Three-dimensional printing of ice structures via evaporative cooling in vacuum

We demonstrate an approach to three-dimensional (3D) printing of ice structures by exploiting evaporative cooling. A micrometer-sized water jet is used to 3D print inside a vacuum chamber. The reduced ambient pressure leads to rapid evaporation of the extruded water, extracting latent heat, and quickly cooling the water well below 0 °C. Once deposited, the water freezes almost instantaneously into stable ice structures. We achieved high-fidelity printing via two distinct deposition techniques: layer-by-layer deposition for intricate 3D structures (e.g., a Christmas tree), and support-free mid-air printing for upright profiles (e.g., an in profile face), all achieved without cryogenic infrastructure, supporting materials, or external refrigeration. This approach directly visualizes fundamental thermodynamic principles—latent heat, evaporative cooling, and pressure-dependent phase transitions—while offering a relatively simple and scalable platform for ice-templated microfluidics and tissue engineering, or even extraterrestrial 3D printing.