(351e) Bio-Inspired Assembly of Nanoplatelets by Electrical Field

Bottom-up self-assembly of nonspherical colloidal building blocks is of great interest for the development of new materials with potential applications in optoelectronics, photonics, magnetics, catalysis, and mechanics. Oriented assembly of platelet-like particles is particularly interesting as it enables the production of nanocomposites with greatly improved mechanical properties. This is inspired by the ordered assemblies of aragonite (a mineral form of CaCO3) platelets in the nacreous layer of mollusk shells. The intricate layered structures consisting of brittle minerals and soft proteins in these natural composites lead to the unique combination of stiffness, strength, and toughness. Here we report a simple electrophoretic deposition technology that enables rapid production of large-area polymer nanocomposites with layered structures mimicking natural nacres. Uniform, electrostatically stabilized gibbsite nanoplatelets with high aspect ratio are preferentially oriented parallel to the electrode surface when an external direct current electric field is applied. Homogeneous, optically transparent nanocomposites are obtained when the interstitials between the aligned nanosheets are infiltrated with polymer. The resulting ceramic-polymer nanocomposites exhibit excellent mechanical properties.