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Huang et al. Soft Sci. 2025, 5, 24 https://dx.doi.org/10.20517/ss.2025.07 Page 13 of 19

maximum TCR value [Figure 5H and Supplementary Table 6] [40-47] , making the PCM organohydrogel
particularly well-suited for complex application scenarios.

Given its robust mechanical properties and excellent strain sensing performance, the PCM organohydrogel
can be effectively assembled into wearable strain sensors for detecting complex physiological movements.
Notably, outstanding adhesion characteristic of PCM organohydrogels allows it to directly adhere to human
skin and conform to joint movements. As depicted in Figure 6A, subtle throat muscle activity, such as
speaking, can be accurately and promptly recognized on account of the high sensitivity and rapid sensing
capability of the PCM organohydrogel. Stable and reproducible response waveforms were observed when
the volunteer repeatedly spoke the phrase “ (ni h”, further demonstrating its excellent sensing
stability and reliability. Thanks to its favorable environmental stability, the PCM organohydrogel was
successfully adhered to the manipulator’s finger to precisely monitor bending deformation even in harsh
environments at -30 °C [Figure 6B] and 60 °C [Figure 6C], which is extremely indispensable in practical
applications. Additionally, the PCM organohydrogel maintained stable and consistent sensing response
signals during knee bending deformation detection after healing [Figure 6D], underscoring the self-healing
ability of the material and its ability to prolong sensor lifespan without compromising strain sensing
performance. Furthermore, the PCM organohydrogel strain sensor can also be employed for information
encryption via Morse code, enabling specific signal transmission through the arrangement of “dots” and
“dashes” [Supplementary Figure 21]. By controlling the deformation time of the PCM organohydrogel, the
output “dot” and “dash” signals can be used to convey different messages, such as “SOS” [Figure 6E] and
“HOT” [Figure 6F], which are translated from sensing signals into visible English letters. These results
validate the potential applications of our PCM organohydrogel in intelligent communication systems.

Thanks to repeatable adhesion and favorable conductivity, the PCM organohydrogel can be effectively
utilized as skin bioelectrodes for collecting high-quality electrophysiological signals. Circular epidermal
electrodes were fabricated and applied to the skin of the bicep [Figure 6G], forearm [Figure 6H], and calf
muscle regions of a volunteer to capture electromyography (EMG) signals generated by corresponding
muscle contraction movements. Low interfacial impedance is crucial for ensuring high-quality sensing
[48]
signals . As shown in Figure 6I, interfacial impedance of the organohydrogel electrode in the
4
physiologically relevant frequency range of 10-10 Hz is consistently lower than that of commercial gel
electrodes. Remarkably, interfacial impedance of the organohydrogel electrode was found to be as low as
7 Ω during the detection of the full spectrum of EMG signals. Even after 20 cycles of adhesion and
detachment, interfacial impedance of the organohydrogel electrode remains below 15 kΩ [Supplementary
Figure 22], demonstrating excellent stability and reliability for continuous EMG signal monitoring.
Interestingly, compared to the commercial gel electrode (9.6 dB), the organohydrogel EMG electrode
exhibits a higher signal-to-noise ratio (SNR) of 14.2 dB, ensuring excellent reliability for EMG signal
detection [Figure 6J]. Remarkably, the organohydrogel EMG electrode can capture characteristic action
signals corresponding to specific gestures, such as the numbers “1” to “3” [Figure 6K]. Similarly, the
organohydrogel EMG can be adhered to the calf muscle region of the volunteer to detect different
movement states, including jumping [Figure 6L] and walking [Supplementary Figure 23], underscoring the
potential application value of PCM organohydrogel in evaluating the muscle health status.

Ball game recognition has become increasingly important in the field of sports training. Five distinct ball
sports (basketball shooting, volleyball bumping, backhand table tennis, badminton smashing, and bowling)
can be efficiently recognized based on the seven-channel electrical sensing signals captured from seven
different parts of the volunteer’s body (i.e., thumb, index finger, middle finger, ring finger, little finger,
wrist, and elbow). Each set of response signals shows subtle variations for every repeated instance of the