Robert E. Birdsall, Brooke M. Koshel, Yimin Hua, Saliya N. Ratnayaka and Mary J. Wirth
Electrophoresis 2013, 34, pp. 753–760. DOI: 10.1002/elps.201200413
The process of colloidal crystal formation is captured in the center color image, where the silica particles exhibit an ordered arrangement in a concentrated slurry, as indicted by the red color from Bragg diffraction. The particles then condense into a solid colloidal crystal, as indicated by the Bragg diffraction shifting to the green color due to closer lattice spacing. The crystalline order is detailed in the SEM image, which was obtained for a colloidal crystal made in a channel. The interparticle dimensions in this crystal reach the dimensions of proteins, enabling sieving in electrophoresis. The right image illustrates that classic sieving behavior is observed for these media.