Compared to sensors based on a single sensing principle, dual-mode sensors that combine two sensing mechanisms offer significant advantages in terms of detection range and thresholds. However, the current fabrication process for dual-mode pressure sensors is complex, increasing equipment requirements and costs while limiting their widespread applications. This work formulates a simple strategy for fabricating a fabric-based resistive-capacitive dual-mode pressure sensor system using direct laser writing (DLW). Compared to single-mode resistive and capacitive pressure sensors fabricated using the same DLW method, the dual-mode pressure sensor exhibited a 94.17% reduction in the minimum detection threshold and a 150% increase in the pressure-detection range. In addition to conventional physiological monitoring, the dual-mode sensing system can be integrated into safety helmets to monitor drivers' microexpressions and external forces. By leveraging the inherent advantages of fabric, this system enables the simultaneous integration of cargo packaging and force-monitoring functions. The proposed method effectively simplifies the fabrication process, reduces material consumption, and broadens the application of pressure sensors in road safety and logistics transportation. The simple fabrication of a dual-mode pressure sensor system via DLW offers a pathway to the low-cost, efficient development of high-performance flexible sensors.

Micro-Electro-Mechanical Systems (MEMS) are extensively utilized in many different applications because of its compact design, low power consumption and greater sensitivity. Compared to piezoresistive alternatives, a MEMS- based Touch Mode Capacitive Pressure Sensor (TMCPS) is designed and simulated to achieve better sensitivity, stability and linearity. This work presents a Double Touch Mode MEMS-based Capacitive Pressure Sensor (DTMCPS) with a flexible circular diaphragm integrated into an M-shaped silicon substrate. By increasing the diaphragm-substrate contact area, the proposed M-shaped structural arrangement improves sensor linearity and sensitivity. The diaphragms deflection characteristics are modeled using small deflection theory to minimize nonlinearity. A comprehensive analysis of the sensors capacitive behavior is carried out. The analytical formulations for capacitance, capacitive sensitivity and mechanical sensitivity are derived and generated using MATLAB based simulations. The diaphragm deformation is further assessed through structural analysis using COMSOL Multiphysics. The goal is to improve the performance of the conventional DTMCPS by integrating a silicon (Si) circular diaphragm with an M-shaped silicon substrate. The position of the touch point is crucial in defining the overall sensitivity, hence the notch size have a considerable impact on the sensors operational properties. Small deflection theory is used to model the diaphragm behavior in order to minimize nonlinear effects. These results show the potential use in cutting edge medical, automotive, aerospace and industrial sensing applications by demonstrating the higher sensitivity, accuracy and durability of the preferred TMCPS design.

Simulation study on thermal drift effects of high-temperature MEMS SiC capacitive pressure sensors

Three-dimensional (3D) flexible transparent electrodes (FTEs) with high conductivity and mechanical robustness are essential for high-performance wearable optoelectronic devices. Silver nanowires (AgNWs) are attractive candidates for the FTEs due to their high transparency, flexibility, and conductivity; however, poly(vinylpyrrolidone) (PVP) coatings on AgNWs and poor contact at wire junctions increase resistance. Additionally, electrodes fabricated using conventional AgNW deposition methods exhibit poor adhesion between the AgNW layer and polymer surface, resulting in delamination and degraded electrical performance under repeated stimuli. Herein, we propose a transfer method that simultaneously welds and embeds AgNWs into the surface of thermally stable thermoset polymer networks. Thermal annealing (200°C, 1min) welds AgNW junctions while curing the prepolymer, forming mechanical interlocking that anchors AgNWs in the polymer surface. This enables residue-free transfer and fabrication of highly conductive, mechanically robust FTEs while maintaining optical transparency. The FTEs exhibited stable performance after 1000 bending cycles (radius of curvature = 3.5mm) and 5000 pressure cycles at 70kPa. Capacitive pressure sensors incorporating these FTEs demonstrated reliable performance, while enhanced conductivity enabled efficient Joule heating, reaching 42.9°C at 3.7V, demonstrating suitability for wearable heaters. These confirm the proposed method as a reliable approach for high-performance 3D FTEs.

High- performance flexible capacitive pressure sensors with a wrinkled ionic gel dielectric

Bioinspired ionic capacitive pressure sensor based on multilevel rigid-soft coupled architecture for foot-type classification and human-machine interaction

Analysis of fringing effects in MEMS capacitive pressure sensors with vertically offset guard rings

Willow fibers, harvested from willow genus trees of the Salicaceae family, possess characteristics that make them suitable for the production of flexible capacitive sensors. The aim of this study is to examine the physical properties of willow fiber in comparison with other prominent natural fibers including cotton, poplar, wool and kapok fibers. Due to their finer diameter and shorter length (<1 cm) compared to these commonly used natural fibers, willow fibers are often considered as ecological waste, limiting their use in textiles. To promote sustainable utilization of this waste, this study explores their potential in producing flexible capacitive sensors. Herein, round-shaped and porous nonwoven pads are fabricated by spraying a spandex/DMAc solution onto cleaned willow fibers. To impart electrical conductivity, a dip-coating method is employed, resulting in the formation of silver nanowire (AgNW) networks on the willow fibers. Electrochemical measurements demonstrate that the obtained willow fiber pads have low sheet resistance (1.09–2.42 Ω/sq), high sensitivity (0.255 kPa−1 in the low pressure range) and excellent wash durability, maintaining performance after five washing cycles. The pads also retained conductivity after 10,000 bending cycles. These findings suggest willow fiber-based capacitive sensors as promising candidates for wearable electronics due to their high sensitivity, rapid response and durability.

Skin-inspired ion electronic capacitive flexible pressure sensor with gradient modulus and microstructure for voice recognition

Ionogels combine the mechanical softness of polymers with the ionic conductivity and nonvolatility of ionic liquids, offering a versatile platform for wearable electronics and sensing applications. In particular, their high deformability and ionic responsiveness make them attractive dielectric materials for capacitive pressure sensors. However, conventional ionogels often exhibit dielectric saturation and nonlinear responses at elevated pressures, limiting their usable operating range. Here, we report ion-pair-tuned ionogels that balance ionic mobility and polarizability to mitigate dielectric saturation and broaden the linear sensing range up to the megapascal level while maintaining high sensitivity. To validate broad-range functionality-from subtle physiological pressures to large mechanical loads-we integrate the ionogels into intraocular pressure sensors and prosthetic interface monitors, representing low- and high-pressure regimes. These demonstrations establish ion-pair tuning as an effective strategy for achieving broad linear sensing performance in wearable pressure sensors.

Abstract The advancement of next-generation flexible electronics relies on the development of high-performance components that are lightweight, conformable, and compatible with scalable additive manufacturing processes. Here, we report a fully 3D-printed capacitive pressure sensor featuring a novel dielectric composite ink composed of nickel nanowires (NiNWs), hexagonal boron nitride (h-BN), and polyethylene oxide (PEO). This eco-friendly, water-based ink was engineered for direct ink writing (DIW), enabling the fabrication of printed planar capacitive sensors, with dimensions of 1.5 cm x 0.6 cm, comprised of interdigitated silver electrodes topped with composite dielectric layer on flexible, polyimide substrates. The composite dielectric ink included: h-BN, a 2-D nanomaterial which served as a charge storing nanomaterial with low dielectric loss, and a PEO binder, which stabilized the nanosheets and provided to the necessary viscoelastic properties for print fidelity and structural stability. Adding a small concentration of NiNWs to the hBN/PEO composite enhanced the dielectric properties due to an increase in interfacial polarization. The printed capacitive sensors incorporating an hBN/PEO/NiNW dielectric layer exhibited reliable pressure-responsive behavior across a wide sensing range (0–466 kPa), with sensitivities of 0.024 and 0.008 kPa⁻¹ in low - medium, and high-pressure regimes, respectively; these sensitivities were 7 – 8 times higher than for similar devices with hBN/PEO dielectric layers without NiNWs. Sensors demonstrated fast response times, low hysteresis, mechanical durability over cyclic loading, and high signal fidelity under dynamic pressure. Furthermore, the sensors enabled real-time monitoring of physiological signals including pulse, voice, and motion, underscoring their applicability in wearable health diagnostics and soft human–machine interfaces.

Flexible and wearable electronics require soft sensing materials that balance mechanical compliance, stable signal transduction, and durability for human-machine interfaces (HMIs). To address the limitations of single-filler systems, we propose a poly(vinyl alcohol) (PVA)/aramid nanofiber (ANF)/MXene organogel (PAM) as a multifunctional soft platform. This design integrates a PVA physically crosslinked network with ANF for mechanical reinforcement and MXene for electrical functionality. The optimized PAM composite exhibits outstanding mechanical properties, including a fracture stress of 2931 kPa, a fracture strain of 676%, and a fracture toughness of 9.04 MJ m-3. Importantly, PAM serves as a single material platform configurable into three sensing modalities. The resistive strain sensor achieves a gauge factor of 3.1 over 10-100% strain and enables the reliable recognition of human joint movements and gestures. The capacitive pressure sensor delivers a sensitivity of 0.298 kPa-1, rapid response/recovery times of 30/10 ms, and is integrated with a wireless module to control a smart car. Furthermore, the PAM-based triboelectric nanogenerator (TENG) delivers excellent electrical outputs (Voc = 123 V, Isc = 0.52 μA, Qsc = 58 nC) and functions as a self-powered smart handwriting pad, achieving a machine-learning-based recognition accuracy of 97.6%. This work demonstrates the immense potential of the PAM organogel for advanced, self-powered HMIs.

ABSTRACT The advancement of intelligent human‐computer interaction systems urgently requires sensing technologies that can seamlessly integrate with the human body and decode multidimensional physiological and physical information. Herein, a novel flexible bimodal sensor is architected for the synchronous perception of tactile pressure and bioelectrical signals. The core of the tactile sensing unit is a capacitive pressure sensor, which synergistically integrates a cold‐pressing microstructured poly(vinylidene fluoride‐hexafluoropropylene) [P(VDF‐HFP)] dielectric layer with compressible carbon fabric (CF) electrodes. This composite structure achieves exceptional compressibility and controlled micro‐gaps, enabling an ultrahigh and broad‐range sensitivity of 0.221 kPa −1 (0–8 kPa) and 14.11 MPa −1 (65–240 kPa). Impressively, the CF electrode also establishes low‐impedance epidermal coupling, which is critical for high‐fidelity bioelectrical sensing. This capability is confirmed through clear electrocardiogram (ECG) traces with distinct PQRST peaks and a high signal‐to‐noise ratio (SNR) of 21.66 dB (curling) and 12.50 dB (gripping), which are comparable to those obtained with a commercial bioelectrode. The practical utility of the integrated system is further demonstrated through real‐time dexterous control of a robotic hand and the machine learning‐assisted transmission and decryption of a doubly‐encrypted Morse code communication system. This work establishes a new design paradigm for multifunctional sensing interfaces toward next‐generation intelligent systems.

Real-time sensing and processing of a large amount of tactile information is essential for intelligent robotics and wearable technology. However, physical separation between sensors and processors in the traditional tactile sensing scheme makes these functionalities inaccessible, posing a major roadblock to the rapid advance of skinomorphic electronics. Here, we propose a massively parallel in-sensor skinomorphic computing scheme and demonstrate its promising applications in intelligent tactile perception. This scheme allows for achieving parallel sensing and processing of tactile information directly within sensor. We implement this proposed scheme by fabricating a 32×32 flexible capacitive pressure sensors array with excellent uniformity and endurance, and by cascading the sensors array with a memristive crossbar array. We experimentally demonstrate that the broken pressure patterns of the letter ‘NJU’ loaded on the sensors array can be sensed and restored in parallel, which is inaccessible with previously reported tactile technologies. Moreover, by networking the pressure sensors array with two memristive crossbar arrays, we show that textural features of the loaded complex pressure patterns can be directly extracted in a parallel manner and the tactile information can thus be compressed. Our work opens up an avenue for developing intelligent skins capable of real-time and high-throughput tactile perception.

Single-sided capacitive pressure sensor with tunable performance over a wide pressure range

Interface engineering by polarization derives a plethora of distinctive phenomena. Most of them focus on modulation of barrier height for controlling carrier transport of direct-current electronics. However, modulating interface width under alternating-current settings and its resultant effects have not been explored. Here, we report the capacitive piezotronics, which utilizes piezoelectric polarization to control the interface width of heterostructures and modulate junction capacitance at high frequency. The built-in electric potential and the interface width can be reversibly tuned with amplitude as high as 0.11 V and 10.5 nm, which presents a high strain sensitivity ( > 110 fF/mbar), and surpasses that of commercial capacitive pressure sensors ( ~ 0.1-0.7 fF/mbar). It possesses a capacity of mechanically tuning transmission signal of communication systems with an amplitude > 11 kHz, and substantially improving the filtering characteristics particularly for high frequency noise ( > 300 kHz). The strain-tuned alternating-current electronics offer a distinctive approach for high quality communication.

Flexible capacitive pressure sensors have gained widespread application in health monitoring, robotics, and structural diagnostics. However, conventional designs that rely on flat or micropatterned dielectric layers typically offer high sensitivity only at low pressures and possess limited tunability, which makes them unsuitable for dynamic or harsh environments. In this study, we present a tunable capacitive pressure sensor fabricated via buckling-guided assembly and laser cutting, which transforms 2D precursors into 3D cage-like architectures. The sensor exhibits pressure-dependent sensitivity, characterized by low sensitivity under small loads and significantly enhanced sensitivity at higher loads due to nonlinear variations in electrode spacing. It achieves outstanding performance, including high durability over 6000 cycles, a low detection limit (~2 Pa), minimal hysteresis (~4%), and rapid response and recovery times (131/140 ms). Finite element analysis and experimental validation confirm the tunable mechanical response and accurate electromechanical behavior enabled by geometric design. The sensor also allows reversible tuning through lateral strain and liquid encapsulation, enhancing environmental robustness. Moreover, a compression-induced rotation mechanism further improves sensitivity by increasing electrode overlap during loading. Wind tunnel experiments validate the sensor's performance under extreme conditions, demonstrating strong potential for practical applications.

High-performance capacitive pressure sensors are crucial for advancing wearable electronics and human-computer interaction, yet it remains challenging to simultaneously achieve high sensitivity and a broad linear working range. To overcome the inherent sensitivity-range trade-off in conventional designs, this work reports a confined evaporation strategy to fabricate the ionic dielectric layer featuring bioinspired microstructures for capacitive sensors. The dielectric layer mimics the surface morphology of Calathea zebrina leaves and spontaneously generates randomly distributed, pinecone-like microcones with a wide size distribution. Under external pressure, these microstructures demonstrate hierarchical deformation characteristics; smaller microcones activate preferentially under low pressure, while larger structures engage progressively with increasing load. This sequential engagement mechanism nonlinearly amplifies the effective contact area with electrodes. The expanded interfacial area synergizes with the electric double-layer effect from incorporated ionic liquid, substantially enhancing sensitivity, while the graded activation of different-sized microstructures enables an extended linear operating range. The flexible BC-MB electrode incorporates Ti3C2Tx MXene nanosheets with bacterial cellulose to form a conductive network, enhancing stability and sensitivity. The resulting capacitive sensor with flexible BC-MB electrodes achieves remarkable performance, ultrahigh sensitivity (692.30 kPa–1), wide linear response range, ultralow detection limit (0.53 Pa), fast response/recovery (61/32 ms), and excellent cycling stability (10,000 cycles). Meanwhile, this sensor demonstrates exceptional capability in capturing subtle physiological signals, including detailed arterial pulse waveforms for cardiovascular assessment, while enabling dual-mode human-computer interaction through Morse code gesture recognition and dynamic handwriting identification. Successful integration with wireless communication systems confirms its practical implementation potential in wearable health monitoring and interactive interfaces. This work establishes a scalable microstructure-engineering approach for high-performance capacitive sensors, effectively transcending conventional material-level constraints.

Hydronephrosis, a serious complication of ureteral stents, can lead to deterioration of renal function due to prolonged increased intrarenal pressure. Currently, the only way to diagnose hydronephrosis is radiographic imaging, and a continuous, non-invasive method is not available. This study introduces the ureteral stent sleeve, UroSleeve, a modular wireless pressure monitoring system that is designed to integrate seamlessly with standard ureteral stents without altering their existing designs or manufacturing processes. The UroSleeve incorporates a flexible printed-circuit-board-based spiral antenna and a surface-micromachined capacitive pressure sensor, forming an inductor-capacitor tank circuit capable of wireless telemetry through near-field inductive coupling. The device was evaluated in an ex vivo porcine kidney model whose internal pressure was externally controlled to mimic a hydronephrosis condition, and kidney pressure changes were successfully monitored by detecting shifts in the resonant frequency of the device. Key results demonstrated a high sensitivity with -5.3 ± 0.74 kHz/mmHg with a baseline resonant frequency of 15.234 MHz at 8.5 mmHg. The frequency response showed a strong correlation with kidney pressure, and the device maintained consistent performance in a relevant biological environment. The results indicate that UroSleeve offers a practical and versatile solution for wireless intrarenal pressure monitoring, amenable to future clinical translation.

Poly(vinyl alcohol) (PVA) has been widely used owing to its excellent processability and mechanical strength. However, films formed via strong hydrogen bonding are typically dense and brittle, which limits their practical applicability. Although various strategies have been investigated to overcome this issue, most approaches rely on hydrogel systems that often exhibit low mechanical strength and reduced durability due to solvent evaporation. In this work, a flexible and self-healable PVA-based elastomer film was successfully developed. The film was synthesized by incorporating polyethylene glycol (PEG) and 2,2′-ethylenedioxydiethanethiol (EDDET) into the PVA structure through disulfide covalent bonding. The resulting film exhibited excellent mechanical properties, with a tensile strength of 2.4 ± 0.2 MPa (mean ± SD, n = 5) and an elongation at break of 210 ± 3.2% (mean ± SD, n = 5), as well as a high dielectric constant of 12.4 ± 0.3 (mean ± SD, n = 5) at 105 Hz. When used as the dielectric layer in a capacitive tactile sensor, the film showed high sensitivity and maintained stable performance even after 10,000 cycles of repeated pressure loading. Furthermore, owing to the reversible nature of disulfide bonds, the film demonstrated effective self-healing behavior upon mechanical damage.