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A flexible organohydrogel-based humidity sensor for noncontact artificial sensation

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Abstract

In this paper, we propose a simple organohydrogel based capacitive humidity sensor for noncontact artificial sensation applications. The sensor is simple in design and consists of a transparent polyacrylamide organohydrogel thin film attached on a flexible inter-digit electrode layer. The process of water absorption and desorption is reversible, thus the dielectric of the organohydrogel film as well as the overall capacitance is dependent on environmental humidity. The water absorption capacity and structural reliability of the device have been largely improved by adding glycerol in the organohydrogel network. By optimizing both the glycerol concentration and organohydrogel film thickness, the sensor can respond to cyclic humidity changes in a period of 300 ms. In addition, this sensor achieves a high relative capacitance increase (by 20 folds) in a wide relative humidity range (12%–95%). The sensor also exhibits high stability under different bending curvatures (up to 6.81 mm), wide temperature changes (20°C–40°C) and external pressures (0–8 N). To demonstrate the applications in wearable electronics, we found that the sensor was successful in detecting respiration intensity and rate as well as the difference in moisture content in various objects, i.e., human skin and leaf surface. This sensor is highly sensitive and can be useful in the detection of the wide-range of humidity changes.

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Authors and Affiliations

  1. Medical Image Processing, Analysis and Visualization (MIPAV), School of Electronic and Information Engineering, Soochow University, Suzhou, 215000, China

    Yu Zhang, Chen Li, Han Yang, XinJian Chen & BaoQing Nie

  2. State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215000, China

    Rui Zhao, XinJian Chen & Liang Hu

Authors
  1. Yu Zhang
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  2. Chen Li
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  3. Han Yang
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  4. Rui Zhao
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  5. XinJian Chen
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  6. BaoQing Nie
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  7. Liang Hu
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Corresponding authors

Correspondence to BaoQing Nie or Liang Hu.

Additional information

This work was supported by the National Natural Science Foundation of China (Grant Nos. 61601317 and 51873137), the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No. 20KJB510001), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and the National Key R&D Plan “Key Scientific Issues of Transformative Technology” (Grant No. 2018YFA0701700). The authors also thank GENG JiaLei, XIAO WenYe, ZHAO MengYing, and FENG TingTing for their helps in photo shooting in this work. The authors would like to express their gratitude to EditSprings (https://www.editsprings.com/) for the expert linguistic services provided.

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The supporting information is available online at https://tech.scichina.com and https://link.springer.com. The supporting materials are published as submitted, without typesetting or editing. The responsibility for scientific accuracy and content remains entirely with the authors.

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Zhang, Y., Li, C., Yang, H. et al. A flexible organohydrogel-based humidity sensor for noncontact artificial sensation. Sci. China Technol. Sci. 65, 191–200 (2022). https://doi.org/10.1007/s11431-021-1912-1

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  • DOI: https://doi.org/10.1007/s11431-021-1912-1

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