Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 63: Polymer and Molecular Dynamics II

CPP 63.9: Vortrag

Donnerstag, 15. März 2018, 11:45–12:00, C 264

Relaxation of Disentangled and Collapsed Polymer chains in a melt — •Manjesh Kumar Singh, Hsiao-Ping Hsu, and Kurt Kremer — Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany

Entanglements dominate the rheological behavior of high molecular weight polymeric melts. Experimental studies [1] show that slow and careful melting of disentangled polymer crystals lead to formation of metastable melt exhibiting lower viscosity. With an objective of studying the non-linear rheological behavior of fully disentangled globules in a melt under elongation, we follow the similar strategies developed in Ref. [2], and perform standard bead-spring model based molecular dynamics simulations to our polymer melt systems. The system is prepared by first forming independent single globules of polymer chains. We observe that for short chains (N ≤ 200) our melt systems of disentangled globules reach their entangled and fully equilibrated state at t ≈ τ_R,N (τ_R,N: the Rouse time for chains of size N) while for N = 1000, the system has not reached its equilibrated state even at t ≈ 10 τ_R. Through the primitive path analysis [3], we show the development of entanglements during the relaxation process from disentangled globules to entangled states. [1] Rastogi, et al. Nat. Mater. 4, 635 (2005). [2] Vettorel, Kremer, Macromol Theory Simul. 19, 44 (2010). [3] Everaers, et al. Science 303, 823 (2004).