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

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Figure 10. (A) the self-healing process and resistance change of the PVDF-NFs/PVDF-HFP/FS3000 e-skin ; (B) the structure and
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healing mechanism of the Clay/P(MEO MA-co-OEGMA) sensor ; (C) the structure of PDMS/MWCNT+LM capacitive strain sensing
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e-skin . Laponite XLG Clay: 92.32 wt.% [Mg Li Si O (OH) ]Na and 7.68 wt.% Na P O ; KPS: potassium persulfate; TEMED:
5.34 0.66 8 20 4 0.66 4 2 7
N,N,N′,N′-tetramethylethylenediamine; GW: glycerol-water cosolvent; LM: liquid metals; RT: room temperature; PVDF: polyvinylidene
fluoride; NFs: nanofibers; HFP: hexafluoro propylene; P(MEO MA-co-OEGMA): poly(methoxyethyl acrylate-co-oligo(ethylene glycol)
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methacrylate; PDMS: polydimethylsiloxane.
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(elongation ~600%), and conductivity (~3.32 × 10 S·cm ), and the abundant hydrogen bonding
interactions between the clays and the P(MEO MA-co-OEGMA) chains contribute to a good self-healing
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ability (healing efficiency of 84.8%).
On the other hand, the self-healing function of e-skins needs to repair not only mechanical damage but also
damage to the conductive pathways inside the device [166-168] . A fashionable approach is to use liquid metals
(LM) with high conductivity and fluidity, such as eutectic gallium indium (EGaIn) alloys, Fe-particle doped
EGaIn (Fe-EGaIn), to make e-skins [169-174] . The LM will form a shell with the surrounding resin matrix and
air, encasing it inside. When the device is damaged, this shell ruptures and the LM inside will flow out,
re-forming the conduction path and a new shell, where the resin matrix obviously also serves as an
encapsulation in the device [175-180] .

Chen et al. fabricated a self-healing resin matrix + LM capacitive strain sensing e-skin by combining
nanoimprinting and printing technologies [Figure 10C] MWCNT-reinforced reversible imine-bonded self-
healing poly (dimethylsiloxane) elastomers (PDMS/MWCNT) were used as the substrate, and their good
imprintability was utilized to prepare embedded LM patterned circuits, which were assembled to form a
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capacitive strain sensor that is fully stretchable and self-healing . The related e-skin possesses extremely