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RESEARCH PRODUCT
Phase behaviour of deionized binary mixtures of charged colloidal spheres.
Thomas PalbergHans Joachim SchoepeHolger ReiberDirk Holland-moritzPatrick WetteTsuneo OkuboIna KlassenDieter M. HerlachNina Lorenzsubject
Range (particle radiation)Materials scienceFOS: Physical sciencesBinary mixtures solloidal spheresHard spheresCondensed Matter - Soft Condensed MatterCondensed Matter Physics530Condensed Matter - Other Condensed MatterColloidChemical physicsPhase (matter)AzeotropeParticleSoft Condensed Matter (cond-mat.soft)General Materials Scienceddc:530Phase diagramEutectic systemOther Condensed Matter (cond-mat.other)description
We review recent work on the phase behaviour of binary charged sphere mixtures as a function of particle concentration and composition. Both size ratios and charge ratios are varied over a wide range. By contrast to hard spheres the long ranged Coulomb interaction stabilizes the crystal phase at low particle concentrations and shifts the occurrence of amorphous solids to particle concentrations considerably larger than the freezing concentration. Depending on size- and charge ratios we observe upper azeotrope, spindle, lower azeotrope and eutectic types of phase diagrams, all known well from metal systems. Most solids are of body centred cubic structure. Occasionally stoichiometric compounds are formed at large particle concen-trations. For very low size ratios entropic effects dominate and induce a fluid-fluid phase separation. As for charged spheres also the charge ratio is decisive for the type of phase behaviour, future experiments with charge variable silica spheres are suggested.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2009-01-01 | Journal of physics. Condensed matter : an Institute of Physics journal |