Dresden 2014 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 58: Polymer Dynamics II

CPP 58.5: Talk

Friday, April 4, 2014, 10:45–11:00, ZEU 114

Passive and active microrheology of a polymer melt studied by molecular dynamics simulation — •Anja Kuhnhold and Wolfgang Paul — Institute of Physics, Martin-Luther-University Halle-Wittenberg

The rheological behaviour of a material is determined by the relaxation of it’s stress autocorrelation [1]. In simulation studies the stress tensor can explicitely be calculated and serves as a reference for the microrheological results, that are based on the behaviour of suspended particles [2]. The system under study is the well established bead-spring polymer melt model [3] including one or two nanoscopic particles.

Passive microrheology yields linear response properties of the polymer melt by looking at the thermal motion of the nanoparticles. From the mean squared displacement of the nanoparticles the complex modulus G^*(ω) of the melt is determined by using a generalized Stokes-Einstein equation. The results are in very good agreement to the stress autocorrelation results. With regard to hydrodynamic effects, a more complete form of the analysis is discussed [4].

[1] M. Vladkov, J.-L. Barrat, Macromol. Theory Simul. 15, 252 (2006).

[2] T. G. Mason, Rheol. Acta 39, 371 (2000).

[3] C. Bennemann et al., Phys. Rev. E 57, 843 (1998).

[4] A. Erbas et al., Eur. Phys. J. E 32, 147 (2012).