Atomistic and Multi-scale Modelling of Functionalized Graphene and Hydrogen Diffusion in Advanced Materials

2016年，世界经济论坛新兴技术元理事会将二维材料确定为全球十大新兴技术之一。石墨烯等二维材料由单层原子片组成，可用于制造新材料和新设备。它们被广泛应用于传感器技术、复合材料、储能、环境滤波器、药物输送系统和光电子学等领域。石墨烯是一种重要的二维材料，其重要性得到了2010年诺贝尔物理学奖的认可。石墨烯的应用需要在主体材料中均匀分散，并与其他材料形成牢固的键。化学功能化可以改善石墨烯的分散性，形成强界面。氧化石墨烯（GO）被用于具有成本效益的功能化石墨烯的大规模生产。氧化石墨烯可以由大块石墨生产。它具有分散性，并具有羟基和其他功能键，可以促进与材料更好的相互作用。目前，关于功能化石墨烯和氧化石墨烯的力学性能和界面性能的研究非常有限。拟议研究计划的第一部分研究功能化石墨烯和氧化石墨烯及其界面的力学和机械性能，以支持新材料和设备的设计。将使用基于计算机的原子和多尺度建模方法，并在选定的情况下与实验进行比较。本课题将培养博士生2名、硕士生2名、本科生3名。******提出的研究计划的第二部分旨在获得氢在锆和锆钛酸铅（PZT）中的扩散的基本理解。锆压力管是核电站的关键部件，而PZT作动器在现代喷油器中得到广泛应用。实验研究证实了压力管中氢化物的形成，以及由此产生的氢化物驱动的开裂是主要的安全问题。实验还证实了PZT的极化损失，这是阻碍PZT喷射器在氢气技术应用中的一个障碍。氢化物驱动裂纹的确切机理尚不完全清楚，PZT与氢的相互作用也知之甚少。该计划涉及氢在锆和PZT晶格中的相互作用和扩散的综合计算机原子模型以及扩散的多尺度模型。这一发现将为压力管的安全设计和氢气技术喷射器的开发提供支持。本研究将培养两名博士生和两名本科生。受训者将通过同行评审的出版物、会议和与业界的互动来传播研究成果。该项目将使用WestGrid/Compute Canada的高性能计算设备。

In 2016, the Meta Council of Emerging Technologies of World Economic Forum identified two-dimensional (2D) materials as one of the top ten emerging technologies of the world. 2D materials such as graphene consist of single-layer atom sheets that can be used to build new materials and devices. They are proposed for a wide range of applications, such as sensor technology, composite materials, energy storage, environmental filters, drug delivery systems, and optoelectronics. Graphene is an important 2D material and its significance was recognized by the 2010 Nobel Prize in Physics. Application of graphene requires homogeneous dispersion in host materials and creation of strong bonds with other materials. Chemical functionalization is used to improve dispersion of graphene and form strong interfaces. Graphene-oxide (GO) is used for cost-effective mass production of functionalized graphene. GO can be produced from bulk graphite. It is dispersive and has hydroxyl and other functional bonds that can facilitate better interaction with materials. Currently, very limited research exists on the mechanical and interfacial properties of functionalized graphene and GO. The first part of the proposed research program examines the mechanics and mechanical properties of functionalized graphene and GO and their interfaces to support novel material and device design. A computer-based atomistic and multi-scale modeling approach will be used and comparisons with experiments will be made in selected cases. Two PhD students, two MSc students and three undergraduates will be trained on this research. ******The second part of the proposed research program aims to obtain a fundamental understanding of diffusion of hydrogen in Zirconium and Lead Zirconate Titanate (PZT). Zirconium pressure tubes are key elements of nuclear power plants, and PZT actuators are used in modern fuel injectors. Experimental studies confirm hydride formation in pressure tubes, and the resulting hydride-driven cracking as a major safety concern. Experiments also confirm the loss of polarization of PZT due to hydrogen, which is a barrier for the use of PZT-based injectors in hydrogen technology applications. The exact mechanism of hydride-driven cracking is not fully understood, and little is known about the interaction of PZT with hydrogen. The proposed program involves comprehensive computer-based atomistic modeling of hydrogen interaction and diffusion in zirconium and PZT lattices and a multi-scale model for diffusion. The findings will support safe design of pressure tubes and development of injectors for hydrogen technology. Two PhD students and two undergraduates will be trained on this research. The trainees will disseminate the research findings through peer-reviewed publications, conferences, and interaction with industry. High-performance computing facilities of WestGrid/Compute Canada will be used in this project.