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

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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.