Intrinsic elastic conductors with internal buckled electron pathway for flexible electromagnetic interference shielding and tumor ablation

The elastic conductor is crucial in wearable electronics and soft robotics. The ideal intrinsic elastic bulk conductors show uniform three-dimensional conductive networks and stable resistance during large stretch. A challenge is that the variation of resistance is high under deformation due to disconnection of conductive pathway for bulk elastic conductors. Our strategy is to introduce buckled structure into the conductive network, by self-assembly of a carbon nanotube layer on the interconnecting micropore surface of a prestrained foam, followed by strain relaxation. Both unfolding of buckles and flattening of micropores contributed to the stability of the resistance under deformation (2.0% resistance variation under 70% strain). Microstructural analysis and finite element analysis illustrated different patterns of two-dimensional buckling structures could be obtained due to the imperfections in the conductive layer. Applications as all-directional interconnects, stretchable electromagnetic interference shielding and electrothermal tumor ablation were demonstrated.