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Cover Picture: Osmotic Pressure and Phase Boundary Determination of Multiphase Systems by Analytical Ultracentrifugation (ChemPhysChem 6/2008)
Author(s) -
Page Miles G.,
Zemb Thomas,
Dubois Monique,
Cölfen Helmut
Publication year - 2008
Publication title -
chemphyschem
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200890022
Subject(s) - chemistry , isotropy , phase (matter) , analytical ultracentrifugation , osmotic pressure , phase boundary , analytical chemistry (journal) , chromatography , ultracentrifuge , thermodynamics , optics , biochemistry , organic chemistry , physics
The cover picture illustrates a system of Laponite clay particles, investigated by M. G. Page, H. Cölfen et al. (p. 882) under analytical ultracentrifugation. Separation into its dilute phase, a biphasic isotropic gel and nematic concentrated phase occurs during centrifugation, whilst a laser and detection system mounted on the rotor determines in situ the concentration throughout the sample cell. The plot shows the variation of concentration as a function of radial distance, approaching equilibrium over time. At equilibrium the entire equation of state can be extracted, with both single‐biphasic boundary concentrations directly observed, and the osmotic pressure is calculated versus concentration over the entire radial distance.