Figure 8. Apparent viscosity of crude oil-in-water emulsions formed by PAA core (black) and PAA-PVK brushes (red) under different storing times. The inset figures are optical images of crude oil-in-water emulsions formed by oil soluble PAA-core (left) and PAA-PVK brushes (right) after storing for 30 days. Solid content for PAA core and PAA-PVK brushes was 2 mg/mL.