Figure 4. Temporal evolution of gelation.

(a) The typical coffee-ring effect appeared in the colloidal suspension drops (Supplementary Movie 3), identical to the sample of Fig. 3a, (b) while the gelation by addition of polymer at C_p = 4.0 mg/ml (Supplementary Movie 4), identical to the sample of Fig. 3d, displayed significant retardation of the outward coffee-ring effect (by the arrows). This result was repeated in the side-view sequential confocal images without the polymer addition in (c) (Supplementary Movie 5) and with polymer addition in (d) (Supplementary Movie 6).