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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Poster 2

CPP 17.38: Poster

Dienstag, 6. September 2022, 11:00–13:00, P2

Computational study of the rheology of nanoparticle-polymer composites — •Leon Hillmann, Niklas Blagojevic, and Marcus Müller — Institute for Theoretical Physics, Georg-August-Universität Göttingen, Germany

Matrix-filler interactions in nanoparticle-polymer composites play a crucial role in the manufacturing process as well as the properties of the final material. Therefore, understanding the interplay between the parameters, such as shape, concentration, and size, is paramount for the design process of new composites. Computer simulations of these materials, however, pose several challenges due to the vast differences in the length scales involved, ranging from atomistic forces up to large-scale self-assembling structures. Here, a single nanoparticle embedded in polymer melt, represented by a highly coarse-grained, Gaussian, bead-spring model, is studied by dissipative particle dynamics (DPD) simulations. The nanoparticle-polymer interaction is adjusted with iterative Boltzmann inversion to match predictions of the density profile from atomistic simulations. Measurements of the nanoparticle’s velocity autocorrelation function are then used to determine the memory kernel in a generalized Langevin equation. To what extent does the motion of the nanoparticle provide information about the viscoelastic properties of the surrounding melt? To this end, a numerical solution of the corresponding inverse problem is presented, which arises from a reformulation of the problem as the inversion of a triangular Toeplitz matrix. The results are finally compared with the predictions made by the Rouse model for unentangled polymer melts.