Paper-Based Wearable Sensors for Humidity and VOC Detection

Abstract

Acceptable indoor air quality is a concern for the comfort and health of humans, in which the 40–70% of relative humidity (RH) is comfortable for the human body and the existence of volatile organic compounds (VOCs) may be harmful for our health. Therefore, the development of wearable sensors that can monitor the RH and VOCs in real time is highly desired. In this work, a mixture of conductive carbon black and exfoliated graphene was dip-coated on filter paper to easily fabricate a paper-based flexible sensor, which can detect RH in the range of 33–95% and VOCs including methanol (MeOH), ethanol (EtOH), toluene (PhMe), dichloromethane (DCM), acetone, and petroleum ether (PE) with relatively short response time. The device can be used to monitor the indoor RH and human breath under various conditions. It also can work as a sensitive and quick-response alarm for the VOC exposure. Furthermore, this flexible sensor is disposable by ultrasonic treatment without producing hazardous residues, thus considered as an environment-friendly electronic. This versatile and green flexible electronic device may find applications in wearable air monitoring devices and health care.

Digital Transformation in Toxicology: Improving Communication and Efficiency in Risk Assessment

“…These devices can be used to support digital toxicology by collecting data on chemical exposure and other toxicology-related factors . Wearable air monitoring devices can continuously measure airborne chemicals including pollutants and VOCs. , Even wearable chemical exposure monitoring devices can be worn to measure the levels of chemicals present in the environment as well as the levels of chemicals present in the body . Wearable toxicology devices measure physiological responses to chemical exposure including heart rate, respiratory rate, and body temperature.…”

Flexible functional composites for athlete health monitoring and auxiliary training applications

“…All finger, wrist, and knee joint movements, pronunciation, breathing, and swallowing can be detected using these strain sensors. Moreover, Liu et al (2021) applied wearable paper-based carbon black/graphene sensors for humidity and volatile organic compounds (VOC) detection. The sensors can detect relative humidity of 33 to 95% and VOCs of methanol, toluene, and petroleum ether with relatively short response time.…”

In Situ All‐Weather Humidity Visualization by Using a Hydrophilic Sponge

“…[ 1–5 ] The different application scenarios need different monitoring techniques, for example, for earth humidity monitoring, such remote techniques as microwave, millimeter, and terahertz (THz), should be employed to provide all‐weather observations of the atmosphere on a global basis; [ 6,7 ] while in human daily lives for such fields as food storage, concrete structures, the internet of things (IoT), electronic devices, respiration monitoring, disease diagnosis, and treatment, the humidity monitoring and evaluating require the sensitive materials with the features of short response and recovery times, as well as diverse‐configuration compatibility, that can meet the spatial and temporal humidity gradients measurements. [ 8–15 ] To date, many efforts have been performed for the fabrication of sensitive materials, including metal oxides, ceramics, perovskites, carbon compounds, and organic polymers, to realize high‐performance humidity monitoring. [ 16–20 ] However, the complicated steps for device construction, the low flexibility, as well as the extreme dependence on external energy‐supply systems or coupled circuits, have obstructed to some extent the broad application of these reported sensor devices.…”

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the humidity monitoring and evaluating require the sensitive materials with the features of short response and recovery times, as well as diverse-configuration compatibility, that can meet the spatial and temporal humidity gradients measurements. [8][9][10][11][12][13][14][15] To date, many efforts have been performed for the fabrication of sensitive materials, including metal oxides, ceramics, perovskites, carbon compounds, and organic polymers, to realize high-performance humidity monitoring. [16][17][18][19][20] However, the complicated steps for device construction, the low flexibility, as well as the extreme dependence on external energy-supply systems or coupled circuits, have obstructed to some extent the broad application of these reported sensor devices.

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