Developments in 4D-printing:a review on current smart materials,technologies,and applications

摘要

Recent advances in additive manufacturing(AM),commonly known as three-dimensional(3D)-printing,have allowed researchers to create complex shapes previously impossible using traditional fabrication methods.A research branch that originated from 3D-printing called four-dimensional(4D)-printing involves printing with smart materials that can respond to external stimuli.4Dprinting permits the creation of on-demand dynamically controllable shapes by integrating the dimension of time.Recent achievements in synthetic smart materials,novel printers,deformation mechanism,and mathematical modeling have greatly expanded the feasibility of 4D-printing.In this paper,progress in the 4Dprinting field is reviewed with a focus on its practical applications.We discuss smart materials developed using 4D-printing with explanations of their morphing mechanisms.Additionally,case studies are presented on self-constructing structures,medical devices,and soft robotics.We conclude with challenges and future opportunities in the field of 4D-printing.