Inkjet printing-based fabrication of microscale 3D ice structures

This study proposed a method for fabricating 3D microstructures of ice without a supporting material. The inkjet printing process was performed in a low humidity environment to precisely control the growth direction of the ice crystals. In the printing process, water droplets (volume = hundreds of picoliters) were deposited onto the previously formed ice structure, after which they immediately froze. Different 3D structures (maximum height = 2000 µm) could be formed by controlling the substrate temperature, ejection frequency and droplet size. The growth direction was dependent on the landing point of the droplet on the previously formed ice structure; thus, 3D structures could be created with high degrees of freedom. Using inkjet printing technology, a method has been developed for fabricating 3-D ice microstructures, where the ice patterns possess geometries with a resolution of tens of micrometers. Recently, inkjet technology has gained attention for use in micromanufacturing, with different deposition processes being utilized to apply a material onto a substrate. Through the phase transition of water to ice, water offers many advantages as a material in this regard, though existing technologies demand expensive equipment and a supporting layer. A team headed by Zhihong Li at Peking University, China has succeeded in developing a method where inkjet printing is used to precisely control the growth of ice crystals in the fabrication process without needing a supporting layer. The authors believe their system offers considerable potential for application with biomicrofluidic devices, such as drug delivery systems.