Collaborative Research: Stronger than Glass Fibers; Stiffer than Steel Wires: A New Perspective into the Mechanics of Cellulose Nanocrystals

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ID: MPS/DMR/BMAT(7623) 1100806 PI: Shahbazian-Yassar, Reza ORG: Michigan TechID: MPS/DMR/BMAT(7623) 1100572 PI: Simonsen, John ORG: Oregon StateTitle: Collaborative Research: Stronger than Glass Fibers, Stiffer than Steel Wires: A New Perspective into the Mechanics of Cellulose NanocrystalsINTELLECTUAL MERIT: Cellulose nanocrystals (CNCs) are highly crystalline organic polymers that can be extracted from natural materials. They are stiffer than aluminum and theoretical calculations place their tensile strength at 7500 MPa, higher than glass fibers or steel. Inasmuch as these crystals are biocompatible, lightweight, low cost, and sustainable they offer potential for applications in biomedical materials, energy technologies, electronics, and microelectromechanical systems devices. To date, no experimental tests have been utilized to investigate the strength properties of CNCs. This proposal aims to fill these gaps. In order to evaluate such properties the underlying mechanisms responsible for nanoscale mechanics should be determined. In-situ experiments and multiscale models for deformations in small-scale components can open possibilities for improved design and applications of CNCs. The objectives of this research are (1) to explore the nanoscale mechanics of individual CNCs as a function of the biological source, (2) to determine the dependence of CNC's mechanical properties on cellulose crystal dimensions, and (3) to fully characterize the elastic moduli of CNCs as function of their crystallographic orientations. To meet these objectives, nanomechanical properties will be investigated through the use of a novel in-situ characterization technique that enables atomic force microscopy (AFM) experiments inside the chamber of a transmission electron microscope. The in-situ data will then be used to develop and validate the continuum mechanics and molecular dynamics models of CNCs.BROADER IMPACTS: CNC-based materials are expected to have beneficial uses in a variety of technical applications, such as composite materials, packaging, tissue engineering scaffolds, drug delivery vectors, Li-ion batteries, and electronic displays. Several exchanges of OSU and Michigan Tech students are planned to promote multidisciplinary education (microscopy, cellulose nanocrystals preparation, and computational mechanics). The PIs will recruit female and minority undergraduate research students through the Michigan Community College/University Partnership program at Michigan Tech and the Saturday Academy's Apprenticeships in Science and Engineering Program at OSU. The Michigan Tech PI will also participate in outreach activities for local high school female and underrepresented students during the Engineering Scholars Program at Michigan Tech. The Oregon State PI will increase local area awareness by providing lectures/discussions on Oregon State Public Radio. In-situ videos of microscopy experiments will also be made available to the community via YouTube©, ACS Chemical and Engineering News, and the NanoHuB© network.