抄録
We examined influences of the particle volume fraction ϕ and effective charge number Zeff on the crystal structures of charged colloids, by means of the reflection spectroscopy and Kikuchi-Kossel diffraction measurements. We employed dilute salt-free aqueous dispersions of charged polystyrene (PS) particles (the diameter d = 110 to 120 nm; Zeff = about 1300) and colloidal silica (d = 120 nm, Zeff = about 550). The PS colloids had the BCC structure at ϕ ≤ 0.01 and exhibited the structural phase transition into the FCC lattice on increasing ϕ. The silica colloids, which had lower Zeff, took the BCC structures at all ϕs examined (ϕ≤ 0.04).
