(513e) Nature Inspired Functional Polymer Composites with Novel Properties

Advanced technologies require advanced material platforms with unique combinations of material properties. Our motivation is to translate the perfect nanoscale electrical, thermal and mechanical properties of carbon nanotubes (CNT) and graphene to tangible macroscale composite materials with tunable combinations of properties by taking advantage of Nature’s intriguing design. Layer-by-layer (LBL) assembly of CNT composites, with its ubiquitous nanometer resolution, can be used to tune the energy gap of CNT in a way that optimizes both the optoelectric and mechanical properties of the resulting composite. The universality of layer-by-layer assembly is further demonstrated to give both CNT and graphene composites a highly desirable balance of strength and toughness. Alternatives to LBL assembly have been developed to speed up the film production process and allow for non-aqueous systems to be used. Here we show an evaporation assisted spray technique that can quickly deposit polymers and nanofillers with controlled volume and thickness while preserving the uniformity of the coatings. We also introduce vacuum assisted assembly and template infiltration techniques which are capable of producing materials with similar mechanical properties to LBL assembled graphene nanocomposites and can be used to prepare hydrophobic polyurethane and epoxy composites. In addition, these techniques are further exploited to be used in other nanofiller systems, such as with aramid (Kevlar) fibers to obtain nanocomposites with excellent mechanical properties.  Along with the unique electrical and mechanical properties of hierarchical nanocomposites, our graphene oxide assembly demonstrates negative thermal expansion properties, which have potential applications in areas such as sensors, actuators and other MEMS/NEMS applications. Coefficient of thermal expansion of our composite can also be easily tuned allowing for a composite by design to be created.