Table 1 Physico-chemical parameters of the test materials
Property | MWCNT | Graphene | Graphite nanoplatelets | Carbon black | ||||
|---|---|---|---|---|---|---|---|---|
Representative images (SEM) | See Figure 1 | See Figure 1 | See Figure 1 | See Figure 1 | ||||
Particle size Distribution (SEM)primary structure | 15 nm, fiber shape | Up to 10,000 nm diameter, flakes | Up to 30,000 nm diameter, flakes | 50-100 nm, globular | ||||
State of agglomeration | ~20,000 nm, bundles | ~40,000 nm, ‘crumpled napkin’ | >50,000, ‘crumpled cardboard’ | >20,000 nm | ||||
Crystallite size (XRD) | Dominatingly amorphous in XRD | Dominatingly amorphous in XRD | Contains amorphous material, but has sharp diffraction peak corresponding to 19 nm crystallite size | Dominatingly amorphous in XRD | ||||
Crystalline phase (XRD) | Graphite, C hexagonal with modified lattice const. | Possibly graphite, sync –C– hexagonal or carbon –C– hexagonal, or carbon –C– cubic or carbon - C | Graphite, sync– C - hexagonal | Graphite, C hexagonal with modified lattice const. | ||||
Pore sizes (Hg intrusion) | 25 nm, 400 nm, 150,000 nm | 9 nm, 100 nm, 40,000 nm | 6,000 nm, 30,000 nm, 150,000 nm | 100 nm, 150,000 nm | ||||
Surface area (Hg) [mg/m2] | 161 | 131 | 74 | 32 | ||||
Apparent density (g/mL) | 0.15 | 0.02 | 0.04 | 0.52 | ||||
Agglomerate density (g/mL) | 0.39 | 0.29 | 0.89 | 1.05 | ||||
Surface chemistry (%) (XPS) | C | 99 | C | 84.1 | C | 84.3 | C | 98 |
O | 1 | O | 8.8 | O | 9.0 | O | 1 | |
S | 5.4 | S | 1.7 | S | 1 | |||
Na | 0.6 | Na | 3.0 | Cl | <<1 | |||
Si | 0.4 | Ca | 1.5 | |||||
Cl | 0.6 | Si | 0.6 | |||||
Raman peak positions (cm-1) (Laser spectroscopy) | G | 1574 | 1574 | 1573 | 1590 | |||
D | 1338 | 1338 | 1348 | 1348 | ||||
D/G | 1.16 ± 0.04 | 1.40 ± 0.05 | 0.01 ± 0.01 | - | ||||
Dispersability (by AUC) | agglomerated | agglomerated | agglomerated | agglomerated | ||||
In water | <0.01 wt% below 100 nm | <0.01% below 100 nm | <0.01% below 100 nm | 1,920 nm | ||||
In DMEM/FCS | agglomerated at several μm | Dispersed below 100 nm | ||||||
Purity (combined assessment from XRD, ICP-MS, XPS data) | 99% | < 85% | < 85% | 98% | ||||
Identified impurities | None significant | Sulfur impurity (presumably from acid intercalation before exfoliation) | Na-, Ca, Si-containing minerals | None significant | ||||
3D-Graphite (not 2D-Graphene) impurities | 3D-Graphite (not 2D-Graphene) impurities | |||||||