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Page 6 of 19 Huang et al. Soft Sci. 2025, 5, 24 https://dx.doi.org/10.20517/ss.2025.07

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reveals that the N of CS interacts strongly with amide group of PAM and -P(OH) of PA [Figure 1G]. The
3
-1
E for the PAM-CS-PA-GL-H O system is as high as -556.17 kcal·mol , which is nearly 4.9, 4.1, and 3.3
2
int
times higher than that of PAM-CS-PA, PAM-CS-PA-H O, and PAM-CS-PA-GL, respectively, indicating
2
that the GL/H O/PA trisolvent exhibits stronger hydrogen bond with the crosslinked polymer networks
2
than single-solvent or binary-solvent systems [Figure 1G, Supplementary Figures 5-7, and Supplementary
Tables 1-4]. The stronger E in the PCM organohydrogel is attributed to the strong multiple dynamic
int
hydrogen bonds between water, GL, PA, and polymer chains, disrupting the formation of hydrogen bond
networks between water molecules and endowing the PCM organohydrogel with excellent environmental
stability.
PCM organohydrogels demonstrate high stretchability, withstanding direct and twisted stretching up to
2,800% and 2,200% strain without fracture, respectively [Figure 2A]. Furthermore, the PCM organohydrogel
can support a 100 g weight without significant damage [Figure 2B], showcasing its excellent toughness.
Mechanical properties of PCM organohydrogels were further analyzed as a function of MXene content
[Figure 2C], and the incorporation of MXene enhances both tensile strength and elongation at break, with
these properties peaking at an optimized MXene content and declining at higher concentrations
[Figure 2D]. Here, the MXene content dependent mechanical properties can be explained as follows: when
-1
the MXene content is relatively low (< 0.2 mg·g ), secondary crosslinking occurs between the MXene
nanosheets and the organohydrogel framework through the abundant hydrophilic functional groups of
MXene. This promotes the uniform dispersion of MXene in the hydrogel system and increases crosslinking
[24]
density, thereby improving tensile strength and elongation at break . However, when the MXene content
rises to 0.3 mg·g , excess MXene nanosheets tend to aggregate, disrupting the uniformity of the hydrogel
-1
and reducing tensile strength and elongation at break . As a result, the PCM organohydrogel with the
[25]
optimized MXene content of 0.2 mg·g exhibits a tensile strength of 80 kPa and an elongation at break of
-1
2,800%, indicating that the incorporation of CS can improve mechanical properties of the nanocomposite
organohydrogel [Supplementary Figure 8]. Moreover, incorporating MXene nanosheets also enhances
conductivity of the PCM organohydrogel due to the excellent metallic conductivity of MXene and its ability
to provide sufficient electron transport channels in the organohydrogel [Supplementary Figure 9]. Based on
the optimal balance between mechanical properties and conductivity, the PCM organohydrogel is selected
0.2
for further experiments.

Cyclic loading-unloading tests were conducted to further investigate the energy dissipation behavior and
anti-fatigue ability of PCM organohydrogels. Figure 2E exhibits consecutive loading-unloading
measurements of the PCM organohydrogel under increased strains, where clear hysteresis loops are
observed during the loading-unloading cycles. As the tensile strain increases from 100% to 1,000%, the
dissipated energy (U ) of the PCM organohydrogel rises from 2.7 to 37.2 kJ·m [Figure 2F]. Meanwhile, the
-3
hys
subsequent loading curve does not completely overlap with the previous unloading curve, which is
attributed to the partial quick re-association of dissociated noncovalent bond interactions during loading,
contributing to the energy dissipation . Exceptional fatigue resistance is critical for ensuring the cycle
[26]
stability and prolonged service life of CH-based sensors. To evaluate the anti-fatigue ability, the PCM
organohydrogel was subjected to 20 consecutive loading-unloading cycles. The PCM organohydrogel
-3
presents a pronounced hysteresis loop with the U of 46.8 kJ·m in the first cycle [Figure 2G], which is
hys
attributed to the rearrangement of polymer chains and multiple noncovalent bond interactions within the
[27]
PCM organohydrogel . However, hysteresis loops of the subsequent nineteen cycles overlap almost
perfectly, and the U stabilizes at approximately 5.2 kJ·m [Figure 2H]. This stable energy dissipation
-3
hys
across cycles highlights the excellent fatigue resistance of the PCM organohydrogel, which is attributed to its
rapid self-recovery behavior . This ability ensures the hydrogel’s durability and effectiveness as a flexible,
[28]