CAREER: Control Tools for Nanoscale Rapid Broadband Viscoelasticity Measurement and Mapping of Soft Materials

本学院早期职业发展（CAREER）项目的研究目标是开发一种新的系统识别和控制方法，使快速宽带粘弹性测量。通过映射软材料的响应在多个尺度上，所提出的方法将实现在纳米级测量使用扫描探针显微镜（SPM）。目前，在纳米、介观和宏观尺度上测量材料特性存在许多障碍。它们包括（i）准静态或正弦振荡激励方法，其要么太简单要么太慢而不能快速地激励软材料所表现出的复杂行为，（ii）硬件动态蠕变到所测量的材料特性中，特别是当测量处于高频时，以及（iii）显著的非线性（例如滞后）和系统不确定性。所提出的研究将克服这些障碍，通过集成的最优输入设计的时变vescoelastic模型识别与系统反演理论的快速跟踪过渡切换和大系统的不确定性。新的迭代控制和最优控制技术也将被开发，以允许高速输出跟踪所需的发挥最佳的激励输入与系统带宽的最小的权衡。拟议的研究成果预计将是软材料的时变粘弹性参数的测量超过至少10倍大的频率范围内，在一个时间框架内至少10倍短。这项工作将引入多尺度软材料科学和工程的新范式，并通过将宏观/介观尺度测量与纳米尺度联系起来，帮助解开伤口愈合等速率依赖现象。在纳米尺度上实现所提出的方法将改进SPM作为纳米科学和纳米技术的关键使能工具，推进我们对快速纳米尺度现象（如牙本质胶原脱水）的理解，并加速纳米/生物材料（包括用于药物递送的生物相容性聚合物）的合成和设计。私家侦探？与领先的SPM制造商的密切合作将加速技术转让。拟议的职业教育活动将通过改进课程（包括一门新课程、一个教学模块和一个基于网络的SPM模拟器）、利用国际空间大学两个完善的外联方案为总共450名高中女生提供开放实验室图尔斯参观、为本科女生和高中理科教师提供实习机会以及为研究生提供工业实习机会，促进机械工程中的纳米技术教育。

The research objective of this Faculty Early Career Development (CAREER) project is to develop a new system identification and control methodology to enable rapid broadband viscoelastic measurements. By mapping soft material responses at multiple scales, the proposed methodology will be realized in nanoscale measurements using scanning probe microscopy (SPM). Currently there are many barriers to measurements of material properties at the nano-, meso-, and macro-scales. They include (i) quasi-static or sinusoidal-oscillatory excitation methods which are either too simple or too slow to rapidly excite the complex behaviors exhibited by soft materials, (ii) hardware dynamics creeping into the measured material properties, particularly when the measurement is at a high frequency, and (iii) significant nonlinearity (such as hysteresis) and system uncertainties. The proposed research will overcome these barriers through the integration of optimal input design for time-varying vescoelastic model identification with the system-inversion theory for rapid tracking-transition switching and large system uncertainties. New iterative control and optimal control techniques will also be developed to allow the high-speed output tracking needed for exerting the optimal excitation input with minimal trade-off of system bandwidth. The outcome of the proposed research is expected to be the measurement of time-varying viscoelastic parameters of soft materials over a frequency range at least 10 fold larger and within a time frame at least 10 fold shorter. The work will introduce a new paradigm of multi-scale soft material sciences and engineering, and help unravel rate-dependent phenomena like wound healing by linking the macro-/meso- scale measurements to the nano- scale. The realization of the proposed methodology at the nanoscale will improve SPM as the key enabling tool for nanosciences and nanotechnologies, advance our understanding of rapid nanoscale phenomena like dentin collagen dehydration, and accelerate the synthesis and design of nano-/bio- materials including bio-compatible polymers for drug delivery. The PI?s close collaboration with a leading SPM manufacturer will accelerate the technology transfer. The proposed CAREER education activities will promote nanotechnology education in mechanical engineering, through curriculum improvements (including a new course, a teaching module and a web-based SPM simulator), open lab tours for a total of 450 high-school girls by leveraging two well-established outreach programs at ISU, internships for undergraduate women students and high-school science teachers, and industrial internships for graduate students.