Direct Measurement of the role of Confinement and Chemistry on Local Physical and Mechanical Properties of Polymers

该奖项的研究目标是利用基于两种不同物理的技术来研究界面附近聚合物的热和机械性能。在一种情况下，纳米级的机械压痕是通过测量将小尖端从顶部或侧面推入样品所需的力来实现的。在第二种情况下，嵌入荧光探针上的光谱学测量样品在不同温度下发射的光的变化。这些技术是互补的和正交的，这两种分析都可以在相同的物理样品上进行。目前的文献表明，衬底刚度可能在对受限聚合物的影响中起着重要作用。在测量技术同步后，我们将研究不同硬度的各种衬底上的机械界面。这项研究将通过高模数硅片覆盖橡胶衬底。还将研究聚合物-基材化学相互作用的差异的影响。纳米聚合物是各种重要系统的重要组成部分，包括轻质结构材料、生物医学设备和能量存储。遗憾的是，受限聚合物的未知力学性质导致了新器件设计和应用的不确定性。对界面聚合物性能的准确评估将允许更强大的设计空间和更高程度的材料属性定制。拟议的研究还将成为研究生和博士后研究员在基于结构的材料设计的关键前沿领域的一个极好的培训平台。面向本科生、代表性不足的群体和当地中学生的宣传被纳入教育计划，使更大的社会群体接触到材料设计原则和技术开发过程。参与这个项目的学生还将有机会与国家实验室(Argonne)和行业(杜邦和波音)的科学家在设计项目上进行合作。

The research objective of this award is to utilize techniques based on two different physics to investigate the thermal and mechanical properties of polymers near interfaces. In one case, nanoscale mechanical indentation is performed by measuring the force required to push small tips into the sample either from the top or side surfaces. In the second case, spectroscopy on embedded fluorescent probes measures the change in light emitted from the sample at different temperatures. These techniques are complimentary and orthogonal and both analyses can be performed on the same physical samples. Current literature reveals that substrate stiffness may play an important role in the effects on the confined polymer. After synchronization of the measurement techniques, we will investigate the mechanical interphase on a variety of substrates with different stiffness. This study will encompass rubbery substrates through high modulus silicon wafers. The effect of differences in polymer-substrate chemical interactions will also be investigated. Nanostructured polymers are important components of a variety of important systems, including lightweight structural materials, biomedical devices, and energy storage. Unfortunately, the unknown mechanical properties of confined polymers leads to uncertainty in design of novel devices and applications. Accurate assessment of interfacial polymer properties will allow for a more robust design space and tailoring of material properties to a higher degree. The proposed research will also serve as an excellent training platform for graduate students and postdoctoral fellows in the critical frontier of structure-based material design. Outreach to undergraduates, underrepresented groups and local middle-school students are included in the education plan, exposing larger societal groups to materials design principles and the technological development process. Students participating in this project will also have opportunities to collaborate with scientists at national labs (Argonne) and industries (Dupont and Boeing) in design projects.