Hierarchical Structure of Graphene Oxide-Polymer Nanocomposites

Biological organisms utilize hierarchical structures to create materials with outstanding properties.  Synthetic composites typically utilize inorganic reinforcement with one length scale of structure, resulting in materials that involve tradeoffs between properties such as strength and stiffness.  Synthesis of biomimetic composites requires materials with multiple length scales of structure.  Graphene oxide papers are simple to fabricate, yet elegantly demonstrate the power of hierarchical structures.  Work on graphene oxide papers has typically focused on the nanometer, sheet-to-sheet spacing because this is the simplest to measure through techniques such as x-ray diffraction.  However, recent investigations have shown the existence of longer length scale structures that have a profound impact on the properties of the material.  In this presentation, the hierarchical structure of graphene oxide papers, and their associated composites will be shown on the nanometer (sheet-to-sheet spacing), 100-nm (lamellae), and micron (whole paper) length scales.  Through modification of these structures with small molecules and polymers we can begin to understand the structure-property relationships in these hierarchical composites.