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Flexible electronic equipment is an emerging field in recent years, which attaches more attention to be researched and applied in health monitoring and human–machine interface. However, for the existing pressure sensors, even a very slight pressure will greatly reduce their sensitivity, so it is an urgent problem to be solved for achieving high sensitivity and wide application range simultaneously. Hence, a high‐performance piezoresistive pressure sensor based on PAN nanofiber films (PAN NFs) and MXene (Ti3C2Tx) is proposed. The realization of high sensitivity and wide sensing range is based on the microstructure of accordion‐like MXene and the macrostructure of fluffy porous blowing spinning PAN nanofibers, which exhibits a high sensitivity of 81.89 kPa−1 over a wide sensing range of 0.83–38.13 kPa and the dynamic responses to external pressures can reach 98.73 kPa. The pressure sensors based on skin surface‐like 3D patterned interwoven structure are used for health monitoring and tiny pressure detecting. Moreover, the application in human–machine interface is demonstrated. Additionally, to meet the requirement of long‐term wearing, the structure of the sensor is optimized and endowed with excellent breathability and conformal properties, which promotes the further development of flexible electronic equipment. [ABSTRACT FROM AUTHOR]

The development of tunable UV‐curable polymeric composites for functional applications, taking into consideration environmental issues and additive manufacturing technologies, is a research topic with relevant challenges yet to be solved. Herein, acrylic composites filled with 0–3 wt.%. polyaniline/ multiwalled carbon nanotubes (PANI/MWCNT) are prepared by Digital Light Processing (DLP) in order to tailor morphology, thermal, mechanical, and electromechanical properties. Viscosity, real‐time infrared spectroscopy, and cure depth tests allow optimizing resin composition for suitable DLP printing. 2 wt.% is the maximum filler content reproducibly embedded in the polymer matrix. The advantages of PANI/MWCNT (50/50 wt.%) compared with single‐component composites include safety issues, enhanced printability, increased electrical conductivity and thermal stability, and lower electrical percolation threshold (0.83 wt.%). Above this threshold the composites display excellent piezoresistive response, no hysteresis, and stability for over 400 compression cycles. The pressure sensibility (PS) of 2 wt.% composites decreases with applied pressure from PS ≈ 15 to 0.8 Mpa−1 for maximum pressures of 0.02 and 0.57 MPa, respectively. A proof‐of‐concept of the functionality of the novel materials is developed in the form of a tactile sensor, demonstrating their potential for pressure sensing applications as cost‐effective, sustainable, and flexible materials for printed electronics. [ABSTRACT FROM AUTHOR]

Fabrics are among the best ideal materials for fabricating low‐cost flexible pressure sensors due to their outstanding air permeability, flexibility, and micro/nanorough structure. However, most of the fabric‐based pressure sensors suffer from poor stability, which severely limits their applications in the real life. In the previous work, the pressure sensor assembled from polyester fabric and polyurethane sponge in an integrated design shows good stability. Herein, a novel type of wearable pressure sensors with high sensitivity and long durability is prepared by the unique combination of a dense integrated material consisting of nylon fabric–latex sponge–nylon fabric (FSF), reduced graphene oxide (rGO), and in‐situ‐formed polypyrrole (PPy). Benefiting from the excellent electrical conductivity, compression performance, and piezoresistive property, the obtained PPy/rGO/FSF pressure sensor exhibits low operating voltage (1.0 V), high sensitivity (0.51 kPa−1), long durability (over 7500 cycles), as well as short response time (243 ms). As a result, the pressure sensor demonstrates high performance in monitoring human activities such as wrist pulses, exhalation/inhalation, head shaking, knee bending, and finger bending, indicating its great potential in human health monitoring and human–computer interaction. [ABSTRACT FROM AUTHOR]

Paper-based flexible pressure sensors have received extensive attention owing to their recoverability and accessibility. This study, proposes a graphical pressure sensor array with a multilayered structure. A simple writing method is adopted to realize the adsorption of sensitive materials on the fiber structure of cellulose paper. Pressure sensors with 1, 3, 5, and 7 stacked layers are fabricated and compared. The results show that the seven-layer sensor achieves a high sensitivity (44 kPa-1) and fast time response (less than 150 ms). The highly sensitive stacked paper-based sensor array realizes the pressure detection in objects and special-shaped surfaces. A pressure sensor based on a commercial corrugated box is also fabricated for comparison. The corrugated carton array is used to switch the reminder devices for convenience and accessibility. Because many scenarios require a safe distance to be maintained, particularly under the influence of COVID-19, the writable paper-based sensor array is used to realize graphical distance perception and provide warnings. [ABSTRACT FROM AUTHOR]

Due to its porous structure and good elasticity, conductive polyurethane (PU) sponge is used as the main substrate of the flexible piezoresistive pressure sensor. The effective combination of conductive PU sponge and electrode material is the foundation for the pressure sensor, but it needs to be bonded by expensive conductive silver paste or copper paste. In addition, the common electrode materials weaken the flexibility of the PU sponge pressure sensors because of their rigidity. Herein, PU sponge and polyester (PET) fabric are first bonded to produce (PET‐PU) composite, which is then impregnated with graphene oxide (GO). The obtained reduced graphene oxide(rGO)@PET fabric and rGO@PU are used as electrode and piezoresistive material, respectively. Then rGO@(PET‐PU) composite is assembled into a pressure sensor only by using wire connections in the rGO@PET fabric. Benefiting from excellent piezoresistive behavior, rGO@(PET‐TPU) pressure sensor displays high sensitivity (0.255 kPa−1 at below 2.6 kPa), wide detection limit (≈0–85.0%), and long durability (over 1800 cycles). Besides, the pressure sensor demonstrates good performance in monitoring human activities, including finger bending, clicking keyboard, breathing, elbow bending, and walking posture, thus providing a promising material for human activity monitoring. [ABSTRACT FROM AUTHOR]

Piezoresistive pressure sensors based on sponge are widely concerned because of their wide strain range, convenient signal acquisition, and good compressibility, yet it is still a challenge to acquire sponge‐based pressure sensors with low cost and excellent sensing performance. Herein, low‐priced FeCl3.6H2O and pyrrole (Py) are dispersed in deionized water to form FeCl3.6H2O/Py solution. Commercial latex sponge is impregnated into this solution to prepare conductive polypyrrole/latex (PPy/latex) sponge through low‐temperature interfacial polymerization. The surface of latex sponge is covered by the micro‐wrinkled PPy, which endows the PPy/latex sponge with a certain electrical conductivity. The specific porous structure and high elasticity of the latex sponge are the basic conditions for PPy/latex sponge excellent piezoresistive behaviors. PPy/latex sponge based piezoresistive pressure sensor shows high sensitivity (0.084 kPa−1 at below 3.12 kPa), wider sensing range (0–85.0%) and long durability over 3800 s (1800 cycles). At the same time, the ability of the PPy/latex sponge based piezoresistive pressure sensor to monitor human movement has been successfully evaluated in some application scenarios, such as bending fingers, grabbing objects, tiptoe rising, and crouching. [ABSTRACT FROM AUTHOR]

Fabricating flexible pressure sensors with high sensitivity in a broad pressure range is still a challenge. Herein, a flexible pressure sensor with engineered microstructures on polydimethylsiloxane (PDMS) film is designed. The high performance of the sensor derives from its unique pyramid‐wall‐grid microstructure (PWGM). A square array of dome‐topped pyramids and crossed strengthening walls on the film forms a multiheight hierarchical microstructure. Two pieces of PWGM flexible PDMS film, stacked face‐to‐face, form a piezoresistive sensor endowed with ultrahigh sensitivity across a very broad pressure range. The sensitivity of the device is as high as 383 665.9 and 269 662.9 kPa−1 in the pressure ranges 0–1.6 and 1.6–6 kPa, respectively. In the higher pressure range of 6.1–11 kPa, the sensitivity is 48 689.1 kPa−1, and even in the very high pressure range of 11–56 kPa, it stays at 1266.8 kPa−1. The pressure sensor possesses excellent bending and torsional strain detection properties, is mechanically durable, and has potential applications in wearable biosensing for healthcare. In addition, 2 × 2 and 4 × 4 sensor arrays are prepared and characterized, suggesting the possibility of manufacturing a flexible tactile sensor. [ABSTRACT FROM AUTHOR]

Pressure sensors have attracted tremendous attention because of their potential applications in the fields of health monitoring, human–machine interfaces, artificial intelligence, and so on. Improving pressure‐sensing performances, especially the sensitivity and the detection limit, is of great importance to expand the related applications, however it is still an enormous challenge so far. Herein, highly sensitive piezoresistive pressure sensors are reported with novel light‐boosting sensing performances. Rose petal–templated positive multiscale millimeter/micro/nanostructures combined with surface wrinkling nanopatterns endow the assembled pressure sensors with outstanding pressure sensing performance, e.g. an ultrahigh sensitivity (70 KPa−1, <0.5 KPa), an ultralow detection limit (0.88 Pa), a wide pressure detect ion range (from 0.88 Pa to 32 KPa), and a fast response time (30 ms). Remarkably, simple light illumination further enhances the sensitivity to 120 KPa−1 (<0.5 KPa) and lowers the detection limit to 0.41 Pa. Furthermore, the flexible light illumination offers unprecedented capabilities to spatiotemporally control any target in multiplexed pressure sensors for optically enhanced/tailorable sensing performances. This light‐control strategy coupled with the introduction of bioinspired multiscale structures is expected to help design next generation advanced wearable electronic devices for unprecedented smart applications. [ABSTRACT FROM AUTHOR]

Improvement of sensitivity of electrical piezoresistive sensors is critical for high‐precision and ultrasensitive detection, which mainly depends on the modulation ability of total resistance of sensor under applied pressure. However, in most of the reported sensor devices, the contact resistance and body resistance (the key parts of total resistance of sensor) generally cannot be modulated simultaneously, which results in the limited sensitivity. In this work, an ultrahighly sensitive piezoresistive pressure sensor with an exquisitely designed structure is demonstrated, providing an uncomparable advantage of synergistic modulation of contact resistance and body resistance under applied pressure. As a result, the sensor shows excellent sensing performance, with the highest sensitivity up to 11 668.6 kPa−1, the detection limit as low as 0.425 Pa, and the great stability over 20 000 cycle measurements. In respect of practical application, the high sensitivity endows the sensor with high‐precision recognition ability for detecting the weak pressure signals such as sound wave of ringtone and fluctuation of breath or pulse. These results suggest the synergistic resistance modulation to be an effective method toward piezoresistive pressure sensors with ultrahigh sensitivity and offer a new strategy for the achievement of high‐performance pressure sensors. [ABSTRACT FROM AUTHOR]

A piezoresistive pressure sensor has been fabricated with a newly proposed fabrication process, which is quite suitable for fabricating MEMS devices. The fabricated pressure sensors are wire‐bonded and have been tested under the pressure range from 100–1012hPa. The results show that the output voltage increases with the applied pressure. For the structures with membrane length of 800 and 900 µm, the output voltage is linear to the pressure applied and the sensitivity of the sensor is about 0.75 and 0.877mV/hPa. The test results also show that, in order to get a linear output, the membrane length should be less than 1000 µm. [ABSTRACT FROM AUTHOR]