Details

Autor(en) / Beteiligte

• Wu, Zixuan
• Shi, Wenxiong
• Ding, Haojun
• Zhong, Bizhang
• Huang, Wenxi
• Zhou, Yubin
• Gui, Xuchun
• Xie, Xi
• Wu, Jin

Titel

Ultrastable, stretchable, highly conductive and transparent hydrogels enabled by salt-percolation for high-performance temperature and strain sensing

Ist Teil von

• Journal of materials chemistry. C, Materials for optical and electronic devices, 2021-10, Vol.9 (39), p.13668-13679

Ort / Verlag

Cambridge: Royal Society of Chemistry

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Ionic hydrogels are promising candidates for fabricating stretchable electronics, but the deficiency in drying and freezing tolerances severely limits their application. Here, we report a facile and versatile salt-percolated strategy to fabricate hydrogels with exceptional freezing and drying tolerances, high conductivity, and anti-swelling ability for sensitive temperature and strain detection within a broad temperature range. We discovered that lithium bromide (LiBr) was the most effective drying and freezing inhibitor for hydrogels among the various salts. The 50 wt% LiBr-percolated hydrogels retained ultrahigh stretchability (625% strain) and conductivity even at −78.5 °C or in ambient air for a year. The important role of LiBr in inhibiting the drying and freezing of hydrogels was understood using density functional theory (DFT) simulations on a molecular scale, revealing the formation of stable Li + -H 2 O and Br − -H 2 O clusters. It was found that the introduction of LiBr enhanced the temperature and strain sensing performance, e.g. , the stability and working temperature range. Multifunctional transparent sensors exhibited a high thermal sensitivity (2.54%/°C), broad temperature detection range (−78.5 to 97 °C), low detection limit (0.1% strain), and low hysteresis and baseline drift in cycling strain sensing. Attributed to the high tolerance of hydrogels to a wide range of temperatures, the strain sensing ability was maintained even at −20 °C. Various physiological signals, such as facial expressions, word pronunciation and knee bending, are real-time monitored using hydrogel-based epidermal sensors. Salt-percolated hydrogels show excellent anti-freezing and anti-drying abilities, high conductivity at ultralow temperatures (−78.5 °C), and excellent thermal and strain sensing performance, which can monitor various physiological signals.