Figure 6.

Self-healing and remolding of SHARK. (a) Optical images showing cutting, rejoining and stretching of SHARK. The band was only knotted to allow healing for seconds under stress. Scale bar = 5 mm. (b) Stress-strain curves of the initial and healed SHARK band in a continuous test. Insets correspond to schematics of the original, cut and healed samples. (c) Typical stress-strain curves of hydrogels healed for different healing times at room temperature (healing pressure ∼25 kPa). The inset shows the time-dependent recovery percentage of fracture strain. (d) Time evolution of multiple electrical healing processes for the same sample by gently touching the broken surfaces together (healing pressure ∼25 kPa, healing time ∼5 s). (e) Healing of the electrical properties after different healing times (top, healing pressure ∼25 kPa) and pressures (bottom, healing time ∼5 s). (f) Remolding of SHARK into different shapes. Scale bar = 5 mm. (g) Stretching the same sample before and after remolding. Scale bar = 5 mm. (h) Reciprocal of capacitance (1/capacitance) vs strain and stress vs strain for a remolded band-shaped SHARK sensor in a tensile strain range of 0–15 mm mm⁻¹. (i and j) Change in the capacitance of remolded SHARK in multiple bending (i) and stretching (j) cycles at a strain of 0.5 mm mm⁻¹. Insets show schematics of the bending and stretching cycles. (k) Demonstration of extrusion-based 3D printing of SHARK into different 2D shapes. (l) Optical and SEM images of multiple-layer mesh structured SHARK prepared by 3D printing.