Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 69: Focus: Polymers in Multi-Component and Aqueous Solutions I - organized by Jens-Uwe Sommer and Debashish Mukherji
CPP 69.3: Vortrag
Donnerstag, 15. März 2018, 15:45–16:00, C 130
Entropic Segregation in Mixtures of Dendrimers and Linear Polymer Solutions — •Martin Wengenmayr1,2, Ron Dockhorn1,2, and Jens-Uwe Sommer1,2 — 1Leibniz-Institut für Polymerforschung Dresden, Germany — 2Technische Universität Dresden, Germany
In mixtures of chemically compatible branched and linear polymers demixing effects are observed suggesting entropic forces caused by a difference in architecture only. For a better understanding of topological effects in mixtures of chemically identical polymers we investigate dendrimers of different sizes dissolved in a polymer solution of various chain lengths. We find that linear chains do always interpenetrate the volume of the dendrimer, whereas a collapsed state of the dendrimer known for poor solvent conditions, does not appear. Based on a scaling analysis of the dendrimer size we suggest that a thread length of the dendrimer, i.e. the longest path from the core to the terminal groups, is the relevant variable which should be compared with the chain length of the linear polymers. We can identify two scaling regions: When the chains are short compared to the length of the thread the dendrimer displays good solvent behavior, whereas longer chains lead to a θ-state of the dendrimer. Using umbrella sampling we observe an effective attraction between two dendrimers immersed in the solution of long linear chains. These insights are used to understand dendrimers used as processing aids in extrusion processes.