Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 18: Poster: Polymer Dynamics

CPP 18.8: Poster

Dienstag, 12. März 2013, 18:15–20:15, Poster C

Passive and active microrheology of a polymer melt studied by molecular dynamics simulation — •Anja Kuhnhold and Wolfgang Paul — Institut fuer Physik, Martin-Luther-Universitaet, 06099 Halle

The rheology of polymer melts can be observed from the behaviour of suspended particles (microrheology). Therefore MD simulations of a bead-spring polymer melt model including one or two nanoscopic particles are carried out. Passive microrheology yields linear response properties of the polymer melt by looking at the thermal motion of the nanoparticles. From the mean square displacement of the nanoparticles the complex modulus G^*(ω) of the melt is determined by using a generalized Stokes-Einstein equation . Results for one- and two-particle microrheology are compared. Furthermore the nonlinear response of the polymer melt is investigated by applying forces to the melt. Here a nanoparticle-oscillator is used; i.e. two nanoparticles are connected by a harmonic potential and the compressed oscillator is put into the polymer melt. The resulting oscillation of the nanoparticles is studied for different melt temperatures and different spring constants.