4D Printing Strain Self-Sensing and Temperature Self-Sensing Integrated Sensor-Actuator with Bioinspired Gradient Gaps.

Integrated sensor-actuators with exciting functionalities, such as action self-sensing, position self-sensing, posture self-sensing, or active sensing, are promising for applications in biomedical device, human-machine interaction, intelligent self-protection devices, and humanoid robots. Despite recent progress, it remains challenging to achieve a macroscopical integrated sensor-actuator in a material system with microstructures. To address this critical challenge, a 4D printing bioinspired microstructure strategy is reported to design a high-performance integrated sensor-actuator capable of simultaneous actuation and sensation. Decoupled thermal stimulation and strain sensation is achieved by combining nanocarbon black/polylactic acid composites with bioinspired gradient microgap structures. As a result, printed integrated sensor-actuators can actively touch objects triggered by thermal stimulation and self-sense the touching state through the resistance change. It is anticipated that the basic design principle underlying this behavior can be used to develop integrated sensor-actuators of various shapes and functionalities to meet desirable applications.