SEES Fellows: Understanding the hierarchical assembly and economics of cellulose to enable high-performance, biomimetic, and sustainable composite materials

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

Non-technical: The project, supported by the Division of Materials Research and the Division of Chemistry, is made under the auspices of the NSF Science, Engineering and Education for Sustainability Fellows (SEES Fellows) program, with the goal of helping to enable discoveries needed to inform actions that lead to environmental, energy and societal sustainability while creating the necessary workforce to address these challenges. Sustainability science is an emerging field that addresses the challenges of meeting human needs without harm to the environment, and without sacrificing the ability of future generations to meet their needs. A strong scientific workforce requires individuals educated and trained in interdisciplinary research and thinking, especially in the area of sustainability science. With the SEES Fellowship support, this project will enable a promising early career researcher to establish himself in an independent research career related to sustainability. This project addresses the use of composite materials that are increasingly prevalent in applications where their high specific strength and stiffness outweigh the cost of their production. The use of sustainable materials in demanding applications demonstrate how additive systems enhance manufacturing processes both economically and environmentally. Working with Prof. John Hart of the Department of Mechanical Engineering at MIT and Prof. Eric Stach of the Center for Functional Nanomaterials at Brookhaven National Lab, this SEES Fellow investigates methods for combinatorial variation and in-situ characterization of cellulose source and treatments to discern and understand structural variation in all-cellulose composites. Significant professional development for the SEES Fellow will result from gaining experience in a new discipline, learning new experimental and computational techniques, as well as development of courses in sustainable 3D printing and CAD to enable wider participation in the opportunities for product design enabled by additive techniques and to educate the public in the environmental aspects of manufacturing. This will contribute to existing MIT educational programs for K-12 students, the local community, and, through massively open online courses, the wider world. Technical: This project addresses the cross-disciplinary factors necessary to make cellulose composites competitive and thus to advance the use of sustainable materials in manufacturing. The physical properties of cellulose composites are limited by the lack of understanding of how structure and interfacial bonding translate to mechanical behavior. This project studies study how biomimetic structuring of cellulose composites can enhance mechanical properties by local control of fiber alignment, porosity, and composition through a 3D printing process. Computational modeling is used to understand and predict optimal material architectures. Additionally, the project explores whether cellulose-bonding reversibility can enable a form of sustainable programmable matter. For these novel composites to contribute to global sustainability they will need to be adopted by industry and bring environmental benefits. In collaboration with Prof. Erica Fuchs of the Department of Engineering and Public Policy at Carnegie Mellon University, simulation modeling and empirical data will be used to compare the competitive position and environmental impact of additively manufactured biomimetic cellulose composites with glass fiber composites using prostheses as a case study. Comparing data on existing processes with the assumptions required to make the new materials competitive will elucidate how the technology must develop to become viable and the applications where it will have the greatest economic and environmental impact. The scientific focus of the project is on understanding structure-property relationships and subsequent formulation of rational strategies to enhance mechanical behavior in cellulose composites, which will also be applicable to other biomaterials and composites such as collagen or chitin. The ability to adapt biomaterial design principles by programming material properties across multiple length scales using 3D printing may also open a new avenue in the design of composites. This work will also advance understanding of how technology development can be guided towards viable applications using cost modelling.