Phase separation of Ag colloids. (A) Scanning electron micrograph of a SiO₂-Ag microsphere. (B) SiO₂-Ag particles attract each other in dilute H₂O₂. (C) Optical micrographs of the phase separation of SiO₂-Ag (dark) with population density φ = 17% in 0.001 wt% H₂O₂ aqueous solution. (D) The 2D packing fraction of clusters and (E) the characteristic length of the clusters in (C) as a function of time. The particle density is obtained by identifying the area fraction of the particles by imageJ, see Figure S2 for details. The characteristic length (L) refers to the length corresponding to the first root of the spatial correlation function of the micrographs, see Figure S3 for details. Both the x and y axis in (E) are in log10 scale. Solid red lines in (E) are linear fits.