Strain gauges serve as fundamental sensors for structural deformation monitoring, yet their conventional counterparts exhibit pronounced temperature effect, compromising measurement accuracy and stability under thermal fluctuations. Based on micro-electromechanical systems (MEMS) fabrication technology, this study systematically investigates the evolution of micro-morphology and surface roughness of sputtered thin films. The core focus lies in elucidating the internal electron scattering mechanisms and their intrinsic correlation with the Temperature Coefficient of Resistance (TCR). Specifically, we analyze how static scattering interacts with and compensates for the temperature-dependent lattice vibration scattering during the heating process. Guided by these physical insights, a composite thin-film strain gauge was fabricated via co-sputtering to validate the proposed scattering regulation strategy. The device demonstrates a near-zero TCR of -2.5 ppm/degrees C, a gauge factor of 1.9, and a highly linear response to strain (R2 approximate to 99.8 %) alongside remarkable cyclic stability. This work provides a fundamental physical insight into scattering engineering for designing precise strain sensors in thermally dynamic environments.

Capillary-driven microfluidics is an emerging pump-free microfluidic technology that exploits surface tension, contact angle, wettability, and capillary pressure at liquid-solid interfaces to achieve spontaneous fluid transport. This technology shows broad application prospects in point-of-care testing, biosensing, chemical analysis, environmental monitoring, and on-chip reaction systems owing to its simple architecture, external-power-free operation, low reagent consumption, portability, and compatibility with disposable analytical chips. In order to harness the capillary-driven microfluidics' power-free operation potentials, it is critical to achieve comprehensive control of stationary capillary components as well as passive valve functions. Therefore, a full package of technologies including material selection, microfluidic design, surface modification, and microfabrication strategy needs to be tailored toward the successful implementation of capillary-driven microfluidics. This review focuses on functional units, interfacial physics, passive flow-control structures, material selection, and fabrication strategies of a capillary-driven microfluidic system, aiming at a comprehensive overview of recent advances in this new field of microfluidics. The core of the review assesses representative components, from passive flow-control elements to programmable capillaric systems, highlighting their operating mechanisms, design principles, and integration strategies. We further summarize recent applications in biomedical diagnostics, chemical and environmental analysis, food safety monitoring, and autonomous lab-on-a-chip platforms. Finally, current challenges and future opportunities toward programmable, intelligent, multimaterial, and portable capillary microfluidic systems are discussed.

During the last three decades, the demand for means of highly efficient heat dissipation has increased dramatically with the development of electronic devices towards slimness, high power density, and miniaturization. Microchannel heat sinks (MCHS), with their highly efficient, thermal load-bearing capacity, have emerged as a reliable solution for enhancing heat dissipation. Recent research on MCHS has focused on optimizing their microchannel structures, enhancing their internal flow dynamics, improving their surface treatments, and developing new materials to enhance their performance. Herein, we combine composite electrodeposition and UV-LIGA techniques to fabricate a microchannel heat transfer in copper matrix composites reinforced with SiC whiskers. We established a simulation model to conduct experimental and numerical studies on the heat transfer characteristics of the fabricated microchannel. Notably, the calculated heat dissipation efficiency (1162 W/cm2) closely matched the experimental data of the fabricated sample (approximately 1105 W/cm2), confirming the model’s validity in simulating the heat transfer process. In addition, simulations of parameters, such as reinforcement volume fraction, heat sink height, and turbulator columns, demonstrated that the thermal conductivity of the composite material significantly influences the heat dissipation efficiency of the heat sink. The originality of this work lies then in its Silicon carbide whisker reinforced copper based composite material. It provides a promising approach to advancing chip cooling technologies and a scalable solution for improving heat dissipation efficiency.

A flexible pressure sensor based on sequential contact sensing mechanism and distributed micro-structure (SCDS) for concurrent optimization of sensitivity, linearity and measurement range is developed. On the basis of a multiscale math-physical model of the sequential contact sensing mechanism, the optimal sensitivity and linearity enhancement methods are present. The mechanics properties are calculated on analysis of threshold force (F-t) and reactive force (F-r), and the gravity deformation, to optimize the structure parameters. High sensitivity (0.66-7.47/kPa) and wide measurement (similar to 230 kPa) are realized when the density of pixels is 1183 /cm(2). Through the optimization of micro pixels distribution gradient, the SCDS pressure sensor, with pixels density of 609 /cm(2), achieves high-linearity (R-2 = 0.992) and high sensitivity (2.24 /kPa) detection across a wide measurement range (similar to 350 kPa). And the SCDS pressure is also realized rapid response, corresponding to 6 ms for response time and 8 ms for recovery time. Finally, as operating levers, the SCDS pressure sensors are integrated into a customized mechanical arm system to show applications for cross-range measurement capability of mechanical control field.

This paper reports a sandwich-structured flexible metal-based thermal interface material (FMTIM), which is composed of the thin Cu layers (top/bottom layers) and Cu microstructure array embedded in polydimethylsiloxane (PDMS) (compressible middle layer). The research results show that the FMTIM simultaneously achieves the metallevel vertical thermal conductivity ($k_{\perp}=194.66 \mathrm{W} \cdot \mathrm{m}^{-1} \cdot \mathrm{K}^{-} { }^{1}$) and silicone-level elastic recovery rate (36.6 %). This work breaks the traditional usage of TIMs by directly fabricating the FMTIM on the heat source and further processing the top Cu layer into an integrated Cu lid to achieve zero contact thermal resistance. Moreover, the FMTIM demonstrates excellent heat transfer performance in testing, even without additional pressure.

Continuous and accurate blood pressure monitoring is vital for the diagnosis and management of life-threatening cardiovascular diseases. Conventional fluid-filled catheter systems are fundamentally constrained by distortion, infection risks, and limited portability. In parallel, Micro-Electro-Mechanical System (MEMS) sensors assembled to catheters face miniaturization bottlenecks and packaging complexity. Here, we present a flexible on-catheter interventional pressure sensor (CIPS), leveraging suspended-graphene arrays for pressure sensing and dual polymer encapsulation layers for hermetic and waterproof encapsulation. The highly integrated CIPS with compact architecture is enabled by cylindrical projection lithography (CPL)-based 3D in situ MEMS fabrication process. By introducing interdigital electrodes (IDEs) in sensitive areas and optimizing structural parameters, CIPS delivers an ultrafast response (<0.36 s), exceptional sensitivity (3.5 × 10⁻⁶·mmHg⁻¹), and a broad detection range (6-380 mmHg), outperforming state-of-the-art suspended-graphene pressure sensors. The dual-layer polymer encapsulation strategy ensures the hermetic and waterproof integrity of CIPS. Crucially, CIPS enables real-time monitoring of arterial pressure in the rat abdominal aorta, marking the first demonstration of suspended graphene in animal-level bioelectronic sensing. This work has also underscored the translational potential for CPL-based 3D in situ MEMS fabrication strategy.

Thin-film evaporation on microstructured surfaces is an efficient phase transition process, but its performance is limited by the thin-film evaporation area and capillary-driven liquid supply. This study enhances liquid transport stability by designing human-hair-cuticle-like sidewall textures. The 3D-printed microtexture provides functional capillary microstructures that guide liquid ascent, inhibit film retraction, and maintain continuous film formation. Based on this stability-enhanced microtexture, we introduce an asymmetric structure that enables directional liquid replenishment and expands the effective thin-film evaporation area. Quantitative analysis shows that the effective thin-film utilization efficiency of the asymmetric design is 2.68 times higher than that of the symmetric structure. This combination of 3D-printing-induced microtexture and asymmetric design establishes a strategy for enhancing thin-film evaporation, highlighting the importance of structural modulation in capillary-driven microfluidic and thermal processes.

In this work, through polymer via (TPV) with a pair of variable wings is proposed to reduce the return loss and insertion loss by diminishing the transmission impedance and decrease crosstalk through cutting off the signal coupling paths. Interposer with the novel TPV also has high thermal conductivity and Young's modulus due to the embedded copper-wings. Two-port and four-port equivalent circuit model based on resistance-inductance-capacitance-conductance parameters are developed to investigate the physical mechanism of wings-embedded TPV (WTPV). The equivalent circuit model can more specifically demonstrate the influence of structural parameters and substrate material characteristics of WTPV on signal transmission performance. The reliability of this equivalent circuit model was validated against simulations, showing the average errors of scattering parameters as follows, 0.17 dB for S11, 0.0032 dB for S21, 0.92 dB for S31 and 0.94 dB for S41. Two theoretical models are established to analyze the thermal and mechanical properties, with average calculation errors of 3.9 % and 3.4 % for thermal conductivity and Young's modulus, respectively. A Bayesian optimized deep neural network prediction model is constructed based on the simulation data of electromagnetism and thermodynamics. It is used to find out the optimal structural parameters. The electromagnetism, thermal and mechanical properties of interposer prototype with optimized WTPV structure are tested. The proposed WTPV structure decreases S11 by down to −27.67 dB @ 14.59 GHz and increases S21 by up to −0.36 dB @ 15.07 GHz. The interposer prototype with optimized WTPV structure has high thermal conductivity (9.07 W/(m*K)) and Young's modulus (6.43 GPa). These measured results demonstrate that this new WTPV structure is helpful to solve the problem of signal integrity and serious heat generation in millimeter-wave integrated circuits.

In this paper, we propose a novel design model for an inertial switch that utilizes metal droplets as the sensing element. The overall device model comprises three components: the substrate layer, the functional structure layer, and the cover layer, along with the liquid metal. The metal droplets within the liquid storage tank are drawn towards the fixed electrode due to inertial forces. When the acceleration exceeds a predetermined threshold, the metal droplet covers the fixed electrode, closing the switch and allowing current to flow through the external circuit. Conversely, when the acceleration load is removed, the metal droplet retracts to the liquid storage tank, disconnecting the fixed electrode. This design is characterized by its simplicity, low manufacturing cost, and stable dynamic response. To evaluate the threshold acceleration of the inertial switch, we developed a threshold evaluation equation through theoretical analysis and successfully fabricated an experimental prototype. Test results indicate that the threshold acceleration of the fabricated inertial switch is 0.76g, with a response time of 21 ms and a contact time of 10 ms. The overload test indicates that the device has excellent overload impact resistance and stable dynamic contact. Compared to traditional mechanical contact-type inertial switches, this research not only presents a new scheme for low-threshold inertial switches with a simple structure and low manufacturing cost, but also introduces the concept of deformable liquid metal electrodes into the field of inertial sensing for the first time, opening up a new technical path for applications such as consumer electronics and the Internet of Things that require low power consumption for triggering.

Passive two-phase cooling systems rely on capillary wicking to deliver liquid to heated regions. However, in miniaturized devices, limited liquid-delivery capability and the inherently isotropic nature of capillary pumping restrict directional mass transfer and cooling performance. To achieve efficient liquid transport in confined spaces, we propose a microchannel-embedded wettability-patterned surface (MEWS) that couples two driving forces in complementary stages. The millimeter-scale wettability pattern generates an unbalanced Young's force that provides directionality and high initial acceleration. As the droplet advances, this force progressively decays, whereas the embedded nanostructure-covered microchannels supply a persistent capillary force that compensates for this decay and sustains long-range transport. Consequently, a 5 μL droplet achieves an average velocity of 56.2 mm·s−1 over 35 mm, corresponding to a diameter-normalized transport distance of ∼16.5 and demonstrating rapid long-range directional transport. In droplet-jet cooling experiments, the MEWS achieves a local temperature reduction 2.5 times that of the control surface. The enhanced liquid delivery is projected to increase the maximum heat transfer limit of an ultrathin vapor chamber model by approximately 111%. This self-propelled and stage-coupled liquid transport strategy provides a practical pathway for advanced thermal management and other applications requiring high-efficiency directional liquid delivery.

Achieving low-cost patterning of 10 nm-scale nanostructures remains a critical challenge in nanofabrication. Conventional electron beam lithography has a prolonged processing time and limited throughput due to its intrinsic small-area processing nature. Extreme ultraviolet (EUV) lithography faces prohibitive costs in equipment and materials. While industrial nanoimprinting offers a lower-cost, high-throughput alternative, its resolution is fundamentally constrained by the template's minimum feature size. Herein, we present a new nanofabrication process that exploits the redeposition effect in ion milling to fabricate controllable 10 nm-scale nanogaps. This approach enabled the preparation of gratings and nanorings array integrated with noble metal nanogaps for applications in surface-enhanced Raman spectroscopy (SERS). Furthermore, gratings and nanopillar arrays with sidewalls coated by a metal mask were dry-etched to form a self-aligned stacked nanomorphology on a silicon substrate without optical alignment, inheriting the metal mask's minimum feature size. The resulting high-quality templates subsequently facilitated high-fidelity replication of diminutive structures via nanoimprint lithography (NIL). This scalable strategy holds significant potential as a feasible route for manufacturing applications in nanophononics, biosensing, quantum devices, integrated circuits (ICs), and beyond.

Strain sensors are critical for dynamic strain monitoring in fields such as bridge safety assessment, but their accuracy in variable-temperature environments is hindered by temperature interference, a key issue that limits their reliability despite demands for high sensitivity and strong antitemperature capability. Here, we develop a resistive strain sensor based on a homogeneous composite thin-film, fabricated using microelectromechanical system (MEMS) technology. The design leverages defect-free, dense, and low-roughness microstructures, as well as the balanced electron scattering mechanisms in materials with positive/negative temperature coefficient of resistance (TCR) to clarify the microscopic nature of near-zero TCR. The resulting strain sensor exhibits a near-zero TCR of -3.5ppm/degrees C, strong antitemperature interference, and high long-term stability with a resistance drift rate (DR) of only 0.00019/h. It also shows good linearity and repeatability in strain response. Simulated bridge vibration tests confirm its rapid, consistent response to vibrations of varying amplitudes and ability to detect low-frequency microstrains, providing an effective solution for accurate long-term strain monitoring in variable-temperature scenarios.

In situ monitoring of the temperature distribution on a turbine blade can enhance the real-time evaluation of air-cooling efficacy and facilitate the optimization of cooling channel designs. Microfabricated thin-film thermocouples (TFTCs) provide next-generation in situ temperature monitoring solutions for turbine designers, delivering precise temperature measurement and quick response time. However, significant challenges persist in the conformal and monolithic integration of thermocouple arrays, especially on surfaces with complex geometries and varying curvatures, like those on actual turbine blades. This study has introduced a new method for the conformal integration of thin-film thermocouple arrays on continuously variable curvatures in a single microfabrication process, while maintaining the aerodynamic performance of the turbine blades. By using 3D-printed shadow masks during sputtering processes, this method tackles the difficulties of conformal metal alloy thin-film formation caused by twisted curvatures in conventional microfabrication. E-type TFTCs are conformally microfabricated using a 3D shadow sputtering process on turbine blade test structure surfaces, forming an on-blade in situ temperature characterization network. These microfabricated thin-film thermocouples act as a toolbox for characterizing the temperature distribution on air-cooled turbine blade surfaces. Furthermore, the proposed method presents a strategy for conformal microfabrication and integration of thin-film sensors on multi-scale complex industrial surfaces.

This paper reports a high-sensitivity nanoring array biosensing platform incorporating both roughened surfaces and nanogaps. Nanogaps amplify the local electric field by over 100 -fold, while the rough sidewalls of the nanorings increase the effective capture area for target molecules, rendering the platform highly suitable for fluorescent detection of low-concentration biomolecules. We successfully demonstrated reliable nanofabrication of the designed gold nanoring arrays via a combination of metal co-deposition, ion milling, and dealloying processes. Spectroscopic characterization revealed a strong correlation between resonance wavelength and nanoscale gap-size, facilitating optimal alignment with target wavelengths for biological sensing applications. Furthermore, we validated that this sensitive plasmonbased biosensor enables fluorescent detection of lowconcentration soybean stay-green associated geminivirus (SoSGV), achieving two orders of magnitude enhancement in fluorescence signal intensity.

In microscale capillary-driven systems, droplet motion often impeded by the weakening of interfacial forces, leading to quasi-static stagnation and reduced heat transfer efficiency. Here, we propose a hierarchical dualgradient surface (HDGS) which integrates millimeter-scale asymmetric wettability pattern with frostwork-like micro/nanostructures of progressively increasing density. The dual gradients synergistically create a spatial variation in surface energy, producing a net driving force that enables continuous and directional droplet motion. Meanwhile, the frostwork-like micro-nanostructures provides sufficient capillary driving force due to the high specific surface area. On HDGS, a droplet of 6 mu L travels directionally at an average velocity of 167.22 mm/s over a distance of 15 mm without external energy input. Compare with a bare gradient substrate, the HDGS achieves a twofold improvement in capillary performance, which contributes to a local temperature reduction of 32 degrees C in droplet-jet cooling experiments, significantly surpassing the 18 degrees C drop observed on the bare substrate. As a proof of concept, HDGS is anticipated to demonstrate a 14.6-fold increase in the Coupled Heat Transfer Index and a 155.3% improvement in the heat transfer limit of an ultra-thin vapor chamber model, highlighting its strong potential for advanced thermal management applications.

Real-time monitoring of surface heat flux in high-temperature and temperature-changing environments is gaining significant attention for various promising applications, including aero engines, gas turbines, and nuclear power plants. However, the survivability of most current thin-film heat flux sensors above 1200 degrees C still faces challenges. Here, we designed and fabricated a ceramic thin-film thermopile heat flux sensor on an alumina ceramic substrate by physical vapor deposition (PVD). The ITO-In2O3 was chosen as the sensitive layer, while a multilayered YSZ-Al2O3/Al2O3 ceramic film was used as the protective layer to enhance high-temperature stability. Meanwhile, the microstructure and electrical properties of the sensitive films were investigated under different annealing conditions. The results indicate that the sensitive films have a stable structure and good electrical conductivity. The heat flux sensor reaches a sensitivity of 73.4 mu V/(kW/m2) and can measure heat flux up to 1.06 MW/m2. Interestingly, the sensor has excellent high-temperature survivability, and can withstand temperatures up to 1250 degrees C in the ambient atmosphere. Moreover, the application tests were conducted to simulate engine environments, such as flame combustion, shock resistance. These results also indicate that the fabricated sensor shows great potential for actual working applications.

With the surging demand for dynamic, real-time, and rapid qualitative analysis of chemical components, chip-scale mass spectrometers have attracted widespread attention. Ion traps have become the preferred mass analyzer for chip-scale mass spectrometers due to their excellent analytical performance. However, the miniaturization of ion traps inevitably leads to a reduction in ion storage capacity, which in turn affects their sensitivity and dynamic range. In this study, a Miniature Four-Channel Linear Ion Trap Array (M-FLITA) with hyperbolic electrodes and a 1 mm field radius was established and optimized. Concurrently, unidirectional ion ejection was accomplished by the application of asymmetric RF voltages on M-FLITA. The results demonstrate that, in the stretched structure, the mass resolution is improved to 732, while the unidirectional ion ejection efficiency is maintained at 96%. M-FLITA demonstrates advantages in terms of high ion storage capacity and mass resolution under high ion flux conditions, providing an ideal solution for high-performance micro mass analyzers in chip-scale mass spectrometers.

Palladium-chromium (PdCr) is one of the commonly used sensitive materials for high-temperature strain sensors. However, it is prone to oxidation in high-temperature environments, which affects its stability. Therefore, protective layers are typically employed to mitigate the oxidation of the sensitive layer. This work innovatively proposes an in-situ grown oxide film approach to enhance the stability of PdCr thin-film strain gauges (TFSGs) under high-temperature environments. PdCr thin films were sputter-coated with Cr layers of varying thicknesses (1L, 2L, and 3L) and subsequently oxidized for 3 h, 5 h, and 8 h. Microstructural characterization was conducted to evaluate the protective performance of the oxide layers formed under different conditions. The experimental results indicate that a Cr thickness of 3L, oxidized in an oxygen atmosphere for 5 h, provides optimal protection. Based on this parameter, the PdCr TFSGs were fabricated and tested. The results demonstrate that the sensor achieves a minimum temperature coefficient of resistance (TCR) of 151.78 ppm/degrees C, a drift rate (DR) of 0.0002/h and a gauge factor (GF) of 1.739 at 800 degrees C, outperforming previously reported results in the literature. These findings provide valuable insights for the further development of strain sensors.

High-temperature thin-film strain gauges (HTFSGs) hold significant potential for monitoring extreme environments in fields such as aerospace, nuclear energy, and automotive engineering. With advances in materials science, HTFSGs based on ceramics, metals, and composite materials have progressively achieved high-precision strain measurements in high-temperature environments. In recent years, substantial progress has been made in areas such as material selection, sensor structural optimization, high-temperature oxidation resistance, and testing methodologies, which have enhanced the stability, sensitivity, and durability of HTFSGs under extreme conditions. This article reviews the developmental trajectory of HTFSG research, focusing on the strain mechanisms of sensitive materials and recent advancements in ceramic-metal thin films, ceramic-semiconductor thin films, and metal-based thin films for HTFSGs in terms of structural design, thin-film deposition processes, and material properties. In addition, current challenges and future research directions are discussed to provide valuable insights for future studies.

This paper presents a novel antimony-doped tin dioxide (ATO) thin-film strain gauge (TFSG) designed for strain measurement in ultra-high-temperature environments. Through systematic experimentation, the optimal fabrication conditions were identified as a sputtering atmosphere with an argon-to-oxygen (Ar/O-2) ratio of 40:0, annealing in a nitrogen (N-2) atmosphere, and an annealing temperature of 800 degrees C. Under these conditions, the resistance change rate of the ATO TFSG decreases with increasing temperature. However, between 600 degrees C and 700 degrees C, the resistance change rate temporarily increases before resuming its decline, likely due to phase transitions and oxygen diffusion. Additionally, the ATO TFSG demonstrates exceptional sensitivity and stability, with a gauge factor (GF) of -5.47.