Highly Conductive Multifunctional rGO/CNT Hybrid Sponge for Electromagnetic Wave Shielding and Strain Sensor

Abstract One of the potential applications for carbon nanotube (CNT) sponge prepared through chemical vapor deposition (CVD) is as a strain sensor. However, the sensitivity of CNT sponge is strongly impeded by the point‐to‐point contact between individual CNTs. A novel method is proposed to introduce reduced graphene oxide (rGO) as a conducting bridge into CNT sponge, in order to dramatically improve the CNT contact. The graphene oxide (GO) is coated onto polystyrene (PS) spheres forming a suspension that is infiltrated into the CVD‐derived CNT sponge under vacuum. The PS spheres are decomposed and GO is reduced by postannealing. Scanning electron microscopy confirms the successful introduction of rGO. A small amount of rGO can effectively increase the electrical conductivity of the CNT sponge by ≈30% without an observable increase in density. A dramatic increment of 66% in sensitivity factor is achieved. Compared with CNT sponge, the microwave shielding effectiveness of the rGO/CNT hybrid sponge is 50% larger. This hybrid sponge is very promising for use as a high‐sensitivity strain sensor in different environments (both in the air and under water) and for high‐efficiency electromagnetic shielding protection.