This nanoscale interdisciplinary research team (NIRT) award involves collaboration between participants at Tuskegee University, University of Alabama at Birmingham(UAB) and Cornell University, and is co-funded by the NSF Divisions of Materials Research, Chemistry, Civil and Mechanical Systems, Manufacturing and Industrial Innovation, and Electrical and Communication Systems. Many new engineering materials are composites with anisotropic structure on nanometer and sub-nanometer length scales. While much academic research has been devoted to synthesis and characterization of homogeneous two-component nanocomposite materials, very little attention has been given to understanding and exploiting important synergistic effects that arise when nanostructures are added to multiphase polymer materials. Controlled integration of nanostructures that can compatibilize, align, or alter the crystalline morphology of multi-component polymer mixtures dramatically increases the physical sophistication of conventional nanocomposite materials and provides new strategies for materials design on the nanoscale. The objective of the proposed research is three-fold. First, to develop a new class of functional nanocomposite materials based on dispersed anisotropic nanostructures in single-component and multi-component polymer mixtures. Second, to improve fundamental understanding of how surface functionalized nanostructures affect phase behavior, crystalline morphology, rheology, curing kinetics, and properties of multiphase polymeric materials. Finally, to quantify the effect of processing shear fields and polymer particle interactions on alignment and spatial distribution of anisotropic nanostructures in synthetic polymers. Our work will focus on surface-functionalized carbon nanotubes (CNT) and silica nanorods dispersed in model polymer systems. Each system will be chosen to introduce progressively greater degrees of complexity to the basic nanocomposite motif, providing new insight into methods for controlling polymer structure at the nanoscale using anisotropic nanostructures. Intellectual Merit: The proposed research is important for scientific as well as practical reasons. Our work, for example, exploits the known high surface/volume ratio of nanostructures to simultaneously compatibilize and reinforce polymer mixtures. We also study, for the first time, how processing shear fields influence the spatial distribution of dispersed nanoparticles in polymer hosts and how these effects can be exploited to create macroscopic objects with novel core/shell transport properties. The proposed study is also among the first to utilize solid-state deformation to align nanostructures and polymer molecules in a nanocomposite material. If successful, this work will improve fundamental understanding of nanocomposite materials and will help advance the state of the art for creating polymers with graded property profiles. Broader Impact: Students at Tuskegee, UAB and Cornell that participate in the proposed research will receive unique, broad-based education in materials chemistry, materials physics, flow behavior of multiphase polymer liquids, and solid state properties of nanostructured materials. Students from our institutions will spend time working with a NIRT team member from another institution. This will foster deeper collaborative research relationships among participating faculty and will enhance the quality of the learning experience provided to our students, both graduate and undergraduate. Students at each university will also be exposed to courses in nanostructured materials science and processing. Outreach efforts will include activities involving exposure of K-12 students to nanoscale science and technology.
