Navigation and service


ICS-3 Group seminar
Complex yielding in frustrated states of attractive colloids

Prof. Dr. George Petekidis

IESL-FORTH & Materials Science & Technology Department, University of Crete, Heraklion, Greece.


begin
19 Dec 2017 10:30
end
19 Dec 2017 11:30
venue
Seminarraum A1-3, Building 04.6, Entrance E1

Abstract:

I will present key microscopic mechanisms affecting the structure and particle dynamics when attractive interactions are added in a hard sphere glass.  Furthermore the effect of attractions in the macroscopic response of repulsive (hard-sphere) and attractive glasses during nonlinear rheology and yielding is studied by a combined experimental and computer simulation study.

I mainly focus on the way such systems yield under the application of steady or oscillatory shear via start-up shear tests and large amplitude oscillatory shear, as well as on the mechanisms of structural reformation and related stress relaxation after shear cessation. I discuss the phenomenology of two-step yielding, widely observed experimentally, its relation with quiescent microscopic dynamics and the underlying mechanisms affecting the relevant length- and time-scales during shear. 

Both experiments and Brownian Dynamics (BD) simulations show two peaks in stress versus strain during start-up shear tests with good qualitative agreement suggesting that Hydrodynamic Interactions are not crucially important at such highly concentrated systems. Structural analysis obtained from BD simulations confirms that the first yield is related to the breaking of the structure at the length scales smaller than attraction range while the second yield point is a consequence of cage deformation and breaking.

Contact

Prof. Jan K.G. Dhont
Phone: +49 2461 61-2160
Fax: +49 2461 61-2765
email: j.k.g.dhont@fz-juelich.de

Servicemeu

Homepage

Logo

 

 

 

YOUR OPINION MATTERS!

 

Dear visitor,

To make our website suit your needs even more and to give it a more appealing design, we would like you to answer a few short questions.

Answering these questions will take approx. 10 min.

Start now Close window

Thank you for your support!

 

In case you have already taken part in our survey or in case you have no time to take part now, you can simply close the window by clicking "close".

If you have any questions on the survey, please do not hesitate to contact: webumfrage@fz-juelich.de.

 

Your Team at Forschungszentrum Jülich

 

Note: Forschungszentrum Jülich works with the market research institute SKOPOS to anonymously conduct and analyze the survey. SKOPOS complies with the statutory requirements on data protection as well as with the regulations of ADM (Arbeitskreis Deutscher Markt- und Sozialforschungsinstitute e.V.) and ESOMAR (Europäische Gesellschaft für Meinungs- und Marketingforschung). Your data will not be forwarded to third parties.