Latent Catalysis as an Enabling Tool for Photopolymerization 3D Printing

With the support of the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Dr. Frank A. Leibfarth of the University of North Carolina at Chapel Hill will develop approaches to enhance the properties of materials accessible by 3D printing. Photochemistry-based 3D printing, where a liquid resin is cured into a solid material using light, is an enabling polymer processing technology in applications where high degrees of precision and customization are required. Currently, the properties available from photochemistry-based 3D printing are limited to relatively brittle plastics. By developing an understanding of new catalysts that can be activated by both heat and light, the Leibfarth lab aims to expand the properties available from photochemistry 3D printing to tough plastics, degradable materials, and stretchy elastomers. Access to these valuable properties using inexpensive and widely available 3D printing technology could allow the on-demand, personalized production of materials for automotive parts, medical devices, and performance sportswear when and where they are needed. The ability to expand access to fabrication of these materials will help encourage advanced manufacturing in the US that can be deployed in rural or underserved regions, and it will promote the development of a distributed, highly trained technical workforce. The Leibfarth group will also use hands-on experiences with 3D printing as a platform through which to educate undergraduate and K-12 students about how the chemical structure of plastics influence their properties and recyclability. The Leibfarth group aims to develop a catalyst-driven approach to expand the suite of properties accessible from vat photopolymerization (VP) 3D printing. Thermally and photochemically latent catalysts will be developed that are dormant during printing but can subsequently be revealed to initiate the synthesis of interpenetrating networks whose properties are a synergistic combination of the two networks. Specific objectives of the work include the development of thermally and photochemically latent catalysts, the study of how reactivity is influenced by additives commonly found in 3D printing formulations, and the systematic evaluation of how polymer network architecture influences material properties. The expected outcomes of these studies are a fundamental understanding of catalyst reactivity and selectivity in complex environments relevant to advanced applications, such as VP 3D printing, as well as quantitative structure–property relationships in polymer networks. The focus on synthetic approaches that work in widely available photopolymerization 3D printers means that the broader impacts of these synthetic advances can immediately be translated into finished polymeric parts in modern manufacturing infrastructure. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.