Thermal-, magnetic-, and light-responsive 4D printed SMP composites with multiple shape memory effects and their promising applications

Driven by increasingly complex functional requirements, the shape memory polymer (SMP) is more competitive due to its convertible configuration and tunable properties. In particular, the multi-shape SMP that is not limited to one temporary configuration gives more possibilities for intelligent applications of SMP. However, it is still challenging to manufacture highly controllable and selectively programmable multi-shape SMP in a facile and scalable manner. Here, thermal-, magnetic-, and light-responsive 4D printed SMP composites with up to eight shape memory effects were developed, with the advantages of selective programming, highly controllable deformation in time and space, and configuration customization. The introduction of 4D printing into the manufacturing of multi-responsive SMP composites allowed for easy implementation and rapid manufacturing of controllable and customizable dynamic structures. Through the design of multi-material and multi-structural modules, coupled with 4D printing technology, the multi-responsive SMP composites were endowed with unlimited design freedom. 4D printed multi-responsive SMP composites realized accurate and selective actuation, tripled programmability, and efficient encrypted transmission of multiple types of information (e.g., encrypted transmission of idioms in the form of combined graphs and text), showing attractive application prospects in flexible robots, highly programmed metamaterials, information encryption carriers, etc.