Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 20: Poster: Colloids and Complex Liquids
CPP 20.34: Poster
Dienstag, 12. März 2013, 18:15–20:15, Poster C
The effect of topology on the conformations of cyclic polymers in melts — •Michael Lang1, Jakob Fischer1,2, and Jens-Uwe Sommer1,2 — 1Leibniz Institut für Polymerforschung Dresden, Hohe Straße 6, 01069 Dresden — 2Institut für Theoretische Physik, Technische Universität Dresden, 01069 Dresden
The bond fluctuation method is used to simulate solutions and melts of entangled and interpenetrating cyclic polymers. The swelling of interpenetrating rings upon dilution follows the same laws as for linear chains. We find an exponential decay of the knotting probability of cyclic polymers as function of the number of blobs per chain. A power law dependence fn∼φ R2∼φ0.77N for the average number fn of linked rings of N monomers per cyclic polymer at polymer volume fractions φ larger than the overlap volume fraction of rings φ* is determined from the simulation data. The fraction of non-concatenated cyclic polymers displays an exponential decay POO∼exp(−fn), which indicates fn to provide the entropic effort for not forming concatenated conformations. These observations indicate four different regimes for the conformations of cyclic polymers in melts separated by characteristic lengths NOO, NC and N* that describe the onset of the effect of non-concatenation, the cross-over between weak and strong compression and the cross-over to an overlap dominated concatenation contribution respectively. In these regimes, ring size scales as Nα with α= 1/2, 2/5, 3/8, and 4/9 respectively. The available data is in agreement with the first three regimes. The last regime is still unconfirmed due to the extremely large N necessary to reach this regime.