Size-dependent aggregation of graphene oxide

Graphene oxides (GO) of highly polydisperse size distribution were prepared by the Brodie method and their dispersion stability was characterized. Exfoliation and fractionation led to well-defined particle populations in the Nano, classical Colloidal (submicron) and Micrometer size ranges, as reveal...

Teljes leírás

Elmentve itt :
Bibliográfiai részletek
Szerzők: Szabó Tamás
Maroni Plinio
Szilágyi István
Dokumentumtípus: Cikk
Megjelent: 2020
Sorozat:CARBON 160
doi:10.1016/j.carbon.2020.01.022

mtmt:31123785
Online Access:http://publicatio.bibl.u-szeged.hu/17875
Leíró adatok
Tartalmi kivonat:Graphene oxides (GO) of highly polydisperse size distribution were prepared by the Brodie method and their dispersion stability was characterized. Exfoliation and fractionation led to well-defined particle populations in the Nano, classical Colloidal (submicron) and Micrometer size ranges, as revealed by atomic force microscopy and light scattering measurements. Time-resolved dynamic light scattering experiments revealed that aggregation processes are fully impeded in the intermediate pH regime of 3–13 in the absence of electrolytes. While the resistance against salt-induced aggregation increases with the pH due to the progressive ionization of the surface functional groups of GO sheets, their dispersions are inherently unstable at supramillimolar concentrations of strong acids and submolar concentrations of bases, in line with the DLVO theory. However, the aggregation behavior quantified by the critical coagulation concentrations (CCCs) shows surprisingly substantial platelet size dependence. The CCC of Nano Brodie-GO reaches 360 mm at pH = 12, which is one of the highest values ever reported for GO aqueous dispersions. These results provide useful quantitative information to design processable GO dispersions of pH- and size-tunable stability for future applications.
Terjedelem/Fizikai jellemzők:145-155
ISSN:0008-6223