Carbon Nanostructures: Surface-Mediated Mechanical Response and Topologically Constrained Bonding

碳纳米结构：表面介导的机械响应和拓扑约束键合

• 批准号: 0707332
• 负责人: Vincent Crespi
• 金额: $ 36万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-15 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0707332&HistoricalAwards=false
• 关键词: Carbon; Nanostructures; Surface; Mediated; Mechanical

TECHNICAL SUMMARY:This award supports computational and theoretical ressearch and education in the area of materials research at the nanoscale. Through computer simulation, this project develops several new classes of materials and materials-based systems amenable to use for nanoscale applications. One material under development is a two-dimensional ferroelectric sheet composed of monolayers of cations and anions sandwiching a graphite sheet. Systematic investigations as a function of single and double metallic cations compensated by halogens, chalcogenides and polyatomic anions are underway. A second area of investigation deals with the development of nanomechanical actuators composed of bistable carbon structures. Depending upon the environment these structures may either buckle or collapse. Construction of such actuators on substrates will provide for dense pressure-dependent mechanical memory devices, gas sensors and cantilevers. Particular emphasis is on determining critical aspect ratios, sizes and buckling angles at which the system can recover, with or without hysteresis, and those conditions which lead to irreversible alteration. A third related area of investigation deals with the development of concentric coaxial carbon nanotubes to investigate the possibility of developing nanoscale pistons, screws and transducers. The final effort deals with the development of open extended frameworks built from N2O and NO2 molecules. Emphasis is on determining pressures required to create stable phases and determine if they are metastable at lower pressures. These projects are performed in concert with substantial experimental collaboration.Common to all of these problems is the need for and use of accurate density functional methods, empirical potentials and tight-binding methodologies to determined both electronic and vibrational effects. The PI will spread the excitement of his research through an internet-based scientific outreach effort aimed at high-school-age students. NON-TECHNICAL SUMMARY:This award supports computational and theoretical ressearch and education that uses sophisticated computational modeling techniques to determine the environmental conditions at which novel nanoscale systems will operate with useful function. One focus is to determine the conditions that cause stiff lightweight carbon-based fibers to bend and buckle. Such fibers may be used to build mechanical memory devices and sensors. These fibers when arranged as a nanoscale coaxial cable have further applications related to miniaturized pistons, screws and transducers. Research here concentrates on immediate application of such fibers and on their use for manipulation of and energy transfer to atoms and molecules. Based upon some of the carbon-based materials and nanosystems studied here, additional computer simulations which investigate fabrication of similar structures composed of nitrogen and oxygen are underway. Simulation of a lightweight strong carbon-based film coated with a metallic foil on one side and a Teflon-like sheet on the other is also underway. The PI will spread the excitement of his research through an internet-based scientific outreach effort aimed at high-school-age students.

技术摘要：该奖项支持纳米级材料研究领域的计算和理论研究和教育。通过计算机模拟，该项目开发了几类新的材料和基于材料的系统，可用于纳米级应用。一种正在开发的材料是二维铁电片，由阳离子的单层和夹在石墨板上的阴离子组成。正在进行的系统研究与卤素，墨西哥盐和多原子阴离子所补偿的单一和双金属阳离子的关系。 第二个调查领域涉及由可动碳结构组成的纳米力学致动器的发展。根据环境，这些结构可能扣紧或塌陷。在底物上建造此类致动器将提供密集的压力依赖性机械记忆设备，气体传感器和悬臂。特别的重点是确定系统可以恢复，无论有无磁滞的临界纵横比，大小和屈曲角，以及导致不可逆变化的条件。 研究的第三个相关领域涉及同心同轴碳纳米管的发展，以研究开发纳米级活塞，螺钉和换能器的可能性。最后的努力涉及开发由N2O和NO2分子构建的开放扩展框架。重点是确定创建稳定阶段所需的压力，并确定它们是否在较低的压力下是可稳定的。 这些项目与实质性的实验协作一起进行。所有这些问题的要求是需要和使用准确的密度功能方法，经验势和紧密结合方法，以确定电子和振动效应。 PI将通过针对高中生学生的基于互联网的科学外展工作来激发他的研究的兴奋。非技术摘要：该奖项支持计算和理论上的教育和教育，该计算和教育使用复杂的计算建模技术来确定新型纳米级系统将在有用功能下运行的新型纳米级系统的环境条件。 一个重点是确定导致僵硬的轻质碳纤维弯曲和扣紧的条件。这样的纤维可用于构建机械记忆设备和传感器。 这些纤维作为纳米级轴心电缆排列时，将进一步应用与微型活塞，螺丝和换能器有关。这里的研究集中于立即应用此类纤维，并用于操纵和转移原子和分子的能量。 基于这里研究的一些碳基材料和纳米系统，正在进行研究的其他计算机模拟，这些计算机模拟正在研究由氮和氧气组成的相似结构的制造。 也正在进行模拟轻巧的强碳基膜，一侧涂有金属箔，另一侧的金属箔片和类似铁氟龙的薄板也正在进行中。 PI将通过针对高中生学生的基于互联网的科学外展工作来激发他的研究的兴奋。