Europhys. Lett.
Volume 72, Number 4, November 2005
Page(s) 664 - 670
Section Interdisciplinary physics and related areas of science and technology
Published online 14 October 2005
Europhys. Lett., 72 (4), pp. 664-670 (2005)
DOI: 10.1209/epl/i2005-10283-y

Depletion and cluster formation in soft colloid - polymer mixtures

E. Stiakakis1, 2, G. Petekidis1, D. Vlassopoulos1, 3, C. N. Likos4, H. Iatrou5, N. Hadjichristidis5 and J. Roovers6

1  Institute of Electronic Structure and Laser-FORTH - Heraklion, Crete, Greece
2  Department of Chemistry, University of Crete - Heraklion, Greece
3  Department of Materials Science and Technology, University of Crete Heraklion, Greece
4  Institut für Theoretische Physik II, Heinrich-Heine Universität Düsseldorf Düsseldorf, Germany
5  Department of Chemistry, University of Athens - Athens, Greece
6  NRC, Institute of National Chemical Process and Enviromental Technology Ottawa, Ontario Canada

received 18 May 2005; accepted in final form 19 September 2005
published online 14 October 2005

The dynamics of colloidal star -linear homopolymer mixtures is investigated by photon correlation spectroscopy. In dilute star solutions, osmotic forces due to the added polymers lead initially to a shrinkage of the stars and eventually, at higher polymer concentrations, to stable star clusters. Furthermore, concentrated glassy star solutions melt upon addition of small amounts of linear polymers, as manifested by the remarkable speed-up of the star self-diffusion. Quantitative description of the experimental findings is provided by calculations of the effective star-star pair potential.

82.70.Dd - Colloids.
61.25.Hq - Macromolecular and polymer solutions; polymer melts; swelling.

© EDP Sciences 2005