Human Nervous System Inspired Modified Graphene Nanoplatelets/Cellulose Nanofibers‐Based Wearable Sensors with Superior Thermal Management and Electromagnetic Interference Shielding

Abstract

Wearable sensing technologies have witnessed rapid development in recent years due to their accessibility, functionality, and affordability. However, heat accumulation and electromagnetic interference in electronic components adversely affect the sensing performance and seriously damage human health. Herein, cellulose nanofibers (CNFs)‐based composites with high thermal conductivity (TC) and excellent electromagnetic interference (EMI) shielding performance are prepared using CNFs as templates followed by coating with tannic acid non‐covalent and 3‐aminopropyltriethoxysilane covalent co‐modified graphene nanoplatelets (denoted as mGNPs) through a simple electrostatic self‐assembly method. The subsequent hot‐pressing process yield order and layer mGNPs in CNFs‐based composites with mGNPs distributed along the orientation and in close contact with CNFs, a fashion similar to the human nervous system. The resulting CNFs‐based composites reveal a high TC of 136.2 W/(m·K) and a superior EMI shielding effectiveness of 105 dB. Thus, they are used as wearable sensors based on the triboelectric effect to monitor human health in real‐time, as well as express emotion through Morse code. In sum, the proposed strategy provides an avenue to prolong the service life of flexible wearable sensors and ensure their safe use, promising for future wisdom in healthcare and smart robotics.

All-Textile Piezoelectric Nanogenerator Based on 3D Knitted Fabric Electrode for Wearable Applications

“…Wearable flexible sensors have received a lot of attention due to their potential applications in energy harvesting, electronic skin, human–computer interaction, medical health, , and motion monitoring. , Wearable sensors are essential for wearable electronics. They can convert external mechanical actions into recognizable signals in real-time.…”

Directional Moisture-Wicking Triboelectric Materials Enabled by Laplace Pressure Differences

“…As basic devices for human–computer interaction control, wearable devices have huge application potential in future. − At present, most wearable sensing materials have insufficient moisture removal capabilities and cannot drain away the moisture produced by the human body in a timely manner, causing the human body to feel sticky and cold, which seriously affects the user’s comfort and experience. − In order to overcome this kind of problem, some studies have given directional moisture-wicking capability to the sensing material, so that it can discharge the moisture generated by human breathing or perspiration, thereby ensuring the wearable electronics equipment comfort . By constructing superimposed hydrophobic layer and hydrophilic layer, the directional moisture-wicking material can drive droplets through the hydrophobic layer and transport them to the hydrophilic layer in a directional way by utilizing the wettability gradient between different materials. − However, when using wettability gradients to directionally transport droplets, the droplets require a large driving pressure to break through the hydrophobic layer, which slows down the directional movement rate of the droplets and leads to water retention . Therefore, it is urgent to break through the limitations of insufficient driving force for droplet delivery, which is of great significance for improving the comfort of wearable electronic devices.…”