3 research outputs found
Melting and Freezing Lines for a Mixture of Charged Colloidal Spheres with Spindle-Type Phase Diagram
We have measured the phase behavior of a binary mixture of like-charged
colloidal spheres with a size ratio of 0.9 and a charge ratio of 0.96 as a
function of particle number density n and composition p. Under exhaustively
deionized conditions the aqueous suspension forms solid solutions of body
centered cubic structure for all compositions. The freezing and melting lines
as a function of composition show opposite behavior and open a wide, spindle
shaped coexistence region. Lacking more sophisticated treatments, we model the
interaction in our mixtures as an effective one-component pair energy
accounting for number weighted effective charge and screening constant. Using
this description, we find that within experimental error the location of the
experimental melting points meets the range of melting points predicted for
monodisperse, one component Yukawa systems made in several theoretical
approaches. We further discuss that a detailed understanding of the exact phase
diagram shape including the composition dependent width of the coexistence
region will need an extended theoretical treatment.Comment: 25 pages, 4 figure