A Facile and Effective Method for Size Sorting of Large Flake Graphene Oxide

The size of the building blocks fundamentally governs physical performances of the macro-scale graphene based structures since larger building blocks usually yields better mechanical and electrical properties. Density gradient centrifugation method has emerged as a versatile and scalable method for sorting colloidal 2D nanomaterials. This paper provides a facile and effective size sorting approach to graphene oxide (GO) flakes with large sizes up to 40 μm. The GO flakes were dispersed within distilled water. The centrifugation process parameters were calculated with respect to specific size ranges of GO flakes. Scanning electron microscopy utilized to prove the effectiveness of the separation process. Image processing analysis showed GO flakes with specific size ranges can be separate from aqueous suspension by controlling rotational speed and centrifugation time. The process was performed by using common benchtop centrifuges with low intensity centrifugal fields which requires low investment for a scalable process.