High-Yield Production of Nano-Lateral Size Graphene Oxide by High-Power Ultrasonication

• Published in: Materials 2021-04, Vol.14 (8), p.1916
• Main Authors: Timochenco, Licínia, Costa-Almeida, Raquel, Bogas, Diana, Silva, Filipa A L S, Silva, Joana, Pereira, André, Magalhães, Fernão D, Pinto, Artur M
• Format: Article
• Language: English
• Subjects: Biomedical materials; Communication; Dispersions; Fourier transforms; Functional groups; Graphene; Graphite; Nanomaterials; Oxidation; Particle size; Surface charge; Transmission electron microscopy; Ultrasonic imaging; Zeta potential
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14081916

Nanographene oxide (GOn) constitutes a nanomaterial of high value in the biomedical field. However, large scale production of highly stable aqueous dispersions of GOn is yet to be achieved. In this work, we explored high-power ultrasonication as a method to reduce particle size of GO and characterized the impact of the process on the physicochemical properties of the material. GOn was obtained with lateral dimensions of 99 ± 43 nm and surface charge of -39.9 ± 2.2 mV. High-power ultrasonication enabled an improvement of stability features, particularly by resulting in a decrease of the average particle size, as well as zeta potential, in comparison to GO obtained by low-power exfoliation and centrifugation (287 ± 139 nm; -29.7 ± 1.2 mV). Remarkably, GOn aqueous dispersions were stable for up to 6 months of shelf-time, with a global process yield of 74%. This novel method enabled the production of large volumes of highly concentrated (7.5 mg mL ) GOn aqueous dispersions. Chemical characterization of GOn allowed the identification of characteristic oxygen functional groups, supporting high-power ultrasonication as a fast, efficient, and productive process for reducing GO lateral size, while maintaining the material's chemical features.