New Approach to Nanoindentation Experiments and Modeling: Toward Fundamental Understanding of Thin Polymer Films and Polymer Nanocomposites

纳米压痕实验和建模的新方法：对聚合物薄膜和聚合物纳米复合材料的基本了解PI：LC Brinson，西北大学该奖项由2009年美国复苏和再投资法案(公共法律111-5)资助。通过纳米压痕实验和理论的新组合，研究了受限区域中聚合物的机械性能。这项工作将直接应用于聚合物薄膜，然后扩展到聚合物纳米复合材料的模型。这些结果将是确定聚合物纳米级局部机械性质的第一个此类结果，为帮助理解界面附近聚合物链运动和响应的物理学提供了新的见解。力学模拟和建模将把从接触力学理论发展起来的方法扩展到具有粘弹性和强表面驱动性质梯度的软材料，并将克服目前的局限性。这项研究是一项创造性的跨学科努力，直接培训研究生、本科生和博士后在研究方法、实验设计、建模和纳米技术方面的应用，如应用于聚合物系统和软材料。研究结果将有助于理解微电子、医疗和结构领域中聚合物产品设计的基本问题。这些应用越来越依赖于小区域和界面上的聚合物，这要求对当地聚合物性质有深入的了解，以便智能地定制小规模建筑。除了对聚合物的研究外，这项工作还对开发一种严格的方法产生了深远的影响，在小样品尺寸的情况下，通过纳米压痕来探测材料的性质，而目前的尺寸效应阻碍了结果。这里开发的分析方法可以扩展到生物样品，具有许多相同的特征和关注，其中越来越多的小规模机械被发现在生物特性和功能中发挥关键作用。

New Approach to Nanoindentation Experiments and Modeling: Toward Fundamental Understanding of Thin Polymer Films and Polymer NanocompositesPI: LC Brinson, Northwestern University This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The mechanical properties of polymers in confined domains are examined from a novel combination of nanoscale indentation experiments and theory. The work will be directly applied to thin polymer films and then extended to model polymer nanocomposites. These results will be the first of their kind to determine the nanoscale, local mechanical properties of polymers, providing new insight to help understand the physics of polymer chain motion and response near interfaces. The mechanics simulation and modeling will extend methods developed from contact mechanics theory to soft materials with viscoelastic properties and strong surface-driven property gradients and will overcome current limitations. The research is a creative, interdisciplinary endeavor, directly training graduate students, undergraduates and postdocs in research methods, experimental design, modeling, and nanotechnology, as applied to polymer systems and soft materials. The results will help understand fundamental issues in design of polymer products in the microelectronics, medical and structural fields ? these applications increasingly hinge upon polymers in small domains and at interfaces, demanding a deep understanding of local polymer properties to intelligently tailor small scale architectures. The work also has far-reaching impacts beyond the study of polymers in the development of a rigorous method to probe properties of materials via nanoindentation in cases of small sample sizes, where current size effects prohibit results. The analysis approach developed here can be extended to biological samples, with many of the same features and concerns, where small scale mechanics are increasingly discovered to play critical roles in biological properties and function.