Figure 7: Settling speeds, , measured (a) for the -MWCNTs treated supersonically at different powers (10 to 15 W), different amounts (10 to 100 mg) in 20 mL ethanol, and different durations (15 to 120 min) at room temperature, (b) for the plasma treated samples soaked in different concentrations of citric acid (0.00–3.0 M), and for different durations (0 to 120 h) at room temperature, and (c) for the -MWNTs plasma treated at different oxygen flows (0 to 10 sccm), RF power (100 to 300 W), and for different durations (10 to 30 min).