Page 102 - Read Online

Huang et al. Soft Sci. 2025, 5, 24 https://dx.doi.org/10.20517/ss.2025.07 Page 9 of 19

indicating that the PCM organohydrogel possesses excellent adhesion reusability. This remarkable
reusability is attributed to the reversible interfacial interactions between the PCM organohydrogel and
substrate surfaces, allowing the adhesion to be maintained even after repeated cycles [Supplementary Figure
11]. This feature will undoubtedly ensure the long-term effectiveness and durability of PCM
organohydrogels in practical applications.

The self-healing ability of PCM organohydrogels is demonstrated through macroscopic, microcosmic and
tensile tests. As shown in Figure 3F, the lighted light-emitting diode (LED) in a simple circuit extinguishes
synchronously once the organohydrogel is cut into two pieces, and then the LED is lit again immediately
and the brightness can return to the original state after healing, giving an intuitive validation of the rapid
self-healing ability. The self-healing process of PCM organohydrogels at the damaged surface is traced via
an optical microscope [Figure 3G]. Two separate pieces of the PCM organohydrogel are recombined
without the application of external stress. After healing for 24 h, the incision in the PCM organohydrogel
nearly disappears [Figure 3H], demonstrating excellent self-healing behavior. Mechanical properties of the
healed PCM organohydrogel were measured to further evaluate the self-healing effect, and the
corresponding healing efficiency (HE) values were quantitatively calculated. As expected, the HE gradually
increases with the healing time [Figure 3I] and reaches 60% for a healing time of 72 h [Figure 3J].
Impressively, the healed organohydrogel shows good fatigue resistance [Supplementary Figure 12], further
confirming excellent self-healing ability and mechanical stability of the PCM organohydrogel. This
outstanding self-healing ability and stable mechanical performance may stem from multiple reversible
noncovalent bonds, such as hydrogen bonds between PAM chains, PA and PAM, PA and CS, PA and
MXene, PAM and MXene as well as CS and MXene, and electrostatic interactions between CS and MXene
nanosheets together with CS and PA within the organohydrogel system [Supplementary Figure 13]. This
remarkable recovery ability underscores the potential of PCM organohydrogels for applications where
durability and long-term functionality are critical, such as in flexible electronics.

Excellent environmental stability is vital for the practical application of organohydrogel, particularly when
used as sensors in both extreme and mild environments. The incorporation of GL and PA in the PCM
organohydrogel enables the formation of robust hydrogen bonds with water molecules within the network,
significantly enhancing the environmental stability of the hydrogel and extending its potential applications.
PCM organohydrogels are capable of sustaining twisting and large stretching deformations, and can even
light up an LED indicator at extreme temperatures of -30 and 60 °C, as well as 25 °C [Figure 4A], visually
demonstrating the excellent environmental stability. Furthermore, the favorable adhesion properties of
PCM organohydrogels can also be well maintained over a wide temperature range from -30 to 60 °C
[Figure 4B]. Temperature resilience of the PCM organohydrogel was probed through differential scanning
calorimetry analyses [Supplementary Figure 14]. The outstanding environmental stability is attributed to the
formation of strong hydrogen bonds between GL and water molecules, effectively reducing the saturated
[30]
vapor pressure of water . The hydrogen bonding network of adjacent molecules was explored through
Raman spectroscopy. The bands between 3,000 to 3,800 cm correspond to the O-H stretching vibration of
-1
water molecules and two type of water present in the spectra can be precisely distinguished , with the
[31]
peaks located at about 3,450 and 3,200 cm corresponding to strong and weak hydrogen bonded water
-1
molecules, respectively [Figure 4C]. Notably, when comparing the PCM hydrogel with the PCM
organohydrogel, a shift of the characteristic peak from 3,345 to 3,366 cm (blue shift) can be observed
-1
[Figure 4D]. This indicates that the strong hydrogen bonds between water molecules in the PCM
organohydrogel are affected by the PA/GL/water trisolvent system. The ratio of strong to weak hydrogen
bonds (I strong weak
/I ) decreases in the PCM organohydrogel [Supplementary Figure 15], suggesting a weakening
of hydrogen bonds in the organohydrogel. The long-term stability of PCM organohydrogels is further
assessed [Supplementary Figure 16].