Researchers develop 4D printing technology for composite materials

The breakthrough, they say, could open up new possibilities for the creation and use of adaptive, composite materials in manufacturing and biomedical applications. The concept developed by the University of Colorado team allows materials to self-assemble into 3D structures. By incorporating shape memory polymer fibres into composite materials, the researchers were able to produce an object fixed in one shape that could later be changed to take on a new shape. "In this work, the initial configuration is created by 3D printing, and then the programmed action of the shape memory fibres creates time dependence of the configuration – the 4D aspect," explained researcher Martin Dunn, from the Singapore University of Technology and Design. The team advanced the concept by creating composite materials that can morph into several different, complicated shapes based on a different physical mechanism. "The secret of using shape memory polymer fibres to generate desired shape changes of the composite material is how the architecture of the fibres is designed, including their location, orientation and other factors," Dunn explained. The researchers also demonstrated that the orientation and location of the fibres within the composite determines the degree of shape memory effects like folding, curling, stretching or twisting. The ability to control those effects is dependent on heating or cooling the composite material. As 3D printing technology matures with more printable materials and higher resolution at larger scales, the researchers believe the technology will help provide a new approach to creating reversible or tuneable 3D surfaces and solids in engineering, like the composite shells of complex shapes used in automobiles, aircraft and antennas.