K.E. Coulter, V.Z. Poenitzsch, S. DiPietro, R. Wei
Southwest Research Institute,
Keywords: layered nanocomposite, nacre, platelets, plasma
Summary:Southwest Research Institute and Exothermics Inc. have been developing a hybrid processing method to fabricate macroscaled, layered nanocomposite materials that mimic the structure of nacre. Current research in the biomimetic field is pointing towards importance of two governing mechanisms that contribute towards energy dissipation in nacre: 1) platelet interlocking features and 2) strong adhesion of a ductile organic phase to the mineral plates. In our current study, we employed a vacuum roll coating process to prepare nano-engineered alumina inorganic platelets with precisely controlled size, shape and morphology of designed interlocking features through top-down physical vapor deposition of multilayer films on embossed substrates. Then a novel plasma source was employed in a roll-to-roll, layer-by-layer method to surface functionalize alumina platelets in order to modify interfacial strength with an organic matrix. Subsequently, slip casting was utilized to fabricate macroscale layered materials with desired in-plane alignment of platelets, physical packing characteristics and percolation behavior when compounded. The microstructure of all compositions of the fabricated nacre-like materials was examined using scanning electron and optical microscopy, while the mechanical properties were analyzed using three-point bend tests. In this presentation, an overview of hybrid processing method and resulting materials will be given with a specific focus on vacuum roll coating, plasma processing and surface functionalization.