A toughened, transparent, anti-freezing and solvent-resistant hydrogel towards environmentally tolerant strain sensor and soft connection

Multifunctional small biomolecules as key building blocks in the development of hydrogel-based strain sensors

“…57 Similarly, Feng et al reported that betaine improved the freeze tolerance of hydrogel strain sensors composed of a polyacrylic acid (PAA)-Al 3+ /poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) network, allowing the hydrogel strain sensors to remain flexible under harsh climatic conditions of −35 °C. 178…”

“…57 Similarly, Feng et al reported that betaine improved the freeze tolerance of hydrogel strain sensors composed of a polyacrylic acid (PAA)-Al 3+ /poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) network, allowing the hydrogel strain sensors to remain exible under harsh climatic conditions of −35 °C. 178 Moreover, the ionic sites on proline enhance its mechanical properties and adhesion to the skin. 57,179 Mechanical properties such as stretchability (∼1800%), elastic moduli, and toughness are improved owing to the -NH 2 + site of proline, which forms H bonds with the -COO − groups of GG polymer chains (Fig.…”

“…However, the large molecular size and polar nature of these small biomolecules may inuence the mobility of free ions, potentially reducing ionic conductivity in certain cases. 172,178 Therefore, it is crucial to investigate this potential effect on the electrochemical properties of hydrogels intended for strain sensing across a wide temperature range, from room temperature to subzero temperatures, to understand the underlying mechanisms better and bolster their practical adaptability. Moreover, future research should focus on selecting hydrogels for strain-sensing applications by optimizing their electrochemical properties in detail, considering the performance indicators of hydrogel-based strain sensors and mechanical considerations.…”

Anti-freezing multifunctional conductive hydrogels: from structure design to flexible electronic devices

“…Several other hydrogels incorporating the zwitterionic penetrant betaine have also been reported, showcasing the favorable behaviour of zwitterionic penetrants in antifreeze hydrogels to varying degrees. [67][68][69] Furthermore, the introduction of proline, a zwitterion, into hydrogel systems can contribute to the preparation of antifreeze hydrogels. Proline, being a biologically significant antifreeze agent, reduces the activity of water molecules and safeguards cellular tissues in living organisms.…”

A novel environment-tolerant hydrogel via a combination effect of a polyurethane coating and hygroscopic salt for underwater monitoring

“…Similar to SBMA-co-AA hydrogels, the (d) water retention, (e) swelling resistance, and (f) anti-freeze performance of different PVA hydrogels were tested, respectively. (g) Summary of recent environment-resistance hydrogels 21,28,35,[44][45][46]. ''N/A'' means ''not available'' in the references.…”