Regensburg 2013 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 45: Colloids and Complex Liquids II
CPP 45.4: Talk
Thursday, March 14, 2013, 16:00–16:15, H40
Finding Colloidal Hard Spheres — Markus Franke1, Achim Lederer1, Sebastian Golde1, Eckhard Bartsch2, and •Hans Joachim Schöpe1,3 — 1Johannes Gutenberg Universität Mainz, Institut für Physik, Staudinger Weg 7, 55099 Mainz, Germany — 2Albert-Ludwigs-Universität Freiburg, Institut für Physikalische Chemie, Albertstr. 21, 79104 Freiburg — 3Max-Planck-Institut für Polymerforschung, Postfach 3148, 55021 Mainz, Germany
In two recent publications it was claimed that there are difficulties in the preparation and characterization of colloids with hard sphere (HS) like interaction [1, 2]. Using PMMA-PHSA particles dispersed in organic solvents serious deviations from the ideal HS behavior have been observed. Furthermore the authors are of the opinion that in general the experimental determination of the particle volume fraction suffers from an inaccuracy of 0.03 to 0.06. Using highly cross linked polystyrene particles dispersed in ethylnaphtalene an optical and gravity matched colloidal model system with HS like interaction can be realized. We performed a comprehensive characterization of our colloidal model system giving us the possibility to determine the particle volume fraction with an accuracy better than 0.01. Analyzing different physical properties (sedimentation velocity, equilibrium phase behavior, crystallization kinetics, equilibrium lattice constant, glass transition dynamics, collective diffusion, short time diffusion) over a large volume fraction range (0.01 up to 0.74) we can show that this particles monitor HS behavior over the entire concentration range. [1] Soft Matter 8, 21 (2012,[2] Soft Matter 9, 17 (2013)