Light activation of 3D-printed structures: from millimeter to sub-micrometer scale

Abstract Three-dimensional (3D) printing enables the fabrication of complex, highly customizable structures, which are difficult to fabricate using conventional methods. Recently, concept four-dimensional (4D) has emerged, adds active and responsive functions 3D-printed structures. Deployable or adaptive structures with desired structural functional changes can be fabricated 4D printing; thus, applied actuators, soft robots, sensors, medical devices, reconfigurable photonic devices. The shape transformed in response external stimuli, such as heat, light, electric magnetic fields, humidity. Light unique advantages a stimulus for devices because it remotely selectively induce changes. There have been studies on light activation nanomaterial composites, but they were limited rather simple planar complex attracted increasing attention. However, there no comprehensive review this emerging topic yet. In paper, we present First, introduce representative smart materials general shape-changing mechanisms printing. Then, focus design recent demonstration remote activation, particularly detailing photothermal activations based composites. We explain from millimeter sub-micrometer scale.