Textile-based electronic techniques that can in real-time and noncontact detect the respiration rate and respiratory arrest are highly desired for human health monitoring. Yarn-shaped humidity sensor is fabricated based on a sensitive fiber with relatively high specific surface area and abnormal cross-section. The response and recovery time of the yarnshaped humidity sensor is only 3.5 and 4 s, respectively, with little hysteresis, because of the hydrophobic property of these functional fibers and the grooves on the surface of the fibers, which is much faster than those of the commercial polyimide materials. Moreover, a batteryfree LC wireless testing system combined with the yarn-shaped sensor is fabricated, which is further successfully imbedded into the intelligent mask to detect human breath. Based on the detection of LC wireless testing system, the frequency of 50.25 MHz under the exhaled condition shifts to 50.86 MHz under the inhaled situation of humidity sensor. In essence, the functional yarns with proper structure, would be an excellent candidature to the yarn-shaped humidity sensor, in which there are good performance and wide application possibilities, eventually offering a facile method for the wireless detection of human physiological signals in the field of electronic fabrics.
Biological nanochannels control the movements of different ions through cell membranes depending on not only those channels' static inherent configurations, structures, inner surface's physicochemical properties but also their dynamic shape changes, which are required in various essential functions of life processes. Inspired by ion channels, many artificial nanochannel‐based membranes for nanofluidics and biosensing applications have been developed to regulate ionic transport behaviors by using the functional molecular modifications at the inner surface of nanochannel to achieve a stimuli‐responsive layer. Here, the concept of a dynamic nanochannel system is further developed, which is a new way to regulate ion transport in nanochannels by using the dynamic change in the curvature of channels to adjust ionic rectification in real time. The dynamic curvature nanochannel‐based membrane displays the advanced features of the anomalous effect of voltage, concentration, and ionic size for applying simultaneous control over the curvature‐tunable asymmetric and reversible ionic rectification switching properties. This dynamic approach can be used to build smart nanochannel‐based systems, which have strong implications for flexible nanofluidics, ionic rectifiers, and power generators.
Integrated fabrics with a smart heating control system (HCS) are attractive in warming and thermotherapy for human healthcare management. Metal nanofibers (NFs) networks with high flexibility, conductivity and gas permeability are ideal functional materials for wearable electronics. Herein, a novel sandwich-structural (Ag NFs/fabrics/Pt NFs) textile for a HCS is constructed, where a Ag NF network film was functioned as a wearable heater and Pt NF network arrays were functioned as wearable temperature sensors. Conductivity and mechanical stability of the metal NFs were enhanced by crosslinking the free-standing fiber networks, resulting in high thermo-stability, thermal resistance (163.5 °C W−1 cm2) and temperature sensitivity (0.135% °C−1) of the HCS. The HCS can simultaneously realize heating and temperature distribution detection, demonstrating only 0.57% average error between the simulated resistance-to-temperature diagram of Pt NF arrays and actual temperature mapping. In addition, the HCS can be stuck on the skin for thermochromic fabrics, real-time heating and temperature detection/control through a Bluetooth device in a smartphone wirelessly.
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