Shape memory polymers (SMP) and shape memory polymer composite (SMPC) can automatically deform when actuated by stimulus, which have the advantages of fast response, high rebound rate, light weight, low cost, easy processing and applications in various intelligent structures and devices [1,2]. Four dimensional (4D) printing refers to adding new additive manufacturing technology on the basis of four dimensional time. The four-dimensional printing of SMPs/SMPCs can rapidly manufacture reconfigurable structures in aerospace, medical and other professional fields. Our team has developed a series of 4-D printed SMPs/SMPCs structures, such as bone scaffolds, vascular scaffolds and expandable spatial structures that can change shape or size in outer space. By designing the molecular structure of shape memory polymer and adding special functional fillers, the printing structure can be driven remotely by light, electricity and magnetic field. It believed that 4D technology will continue to bring more and more opportunities in many fields in the next few years.
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 Wei H, Zhang Q, Yao Y, et al. Direct-write fabrication of 4D active shape-changing structures based on a shape memory polymer and its nanocomposite[J]. ACS applied materials & interfaces, 2016, 9(1): 876-883.
 Leng J, Lan X, Liu Y, et al. Shape-memory polymers and their composites: stimulus methods and applications[J]. Progress in Materials Science, 2011, 56(7): 1077-1135.
Harbin Institute of Technology, China