3D Printing-Assisted Casting of Soft Electronic Materials

It is challenging to balance architectural complexity, electrical conductance, and material generality for the 3D printing of soft electronic materials. In this talk, I will discuss our efforts on 3D printing-assisted casting to alleviate this trade-off. Light-based 3D printing is used to create hollow molds, providing structural complexity and design freedom, whereas the casting nature imparts material versatility. The casting molds are made of superabsorbent polymers and printed in a partially hydrated state. Their dehydration provides significantly enhanced feature resolution and excellent thermal and mechanical properties, making them versatile for casting. After casting and curing desired materials within the mold cavity, over-hydration of the molds facilitate their energy-efficient removal. Using a polymeric conductor, poly(3,4-ethylenedioxythiophene) (PEDOT), as a model system, complex architectures such as octet and truncated octahedron can be achieved. Compositing silver flakes with PEDOT through a thermal injection process leads to prints with conductivity over 6000 S/cm. This method can also be applied to other hard-to-print soft materials and composites, and potentially enable multi-material structures through sequential casting.