Dresden 2011 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 25: Colloids and Complex Liquids I - Structure
CPP 25.6: Vortrag
Mittwoch, 16. März 2011, 12:00–12:15, ZEU 222
Modification of critical adsorption profiles by addition of ions — •Julian Dietrich1, Ursula Nellen1, and Clemens Bechinger1,2 — 12. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany — 2Max-Planck-Institut für Metallforschung, Heisenbergstraße 3, 70569 Stuttgart, Germany
In the last years there is growing interest in the use of binary liquids as dispersion medium for colloidal systems because this leads e.g. to critical Casimir forces or the formation of bicontinuous gels (bijels). We investigate the role of additional salt ions in binary mixtures close to the critical point since this may lead to interesting coupling effects between electrostatic forces and the mixtures' concentration distribution. In our experiments we study the adsorption profile of a critical water/2,6-lutidine mixture in the presence of salt ions. Such temperature-dependent profiles are obtained by measuring the variation of the permittivity with a surface plasmon resonance experiment for different types and concentrations of salts. We compare these results to chemically modified surfaces where the adsorption preference for one of the mixture's components is systematically altered.