DMREF/Collaborative Research: Graphene Based Origami and Kirigami Metamaterials

基于石墨烯的折纸和kirigami超材料非技术描述：折纸和kirigami的造纸术(‘ori’=折叠，‘kiri’=切割)提供了一个强大的框架来设计响应性和可调性的新材料。例如，一系列简单的裁剪就可以把一张纸变成手风琴一样的弹簧，或者一系列的折叠可以把它变成天鹅。事实上，许多生物组织产生的折叠和切割让人想起折纸和Kirigami，这赋予了它们独特而有用的机械性能。似乎可以创造出无限数量的形式，这说明了在纸以外的材料中利用这种设计原则的潜力。这个项目将把这些设计思想扩展到微尺度，使用石墨烯，一种原子薄的二维材料，作为纳米尺度的纸张基础。从半导体行业借用的光刻技术将被用来对石墨烯进行图案化，并将使用各种方法来创建折叠，所有这些方法都是为了实现特定的机械性能。重点是创造机械的“超材料”--材料的特性反映的是折叠和切割的模式，而不是底层纸张的特性。考虑到室温应用，理论工作将重点放在热激活布朗运动在确定具有切割和折叠的石墨烯单层材料特性方面的关键作用。这一受纸张艺术启发的策略有可能从根本上改变为微世界设计材料的方式，并可能在从微型机器人到机械传感器和致动器等领域找到应用，这些领域模仿了生物的“活性”组织。技术描述：使用光刻技术，石墨烯薄片将被打孔和切割，以创建具有指定机械性能的模块。这些模块将被组装成机械超材料，其对施加的压力、温度和其他环境信号的响应可以定制。该项目着重于下列相关目标：(A)对目前对石墨烯热力学性质的预测及其对几何和边界条件的依赖进行实验测试；(B)用切割后的石墨烯薄片创建一个机械可编程模块单元库；(C)设计用基本石墨烯kirigami模块和折纸模块组装而成的超材料以实现特定功能；(D)建立热激发原子薄膜切割和折叠理论，以指导实验和提高对基本原理的理解。这些目标将构成构建通用开源设计工具的基石，工程师可以使用该工具从折纸和基于kirigami的模块中组装材料，模拟其机械性能，并允许迭代设计工作流程。该工具将用于促进原子膜折纸和Kirigami超材料的快速材料发现、开发和性能优化。

Graphene-Based Origami and Kirigami MetamaterialsNon-Technical Description: The paper arts of origami and kirigami ('ori' = fold, 'kiri' = cut) provide a powerful framework to design responsive and tunable new materials. For example, a simple series of cuts can turn a sheet of paper into an accordion-like spring, or a sequence of folds can convert it into a swan. Indeed, many biological tissues develop folds and cuts reminiscent of origami and kirigami that endow them with distinct and useful mechanical properties. The seemingly limitless number of forms that can be created speaks to the potential of exploiting such design principles for materials beyond paper. This project will extend these design ideas to the microscale using graphene, an atomically thin two dimensional material, as the nanoscale paper foundation. Lithographic techniques borrowed from the semiconductor industry will be used to pattern the graphene, and a variety of approaches will be employed to create folds, all chosen to realize a specific mechanical property. The focus is on creating mechanical 'metamaterials' - materials whose properties reflect the patterns of folds and cuts rather than the properties of the underlying paper. With room temperature applications in mind, the theoretical effort will focus on the crucial role of thermally-activated Brownian motion in determining the material properties of graphene monolayers with cuts and folds. This paper-arts-inspired strategy has the potential to fundamentally transform the way materials are designed for the micro-world and could find applications in areas ranging from micro-robotics to mechanical sensors and actuators that mimic biologically 'active' tissues.Technical Description: Using lithographic techniques, graphene sheets will be perforated and cut to create modules with prescribed mechanical properties. These modules will be assembled to create mechanical meta-materials whose response to applied stresses, temperature, and other environmental signals can be tailored. The project focuses on the following interrelated goals: (a) Experimentally testing current predictions for graphene's thermomechanical properties and their dependence on geometry and boundary conditions; (b) Creating a library of mechanically programmable modular units out of cut graphene sheets; (c) Designing meta-materials assembled out of the basic graphene kirigami and origami modules to achieve a particular function; (d) Creating a theory of thermally excited atomically thin membranes with cuts and folds, to guide experiments and improve understanding of the basic principles. These goals will form the cornerstone for building a general-purpose open source design tool that can be used by engineers to assemble materials out of the origami and kirigami based modules, simulate their mechanical properties, and allow for iterative design work flows. This tool will be used to promote rapid materials discovery, development, and property optimization of atomic membrane origami and kirigami metamaterials.