3D Chiral Micro‐Pinwheels Based on Rolling‐Up Kirigami Technology

Expanding micro‐/nanostructures into 3D ones results not only in boosting structural integration level with compact geometry but also enhancing a device's complexity and functionality. Herein, a synergetic 3D micro‐/nanoshape transformation is proposed by combining kirigami and rolling‐up techniques, or rolling‐up kirigami, for the first time. As an example, micro‐pinwheels with multiple flabella are patterned on pre‐stressed bilayer membranes and rolled up into 3D structures. The flabella are designed when they are patterned on a 2D thin film, facilitating the integration of micro‐/nanoelement and other functionalization processes during 2D patterning, which is typically much easier than post‐shaping an as‐fabricated 3D structure by removing redundant materials or 3D printing. The dynamic rolling‐up process is simulated using elastic mechanics with a movable releasing boundary. Mutual competition and cooperation among flabella are observed during the whole release process. More importantly, the mutual conversion between translation and rotation offers a reliable platform for developing parallel microrobots and adaptive 3D micro‐antennas. Additionally, 3D chiral micro‐pinwheel arrays integrated into a microfluidic chip are successfully applied to detect organic molecules in solution using a terahertz apparatus. With an extra actuation, active micro‐pinwheels can potentially serve as a base to functionalize 3D kirigami as tunable devices. Rolling‐up kirigami technology can dynamically transform 2D topographies into 3D micro‐pinwheels with a huge lift displacement and large rotation angle. The mutual conversion between translation and rotation under the external force and organic molecule detection under the terahertz range support active micro‐pinwheels can potentially serve as a base to functionalize 3D kirigami as tunable devices under an extra actuation.