Piezoresistive Fibers with Large Working Factors for Strain Sensing Applications

A Conductive and Anti-impact Composite for Flexible Piezoresistive Sensors

Flexible piezoresistive sensors, which can convert specific mechanical information (such as compression, bending, tensile, and torsion) into a resistance value change signal through the piezoresistive effect, have attracted more and more attention. However, how to achieve the simple, low-cost fabrication of a piezoresistive sensor is still a challenge. Herein, we report a facile strategy that introduces conductive carbon black (CB) and shear thickening gel (SG) composite into a melamine sponge (MS) to generate an MS-SG-CB composite with a unique force-electric coupling effect. A flexible sensor derived from the MS-SG-CB composite can not only accurately identify deformation signals during static stretching and compression while monitoring human movement status in real time but also recognize electrical signals under dynamic impact in a very short time (6 ms). The 3 × 3 flexible array built on this basis can accurately identify the mass and position of heavy objects. Furthermore, based on the flame-retardant properties of MS, the flame-retardant ammonium polyphosphate (APP) is further introduced into MS-SG-CB to obtain MS-SG-CB-APP composite with excellent flame retardancy and stable temperature electrical response behavior, expanding its application in the field of high temperature trigger alarm.

Performance analysis of solution-processed nanosheet strain sensors-a systematic review of graphene and MXene wearable devices

Nanotechnology has led to the realisation of many potentialInternet of Thingsdevices that can be transformative with regards to future healthcare development. However, there is an over saturation of wearable sensor review articles that essentially quote paper abstracts without critically assessing the works. Reported metrics in many cases cannot be taken at face value, with researchers overly fixated on large gauge factors. These facts hurt the usefulness of such articles and the very nature of the research area, unintentionally misleading those hoping to progress the field. Graphene and MXenes are arguably the most exciting organic and inorganic nanomaterials for polymer nanocomposite strain sensing applications respectively. Due to their combination of cost-efficient, scalable production and device performances, their potential commercial usage is very promising. Here, we explain the methods for colloidal nanosheets suspension creation and the mechanisms, metrics and models which govern the electromechanical properties of the polymer-based nanocomposites they form. Furthermore, the many fabrication procedures applied to make these nanosheet-based sensing devices are discussed. With the performances of 70 different nanocomposite systems from recent (post 2020) publications critically assessed. From the evaluation of these works using universal modelling, the prospects of the field are considered. Finally, we argue that the realisation of commercial nanocomposite devices may in fact have a negative effect on the global climate crisis if current research trends do not change.

Insights into Materials, Physics, and Applications in Flexible and Wearable Acoustic Sensing Technology

Sound plays a crucial role in the perception of the world. It allows to communicate, learn, and detect potential dangers, diagnose diseases, and much more. However, traditional acoustic sensors are limited in their form factors, being rigid and cumbersome, which restricts their potential applications. Recently, acoustic sensors have made significant advancements, transitioning from rudimentary forms to wearable devices and smart everyday clothing that can conform to soft, curved, and deformable surfaces or surroundings. In this review, the latest scientific and technological breakthroughs with insightful analysis in materials, physics, design principles, fabrication strategies, functions, and applications of flexible and wearable acoustic sensing technology are comprehensively explored. The new generation of acoustic sensors that can recognize voice, interact with machines, control robots, enable marine positioning and localization, monitor structural health, diagnose human vital signs in deep tissues, and perform organ imaging is highlighted. These innovations offer unique solutions to significant challenges in fields such as healthcare, biomedicine, wearables, robotics, and metaverse. Finally, the existing challenges and future opportunities in the field are addressed, providing strategies to advance acoustic sensing technologies for intriguing real-world applications and inspire new research directions.