Active NIRT: Hierarchical Manufacturing and Modeling for Phase Transforming Active Nanostructures

这项拟议的研究是根据活性纳米结构和纳米系统计划提交的，NSF 06-595，类别NIRT。在纳米医学、纳米电子学、空间探索、国土安全和国防等领域，需要具有驱动和传感能力的主动纳米结构和纳米系统。来自德克萨斯a&m大学和佐治亚理工学院的一个集成团队提出了一个综合的跨学科项目，用于相变磁性形状记忆合金（MSMA）的分层制造和建模。技术：该提案的主要目标是建立一个分层框架，将MSMA纳米层的制造与纳米线的挤压结合起来。然后，这些单片和混合纳米线将通过同轴静电纺丝用于纤维的制造，作为可以通过温度、应力和远程磁场激活的设备。纳米制造的第一级将集中在薄膜上，由纳米到微米尺寸的传统形状记忆合金（SMA）、磁性材料和使用磁控溅射的MSMA组成。薄膜将作为纳米线制造的前驱体，使用成本有效的液压挤压技术。更高水平的纳米制造将涉及使用一种新型同轴静电纺丝，纳米线将在选定的基质中排列，如二氧化硅，用于制造生物传感器、远程控制的纳米/微致动器和活性介孔延展性膜。为了支持纳米制造的努力，选择性多尺度建模将包括原子模拟来解决纳米尺度上的相变现象，以及基于微观结构机制的连续体级本构模型来解决纳米结构的功能和纳米器件的行为。非技术：该研究将尝试开发一种结合形状记忆和磁性的纳米线的多层制造方法。这种分层制造方法将由并行的多尺度建模工作和多尺度最先进的表征技术协助。这些独特的多功能纳米线将利用一种新的同轴静电纺丝方法用于制造生物传感器。该研究具有重要的科学意义，因为它将揭示在晶体长度尺度上发生的纳米尺度现象对通过分层纳米制造的更大尺度功能的影响。该研究还将为新的多功能材料和器件提供结构良好的分层制造方法和架构，用于工程应用中的传感器和致动器，促进微致动器、生物传感器、阀门和活性介孔结构的设计。从这些研究中产生的知识可以彻底改变主动纳米和微尺度系统和组件的设计，这些系统和组件能够经历非常快速的可逆变形，并表现出高驱动、传感和有前途的发电特性。拟议的项目活动将包括编制多功能教材的教学单元，以便纳入本科课程；通过德州农工大学和佐治亚理工学院的夏季合作交流项目，丰富研究生和本科生的研究经验；活性薄膜、纳米线和活性纳米结构研究生课程的开发通过参与地区少数民族服务大学，让代表性不足的群体参与进来，并在中学教育计划的教材中注入实验室示范模型，这将与德克萨斯州农工大学新成立的国家科学基金会纳米级本科教育（NUE）计划相协调。

This proposed research was submitted in response to the Active Nanostructures and Nanosystems initiative, NSF 06-595, category NIRT. Active nanoscale structures and nanosystems capable of actuation and sensing are needed for a wide range of applications in nanomedicine, nanoelectronics, space exploration, homeland security and defense. An integrated team of co-PIs from Texas A&M University and Georgia Tech proposes, as a combined research effort, a comprehensive interdisciplinary program in hierarchical manufacturing and modeling for phase transforming magnetic shape memory alloys (MSMA). Technical: The main goal of the proposal is to establish a hierarchical framework that will combine the fabrication of MSMA nanolayers with the extrusion of nanowires. These monolithic and hybrid nanowires will then be used in the fabrication of fibers, by coaxial electrospinning, to be used as devices that can be activated by temperature, stress, and remotely by magnetic field. The first level of nanomanufacturing will focus on thin films, composed of nano to micron size layers of conventional shape memory alloys (SMA), magnetic materials and MSMA using magnetron sputtering. Thin films will then serve as precursor for nanowire fabrication by using a cost effective hydraulic pressure extrusion technique. The higher level nanomanufacturing will involve the use of a novel coaxial electrospinning whereby nanowires will be aligned in selected matrices such as silica for the purpose of making biosensors, remotely controlled nano/micro actuators, and active mesoporous ductile membranes. To support the nanomanufacturing effort, selective multiscale modeling will involve atomistic simulations to address phase transformation phenomena at nanoscale, and microstructural mechanism-based continuum level constitutive models to address the functionality of the nanostructures and nanodevice behavior. Nontechnical: The proposed research will attempt to develop a multilevel fabrication methodology for nanowires with combined shape memory and magnetic properties. This hierarchical fabrication methodology will be assisted by a parallel multiscale modeling effort, and also by multiscale state-of-the-art characterization techniques. These unique multifunctional nanowires will be utilized in the manufacturing of biosensors using a novel coaxial electrospinning method. The proposed research is scientifically significant because it will reveal the effect of nanoscale phenomena occurring at crystallographic length scales on larger scale functionality through hierarchical nanomanufacturing. The proposed research will also result in well-structured hierarchical fabrication methodologies and architectures for new multifunctional materials and devices to be used as sensors and actuators in engineering applications, facilitating the design of micro-actuators, biosensors, valves and active mesoporous structures. The knowledge generated from these studies could revolutionize the design of active nano and micro-scale systems and components capable of undergoing very fast reversible deformations, and exhibiting high actuation, sensing and promising power generation characteristics. The proposed project activities will include the development of teaching modules in multifunctional materials for incorporation into undergraduate courses; enrichment of graduate and undergraduate research experiences through summer collaborative exchange programs between Texas A&M and Georgia Tech; development of a graduate course in active thin films, nanowires and active nanostructures; involvement of underrepresented groups through participating regional minority serving universities, and injection of laboratory demonstration models in educational material for secondary educational programs, which will be coordinated with the newly established NSF Nanoscale Undergraduate Education (NUE) program at Texas A&M.