Search

Electronic skin (E‐skin) is widely used in bionic prosthesis, soft robotics, and wearable electronic devices. Waterproof and breathable membranes that provide a high level of protection and comfort are promising core materials for meeting the pressing demand for E‐skin. However, creating such materials exhibiting waterproofness, breathability, and ease of fabrication has proven to be a great challenge. In this paper, waterproof, breathable Modal‐based knitted fabric E‐skin is proposed by using a simple, low‐cost three‐step process including the graphene oxide (GO) loading, GO‐reducing, and polydimethylsiloxane loading. The prepared E‐skin is insensitive to common liquids in daily life including water, tea, milk, and coffee, showing superior waterproof capability. The breathability is also tested with a water vapor transmission rate of ≈13.6 mg cm−2 h−1. Besides, this E‐skin can achieve reliable human motion monitoring. The authors believe this E‐skin can provide a reliable principle for further design and development of waterproof and breathable electronic skin. [ABSTRACT FROM AUTHOR]

Hydrogels are considered as promising materials in developing next‐generation wearable sensors due to their intrinsic biocompatibility and low Young's modulus. However, there are few reports on their breathability which is very important for wear comfortability of wearable sensors. Here graphene‐based hydrogel is presented with regular pores using microneedles as templates endowing them with excellent breathability (water vapor transmitting rate 2.8 kg d–1 m–2), which is near ten times that of human skin (water vapor transmitting rate less than 0.3 kg d–1 m–2). A high‐performance strain sensor based on this breathable hydrogel is developed. This sensor not only possesses high sensitivity but also has an excellent linearity with strain ranging from 0% to 110%. Based on these performances, this sensor can be applied in monitoring various joint movements and muscle movements. Moreover, it can achieve barrier‐free communication through Morse code. [ABSTRACT FROM AUTHOR]

Flexible humidity sensors have attracted much attention due to the promising applications in medical health monitoring. Up to now, the realization of such devices with ultrafast response/recovery and wide humidity range still remains a challenge. In this work, we report a new type of humidity sensor based on laser‐induced graphene (LIG) and graphene oxide (GO) with excellent performances. Graphene interdigital electrodes with good conductivity were prepared by the laser‐induced method. Then, the GO dispersion was drop‐coated on the interdigital electrode and heated to form a film as a sensing material. We have systematically studied the performances of the humidity sensor under different humidity levels. The experiment results reveal that the humidity sensor possesses high response, fast response/recovery behavior with 2 and 35 seconds, and wide humidity range from 11% RH to 97% RH. This proposed high‐performance humidity sensors could be applied in practical applications such as human breath monitoring under different states including slow breath, normal breath, fast breath, cough and rhinitis. In addition, the humidity sensors could also be used to monitor the approaching of fingertips, which makes the sensors be ideal non‐contact buttons of the elevator for stopping contacting spread of COVID‐19 viruses. [ABSTRACT FROM AUTHOR]