Table 1.
Graphene oxide | Graphene nanoplatelets | ||
---|---|---|---|
GO-1 | GO-3 | GNP | |
Material source | Commercial | Research | Commercial |
Preparation method | Modified hummers method | Modified hummers method | Microemulsion |
Starting material | Graphite | Natural graphite | Natural graphite |
State as received | Powder | Dispersion | Powder |
Lateral dimensions | 1–40 µm (SEM) | 150 nm ± 44 nm (AFM) | Aggregate size 1–10 µm; mean ~5 µm (SEM) |
Number of layers | Single to few layer | Single layer | Aggregate thickness <5 µm |
C/O ratio (XPS) | 1.7 ± 0.1 | 1.9 ± 0.1 | 24.0 ± 2.5 |
Dispersion in … | Ultra-pure water | Ultra-pure water | 0.1 mg/ml sodium cholate in ultra-pure water |
Dispersion colour | Brown | Brown | Anthracite |
Zeta-potential in ultra-pure water | −39.4 ± 1.3 mV | −43.9 ± 1.4 mV | −62.6 ± 1.9 mV |
Overview on the physicochemical properties of the applied label-free graphene-related materials (GRM) as determined by Kucki et al. [20]. Original material acronyms were retained for sake of clarity