This talk will discuss the use of liquid metals for 3D printing. Gallium-based metal alloys have interesting properties including low-viscosity, low melting point, low toxicity, and negligible volatility. Despite the large surface tension of the metal, it can be molded, patterned and printed into non-spherical shapes due to the presence of a native oxide skin that is only a few nanometers thick. We have harnessed these properties to form a number of electronic devices encased in polymer matrices. The resulting structures take on the mechanical properties of the polymer and can therefore be soft, self-healing, and ultra-stretchable. The metal can be printed and then withdrawn from 3D printed structures as a sacrificial, fugitive ink to create microvasculature in polymer monoliths. In addition, it is possible to 3D print vasculature within polymeric materials printed using conventional 3D printing, and then back-fill the structures with liquid metal to add function in a post-processing step. The metals can be used for adding electrical conductivity as well as toughening. Finally, we have recently demonstrated ways to treat 3D printed polymeric structures so that liquid metal can be injected and withdrawn on demand. This allows for reconfigurable and dynamic structures in which the conductors can be fully recovered. The challenge is to create a coating that can be deposited on the walls inside 3D printed parts without damaging the part. To address this, we have create a solvent-based coating that uses fumed silica to create slightly roughened surface to which the liquid metal does not adhere. This talk will discuss the key processing parameters to enable printing of metal, the applications of such printing, as well as future opportunities and challenges.

3D printing of liquid metals and composites for stretchable, dynamic and recoverable conductors

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.