Asymmetric bilayer CNTs-elastomer/hydrogel composite as soft actuators with sensing performance

Living creatures have the nature of actuating and sensing under external stimuli to better adapt to the environment. For instance, the combination of muscles actuation and skin sensing ensures our intelligent interaction with external environments. In terms of the soft robot, implanting sensation and actuation in one system can assist us to control it better and more efficiently. However, in the development of biomimetic materials, the simultaneous realization of actuating and sensing performance in bionic soft robots is still a great challenge. Here, we propose a novel asymmetric bilayer CNTs-elastomer/PNIPAm hydrogel composite with integrated actuating and sensing performances. Due to the excellent photothermal effect of CNTs and thermo-responsiveness of PNIPAm, under the NIR irradiation, the PNIPAm hydrogel layer would shrink and the bilayer composite would thus perform a bending deformation. At the same time, based on a piezoresistive sensing mechanism of the CNTs-elastomer, the actuating procedure can be recorded. This work may open up a new insight in the designing and fabricating intelligent biomimetic hydrogel soft robots with integrated self-sensing capacity.