populations. Moreover, with the advent of the novel coronavirus disease (COVID-19), significant investment in medical resources is required. Under the umbrella of the global COVID-19 pandemic, the use of biosensors in healthcare and online medical care are becoming ubiquitous, which represent methods that can be used to detect signs from the human body for further health analysis. Furthermore, the internet of things (IoT) technology in healthcare is a method by which biosensorembedded objects can be worn on the human body in everyday life that continuously measure and digitize health information without any burden to the wearer. [1] Recently, various biometric technologies have been developed, wearable devices such as smart watches, invasive biodevices, and devices that sense the everyday surrounding environment of the wearer. Medical data can be collected using such devices, which can then be further analyzed by artificial intelligence (AI). These data can then be used for health promotion, prevention of disease, and early disease diagnosis. Moreover, with the advent of COVID-19, healthcare IoT (HIoT) technology has become extremely important. [2] In terms of the individual, when a mask is constantly worn it may cause lung damage to the user. Therefore, the HIoT would make a significant contribution in this case to offer forewarning about the situations of the lungs As society advances, the shift from passive medical care to health management and preventive medical care has become an important issue, with the realization of wearable monitors becoming desirable. In light of the COVID-19 pandemic, the number of patients who are in urgent need of the monitoring of biological information is increasing. This review focuses on piezoelectric materials and composites that convert kinetic energy into electrical energy to realize self-powered wearable monitoring sensors, outlining the recent research activity on sensors for use in healthcare monitoring. First, a general description of the principles of piezoelectric monitoring sensors is given. Next, the development status of piezoelectric materials and composites aimed at the application of detecting tiny motions of the human body is introduced, and then the research trends on the detection of larger human body movements are highlighted. Finally, after presenting the performance of current piezoelectric sensors and future research guidelines for developing multifunctional systems in the post COVID-19 era, the achievements are summarized. Overall, this review will provide guidance to researchers who are seeking to design and develop highly sensitive self-powered piezoelectric sensors that monitor human motion and physiological signals.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/admt.202200318.

Carbon fiber reinforced plastics (CFRPs) are widely used in the aerospace, automotive, and construction industries. CFRP prepregs (intermediate products) are generally used in CFRP production, with a large number of prepreg cut‐offs being discarded during cutting processes. There is strong demand for a method for recycling carbon fiber prepreg cut‐offs. This paper proposes a method for recycling such material, which is characterized by low cost and high added value, in order to foster the development of a recycling‐oriented society. We prepare carbon tapes (CTs) by cutting discarded cut‐offs according to their size so as to maximize fiber length. Using a simple water CT dispersion method, we fabricate uniform CT sheets and mold a recycled CT‐reinforced composite (R‐CT‐RC). Sample prototyping and mechanical characteristic testing indicate that this R‐CT‐RC is characterized by low recycling cost and desirable mechanical properties. Recycled CT‐reinforced composite with thermoplastic (R‐CT‐RC/TP), which is prepared by adding thermoplastic resin between CTs, can be re‐molded and therefore readily re‐recycled.

Wireless sensor networks are the future development direction for realizing an Internet of Things society and have been applied in bridges, buildings, spacecraft, and other areas. Nevertheless, with application expansion, the requirements for material performance also increase. Although the development of carbon-fiber-reinforced polymer (CFRP) to achieve these functions is challenging, it has attracted attention because of its excellent performance. This study combined the CFRP electrode with epoxy resin containing potassium sodium niobate piezoelectric nanoparticles and successfully polarized the composite sample. Furthermore, a three-point bending method was applied to compare the bending behavior of the samples. The peak output voltage produced by the maximum bending stress of 98.4 MPa was estimated to be 0.51 mV. Additionally, a conversion efficiency of 0.01546% was obtained. The results showed that the piezoelectric resin with CFRPs as the electrode exhibited stress self-inductance characteristics. This study is expected to be applied in manufacturing self-sensing piezoelectric resin/CFRP composite materials, paving the way for developing stable and efficient self-sensing structures and applications.

No abstract

No abstract