Page 24 - Read Online

Zhu et al. Soft Sci 2024;4:17 https://dx.doi.org/10.20517/ss.2024.05 Page 11 of 38

Figure 6. (A) Various gel materials and their characteristics [93] ; (B) Schematic structure and main properties of CS/P(AA-co-
3+
2+
AAm)/MXene@PEI/Fe +Cu nanocomposite dual network hydrogel [94] ; (C) the opaque/transparent transition of SN-PAAM dual-
[95]
responsive ion-conducting hydrogel . KPS: Potassium persulfate; TMEDA: tetramethylethylenediamine; CS/P(AA-co-
AAm)/MXene@PEI: Chitosan/poly(acrylic acid-co-acrylamide)/MXene@polyethyleneimine; SN-PAAM: sodium dodecyl sulfate-
modified poly(acrylamide) hydrogel.
application areas . Some application scenarios require hydrophobicity . Organo-hydrogel- and ionogel-
[96]
[97]
based strain sensors using organic solvents can alleviate these problems and typically exhibit dominance to
freezing, desiccation, and long-term stability [98-100] . Mao et al. developed a poly[oligo(ethylene glycol)
methylacrylate-co-acrylic acid]/hydrated ionic liquid [P(OEGMA-co-AA)/HIL] hydrogel with good
electrical conductivity, self-healing ability, and frost resistance by a simple in situ photopolymerization
strategy . The incorporation of ionic liquid (IL) greatly reduces the freezing point of water, which gives
[101]
the sensor excellent anti-freezing properties. The temperature dependence of the abundant hydrogen
bonding it contains endows this ionic hydrogel with switchable transparency, which allows for the
visualization of ambient temperature, demonstrating the potential of the gel material for temperature
sensing.