Wan Xue, Luo Lan, Liu Yanju, Leng Jinsong
Center for Composite Materials and Structures Harbin Institute of Technology Harbin 150080 P. R. China.
Department of Astronautical Science and Mechanics Harbin Institute of Technology Harbin 150001 P. R. China.
Adv Sci (Weinh). 2020 Jun 29;7(16):2001000. doi: 10.1002/advs.202001000. eCollection 2020 Aug.
4D printing has attracted academic interest in the recent years because it endows static printed structures with dynamic properties with the change of time. The shapes, functionalities, or properties of the 4D printed objects could alter under various stimuli such as heat, light, electric, and magnetic field. Briefly, 4D printing is the development of 3D printing with the fourth dimension of time. Among the fabrication techniques that have been employed for 4D printing, the direct ink writing technique shows superiority due to its open source for various types of materials. Herein, the state-of-the-art achievements about the topic of 4D printing through direct ink writing are summarized. The types of materials, printing strategies, actuated methods, and their potential applications are discussed in detail. To date, most efforts have been devoted to shape-shifting materials, including shape memory polymers, hydrogels, and liquid crystal elastomers, showing great prospects in areas ranging from the biomedical field to robotics. Finally, the current challenges and outlook toward 4D printing based on direct ink writing are also pointed out to leave open a significant space for future innovation.
近年来，4D打印引起了学术界的关注，因为它能使静态打印结构随时间变化而具有动态特性。4D打印物体的形状、功能或属性在诸如热、光、电和磁场等各种刺激下可能会发生改变。简而言之，4D打印是在3D打印基础上发展起来的，增加了时间这一维度。在已用于4D打印的制造技术中，直接墨水书写技术因其对各种材料的开源性而具有优势。在此，总结了通过直接墨水书写进行4D打印这一主题的最新成果。详细讨论了材料类型、打印策略、驱动方法及其潜在应用。迄今为止，大多数工作都集中在形状改变材料上，包括形状记忆聚合物、水凝胶和液晶弹性体，这些材料在从生物医学领域到机器人技术等诸多领域都展现出了广阔前景。最后，还指出了基于直接墨水书写的4D打印当前面临的挑战和前景，为未来的创新留出了很大空间。
