Advanced Materials for Additive Manufacturing

In our Nature Communications paper we demonstrated a way to self-assemble materials using Polymerization-Induced Phase Separation that takes place in vat 3D printing due to spatial and temporal changes in the extent of polymerization.
Advanced Materials for Additive Manufacturing

Additive manufacturing (AM) is a transformative approach that uses direct deposition of materials to yield value-added products. New functional materials compatible with these emerging processes are required to enable smart surfaces and objects with seamlessly integrated sensing and responsive capabilities. To ensure compatibility, materials innovation must be carried out in parallel with the development of evolving manufacturing methods. Key to advanced manufacturing is the creation of carefully designed material packages specifically conceived to function with additive manufacturing.

2D printing is an additive manufacturing process that provides unique advantages such as manufacturing on flexible substrates in large‐areas with high throughput. Steady progress in 2D printed electronics has led to improvements in device performances and has increasingly impacted interactive display technologies, effectively enhancing the human-machine interface. However, the demands to provide increasingly complex, conformal, and stretchable electronics with more diverse functionality is pushing the development of a new generation of printable materials. One emerging opportunity is in-mold electronics, a fabrication methodology that relies on 2D printed electronics that can be molded into any shape using thermoforming. Thus, with suitable materials, in-mold electronics provides a strategy to generate adaptive and sensing conformal surface using additive manufacturing methods and thus enhancing the interactive experience in automotive, aerospace and household applications.

But, we live in a 3D world and thus there is a push to produce smart 3D objects directly? To make smart 3D object directly, what we need are smart materials, where we can exploit fundamental concepts in chemistry/physics, such as self-assembly, to spatially structure multiple and distinct materials over multiple length scales. Through novel chemistries, and the exploitation of controlled self-assembly, various functions (e.g. electrical, optical, magnetic, mechanical) may be introduced into objects as they are being printed. With this level of control, adaptive, interactive, intelligent parts can be 3D printed that will support the next generation of objects for industries including automotive, manufacturing, healthcare and consumer goods.

In our work, we developed a way to self-assemble materials using polymerization-induced phase separation (PIPS) that takes place in vat 3D printing due to spatial and temporal changes in the extent of polymerization. We demonstrated, how PIPS can be used to modulate the spatial distribution of different material phases via controlling the kinetics of gelation, cross-linking density and material diffusivity through the judicious selection of photoresin components. A continuum of morphologies, ranging from functional coatings, gradients and composites are generated enabling the fabrication of 3D piezoresistive sensors, 5G antennas and antimicrobial objects. This strategy is an example illustrating a promising way forward in the integration of dissimilar materials in 3D printing of smart or functional parts. Due to the universality of this approach, 3D PIPS represents a powerful method to create materials with a continuum of morphologies using a vast material set and will accelerate the adoption of vat polymerization as a viable technique to generate functional 3D objects.