Journal Article

PreJuSER-20485

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Semidilute solutions of ultra-soft colloids under shear flow

Fedosov, D. A.FZJ* ; Singh, S. P.FZJ* ; Chatterji, A.FZJ* ; Winkler, R. G.FZJ* ; Gompper, G.FZJ*

2012
Royal Society of Chemistry (RSC) Cambridge

This record in other databases:  

Please use a persistent id in citations: http://hdl.handle.net/2128/7444  doi:10.1039/C2SM07009J

Abstract: We study semidilute star-polymer solutions under shear flow by hybrid mesoscale simulations. Hydrodynamic interactions are modeled by two particle-based simulation techniques, multiparticle collision dynamics (MPC) and dissipative particle dynamics (DPD). Star polymers are considered as a paradigmatic model for ultra-soft colloids with variable softness. The influence of concentration and shear rate on their structural and rheological properties is investigated. Under flow, a star polymer elongates and displays a well-defined alignment angle with respect to the flow direction. Moreover, the structural and rheological properties exhibit a universal behavior as a function of a concentration-dependent Weissenberg number for various concentrations at a given arm length. The rheological properties are characterized by the shear viscosity and the normal-stress coefficients. In dilute solution, the zero-shear viscosity follows the Einstein relation with an effective radius given by the hydrodynamic radius of a star polymer. At high shear rates, the solutions exhibit shear-thinning behavior, where the viscosity decreases faster with increasing shear rate at higher concentrations. We demonstrate that the results obtained from MPC and DPD agree in all scaling properties, with minor quantitative deviations in the numerical values.

Keyword(s): J

Note: We thank J. K. G. Dhont, J. Stellbrink, D. Richter, M. Ripoll (Julich), and D. Vlassopoulos (FORTH Crete) for stimulating discussions. Financial support by the Deutsche Forschungsgemeinschaft (DFG) through the Collaborative Research Center "Physics of Colloidal Dispersions in External Fields" (SFB TR6), and by the EU through the Collaborative Research Project "NanoDirect" (NMP4-SL-2008-213948) is gratefully acknowledged. D. A. F. acknowledges funding by the Humboldt Foundation through a postdoctoral fellowship.

---

Contributing Institute(s):

1. Theorie der weichen Materie und Biophysik (ICS-2)
2. Theorie der Weichen Materie und Biophysik (IAS-2)

Research Program(s):

1. BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung (P45)

Appears in the scientific report 2012

---

Database coverage:
; ; Allianz-Lizenz / DFG ; Current Contents - Social and Behavioral Sciences ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

---