Digital light fabrication of reversible shape memory polymers

Reversible shape memory polymers (SMPs) have received extensive attention because of their unique deformation mechanisms and diverse shape-changing behaviors. However, the traditional methods of fabricating reversible SMPs usually result in the limitation of the accessible shapes and the corresponding shape-shifting behaviors. Herein, a reversible SMP with two crystalline phases is digital light-cured via thiol-acrylate chemistry with the assist of a digital light processing (DLP) technology. Thus, a set of special geometric patterns can be obtained by digitally defined exposure regions with a specified time, allowing the achievement of the 3D kirigami or origami reversible actuation. In addition, this strategy can be extended to the emerging advanced 3D or 4D printing technologies by introducing z-axis dimension or time gradient, facilitating the fabrication of sophisticated reprogrammable reversible shape memory devices, including 4D printed grabber and 3D printed movable cartoon character. Our approach based on DLP enables the rapid and precise manipulation of shape-changing materials, which can extend the possibilities for future development in aerospace and other potential applications.