No abstract

Wearable devices that can be used to monitor personal health, track human motions, and provide thermotherapy, etc., are highly desired in personalized healthcare. In this work, a multifunctional wearable "wrist band" which works as both heater for thermotherapy and sensor for personal health and motion monitoring is fabricated from a flexible and conductive carbon sponge/polydimethylsiloxane (CS/PDMS) composite. The key functional material of the wrist band, namely, the conductive CS, is synthesized from waste paper by a freeze-drying and high-temperature pyrolysis process. When the wrist band works as a heater under 15 V, a stable temperature difference of 20 °C is achieved between the wrist band and the ambient. When the wrist band serves as a wearable strain sensor, the wrist band exhibits fast and repeatable response and excellent durability within the strain range of 0-20% and the working frequency of 0.01-10 Hz. Finally, the typical applications of the multifunctional wearable wrist band, as a heater for thermotherapy and a sensor for blood pulse, breathe, and walk monitoring, are demonstrated. Due to its low cost, high flexibility, moderate conductivity, and excellent strain sensibility, the as-prepared wearable device based on the CS/PDMS composite is promising to be applied for the provision of personal healthcare.

Melamine sponge, also known as nano-sponge, is widely used as an abrasive cleaner in our daily life. In this work, the fabrication of a wearable strain sensor for human motion detection is first demonstrated with a commercially available nano-sponge as a starting material. The key resistance sensitive material in the wearable strain sensor is obtained by the encapsulation of a carbonized nano-sponge (CNS) with silicone resin. The as-fabricated CNS/silicone sensor is highly sensitive to strain with a maximum gauge factor of 18.42. In addition, the CNS/silicone sensor exhibits a fast and reliable response to various cyclic loading within a strain range of 0-15% and a loading frequency range of 0.01-1 Hz. Finally, the CNS/silicone sensor as a wearable device for human motion detection including joint motion, eye blinking, blood pulse and breathing is demonstrated by attaching the sensor to the corresponding parts of the human body. In consideration of the simple fabrication technique, low material cost and excellent strain sensing performance, the CNS/silicone sensor is believed to have great potential in the next-generation of wearable devices for human motion detection.

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