial, as the LM phase imparts ultra-low modulus, outstanding conformability, and high thermal conductivity, which collectively minimize thermal resistance. For practical cooling applications under high dynamic stress, both high strength and low R eff must be considered. Thus, 90 wt% LM was chosen as the standard composition to balance tensile strength (117 MPa) and R eff (≤ 7.7 mm² K W⁻¹) in following application experiments. Under these conditions, LM fully fills the Au-UPE network without forming a surplus surface LM layer. To elucidate the underlying reinforcement mechanism, we performed finite element analysis (FEA) to map the stress distribution of LM/Au-UPE gels under biaxial tension and uniaxial compression (Fig. 3 d). The simulations confirm that the fiber network acts as the primary load-bearing scaffold, concentrating the vast majority of the stress under both loading conditions (red regions, Fig. 3 d). Considering the intrinsic high mechanical strength of UPE fibers (1 ~ 3 GPa), this architecture enables the composite to endure significant mechanical forces 37 . Meanwhile, the LM phase, subjected to minimal stress, deforms compliantly with the fibers, ensuring excellent conformability (deep blue regions, Fig. 3 d). This synergistic architecture, combining ultra-strong fibers with an ultra-soft liquid matrix, yields a material with a highly compliant surface yet a mechanically robust core, an ideal profile for a durable TIM. This strategy of integrating a highly fluidic liquid into a rigid solid framework offers a compelling paradigm for advanced TIMs. It can revitalize many high-performance rigid materials, previously unsuitable for TIM applications due to poor surface conformality. A recently reported system of vertically aligned copper wires filled with LM exemplifies the success of such liquid infused structures 49 . To further assess the stability under complex stress conditions, we simulated a range of challenging operational conditions. As shown in Fig. 3 e, the LM/Au-UPE gel film, merely 2 µm thick, remains stable under a 200 g load, whereas pristine LM deforms under a load as light as 10 g. When placed on a copper plate with a 3 cm radius of curvature, the LM/Au-UPE gel exhibits outstanding shape adaptability and stability, in stark contrast to pristine LM, which is unstable and readily flows (Fig. 3 f). The gel films also withstand severe twisting and stretching (Fig. 3 g), confirming their robustness in stress environments. Remarkably, even after undergoing intense ultrasonic treatment (800 W, 1.0 h) in a series of solvents of varying polarity, including water, ethanol, and petroleum ether, the gel films showed no signs of LM leakage or film rupture (Fig. 3 h). This indicates that the gel film possesses exceptional stability in multifaceted environments where dynamic stresses and liquid atmospheres coexist, pointing to potential applications underwater thermal management and in aerospace applications where condensate or humid conditions are present. Currently commercial TIMs can be generally classified as LM-based composites, polymer-based thermal greases, and polymer-based thermal pads. Among commercial products (Fig. 3 i and Supplementary Table 2), advanced LM-based TIMs achieve the lowest R eff (down to 0.8-6.0 mm²·K·W⁻¹) and BLT (down to 46 µm), but their liquid nature generates negligible yield strengths (< 0.01 MPa) make them prone to leakage 3 . Polymer-based thermal grease is as similar as LM-based TIMs. Polymer-based thermal pads have some strength (1.0–4.0 MPa), but suffer from high R eff (typically ≥ 20 mm²·K·W⁻¹ ) and BLT (~ 100 µm) 3 . In contrast, LM/Au-UPE gel films introduced herein efficiently resolve the triangle problem of low R eff (≤ 8 mm²·K·W⁻¹), high strength (≤ 120 MPa), and low thickness (≤ 2 µm), creating a new class of durable, high-performance, and ultrathin TIMs (Fig. 3 i and Supplementary Table 2). Dynamic stress cooling application of gel film. To assess the stability of the LM/Au-UPE gel film under extreme environmental conditions, it was subjected to compression by a 4.5-ton truck to observe its structural and performance integrity (Fig. 4 a-I). The results show that, after being run over, the color of the tire surface was almost identical to that before compression (Fig. 4 a-II-IV), indicating no leakage of silvery LM and demonstrating stability under extreme dynamic stress. We further measured the thermal resistance of the gel film before and after compression. The post-compression R eff (7.7 mm²·K·W⁻¹) remained close to its pre-compression value (9.9 mm²·K·W⁻¹), and the gel film retained more than 90% of its original weight (Fig. 4 b). In contrast, LM samples without the fiber-reinforced network exhibited drastic changes in both R eff and weight after compression, attributed to leakage and the adhesion of surface contaminants (Fig. 4 b). This confirms that LM/Au-UPE not only maintains its external appearance, but also preserves its internal structure and performance. The thermal demands of high-power electronics such as AI chips have outpaced conventional fan cooling, necessitating a shift to liquid cooling systems. This new paradigm, however, poses a formidable challenge for TIMs, which must now endure the erosive forces of fluid flow while maintaining low thermal resistance. To mimic this demanding environment, we built a custom liquid cooling loop around a chip, incorporating a pump, TIM, and heat sink (Fig. 4 c-d, Supplementary Fig. 9). During operation, the LM/Au-UPE gel film showed no signs of rupture or leakage, even as coolant flowed directly over its surface (Fig. 4 d). We then pushed the system to high-power operation to evaluate its real-world cooling efficacy. Infrared thermal imaging revealed that, on the first day of operation, that the LM/Au-UPE gel and a state-of-the-art commercial LM TIM delivered comparable, excellent cooling performances, lowering the heat sink temperature to 49.0°C and 48.6°C, representing a ~ 13°C reduction compared to the system with air (no TIM) at 61.7°C, (Fig. 4 e, Supplementary Fig. 10). Notably, in the key durable test, after 15 days of continuous operation, a clear performance degradation was observed for the commercial LM composites TIMs, with temperature rising by as much as 4.1°C (Fig. 4 f). In striking contrast, our LM/Au-UPE gel maintained its temperature with virtually no change (≤ 1°C), demonstrating superior long-term stability against the cyclic shear stress of the liquid environment (Fig. 4 f). Failure disassembly analysis provided a vivid confirmation: after 15 days, the commercial LM composites TIMs exhibited clear evidence of leakage and pump-out, whereas the LM/Au-UPE gel appeared as pristine as it was upon installation, a testament to its exceptional structural integrity (Fig. 4 g). This research demonstrates a promising strategy for preparing metal-gel that overcomes the critical stability challenges facing LM TIMs. These gels are characterized by an interface-modified, fiber-reinforced network structure. Within this structure, an alloying interface modification promotes interaction and enables the wetting between the polymer and the LM. Highly aligned fiber-network yields exceptional gel strength, the highest reported for thermal interface materials, while retaining flexibility. Compared with conventional molecular chain network gels, the fiber network gels developed in this work exhibit a significantly thickened (nanometer-thick) network architecture, enabling more stable network and reliable cooling even under severe dynamic stress. These ultra-thin metal-gel films not only enable reliable thermal interface solutions under extreme conditions, such as offshore cloud computing and deep-earth drilling, but also hold promise for a wide spectrum of applications where metallic functionality must be coupled with exceptional gel mechanics, from high-performance conductive coatings to biomedical adhesive interfaces, like brain-computer interface. Methods Materials. Ultra-high molecular weight polyethylene (UPE) resin powder with was offered from Guangdong Suguang Plastic Co., Ltd, with viscosity-average molecular weight grade of around 11 M (SG4850). Galinstan alloy liquid metal (LM, 62.5 wt% gallium, 21.5 wt% indium, 16 wt% tin) was provided by Hunan Santech Materials, China. The white protopet (1S) petrolatum was obtained from Sonneborn, USA. The gold (Au), silver (Ag), and platinum (Pt) target materials were offered from Jiangxi Changyanke New Materials Co., Ltd. Antioxidants (Irganox 1010 and Irgafos 168) were obtained from Jiangxi Sanfeng Fine Chemical Co., Ltd. 3-(Trimethoxysilyl) propyl methacrylate (Silane coupling agent, KH570), dopamine hydrochloride (98%), trimethylaminomethane hydrochloride (Tris-HCl) (pH = 8.8), and ethanol (98%) were purchased from Macklin Co. Ltd (China). Polyvinyl alcohol (PVA) powder with a polymerization degree of ~ 1700 and an alcoholysis degree of ~ 99%, was purchased from Aladdin (China). Glutaraldehyde (GA, 50% aqueous solution) and hydrochloric acid (HCl, 37%), were purchased from Aladdin (China). The water used in this experiment was deionized water. The rest materials, if not mentioned specifically, were supplied by Aladdin, China. Synthesis of UPE film scaffold. As reported in our previously published work 36 , in brief, melted petroleum was used as the solvent of UPE resin to prepare a 3 wt% UPE suspension. Subsequently, 0.1 wt% antioxidants (AO-1010 and AO-168) were added to the suspension, followed by stirring at 80°C for 5 min to ensure uniform mixing. The resulting suspension was transferred to a torque rheometer (XSS‑300, Shanghai Kechuang, China) and processed at 190°C under 25 rpm for 25 min to obtain a UPE/petroleum composite. The composite was then hot-pressed (LP‑S‑30, Labtech Engineering, China) at 190°C for 30 min to form standard-sized sheets, which were subjected to biaxial stretching (KARO IV, Brückner, Germany) at draw ratios around 180 times. The thickness of UPE membranes could be regulated by the thickness of the sheets. The thickness of the film used in this experiment was controlled to around 1.0-1.2 µm. Finally, the membranes underwent Soxhlet extraction with n‑hexane at 100°C for 6 h to remove residual petroleum. After vacuum drying them at 60 ℃ for 2 h, the raw UPE porous scaffold film could be obtained. Synthesis of surface treated UPE. For gold-coated UPE film (Au-UPE), UPE films were sputtered by Au using the sputter coater (Quorum Technologies Q300TD, UK) with different sputtering times on two sides (current ≤ 10 mA). For silver-coated UPE film (Ag-UPE) and platinum-coated UPE film(Pt-UPE), UPE films were sputtered by Ag or Pt for the same time of 20 s (current ≤ 10 mA)for comparison analysis. For silane-treated UPE (silane-UPE), 19.8 g ethanol and 0.2 g 3-(Trimethoxysilyl) propyl methacrylate were mixed and stirring at 50°C for 60 min to obtain the silane coupling agent solution, followed by immersing and pulling out the UPE film in silane solution for 3 times. Silane-UPE was finally obtained after drying the coated film in a 50°C vacuum oven for 8 h. For polydopamine-treated UPE (PDA-UPE), dopamine hydrochloride was dissolved in Tris-HCl buffer solution in a concentration of 0.1 mol/ml by stirred for 6 h at room temperature to obtain the dopamine solution, followed by immersing and pulling out the UPE film in silane solution for 3 times. PDA-UPE was finally obtained after drying the coated film in a 60°C vacuum oven for 6 h. Synthesis of H 2 O/PVA gel. PVA solution was firstly prepared by stirring determined amounts of weights of PVA powder in deionized water at 95°C for 4 h. After the solution became cooled, dropwise add the crosslinking agent GA (2.0 mol% of the hydroxyl groups of PVA) and crosslinking catalyst HCl (0.2 mol% of the hydroxyl groups of PVA) in the above dispersion. Synthesis of LM/Au-UPE gel film. The synthetic process of gold-treated ultra-high molecular weight polyethylene liquid metal gel film (LM/Au-UPE) was divided into two steps. Firstly, different weights of LM droplets were added on two sides of Au-UPE films, followed by the brush coating on the surface to make the LM evenly distributed in LM/Au-UPE. Then, the coated LM/Au-UPE were pressed to fabricate immersed LM/Au-UPE gel films (thickness ≥ 1.5 µm) by putting them in between two polypropylene films, at room temperature and pressure around 30 MPa for 5 min. The weight ratio of Au-UPE and LM is finally revised by the weight change between pristine Au-UPE and final LM/Au-UPE product. Characterization of Au-UPE and LM/Au-UPE. Changes in element valence states on the surface of Au-UPE, LM/UPE, and LM/Au-UPE were obtained using X-ray photoelectron spectroscopy (K-Alpha, Thermo Scientific, USA). The crystal structures of LM, Au-UPE, and LM/Au-UPE were obtained by X-ray diffraction (Ultima IV, Rigaku, Japan) with Cu Kα radiation (wavelength λ = 1.5418Å). Scanning electron microscopy (SEM) images were obtained by Nova NanoSEM450 (Thermo Fisher Scientific, FEI, USA). It is equipped with an energy dispersive spectrometer (EDS) was used to characterize the elemental distribution and morphologies. The height distribution images of UPE, and Au-UPE were respectively detected by the contact mode of probe force microscope (PFM) (Bruker Dimension ICON, USA). The viscoelastic behavior of gels was test with a rotational rheometer (DHR-1, TA, USA). The diameter of the sample plate was 40 mm. Contact angles of film samples were measured by drop shape analyzer (KRUSS DSA30E, Germany). Mechanical performances and thermal performances measurement. The mechanical properties of the sample films were evaluated using a universal testing machine (EM6.501-W, Shenzhen Tesmart, China) equipped with a 10 N load cell, at a speed of 10 mm min⁻¹ and sample size of 15 × 7 mm. The Longwin 9389 steady-state heat-flow method, in accordance with ASTM D5470 standard, was used to analyze the thermal resistance with sample surface area of 25.4 × 25.4 mm 2 at standard pressure of 40 psi and hot plate temperature of 80 ℃. The thickness obtained by directly pressurizing without a spacer is considered the bond line thickness (BLT), and the relevant thermal resistance represents the R eff of materials. All infrared images were obtained using an infrared camera (HIKMICRO-P20maxV2) to record the temperature distribution of the samples. The burn-in liquid circulation test was conducted using a high-power server equipped with an Intel XEON E5 processor (thermal design power ≥ 130 W, ≥ 20 cores) as the computer heat source, with GALDEN HT200 fluorinated coolant (Solvay, Italy) used as the cooling fluid, equipped with home-made circulation systems, including liquid box, liquid pipes, and liquid pumps. Finite Element Analysis Methods. The biaxial tension and uniaxial compression process of LM/Au-UPE film was studied by the finite element analysis (FEA). They were studied by observing the stress distribution evaluations at the cross-section of the films during stretching and pressing. Considering the size of Au particles is too small (< 10 nm) as compared to UPE fiber (~ 100 nm) and LM matrix (~ 100 nm), the films were described as two phase composites (UPE fiber network and LM matrix) to simplify the model. The size and morphology of LM and UPE fiber were set according to Supplementary Fig. 8b. Liner elastic material model was used to calculate the relationship among the stress, the strain and material parameters (modulus, Poisson’s ratio, and density) of each phase 15 . The films were biaxially stretched along the horizontal direction with a constant stretching force of 2 N at two sides (left and right) of the film. The films were pressed from the top of sample with a constant force of 2 N and fixed the bottom of sample. The calculating unit size was set as normal. Calculation of the Surface Energy. The surface free energy ( γ s ) of the solid samples was determined using the Owens method, based on the contact angles measured for two probe liquids: deionized water (polar component) and diiodomethane (dispersion component). According to this approach, the total surface free energy of a solid is expressed as the sum of its dispersion ( γ sd ) and polar ( γ sp ) components: $$\:{\gamma\:}_{s}=\:{\gamma\:}_{sd}+\:{\gamma\:}_{sp}$$ 1 The Owens equation relates the contact angle (θ) of a liquid on the solid surface to these energy components: $$\:{\gamma\:}_{l}\left(1+cos\theta\:\right)=\:2\sqrt{{\gamma\:}_{sd}{\gamma\:}_{ld}}{+\sqrt{{\gamma\:}_{sp}{\gamma\:}_{lp}}}_{\:}$$ 2 where γ l is the total surface tension of the liquid, γ ld and γ lp are the dispersion and polar components of the liquid’s surface tension, respectively. In this study, water ( γ l = 72.8 mN m⁻¹; γ ld = 21.8 mN m⁻¹; γ lp = 51.0 mN·m⁻¹) and diiodomethane ( γ l = 50.8 mN·m⁻¹; γ ld = 50.8 mN·m⁻¹; γ lp = 0 mN m⁻¹) were used as probe liquids. By substituting the measured contact angles of both liquids into the above equation, γ sd was first obtained from diiodomethane data, and subsequently γ sp was calculated using the water data. The sum of γ sd and γ sp yielded the total surface free energy of the solid. The surface energies were automatically calculated via the software in drop shape analyzer (KRUSS DSA30E, Germany) according to aforementioned formula. Reporting summary. Further information on research design is available in the Nature Research Reporting Summary linked to this article. Declarations Competing interests The authors declare no competing financial interests. Reprints and permission information is available online at http://npg.nature.com/reprintsandpermissions/ Author contributions Q. Fu conceived the idea. H. Zhou, X. Chen, and Z. Wang fabricated the materials and measured the material performance. Z. Xie, H. Zhou and Q. Fu analyzed the data. Z. Xie and H. Zhou organized the experimental data and wrote the draft manuscript. Q. Fu revised the manuscript. Q. Fu supervised the overall conception. R. Li, K. Wu, Z. Dou, and W. Lin contributed to the discussion on the results and improved the manuscript. Acknowledgments Z. Xie and H. Zhou contributed equally to this work. Q. Fu acknowledge the support by the National Natural Science Foundation of China (Grant No. 52233002 and 22475139) and National Key Research and Development Project of China (Grant No. 2022YFB3806900). Data availability. All data supporting the findings of this study are included within the paper and its Supplementary Information file. Source data are provided with this paper. Any other relevant data are available from the corresponding authors upon request. References Ji H et al (2025) Liquid–liquid interfacial tension stabilized Li-metal batteries. Nature Shen Q et al (2023) Liquid metal-based soft, hermetic, and wireless-communicable seals for stretchable systems. Science 379:488–493 Wu K et al (2025) Mechanochemistry-mediated colloidal liquid metals for electronic device cooling at kilowatt levels. 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Nat Chem Eng 1:702–709 Sun W et al (2022) Ultrahigh Molecular Weight Polyethylene Lamellar-Thin Framework on Square Meter Scale. Adv Mater 34:2107941 Xu Y et al (2019) Nanostructured polymer films with metal-like thermal conductivity. Nat Commun 10:1771 Shen S, Henry A, Tong J, Zheng R, Chen G (2010) Polyethylene nanofibres with very high thermal conductivities. Nat Nanotechnol 5:251–255 Kim T, Drakopoulos SX, Ronca S, Minnich AJ (2022) Origin of high thermal conductivity in disentangled ultra-high molecular weight polyethylene films: ballistic phonons within enlarged crystals. Nat Commun 13:2452 Kong M et al (2024) Ambient printing of native oxides for ultrathin transparent flexible circuit boards. Science 385:731–737 Xing Z et al (2023) Liesegang Phenomenon of Liquid Metals on Au Film. Adv Mater 35:2209392 Duan Y et al (2025) Constructing electrospun 3D liquid metal adhesion channel on stretchable yarns for broad-range strain-insensitivity smart textiles. 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Appl Phys A 107:701–708 Cheng R et al (2025) Liquid-infused nanostructured composite as a high-performance thermal interface material for effective cooling. Nat Commun 16:794 Chiu C-P, Maveety JG, Tran QA (2002) Characterization of solder interfaces using laser flash metrology. Microelectron Reliab 42:93–100 Dai W et al (2019) Metal-Level Thermally Conductive yet Soft Graphene Thermal Interface Materials. ACS Nano 13:11561–11571 Xu S et al (2020) Electric-Field-Assisted Growth of Vertical Graphene Arrays and the Application in Thermal Interface Materials. Adv Funct Mater 30:2003302 Sun L et al (2019) Wafer-scale vertically aligned carbon nanotubes for broadband terahertz wave absorption. Carbon 154:503–509 Additional Declarations There is NO Competing Interest. Supplementary Files SupplementaryInformationNCOMMS.docx Advanced thermal interface materials based on ultra-thin and ultra-strong metal-gel Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7376124","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":507583082,"identity":"10bb6f6a-554b-434e-984f-002acbb632db","order_by":0,"name":"Qiang Fu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1ElEQVRIiWNgGAWjYDACZhBhwyAH4bERrSWNwZgELQwQLYkNRGvhO8787OGXhMPp89vPGDB8KDvMwD+7Ab8WycNs5sYyCYdzN5zJMWCcce4wg8SdA/i1GBxmMJOW/AHUIsFjwMzbdpjBQCKBkBb2b9ISQIfJzwBq+UucFh4zyQ8JhxMYbgC1MBKjRfIwT5k0Q0K64YYzaQUHe86l80jcIKCF7/zxbZI/Eqzl5dsPb3zwo8xajn8GAS0MB4CxyYNgM/DgVoqkhfEHYWWjYBSMglEwkgEAvfhAmhAnRpcAAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-5191-3315","institution":"Sichuan University","correspondingAuthor":true,"prefix":"","firstName":"Qiang","middleName":"","lastName":"Fu","suffix":""},{"id":507583083,"identity":"1f2295d2-4486-4059-8848-7d645423ac50","order_by":1,"name":"Zilong Xie","email":"","orcid":"","institution":"Sichuan University; National University of Defense Technology","correspondingAuthor":false,"prefix":"","firstName":"Zilong","middleName":"","lastName":"Xie","suffix":""},{"id":507583084,"identity":"5a343c4a-f89a-4c39-89ae-d0d7ff6a7f1d","order_by":2,"name":"Hui Zhou","email":"","orcid":"","institution":"Sichuan University","correspondingAuthor":false,"prefix":"","firstName":"Hui","middleName":"","lastName":"Zhou","suffix":""},{"id":507583085,"identity":"95a1603a-cc50-4718-8f0f-9e1a444050b3","order_by":3,"name":"Runlai Li","email":"","orcid":"","institution":"Sichuan University","correspondingAuthor":false,"prefix":"","firstName":"Runlai","middleName":"","lastName":"Li","suffix":""},{"id":507583086,"identity":"0d8c5dd3-7b1d-4c73-be73-4866f9a78272","order_by":4,"name":"Xizhi Chen","email":"","orcid":"","institution":"Sichuan University","correspondingAuthor":false,"prefix":"","firstName":"Xizhi","middleName":"","lastName":"Chen","suffix":""},{"id":507583087,"identity":"6e03cf8c-101c-4f57-8513-5cb068c77e04","order_by":5,"name":"Zirui Wang","email":"","orcid":"","institution":"Sichuan University","correspondingAuthor":false,"prefix":"","firstName":"Zirui","middleName":"","lastName":"Wang","suffix":""},{"id":507583088,"identity":"e5d80b9c-3da6-4922-876a-55a0d797d831","order_by":6,"name":"Weizhi Lin","email":"","orcid":"","institution":"Sichuan University","correspondingAuthor":false,"prefix":"","firstName":"Weizhi","middleName":"","lastName":"Lin","suffix":""},{"id":507583089,"identity":"6c6f60cf-e926-462b-a77a-b1b3c00e0859","order_by":7,"name":"Zhengli Dou","email":"","orcid":"","institution":"Sichuan University","correspondingAuthor":false,"prefix":"","firstName":"Zhengli","middleName":"","lastName":"Dou","suffix":""},{"id":507583090,"identity":"2b552922-f269-4354-8017-a1a1feff54f4","order_by":8,"name":"Kai Wu","email":"","orcid":"https://orcid.org/0000-0002-7057-0442","institution":"Sichuan University","correspondingAuthor":false,"prefix":"","firstName":"Kai","middleName":"","lastName":"Wu","suffix":""}],"badges":[],"createdAt":"2025-08-14 17:50:38","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7376124/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7376124/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":90316267,"identity":"b6136f03-169d-45b2-a355-4270c71ce549","added_by":"auto","created_at":"2025-09-01 10:20:34","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":499095,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eNetwork design\u003c/strong\u003e\u0026nbsp;\u003cstrong\u003ein LM gel.a\u0026nbsp;\u003c/strong\u003eSchematic illustration detailing the network constructing process: Au particles are deposited on UPE porous film to form an interface alloyed fiber network, facilitating the wetting and compatibility between Au-UPE and LM, followed by coating and pressing to sufficiently immerse the LM in Au-UPE network.\u0026nbsp;\u003cstrong\u003eb\u0026nbsp;\u003c/strong\u003eimage of a large-scale LM gel film with lengthen more than 50 cm, demonstrating the capability for synthesizing substantial film sizes; cross-section and surface SEM image and corresponding EDS image of LM gel film, showcasing a thin film achievement of 1.5 µm thickness and the fully filled network structure.\u0026nbsp;\u003cstrong\u003ec\u003c/strong\u003e. Comparison of the strengthen and thermal resistance of LM/Au-UPE gel with other representative strategies, demonstrating the advantage of ultra-high strengthen and acceptable thermal resistance over previous studies\u0026nbsp;\u003csup\u003e3,\u0026nbsp;24,\u0026nbsp;25,\u0026nbsp;26,\u0026nbsp;44,\u0026nbsp;45,\u0026nbsp;46,\u0026nbsp;47,\u0026nbsp;48,\u0026nbsp;49,\u0026nbsp;50,\u0026nbsp;51,\u0026nbsp;52,\u0026nbsp;53\u003c/sup\u003e. For illustrations in these figures, the LM content in gels is around 90 wt%.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7376124/v1/06ac6f981c5607d38a0e9882.png"},{"id":90315386,"identity":"fd0d3c09-4286-4344-b34e-4429819e8f3b","added_by":"auto","created_at":"2025-09-01 10:12:34","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":483036,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCharacteristics of network in LM gels.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e representative AFM images of UPE and Au-UPE, suggesting the coating of Au layer; SEM images and contact angle images (insets) of LM on UPE and Au-UPE, suggesting the good wetting and immersion of Au-UPE. \u003cstrong\u003eb \u003c/strong\u003eSchematic illustration detailing interface interaction between Au-UPE and LM: Au atoms forms alloy with the Ga, In, Sn atoms from LM, along with the interaction between Au atoms and the active oxide layer of LM. \u003cstrong\u003ec\u003c/strong\u003e XRD spectra comparison of UPE, Au-UPE, LM/Au-UPE, LM, suggesting alloy formation. \u003cstrong\u003ed\u003c/strong\u003e XPS Au 4\u003cem\u003ef\u003c/em\u003e spectra comparison between LM/Au-UPE and Au-UPE, along with Ga 3\u003cem\u003ed\u003c/em\u003e spectra comparison between LM/Au-UPE and LM-UPE, suggesting the formation of Ga-Au alloy. \u003cstrong\u003ee\u003c/strong\u003e XPS O 1\u003cem\u003es\u003c/em\u003e spectra comparison between LM/Au-UPE and LM-UPE, suggesting the interaction between Au atoms and the active oxide layer of LM. \u003cstrong\u003ef \u003c/strong\u003eContact angles of LM on Au-UPE film with different Au sputtering times. \u003cstrong\u003eg\u003c/strong\u003e Rheology curves comparison between LM/Au-UPE gel and H\u003csub\u003e2\u003c/sub\u003eO/PVA gel at the same liquid contents.\u003cstrong\u003e h\u003c/strong\u003e Schematic illustration demonstrating that fiber network LM gels have bigger network scales as compared to common molecular network gel, making them less likely to be disturbed by shear.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7376124/v1/ae43604cfced05de8654c725.png"},{"id":90315390,"identity":"bb8baaa5-db6d-41e1-8934-cf28474ba8d1","added_by":"auto","created_at":"2025-09-01 10:12:34","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":481533,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMechanical stability and thermal resistance\u003c/strong\u003e. \u003cstrong\u003ea\u003c/strong\u003e Strengths of LM/Au-UPE gel with different LM contents. \u003cstrong\u003eb\u003c/strong\u003e Interface thermal resistances of LM/Au-UPE gel with different LM contents. \u003cstrong\u003ec\u003c/strong\u003e Schematic illustration detailing the structure of LM/Au-UPE gel at different LM contents \u003cstrong\u003ed\u003c/strong\u003e Simulated cross-section stress distribution of LM/Au-UPE during compression and tension, showcasing that the strong fiber network bears the stress, and the soft LM provides shape adaptability. \u003cstrong\u003ee\u003c/strong\u003e LM/Au-UPE gel with only 2 μm thickness maintains stable after 200 g loading, while LM deforms even under 10 g loading. \u003cstrong\u003ef\u003c/strong\u003e LM/Au-UPE gel shows good shape adaptability and stability on copper plate (3 cm curvature radius), while LM is instable. \u003cstrong\u003eg-h\u003c/strong\u003e LM/Au-UPE gel films can withstand twist, stretching and sonification (800 W, 1.0 h) at different solvents, suggesting the stability under complex stress environments. \u003cstrong\u003ei\u003c/strong\u003e Comparison of four kinds of mainstream TIMs, suggesting the unique advantage of LM gels in balancing the high strength and low thermal resistance.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7376124/v1/bcaf46edf0fa376c1b060014.png"},{"id":90315392,"identity":"498f9a80-a250-4b53-bde8-2252c46af7b5","added_by":"auto","created_at":"2025-09-01 10:12:34","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":691689,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eApplications in dynamic stress cooling.\u003c/strong\u003e \u003cstrong\u003ea\u003c/strong\u003e Images show that LM/Au-UPE can withstand the weight of a 4.5-ton truck without marks of leakage. \u003cstrong\u003eb \u003c/strong\u003eInterface thermal resistance and weight change of LM/Au-UPE gel and LM after truck crushing, suggesting the performance stability under extreme dynamic stress. \u003cstrong\u003ec\u003c/strong\u003eSchematic illustration and \u003cstrong\u003ed\u003c/strong\u003e images detailing the dynamic cooling application, where LM/Au-UPE gel is integrated between CPU and heat sink and the system is immersed in the circulating cooling fluid to examine the stability at dynamic disturbances from fluid force. \u003cstrong\u003ee\u003c/strong\u003e Thermal distribution images of the heat sink captured by infrared thermal imaging, suggesting the superior cooling performance of LM/Au-UPE as compared to air. \u003cstrong\u003ef\u003c/strong\u003eTemperatures of the heat sinks with different times, suggesting the better colling stability of LM/Au-UPE gel than commercial LM TIMs in long-term operation. \u003cstrong\u003eg\u003c/strong\u003e Images show the better structure integrity of LM/Au-UPE gel than commercial LM TIMs after long-term liquid cooling operation (360 h).\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7376124/v1/f662852fd48f5d13fb8c9861.png"},{"id":94728816,"identity":"62746878-efaa-44a9-8b12-e0c5627dd5dc","added_by":"auto","created_at":"2025-10-30 07:04:18","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2986392,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7376124/v1/608f7b26-3e20-4d8b-9f7a-52154ef5fdd8.pdf"},{"id":90315397,"identity":"c583598c-41d7-4843-89c3-3129bf3b15bb","added_by":"auto","created_at":"2025-09-01 10:12:35","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":8503988,"visible":true,"origin":"","legend":"Advanced thermal interface materials based on ultra-thin and ultra-strong metal-gel","description":"","filename":"SupplementaryInformationNCOMMS.docx","url":"https://assets-eu.researchsquare.com/files/rs-7376124/v1/384464285a69ddf782dc36fd.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Advanced thermal interface materials based on ultra-thin and ultra-strong metal-gel","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThermal interface materials based on liquid metal (TIM-LMs) have garnered significant attention due to their exceptional thermal conductivity and conformability\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. These advantages reduce the interfacial thermal resistance (\u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e) between heat sources and heat sinks, thereby significantly enhance the cooling performance of high-power electronic modules, like high-power microwave, radar, laser, and AI\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. However, the upsurge of applications under the working condition of dynamic load, such as, electric vehicles, electric drones, and hypersonic missile, poses new challenges for TIM-LMs\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. The associated electronic systems are subjected to extreme conditions including high accelerations (30\u0026ndash;700 m s\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e), high vibrations, and high rates (75-1500 m s\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e)\u003csup\u003e12, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. There is an urgent need for TIM-LMs capable of stable operation for a long time without affecting its performance\u003c/p\u003e\u003cp\u003eDue to long-range disordered amorphous structure, LM is intrinsically flowable and easy to leak, lacking structure stability\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. Preparing LM-polymer composites is a simple and effective solution\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. In such composites, a high filling amount is always required to achieve a low \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e \u003csup\u003e\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. But when the LM content is over-high (\u0026gt;60 wt%), the composites become very brittle, accompanied by serious interfacial problems between the polymer and LM, leading low mechanical strengths (typically lower than 3 MPa)\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. Such composites can hardly resist the extremely high dynamic stress in realistic applications. How can LM become strong and stable at high content in LM-polymer composites? Hydrogel give us a good example\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e, in which water is confined and fixed via polymer network. With high liquid contents (\u0026gt;90 wt%), hydrogels show exceptional mechanical performances\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. Hydrogels could be strengthened via a series of intelligent strategies, such as entanglements, networks, alignments, and composite\u003csup\u003e\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. One of the keys is to construct highly ordered and robust network, along with good interfacial interactions\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. Drawing inspiration from fiber networks of bio-tissues, like collagen and tendon, researchers devised oriented fiber-reinforced network, leading gel strengths up to 10\u0026thinsp;~\u0026thinsp;80 MPa\u003csup\u003e\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eAnalogous to hydrogels, transforming LM into metal-gels requires a robust, highly compatible network structure with uniformly distributed nanopores below 100 nm to effectively confine and stabilize LM. In our recent work, we developed an ultra-high molecular weight polyethylene (UPE) porous film through a multi-step stretching process, resulting in a nanofiber network with pore sizes between 40\u0026ndash;60 nm and thickness as low as a few micrometers or even tens of nanometers\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. This porous film exhibits outstanding mechanical properties (strengths up to 1.7 GPa)\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e, and is well-suited as a scaffold for LM immobilization. To enhance compatibility between UPE and LM, we sputter Au particles onto UPE surface, forming an alloyed interface to facilitate the wetting and infiltration of LM. As a result, a large amount (up to 95 wt%) of gallium-indium-tin LM could be easily infiltrated and tightly confined in nanofiber network to form metal-gels. These gels do not leak even under a pressure of 4.5 tons, and are stable over complex conditions, like folding, ultrasonication, solvent erosion, and cooling cycle. Owing to the high thermal conductivity and deformability of LM and the low bond line thickness (\u0026le;\u0026thinsp;2 \u0026micro;m) of the UPE film, the \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e remains very low (7.7 mm\u0026sup2;\u0026middot;K\u0026middot;W⁻\u0026sup1;). The fabrication process of gel only involves three simple steps (sputtering, coating, and pressing), that can be readily integrated with continuous industrial production to make large-area products, showing promise as advanced LM-TIMs in the working conditions of dynamic loading.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cb\u003eNetwork design in LM gel fabrication.\u003c/b\u003e In the fabrication of LM gel, UPE film is selected as framework due to its advantageous mechanical and thermal properties: an iron-like strengthen (≤ 1.7 GPa), flexibility, and high thermal conductivity (≤ 65 W m\u003csup\u003e− 1\u003c/sup\u003e K\u003csup\u003e− 1\u003c/sup\u003e)\u003csup\u003e36, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u003c/sup\u003e. These merits are expected to impart the LM gel with high strength, good conformability and low thermal resistance. A critical challenge in preparing LM gels is how to make the high-surface-energy LM wet and immerse in the network, as well as resolve the interface problem between LM and polymer. We overcome this by introducing an Au interface layer. Au can be stably integrated on UPE through a common ion sputtering method. It offers a metal-metal interaction between Au-UPE and LM to promote wetting\u003csup\u003e\u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e43\u003c/span\u003e\u003c/sup\u003e. At the same time, Au has a high thermal conductivity (\u0026gt; 300 W m\u003csup\u003e− 1\u003c/sup\u003e K\u003csup\u003e− 1\u003c/sup\u003e) to suppress the phonon scattering at the polymer-LM interface. After sputtering Au, coating LM and pressing film, LM can be fully immersed in Au-UPE film to form a metal-gel film (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea). Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb displays the scalable fabrication and the micro-structure of LM gel film. By large-area UPE matrix and the continuous coating, we successfully obtained LM gel film with lengthen more than 50 cm and thickness around 1.5 µm, demonstrating the practical scalability of metal-gels. Considering that UPE films are already widely available as industrial raw materials, and that metal sputtering, coating, and pressing are well-established industrial processes, the LM/Au-UPE gel films hold strong potential for rapid industrial scale-up and production. Corresponding scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) elemental mapping images reveal the atoms distribution of LM in Au-UPE, suggesting the fully wetting and immersion of LM. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec, LM gels integrated with ultra-strong fiber networks exhibit order-of-magnitude improvement in mechanical strength (up to 117 MPa, increased from 10\u003csup\u003e0\u003c/sup\u003e MPa class to 10\u003csup\u003e2\u003c/sup\u003e MPa class) as compared to other types of TIMs (LM-based composites, polymer-based thermal grease/pad, and carbon-based vertically arranged materials), representing the highest strength reported among TIMs to date (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec, Supplementary Table\u0026nbsp;1)\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e44\u003c/span\u003e, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e45\u003c/span\u003e, \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e46\u003c/span\u003e, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e47\u003c/span\u003e, \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e48\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e50\u003c/span\u003e, \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e51\u003c/span\u003e, \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e52\u003c/span\u003e, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e53\u003c/span\u003e\u003c/sup\u003e. The \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e (7.7 mm²·K·W⁻¹) of LM gels is still left behind that of some state-of-the-art LM-based TIMs, but is obviously prior to that of polymer-based and carbon-based TIMs, demonstrating the special adaptability of cooling under high-stress conditions (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec, Supplementary Table\u0026nbsp;1).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eCharacteristics of the network structure in gels.\u003c/b\u003e Atomic force microscopy (AFM) images and SEM images reveal that a uniform gold coating, approximately 20 nm in width, forms on the Au-UPE fiber network surface after sputtering (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea-I, II, Supplementary Fig.\u0026nbsp;1). Correspondingly, SEM images and contact angle measurements show a significant decrease in the LM contact angle, which allows the LM to spread flat and fully infiltrate the network (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea-IV). In contrast, on pristine UPE film, the LM exhibits a large contact angle, with droplets aggregating into spheres that fail to wet the surface (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ea-III), highlighting the remarkable effect of the Au layer in improving wettability and interfacial interactions. We find that LM gels are distinct from common hydrogels or organic gels. In those gels, the continuous phase is water or an organic solvent, and wettability can be enhanced by decorating the fiber network with chemical groups. In LM gels, however, the continuous phase is metallic. Conventional surface modifications, such as silane, dopamine functionalization, etc, do not significantly reduce the LM contact angle (contact angle \u0026gt; 120°, Supplementary Fig.\u0026nbsp;2); only by decorating the UPE fiber network with a metal layer (Au layer) is the wettability improved (contact angle \u0026lt; 60°). Further calculation results for the surface energy (\u003cem\u003eσ\u003c/em\u003e) of differently modified UPE films confirm that only the metal-treated films exhibit a significant increase of \u003cem\u003eσ\u003c/em\u003e from 42 mN m\u003csup\u003e− 1\u003c/sup\u003e of pristine UPE to 51 mN m\u003csup\u003e− 1\u003c/sup\u003e of Au-UPE (Supplementary Fig.\u0026nbsp;3). The enhancement of σ makes the surface properties of metallized film more closely match the high surface tension of the LM, thereby promoting the wetting at the interface. We demonstrate that this metallization-based wetting mechanism is universal to other metals; sputtering either Pt or Ag onto the UPE surface also reduces the LM contact angle to as low as 64° and 53° (Supplementary Fig.\u0026nbsp;4). Considering the balance of chemical stability and thermal conductivity, Au is solely selected as the metal layer.\u003c/p\u003e\u003cp\u003eA more fundamental factor promoting the wetting between UPE and LM is the alloyed interface interaction formed between Au particles and the LM (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eb). On one hand, Au can form an alloy with the LM. On the other hand, the oxide layer on the LM surface is a metastable and active layer that may interact with Au. The appearance of small peaks at (111), (200), and (220) in the X-ray diffraction (XRD) analysis confirms that the filling of LM in Au-UPE leads to the generation of a small amount of AuGa₂ alloy (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ec). The X-ray photoelectron spectroscopy (XPS) spectra also confirm the formation of an Au-Ga alloy: an additional new peak appears in the Au 4\u003cem\u003ef\u003c/em\u003e orbital of LM/Au-UPE at 84.8 eV (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ed), and another new peak appears in the Ga 3\u003cem\u003ed\u003c/em\u003e orbital at 20.6 eV (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ee). In addition, a new peak also emerges in the O 1\u003cem\u003es\u003c/em\u003e spectra of LM/Au-UPE at 533.7 eV. Given that Au is difficult to oxidize, this indicates that the active oxide layer of LM has formed a certain interaction with Au. The wettability of LM on Au-UPE shows a positive correlation with the gold content: as the sputtering time increases from 0 s to 20 s, the contact angle drops from 84° to 54° (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003ef), and the \u003cem\u003eσ\u003c/em\u003e increases gradually from 40.5 mN m\u003csup\u003e− 1\u003c/sup\u003e to 50.1 mN m\u003csup\u003e− 1\u003c/sup\u003e (Supplementary Fig.\u0026nbsp;5), verifying the key role of Au in influencing the interface. A 20 s sputtering time is chosen as the standard parameter for Au layer fabrication in subsequent studies, as shorter times result in insufficient wettability, while longer times cause excessive metal content and film rupture due to the high heat from sputtering. These tests confirm the favorable alloying interaction between Au and the LM.\u003c/p\u003e\u003cp\u003eThe network structure characteristics of the LM gel was investigated using rheological analysis. Oscillatory strain sweeps reveal that at low strains, the storage modulus (G') consistently exceeds the loss modulus (G''), confirming the stable and semi-solid gel structure of LM/Au-UPE, which is analogous to that of conventional PVA hydrogels (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eg). At higher strains, a crossover of G' and G'' occurs, indicating that LM/Au-UPE also undergoes a gel transition characteristic of conventional gels. Notably, for the same liquid content, the gel transition for LM/Au-UPE occurs at a much higher oscillation strain (472% strain) compared to that for conventional hydrogel (40% strain, H₂O/PVA), representing a nearly tenfold increase in the yield strain (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eg). This demonstrates that the fiber network architecture imparts superior mechanical stability, allowing the gel to withstand large dynamic shear strains under which conventional polymer networks fail. Such network stability is further evidenced by frequency sweep tests (Supplementary Fig.\u0026nbsp;6). The modulus (G' and G'') of the LM/Au-UPE gel exhibit markedly weaker frequency dependence than those of the H₂O/PVA gel, a hallmark of a robust and stable network (Supplementary Fig.\u0026nbsp;6). As illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eh, this is mainly because the fiber network structure is composed of rigid and highly crystalline fibers. Their response to external force under strain is small, and they always maintain the structure of fibrous junctions, thus retaining better stability under high shear strain. In contrast, the conventional molecular chain network has low crystallinity and high flexibility. Although there are some cross-linking points, the chain segments between them can be disturbed by dynamic strain, causing entanglement and disentanglement of the molecular chains, which leads to poorer shear stability.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eMechanical stability and thermal resistance of LM gels.\u003c/b\u003e To examine the effect of fiber network in mechanical stabilization, we fabricated a series of LM/Au-UPE gels with varied LM contents (0 to 100 wt%) and assessed their tensile strength (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ea, Supplementary Fig.\u0026nbsp;7). The strength shows a progressive degradation with increasing LM content, dropping from 148 MPa for pristine Au-UPE (0 wt% LM) to 0 MPa for pure LM (100 wt%). Remarkably, the strength of LM/Au-UPE persists at robust levels (≥ 117 MPa) for LM fractions from 0–90 wt%, underscoring the excellent mechanical reinforcement introduced by the fiber network. And a decline in strength is observed when the LM content exceeds 90 wt%, likely due to the network being fully infiltrated, and the additional LM only forming a mechanically irrelevant, zero-strength liquid layer on the surface (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec). The \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e of the LM/Au-UPE gels was measured at 40 psi using a steady-state heat flow method. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eb, with increasing LM content, \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e decreases from 1305 mm² K W⁻¹ for 0 wt% LM (pristine Au-UPE) to 6.0 mm² K W⁻¹ for 100 wt% LM (pure LM). A sharp decline in \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e emerged as the LM content surpassed 70 wt%, eventually stabilizing at exceptionally low values (≤ 7.7 mm²·K·W⁻¹) above 90 wt%. This can be attributed to incomplete filling of the fiber network at LM contents below 70 wt%; sufficient infiltration and filling of the Au-UPE fiber network by LM occurs only at higher LM loadings (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ec, Supplementary Fig.\u0026nbsp;8). This complete infiltration is crucial, as the LM phase imparts ultra-low modulus, outstanding conformability, and high thermal conductivity, which collectively minimize thermal resistance. For practical cooling applications under high dynamic stress, both high strength and low \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e must be considered. Thus, 90 wt% LM was chosen as the standard composition to balance tensile strength (117 MPa) and \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e (≤ 7.7 mm² K W⁻¹) in following application experiments. Under these conditions, LM fully fills the Au-UPE network without forming a surplus surface LM layer.\u003c/p\u003e\u003cp\u003eTo elucidate the underlying reinforcement mechanism, we performed finite element analysis (FEA) to map the stress distribution of LM/Au-UPE gels under biaxial tension and uniaxial compression (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed). The simulations confirm that the fiber network acts as the primary load-bearing scaffold, concentrating the vast majority of the stress under both loading conditions (red regions, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed). Considering the intrinsic high mechanical strength of UPE fibers (1 ~ 3 GPa), this architecture enables the composite to endure significant mechanical forces\u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. Meanwhile, the LM phase, subjected to minimal stress, deforms compliantly with the fibers, ensuring excellent conformability (deep blue regions, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ed). This synergistic architecture, combining ultra-strong fibers with an ultra-soft liquid matrix, yields a material with a highly compliant surface yet a mechanically robust core, an ideal profile for a durable TIM. This strategy of integrating a highly fluidic liquid into a rigid solid framework offers a compelling paradigm for advanced TIMs. It can revitalize many high-performance rigid materials, previously unsuitable for TIM applications due to poor surface conformality. A recently reported system of vertically aligned copper wires filled with LM exemplifies the success of such liquid infused structures \u003csup\u003e\u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e49\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eTo further assess the stability under complex stress conditions, we simulated a range of challenging operational conditions. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ee, the LM/Au-UPE gel film, merely 2 µm thick, remains stable under a 200 g load, whereas pristine LM deforms under a load as light as 10 g. When placed on a copper plate with a 3 cm radius of curvature, the LM/Au-UPE gel exhibits outstanding shape adaptability and stability, in stark contrast to pristine LM, which is unstable and readily flows (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ef). The gel films also withstand severe twisting and stretching (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eg), confirming their robustness in stress environments. Remarkably, even after undergoing intense ultrasonic treatment (800 W, 1.0 h) in a series of solvents of varying polarity, including water, ethanol, and petroleum ether, the gel films showed no signs of LM leakage or film rupture (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eh). This indicates that the gel film possesses exceptional stability in multifaceted environments where dynamic stresses and liquid atmospheres coexist, pointing to potential applications underwater thermal management and in aerospace applications where condensate or humid conditions are present. Currently commercial TIMs can be generally classified as LM-based composites, polymer-based thermal greases, and polymer-based thermal pads. Among commercial products (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ei and Supplementary Table\u0026nbsp;2), advanced LM-based TIMs achieve the lowest \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e (down to 0.8-6.0 mm²·K·W⁻¹) and BLT (down to 46 µm), but their liquid nature generates negligible yield strengths (\u0026lt; 0.01 MPa) make them prone to leakage\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Polymer-based thermal grease is as similar as LM-based TIMs. Polymer-based thermal pads have some strength (1.0–4.0 MPa), but suffer from high \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e (typically ≥ 20 mm²·K·W⁻¹ ) and BLT (~ 100 µm) \u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. In contrast, LM/Au-UPE gel films introduced herein efficiently resolve the triangle problem of low \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e (≤ 8 mm²·K·W⁻¹), high strength (≤ 120 MPa), and low thickness (≤ 2 µm), creating a new class of durable, high-performance, and ultrathin TIMs (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003ei and Supplementary Table\u0026nbsp;2).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eDynamic stress cooling application of gel film.\u003c/b\u003e To assess the stability of the LM/Au-UPE gel film under extreme environmental conditions, it was subjected to compression by a 4.5-ton truck to observe its structural and performance integrity (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea-I). The results show that, after being run over, the color of the tire surface was almost identical to that before compression (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea-II-IV), indicating no leakage of silvery LM and demonstrating stability under extreme dynamic stress. We further measured the thermal resistance of the gel film before and after compression. The post-compression \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e (7.7 mm²·K·W⁻¹) remained close to its pre-compression value (9.9 mm²·K·W⁻¹), and the gel film retained more than 90% of its original weight (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb). In contrast, LM samples without the fiber-reinforced network exhibited drastic changes in both \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e and weight after compression, attributed to leakage and the adhesion of surface contaminants (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eb). This confirms that LM/Au-UPE not only maintains its external appearance, but also preserves its internal structure and performance.\u003c/p\u003e\u003cp\u003eThe thermal demands of high-power electronics such as AI chips have outpaced conventional fan cooling, necessitating a shift to liquid cooling systems. This new paradigm, however, poses a formidable challenge for TIMs, which must now endure the erosive forces of fluid flow while maintaining low thermal resistance. To mimic this demanding environment, we built a custom liquid cooling loop around a chip, incorporating a pump, TIM, and heat sink (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ec-d, Supplementary Fig.\u0026nbsp;9). During operation, the LM/Au-UPE gel film showed no signs of rupture or leakage, even as coolant flowed directly over its surface (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ed). We then pushed the system to high-power operation to evaluate its real-world cooling efficacy. Infrared thermal imaging revealed that, on the first day of operation, that the LM/Au-UPE gel and a state-of-the-art commercial LM TIM delivered comparable, excellent cooling performances, lowering the heat sink temperature to 49.0°C and 48.6°C, representing a ~ 13°C reduction compared to the system with air (no TIM) at 61.7°C, (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ee, Supplementary Fig.\u0026nbsp;10). Notably, in the key durable test, after 15 days of continuous operation, a clear performance degradation was observed for the commercial LM composites TIMs, with temperature rising by as much as 4.1°C (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ef). In striking contrast, our LM/Au-UPE gel maintained its temperature with virtually no change (≤ 1°C), demonstrating superior long-term stability against the cyclic shear stress of the liquid environment (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ef). Failure disassembly analysis provided a vivid confirmation: after 15 days, the commercial LM composites TIMs exhibited clear evidence of leakage and pump-out, whereas the LM/Au-UPE gel appeared as pristine as it was upon installation, a testament to its exceptional structural integrity (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eg).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThis research demonstrates a promising strategy for preparing metal-gel that overcomes the critical stability challenges facing LM TIMs. These gels are characterized by an interface-modified, fiber-reinforced network structure. Within this structure, an alloying interface modification promotes interaction and enables the wetting between the polymer and the LM. Highly aligned fiber-network yields exceptional gel strength, the highest reported for thermal interface materials, while retaining flexibility. Compared with conventional molecular chain network gels, the fiber network gels developed in this work exhibit a significantly thickened (nanometer-thick) network architecture, enabling more stable network and reliable cooling even under severe dynamic stress. These ultra-thin metal-gel films not only enable reliable thermal interface solutions under extreme conditions, such as offshore cloud computing and deep-earth drilling, but also hold promise for a wide spectrum of applications where metallic functionality must be coupled with exceptional gel mechanics, from high-performance conductive coatings to biomedical adhesive interfaces, like brain-computer interface.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cb\u003eMaterials.\u003c/b\u003e Ultra-high molecular weight polyethylene (UPE) resin powder with was offered from Guangdong Suguang Plastic Co., Ltd, with viscosity-average molecular weight grade of around 11 M (SG4850). Galinstan alloy liquid metal (LM, 62.5 wt% gallium, 21.5 wt% indium, 16 wt% tin) was provided by Hunan Santech Materials, China. The white protopet (1S) petrolatum was obtained from Sonneborn, USA. The gold (Au), silver (Ag), and platinum (Pt) target materials were offered from Jiangxi Changyanke New Materials Co., Ltd. Antioxidants (Irganox 1010 and Irgafos 168) were obtained from Jiangxi Sanfeng Fine Chemical Co., Ltd. 3-(Trimethoxysilyl) propyl methacrylate (Silane coupling agent, KH570), dopamine hydrochloride (98%), trimethylaminomethane hydrochloride (Tris-HCl) (pH = 8.8), and ethanol (98%) were purchased from Macklin Co. Ltd (China). Polyvinyl alcohol (PVA) powder with a polymerization degree of ~ 1700 and an alcoholysis degree of ~ 99%, was purchased from Aladdin (China). Glutaraldehyde (GA, 50% aqueous solution) and hydrochloric acid (HCl, 37%), were purchased from Aladdin (China). The water used in this experiment was deionized water. The rest materials, if not mentioned specifically, were supplied by Aladdin, China.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSynthesis of UPE film scaffold.\u003c/b\u003e As reported in our previously published work\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e, in brief, melted petroleum was used as the solvent of UPE resin to prepare a 3 wt% UPE suspension. Subsequently, 0.1 wt% antioxidants (AO-1010 and AO-168) were added to the suspension, followed by stirring at 80°C for 5 min to ensure uniform mixing. The resulting suspension was transferred to a torque rheometer (XSS‑300, Shanghai Kechuang, China) and processed at 190°C under 25 rpm for 25 min to obtain a UPE/petroleum composite. The composite was then hot-pressed (LP‑S‑30, Labtech Engineering, China) at 190°C for 30 min to form standard-sized sheets, which were subjected to biaxial stretching (KARO IV, Brückner, Germany) at draw ratios around 180 times. The thickness of UPE membranes could be regulated by the thickness of the sheets. The thickness of the film used in this experiment was controlled to around 1.0-1.2 µm. Finally, the membranes underwent Soxhlet extraction with n‑hexane at 100°C for 6 h to remove residual petroleum. After vacuum drying them at 60 ℃ for 2 h, the raw UPE porous scaffold film could be obtained.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSynthesis of surface treated UPE.\u003c/b\u003e For gold-coated UPE film (Au-UPE), UPE films were sputtered by Au using the sputter coater (Quorum Technologies Q300TD, UK) with different sputtering times on two sides (current ≤ 10 mA). For silver-coated UPE film (Ag-UPE) and platinum-coated UPE film(Pt-UPE), UPE films were sputtered by Ag or Pt for the same time of 20 s (current ≤ 10 mA)for comparison analysis. For silane-treated UPE (silane-UPE), 19.8 g ethanol and 0.2 g 3-(Trimethoxysilyl) propyl methacrylate were mixed and stirring at 50°C for 60 min to obtain the silane coupling agent solution, followed by immersing and pulling out the UPE film in silane solution for 3 times. Silane-UPE was finally obtained after drying the coated film in a 50°C vacuum oven for 8 h. For polydopamine-treated UPE (PDA-UPE), dopamine hydrochloride was dissolved in Tris-HCl buffer solution in a concentration of 0.1 mol/ml by stirred for 6 h at room temperature to obtain the dopamine solution, followed by immersing and pulling out the UPE film in silane solution for 3 times. PDA-UPE was finally obtained after drying the coated film in a 60°C vacuum oven for 6 h.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSynthesis of H\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e\u003cb\u003eO/PVA gel.\u003c/b\u003e PVA solution was firstly prepared by stirring determined amounts of weights of PVA powder in deionized water at 95°C for 4 h. After the solution became cooled, dropwise add the crosslinking agent GA (2.0 mol% of the hydroxyl groups of PVA) and crosslinking catalyst HCl (0.2 mol% of the hydroxyl groups of PVA) in the above dispersion.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSynthesis of LM/Au-UPE gel film.\u003c/b\u003e The synthetic process of gold-treated ultra-high molecular weight polyethylene liquid metal gel film (LM/Au-UPE) was divided into two steps. Firstly, different weights of LM droplets were added on two sides of Au-UPE films, followed by the brush coating on the surface to make the LM evenly distributed in LM/Au-UPE. Then, the coated LM/Au-UPE were pressed to fabricate immersed LM/Au-UPE gel films (thickness ≥ 1.5 µm) by putting them in between two polypropylene films, at room temperature and pressure around 30 MPa for 5 min. The weight ratio of Au-UPE and LM is finally revised by the weight change between pristine Au-UPE and final LM/Au-UPE product.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCharacterization of Au-UPE and LM/Au-UPE.\u003c/b\u003e Changes in element valence states on the surface of Au-UPE, LM/UPE, and LM/Au-UPE were obtained using X-ray photoelectron spectroscopy (K-Alpha, Thermo Scientific, USA). The crystal structures of LM, Au-UPE, and LM/Au-UPE were obtained by X-ray diffraction (Ultima IV, Rigaku, Japan) with Cu Kα radiation (wavelength λ = 1.5418Å). Scanning electron microscopy (SEM) images were obtained by Nova NanoSEM450 (Thermo Fisher Scientific, FEI, USA). It is equipped with an energy dispersive spectrometer (EDS) was used to characterize the elemental distribution and morphologies. The height distribution images of UPE, and Au-UPE were respectively detected by the contact mode of probe force microscope (PFM) (Bruker Dimension ICON, USA). The viscoelastic behavior of gels was test with a rotational rheometer (DHR-1, TA, USA). The diameter of the sample plate was 40 mm. Contact angles of film samples were measured by drop shape analyzer (KRUSS DSA30E, Germany).\u003c/p\u003e\u003cp\u003e\u003cb\u003eMechanical performances and thermal performances measurement.\u003c/b\u003e The mechanical properties of the sample films were evaluated using a universal testing machine (EM6.501-W, Shenzhen Tesmart, China) equipped with a 10 N load cell, at a speed of 10 mm min⁻¹ and sample size of 15 × 7 mm. The Longwin 9389 steady-state heat-flow method, in accordance with ASTM D5470 standard, was used to analyze the thermal resistance with sample surface area of 25.4 × 25.4 mm\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e at standard pressure of 40 psi and hot plate temperature of 80 ℃. The thickness obtained by directly pressurizing without a spacer is considered the bond line thickness (BLT), and the relevant thermal resistance represents the \u003cem\u003eR\u003c/em\u003e\u003csub\u003eeff\u003c/sub\u003e of materials. All infrared images were obtained using an infrared camera (HIKMICRO-P20maxV2) to record the temperature distribution of the samples. The burn-in liquid circulation test was conducted using a high-power server equipped with an Intel XEON E5 processor (thermal design power ≥ 130 W, ≥ 20 cores) as the computer heat source, with GALDEN HT200 fluorinated coolant (Solvay, Italy) used as the cooling fluid, equipped with home-made circulation systems, including liquid box, liquid pipes, and liquid pumps.\u003c/p\u003e\u003cp\u003e\u003cb\u003eFinite Element Analysis Methods.\u003c/b\u003e The biaxial tension and uniaxial compression process of LM/Au-UPE film was studied by the finite element analysis (FEA). They were studied by observing the stress distribution evaluations at the cross-section of the films during stretching and pressing. Considering the size of Au particles is too small (\u0026lt; 10 nm) as compared to UPE fiber (~ 100 nm) and LM matrix (~ 100 nm), the films were described as two phase composites (UPE fiber network and LM matrix) to simplify the model. The size and morphology of LM and UPE fiber were set according to Supplementary Fig.\u0026nbsp;8b. Liner elastic material model was used to calculate the relationship among the stress, the strain and material parameters (modulus, Poisson’s ratio, and density) of each phase\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. The films were biaxially stretched along the horizontal direction with a constant stretching force of 2 N at two sides (left and right) of the film. The films were pressed from the top of sample with a constant force of 2 N and fixed the bottom of sample. The calculating unit size was set as normal.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCalculation of the Surface Energy.\u003c/b\u003e The surface free energy (\u003cem\u003eγ\u003c/em\u003e\u003csub\u003es\u003c/sub\u003e) of the solid samples was determined using the Owens method, based on the contact angles measured for two probe liquids: deionized water (polar component) and diiodomethane (dispersion component). According to this approach, the total surface free energy of a solid is expressed as the sum of its dispersion (\u003cem\u003eγ\u003c/em\u003e\u003csub\u003esd\u003c/sub\u003e) and polar (\u003cem\u003eγ\u003c/em\u003e\u003csub\u003esp\u003c/sub\u003e) components:\u003c/p\u003e\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:{\\gamma\\:}_{s}=\\:{\\gamma\\:}_{sd}+\\:{\\gamma\\:}_{sp}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003cp\u003eThe Owens equation relates the contact angle (θ) of a liquid on the solid surface to these energy components:\u003c/p\u003e\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:{\\gamma\\:}_{l}\\left(1+cos\\theta\\:\\right)=\\:2\\sqrt{{\\gamma\\:}_{sd}{\\gamma\\:}_{ld}}{+\\sqrt{{\\gamma\\:}_{sp}{\\gamma\\:}_{lp}}}_{\\:}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003cp\u003ewhere \u003cem\u003eγ\u003c/em\u003e\u003csub\u003el\u003c/sub\u003e is the total surface tension of the liquid, \u003cem\u003eγ\u003c/em\u003e\u003csub\u003eld\u003c/sub\u003e and \u003cem\u003eγ\u003c/em\u003e\u003csub\u003elp\u003c/sub\u003e are the dispersion and polar components of the liquid’s surface tension, respectively. In this study, water (\u003cem\u003eγ\u003c/em\u003e\u003csub\u003el\u003c/sub\u003e = 72.8 mN m⁻¹; \u003cem\u003eγ\u003c/em\u003e\u003csub\u003eld\u003c/sub\u003e = 21.8 mN m⁻¹; \u003cem\u003eγ\u003c/em\u003e\u003csub\u003elp\u003c/sub\u003e = 51.0 mN·m⁻¹) and diiodomethane (\u003cem\u003eγ\u003c/em\u003e\u003csub\u003el\u003c/sub\u003e = 50.8 mN·m⁻¹; \u003cem\u003eγ\u003c/em\u003e\u003csub\u003eld\u003c/sub\u003e = 50.8 mN·m⁻¹; \u003cem\u003eγ\u003c/em\u003e\u003csub\u003elp\u003c/sub\u003e = 0 mN m⁻¹) were used as probe liquids. By substituting the measured contact angles of both liquids into the above equation, \u003cem\u003eγ\u003c/em\u003e\u003csub\u003esd\u003c/sub\u003e was first obtained from diiodomethane data, and subsequently \u003cem\u003eγ\u003c/em\u003e\u003csub\u003esp\u003c/sub\u003e was calculated using the water data. The sum of \u003cem\u003eγ\u003c/em\u003e\u003csub\u003esd\u003c/sub\u003e and \u003cem\u003eγ\u003c/em\u003e\u003csub\u003esp\u003c/sub\u003e yielded the total surface free energy of the solid. The surface energies were automatically calculated via the software in drop shape analyzer (KRUSS DSA30E, Germany) according to aforementioned formula.\u003c/p\u003e\u003cp\u003e\u003cb\u003eReporting summary.\u003c/b\u003e Further information on research design is available in the Nature Research Reporting Summary linked to this article.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eCompeting interests\u003c/h2\u003e\u003cp\u003eThe authors declare no competing financial interests.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003ch2\u003eReprints and permission information\u003c/h2\u003e\u003cp\u003e is available online at \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://npg.nature.com/reprintsandpermissions/\u003c/span\u003e\u003cspan address=\"http://npg.nature.com/reprintsandpermissions/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor contributions\u003c/h2\u003e\u003cp\u003eQ. Fu conceived the idea. H. Zhou, X. Chen, and Z. Wang fabricated the materials and measured the material performance. Z. Xie, H. Zhou and Q. Fu analyzed the data. Z. Xie and H. Zhou organized the experimental data and wrote the draft manuscript. Q. Fu revised the manuscript. Q. Fu supervised the overall conception. R. Li, K. Wu, Z. Dou, and W. Lin contributed to the discussion on the results and improved the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e\u003cp\u003eZ. Xie and H. Zhou contributed equally to this work. Q. Fu acknowledge the support by the National Natural Science Foundation of China (Grant No. 52233002 and 22475139) and National Key Research and Development Project of China (Grant No. 2022YFB3806900).\u003c/p\u003e\u003ch2\u003eData availability.\u003c/h2\u003e\u003cp\u003eAll data supporting the findings of this study are included within the paper and its Supplementary Information file. Source data are provided with this paper. Any other relevant data are available from the corresponding authors upon request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eJi H et al (2025) Liquid\u0026ndash;liquid interfacial tension stabilized Li-metal batteries. Nature\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eShen Q et al (2023) Liquid metal-based soft, hermetic, and wireless-communicable seals for stretchable systems. Science 379:488\u0026ndash;493\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWu K et al (2025) Mechanochemistry-mediated colloidal liquid metals for electronic device cooling at kilowatt levels. Nat Nanotechnol 20:104\u0026ndash;111\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePark JJ, Ko SH (2025) Nanoscale gradient interface for efficient heat transfer. 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Carbon 154:503\u0026ndash;509\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"thermal interface materials, liquid metal gel, polymer composites, strengthen, thermal conductive composites","lastPublishedDoi":"10.21203/rs.3.rs-7376124/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7376124/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eLiquid metal-based thermal interface materials offer exceptional thermal conductivity and conformability, yet their low strength and stabilities remain huge challenges, which largely limits their applications under working conditions of dynamic loading. Here, we utilize an ultrathin nanofiber polymer film as a structural scaffold, which features a robust network essential for effectively confining liquid metal, resulting in unique interpenetrating metal-gel. Surface modification of polymer film with sputtered metals enhances compatibility, enabling uniform infiltration and stabilization of liquid metal. The obtained metal-gels exhibit a remarkable tensile strength of 117 MPa, the highest reported for thermal interface materials, while maintaining good flexibility. They can be fabricated as ultrathin films (\u0026le;\u0026thinsp;2 \u0026micro;m), delivering an ultralow bond line thickness and interfacial thermal resistance (7.7 mm\u0026sup2;\u0026middot;K\u0026middot;W⁻\u0026sup1;). With impressive stability against pressure, folding, solvent exposure, and cooling cycling, this work overcomes key reliability issues of liquid metal, offering promise for advanced cooling applications.\u003c/p\u003e","manuscriptTitle":"Advanced thermal interface materials based on ultra-thin and ultra-strong metal-gel","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-01 10:12:29","doi":"10.21203/rs.3.rs-7376124/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4f973b8c-ec3a-4351-b66f-7ab0275c568d","owner":[],"postedDate":"September 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":53919917,"name":"Physical sciences/Materials science/Structural materials/Composites"},{"id":53919918,"name":"Physical sciences/Materials science/Soft materials/Gels and hydrogels"}],"tags":[],"updatedAt":"2025-10-29T15:41:44+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-01 10:12:29","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7376124","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7376124","identity":"rs-7376124","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}