Fig. 5. Peeling-induced shape morphing for 3D and 4D electronics.

a Graph showing that increased bending (measured as curvature) results in only a slight increase in resistance for Au-PTFE films. b A 3D circuit morphed from the 2D one with a light emitting diode (LED) connected to two helical wires with different chirality. c The stretching processes of the circuits in (b) with the LED rotating during the stretch but without compromising the light intensity. Left: schematic showing the position changes of the LED. d Schematic illustrations of the 3D cantilever-based piezoelectric systems. The piezoelectric system is of sandwich structure with two electrode layers and a piezoelectric layer. The 2D cantilevers can be transformed into 3D spiral-like structures by peeling-induced shape morphing. e, f The generated voltages of the single cantilever (e) and multi-arm cantilever (f) piezoelectric systems at different frequencies indicating the peeling-induced 3D cantilevers can sense broader vibrational frequencies and generate higher voltage than the straight one and the integration of the 3D cantilevers can further enhance the performance of the piezoelectric system. Scale bars are 1 cm. g Schematic illustrating the shape morphing of a bilayer actuator composed of an active plastic layer (PEO in our case) and a passive layer (PDMS). Subsequent exposure to humidity transforms the bilayer into 4D shapes. h Photographs showing polygonal PEO/PDMS films with PEO outwards transformed from hexagon to triangle and ellipse-like shape as humidity increases. i Humidity-responsive transformation of PEO/PDMS cylindrical helices. With active PEO inwards, the cylindrical helix became tight under lower humidity and loose under higher humidity. On the contrary, the cylindrical helix with PEO outwards exhibited opposite humidity-responsive motions. Source data are provided as a Source Data file.