|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Additive Manufacturing: Nano/Micro-mechanics and Length-scale Phenomena
||Crack-Free Three-Dimensional Electrical Interconnects 3D Printed on Soft PDMS Substrates
||Jacob Brenneman, Derya Tansel, Gary Fedder, Rahul Panat
|On-Site Speaker (Planned)
Nanoparticle 3D printing and sintering is a promising method to achieve freeform interconnects on compliant substrates. Previous strategies to sinter metallic nanoparticles while preserving the soft polymer substrate are rife with problems such as cracking and low conductivity of the metallic features. Capillary force between nanoparticles developed through rapid solvent evaporation in the colloidal ink is hypothesized to initiate cracking during drying. An experimental step-wise variation of the thermal/atmospheric process conditions supports this hypothesis and shows that the presence of air during a low temperature drying step reduces the capillary stress to produce crack-free interconnects with high conductivities (up to 56% of bulk metal) while having an excellent compatibility with the underlying polymer materials. This result is then used to realize interconnects fully-encapsulated by a soft polymer with three-dimensional pillar architectures providing external connections through the polymer, thus also solving an important ‘last-mile’ problem in the packaging of stretchable electronics.