Self-folding magnetic Ti–Ni Bi-metallic micro-origami

With the maturity of micro–nano-technology and the increasing demand for low-dimensional metals, the research on the transformation from two-dimensional metal to three-dimensional structure has become a flourishing topic. Due to its unique function, the different transformed 3D shapes could meet different functional requirements while retaining the advantages of micro/nano-metal processing. Here, a simple method was developed to form two-dimensional metal films into three-dimensional structures by self-folding or crimping (also known in the literature as origami). Unlike previous works, this research uses Bi-layers as a two-dimensional metal film, adding Nickel's magnetic metal to ordinary micro-origami. The magnetic nature of added metals takes the primary response to achieve the feature that wireless or contactless methods can control micro-3D structures. The Bi-layers could be magnetically controlled to move on the liquid surface for self-expansion. This achievement shows that this unique control method has great potential for new applications.