Jeong Hoon Yeub, An Soo-Chan, Jun Young Chul
Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
Nanophotonics. 2022 Jan 11;11(3):461-486. doi: 10.1515/nanoph-2021-0652. eCollection 2022 Jan.
Three-dimensional (3D) printing enables the fabrication of complex, highly customizable structures, which are difficult to fabricate using conventional fabrication methods. Recently, the concept of four-dimensional (4D) printing has emerged, which adds active and responsive functions to 3D-printed structures. Deployable or adaptive structures with desired structural and functional changes can be fabricated using 4D printing; thus, 4D printing can be applied to actuators, soft robots, sensors, medical devices, and active and reconfigurable photonic devices. The shape of 3D-printed structures can be transformed in response to external stimuli, such as heat, light, electric and magnetic fields, and humidity. Light has unique advantages as a stimulus for active devices because it can remotely and selectively induce structural changes. There have been studies on the light activation of nanomaterial composites, but they were limited to rather simple planar structures. Recently, the light activation of 3D-printed complex structures has attracted increasing attention. However, there has been no comprehensive review of this emerging topic yet. In this paper, we present a comprehensive review of the light activation of 3D-printed structures. First, we introduce representative smart materials and general shape-changing mechanisms in 4D printing. Then, we focus on the design and recent demonstration of remote light activation, particularly detailing photothermal activations based on nanomaterial composites. We explain the light activation of 3D-printed structures from the millimeter to sub-micrometer scale.
三维（3D）打印能够制造复杂的、高度可定制的结构，而这些结构使用传统制造方法很难制造出来。最近，四维（4D）打印的概念已经出现，它为3D打印结构增添了主动和响应功能。利用4D打印可以制造出具有所需结构和功能变化的可展开或自适应结构；因此，4D打印可应用于致动器、软体机器人、传感器、医疗设备以及有源和可重构光子器件。3D打印结构的形状可以响应外部刺激而改变，如热、光、电场、磁场和湿度。光作为有源器件的刺激源具有独特的优势，因为它可以远程且选择性地诱导结构变化。已经有关于纳米材料复合材料光激活的研究，但这些研究仅限于相当简单的平面结构。最近，3D打印复杂结构的光激活受到了越来越多的关注。然而，对于这个新兴主题尚未有全面的综述。在本文中，我们对3D打印结构的光激活进行了全面综述。首先，我们介绍4D打印中的代表性智能材料和一般形状变化机制。然后，我们重点关注远程光激活的设计和近期演示，特别详细介绍基于纳米材料复合材料的光热激活。我们从毫米尺度到亚微米尺度解释3D打印结构的光激活。
