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

ID：MPS/dmr/bmat(7623)1100806 PI：Shahbazian-Yassar，Reza ORG：Michigan TechID：MPS/dmr/bmat(7623)1100572 PI：Simonsen，John ORG：Oregon State标题：协作研究：比玻璃纤维更强，比钢丝更硬：纤维素纳米晶力学的新视角INTELLECTUAL优点：纤维素纳米晶(CNCS)是可以从天然材料中提取的高度结晶的有机聚合物。它们比铝更硬，理论计算表明它们的抗拉强度为7500兆帕，高于玻璃纤维或钢。由于这些晶体具有生物相容性、重量轻、成本低和可持续发展等特点，它们在生物医学材料、能源技术、电子和微型机电系统设备中具有潜在的应用前景。到目前为止，还没有实验测试来研究碳纳米管的强度特性。这项提议旨在填补这些空白。为了评估这些特性，应该确定纳米尺度力学的基本机制。小尺度构件变形的现场实验和多尺度模型可以为改进CNCS的设计和应用提供可能。本研究的目的是(1)探索作为生物源的单个CNCS的纳米尺度力学，(2)确定CNCS的力学性能与纤维素晶体尺寸的依赖关系，以及(3)充分表征CNCS的弹性模数作为其晶体取向的函数。为了达到这些目标，将通过使用一种新的原位表征技术来研究纳米机械特性，该技术能够在透射电子显微镜的腔内进行原子力显微镜(AFM)实验。然后，现场数据将被用于开发和验证CNC的连续介质力学和分子动力学模型。BROADER影响：基于NC的材料有望在各种技术应用中具有有利的用途，如复合材料、包装、组织工程支架、药物输送载体、锂离子电池和电子显示器。俄亥俄州立大学和密歇根理工大学的学生计划进行几次交流，以促进多学科教育(显微镜、纤维素纳米晶制备和计算力学)。PIS将通过密歇根理工大学的密歇根社区学院/大学伙伴计划和俄亥俄州立大学的周六学院的科学与工程学徒计划招收女性和少数族裔本科生。在密歇根理工学院工程奖学金计划期间，密歇根理工学院PI还将参加针对当地高中女生和代表不足的学生的外展活动。俄勒冈州PI将通过在俄勒冈州立公共广播电台提供讲座/讨论来提高当地的意识。显微镜实验的现场视频还将通过YouTube、ACS化学和工程新闻以及NanoHuB©网络提供给社区。

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.