Yarn-based superhydrophobic wearable sensors for ammonia gas detection at room temperature

Abstract

Conventional metal-oxide-semiconductor (MOS) gas sensors are limited in wearable gas detection due to their non-flexibility, high operating temperature, and less durability. In this study, a yarn-based superhydrophobic flexible wearable sensor for room-temperature ammonia gas detection was prepared based on the nano-size effect of both nanocore yarns prepared through electrostatic spinning and MOS gas-sensitive materials synthesized via a two-step hydrothermal synthesis approach. The yarn sensor has a response sensitivity of 13.11 towards 100 ppm (1 ppm = 10⁻⁶) ammonia at room temperature, a response time and a recovery time of 36 and 21 s, respectively, and a detection limit as low as 10 ppm with the sensitivity of up to 4.76 towards ammonia. In addition, it displays commendable linearity within the concentration range of 10‒100 ppm, accompanied by remarkable selectivity and stability, while the hydrophobicity angle reaches 155.74°. Furthermore, its sensing performance still maintains stability even after repeated bending and prolonged operation. The sensor also has stable mechanical properties and flexibility, and can be affixed onto the fabric surface through sewing, which has a specific potential for clothing use.

Graphical abstract

Keywords

ammonia sensor / superhydrophobicity / metal oxide semiconductor / flexible wearable sensor

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Declaration of competing interests

The authors declare no competing interests that are relevant to the content of this article.

Acknowledgements

This work was supported by the Fund of China National-Textile and Apparel Council (Grant Nos. 2022033 and 2022015). We would like to thank the Analytical & Testing Center of Tiangong University for the relevant test work on the surface morphology and structural component of materials.

Online appendix

Electronic supplementary material (ESM) can be found in the online version at https://doi.org/10.1007/s11706-025-0715-2 and https://journal.hep.com.cn/foms/EN/10.1007/s11706-025-0715-2 that includes Figs. S1–S2 and Tables S1‒S2, illustrating different process parameters and corresponding ammonia responses of hydrothermal syngas sensitive materials.

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