University of Texas at Arlington researchers have developed a technique that programs 2D materials to transform into complex 3D shapes. The goal of the work is to create synthetic materials that can mimic how living organisms expand and contract soft tissues and thus achieve complex 3D movements and functions. Programming thin sheets, or 2D materials, to morph into 3D shapes can enable new technologies for soft robotics, deployable systems, and biomimetic manufacturing, which produces synthetic products that mimic biological processes.1

Their research, supported by a National Science Foundation Early Career Development Award that Yum received in 2019, was published in January in Nature Communications.2

With this inspiration, the researchers developed an approach that can uniquely create 3D structures with doubly curved morphologies and motions, commonly seen in living organisms but difficult to replicate with human-made materials.

  • 1. Kyungsuk Yum, an associate professor in the Materials Science and Engineering Department, and his team have developed the 2D material programming technique for 3D shaping. It allows the team to print 2D materials encoded with spatially controlled in-plane growth or contraction that can transform to programmed 3D structures.
  • 2. "There are a variety of 3D-shaped 2D materials in biological systems, and they play diverse functions," Yum said. "Biological organisms often achieve complex 3D morphologies and motions of soft slender tissues by spatially controlling their expansion and contraction. Such biological processes have inspired us to develop a method that programs 2D materials with spatially controlled in-plane growth to produce 3D shapes and motions."

Amirali Nojoomi, Junha Jeon, Kyungsuk Yum. 2D material programming for 3D shaping. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-20934-w

Two-dimensional (2D) growth-induced 3D shaping enables shape-morphing materials for diverse applications. However, quantitative design of 2D growth for arbitrary 3D shapes remains challenging. Here we show a 2D material programming approach for 3D shaping, which prints hydrogel sheets encoded with spatially controlled in-plane growth (contraction) and transforms them to programmed 3D structures. We design 2D growth for target 3D shapes via conformal flattening. We introduce the concept of cone singularities to increase the accessible space of 3D shapes. For active shape selection, we encode shape-guiding modules in growth that direct shape morphing toward target shapes among isometric configurations. Our flexible 2D printing process enables the formation of multimaterial 3D structures. We demonstrate the ability to create 3D structures with a variety of morphologies, including automobiles, batoid fish, and real human face.

Fig. 2: Growth-induced 3D shaping
Fig. 2: Growth-induced 3D shaping - a–d Target 3D shapes: 3D shape defined by a height function (a), sea shell (b), leaves (c), and automobile with open windows (d). e–h 2D growth Ω for the target shapes in a–d. i–l Experimentally printed structures using Ω in e–h. We printed three leaves with the same shape but different sizes in k. m 3D scanning and printing of a model automobile. Scale bars: 5 mm in e–h; 3 mm in i; 2 mm in j; 5 mm in k; 2 mm in l; 5 mm (left) and 2 mm (right) in m.