Dresden 2020 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 35: Modelling and Simulation of Soft Matter I (joint session CPP/DY)
DY 35.7: Talk
Wednesday, March 18, 2020, 11:30–11:45, ZEU 255
Modeling Depletion Interactions in Blends of Branched and Linear Polymers — •Martin Wengenmayr1,2, Ron Dockhorn1, and Jens-Uwe Sommer1,2 — 1Leibniz Institute of Polymer Research, Dresden, Germany — 2TU Dresden, Germany
Effective attractive interactions in colloidal systems are well understood and described by depletion potentials. Similar effective attractions have been found for a wide range of soft matter systems like brush coated particles and dendrimers as well. For colloidal particles the depletion potentials are deduced from volume exclusion layers around the hard particles, but this is not applicable for soft particles, which are interpenetrated by the depletant. In this work we present a mean field free energy approach modeling the origin of the soft matter depletion interactions by balancing the excess free energy between the soft particle and the depletant with the elastic repulsion between particles. This approach is adopted for a model system containing dendrimers as soft particles in the melt of linear polymer chains acting as depletant. From recent investigations [1] it is known that the dendrimers display so called crowded conformations that are compact but not fully collapsed and the dendrimers are strongly interpenetrated by linear chains. The mean field model is compared with coarse grained computer simulations applying the bond fluctuation model. This work contributes to the understanding of soft matter interactions and provides predictions for the occurrence of depletion interactions in experimental setups.
[1] Wengenmayr, Dockhorn, Sommer; Macromolecules 2019, 52, 2616-2626