DPG Phi
Verhandlungen
Verhandlungen
DPG

Regensburg 2010 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 23: Polymer Dynamics

CPP 23.3: Vortrag

Mittwoch, 24. März 2010, 10:30–10:45, H48

Bond-correlation functions determined in MD simulations of entangled polymer melts — •Hendrik Meyer — Institut Charles Sadron, CNRS UPR22, 67034 Strasbourg, France

The polymer dynamics of entangled bead-spring chains is analysed based on large scale molecular dynamics simulations. As found in previous studies, the predicted power law regimes of mean-square displacements attributed to Rouse-motion in the tube (cross-over from t0.5 to t0.25) are only well developed beyond Z≥ 10 entanglements per chain. Similar power law regimes are present for bond time-autocorrelation functions (P1t−0.5 and t−0.25). NMR experiments measure a correlation function proportional to the second Legendre polynomial P2 of the bond correlations, which is found to be proportional to the square of P1 only for flexible chains, whereas a slower time decrease is found for chains with a small angular potential. Clear evidence is found that the terminal relaxation time increases stronger than predicted by reptation theory for Z>5. We critically compare this finding with theories of contour length fluctuations, often invoked as the main explanation of this slowing down.

100% | Mobil-Ansicht | English Version | Kontakt/Impressum/Datenschutz
DPG-Physik > DPG-Verhandlungen > 2010 > Regensburg