2025 AIChE Annual Meeting

(553c) Digital Light Processing of Multi-Materials with Extreme Stiffness Contrast

Authors

Nadia Chapple, University of California, Santa Barbara
Claire Nelson, University of California, Santa Barbara
Adarsh Krishnamurthy, Iowa State University
Baskar Ganapathysubramanian, Iowa State University
Angela A. Pitenis, University of California, Santa Barbara
Michael L. Chabinyc, University of California, Santa Barbara
Craig J. Hawker, University of California, Santa Barbara
Christopher M. Bates, University of California, Santa Barbara
Biology is replete with robust, strong, and functional multi-materials (e.g., nacre, bones). These properties are ascribed to their precise hierarchical structure and stiffness mismatch. Gaining inspiration from these, synthetic polymers and composites, owing to their versatility, have garnered interest as mimics for natural systems. This presentation will discuss the design and 3D printing of polymeric multi-materials with spatially controlled stiffness via digital light processing.

Orthogonal photoinitiation and curing of two independent polymer networks – polyethylene glycol-based bottlebrushes and epoxy-based resin – will be shown to result in super-soft and stiff domains, respectively. While the bottlebrush networks are formed via free radical polymerization, initiated by a shorter wavelength of light, the epoxy-based resin is cured via cationic ring-opening polymerization in the presence of visible light. The pivotal role of the photochemical components, polymerization mechanisms, and curing kinetics (role of exposure time and light intensity) on the printability of these materials will be discussed. Finally, the toughness, tensile strength, and elastic moduli of these multi-materials will be compared to biologically relevant hierarchical systems.