CAREER: Extrusion-based Additive Manufacturing of Sustainable Thermoplastics via Enzyme Encapsulation and Microfluidic Structuring of Hierarchical Composites

Additive manufacturing (AM) of thermoplastics serves a large and growing market to produce parts for industries such as consumer electronics, automotive, aerospace and medical, etc. As the demand continues to increase, there is a need to advance the science of AM to create processing and materials that not only achieve a balance of performance, efficiency and cost, but especially also address impacts on the environment.

This Faculty Early Career Development (CAREER) award supports fundamental research into novel AM processes combining sustainable plastic composite blends with thermally-protected biological components and electrically conductive fillers. The approach will leverage innovations in microfluidic print technologies, which enable precise thermoplastic processing of materials to combine a variety of unique material properties.

Once completed, the project will inform materials selection for a variety of performance-driven applications, accelerating widespread adoption and commercial viability of such materials as degradable-by-design plastics and environmental sensors. At its central effort, this project will establish education and outreach activities for a variety of student groups, including those historically underrepresented in these areas of research.

In particular, this project will develop interactive hands-on three-dimensional printing experiences for rural high school and tribal college students and integrate additive manufacturing research of sustainable, hierarchical polymers into curricula at Montana State University.

The overarching goal of this interdisciplinary research, integrating manufacturing, materials science and chemistry, is to enable novel multi-material thermoplastic composite structures that incorporate functional biologics, such as enzymes, and electrically conductive fillers. There are two research thrusts in this CAREER endeavor. The first is to understand the conditions needed to create additive manufacturing filaments that can successfully encapsulate heat-sensitive biologically derived enzymatic constituents, such that their biological activity is substantially retained upon thermoplastic processing into final composites.

The amount of thermal shielding will be quantified by analyzing the environmental degradability of complete composite samples manufactured via microfluidic controls of material extrusions through custom-design print-heads for fused filament fabrications. The second thrust is to explore the processing and properties of electrically-conductive components using the developed methods to hierarchically structure multi-material systems.

An innovative microfluidic technique, based on combining materials with precise local structural and thermal control through engineered AM print-heads, will be utilized to better understand the required process conditions. Further, topology optimization and microfluidic modeling will be used in conjunction with experiments to determine processing parameter space.

The culmination of these two research efforts will be a successful demonstration of an additively manufactured bio-based passive sensor that biodegrades in response to humidity. This project is jointly funded by the division of Civil, Mechanical and Manufacturing Innovation (CMMI) and the Established Program to Stimulate Competitive Research (EPSCoR).

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.