Bioinspired Flexible Volatile Organic Compounds Sensor Based on Dynamic Surface Wrinkling with Dual‐Signal Response

Abstract

Living systems can respond to external stimuli by dynamic interface changes. Moreover, natural wrinkle structures allow the surface to switch dynamically and reversibly from flat to rough in response to specific stimuli. Artificial wrinkle structures have been developed for applications such as optical devices, mechanical sensors, and microfluidic devices. However, chemical molecule‐triggered flexible sensors based on dynamic surface wrinkling have not been demonstrated. Inspired by human skin wrinkling, herein, a volatile organic compound (VOC)‐responsive flexible sensor with a switchable dual‐signal response (transparency and resistance) is achieved based on a multilayered Ag nanowire (AgNW)/SiOx/polydimethylsiloxane (PDMS) film. Wrinkle structures can form dynamically in response to VOC vapors (such as ethanol, toluene, acetone, formaldehyde, and methanol) due to the instability of the multilayer induced by their different swelling capabilities. By controlling the modulus of PDMS and the thickness of the SiOx layer, tunable sensitivities in resistance and transparency of the device are achieved. Additionally, the proximity mechanism of the solubility parameter is proposed, which explains the high selectivity of the device toward ethanol vapor compared with that of other VOCs well. This stimuli‐responsive sensor exhibits the dynamic visual feedback and the quantitative electrical signal, which provide a novel approach for developing smart flexible electronics.

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“…e–g) Reproduced with permission. [ 257 ] Copyright 2019, Wiley‐VCH. h) Performance improvement of the wearable multisensory marine skin gadget with a reliable interlocking mechanism showing all the components.…”

“…The real‐time monitoring of the volatile organic compound (VOC) explosion limit, such as ethanol, toluene, acetone, formaldehyde, and methanol, is of great significance in industrial production and environmental management. Inspired from the wrinkles formed on the skin during long‐term exposure to ethanol vapor (Figure 15e), [ 257 ] a chemical molecule triggered smart wearable sensor based on AgNW/SiO x /PDMS multilayered film was constructed (Figure 15f), which can respond to VOCs with dual‐signal response of both dynamic visual and electrical signal feedback (transparency and resistance) (Figure 15g). This platform can be versatilely exploited for other chemical stimuli‐responsive sensors in the environmental monitoring and wearable electronics.…”

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