4d Printing of Actuators Possessing Spatially Continuous Motions via Speed-Defined Microstructure Assemblies
摘要：Microstructures with the capacity to deform actively have been employed by nature for billion years to perform dynamic functions of biological organisms. But so far, it is still difficult or not yet possible to duplicate in synthetic systems. Recently, the emergence of 4D printing offers an attractive option to fabricate dynamic bioinspired materials given its unparalleled flexibility in producing complex shapes and exquisite architectures. However, the potential of 4D printing has not been fully excavated yet. Here, it is discovered that simply by modifying certain processing parameters（namely print speed in our work）, microstructure assemblies and dynamic performance of active materials could be manipulated. Through this approach, not only the domains but also the amplitude of deformation could be modified on the fly. The spatially continuous motions in each layer, each path or even in one path are attainable. Moreover, the underlying mechanism is revealed via two theories and confirmed by ultrasound image diagnosis. This study mines the potential of 4D printing on the performance management of smart materials, and provides an efficient and versatile pathway in developing soft actuators with localized and intelligent response.