Development of PDMS-Based Ink for 3D Printing Applications

Unique processes and technologies based on polymer-based additive manufacturing (AM), or three-dimensional (3D) printing, have attracted a great deal of interest, due to their potential applications in automotive, biomedicals, electronic devices, aerospace, and energy. In contrast to traditional manufacturing, AM technology is increasingly used to create customized items and components with complex geometries that were previously unattainable. However, polymer-based feedstocks suitable for AM processes, particularly direct-ink-writing, are very limited due to challenges on controlling the inks’ rheological properties and complicated formulation chemistry. Here we report new polydimethylsiloxane-based inks with optimized rheological properties, tailored through solubility parameters and intermolecular interactions via molecular dynamics simulations. We found that the surface characteristic of silica affects the miscibility between components in the ink formulation, showing a similar trend for both computational and experimental results. With the assistance of molecular dynamics, quantifying the yield stress of inks allowed us to design appropriate ink formulations offering 3D printability without sagging issues during the printing process. Our results demonstrate that the hierarchical calculations from simplified models for solubility parameters to mixed-layer models for interaction energy and dynamics behavior successfully support experimental design to conceive optimized polydimethylsiloxane-based 3D printable ink formulations. Furthermore, this approach allows for a better understanding of the relationship between structures and the final properties of the inks. The present computational approach provides valuable insight on the chemical interaction between the components that make-up the ink, and also on guiding material development to further improve performance to expand AM technology applicability.