Regensburg 2025 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 23: Polymer and Molecular Dynamics, Friction and Rheology
CPP 23.4: Talk
Wednesday, March 19, 2025, 10:30–10:45, H34
Polymer chains under oscillatory force in solvents of variable quality — •Bogumiła Szostak1,2, Ron Dockhorn2, Jens-Uwe Sommer2, and Jarosław Paturej1,2 — 1University of Silesia in Katowice, Bankowa 12, 40-007 Katowice, Poland — 2Leibniz Institute of Polymer Research Dresden, Hohe Straße 6 D-01069 Dresden, Germany
Polymers are key materials in soft condensed matter with diverse applications. Recently, significant attention has been given to understanding the micromechanical behavior of single macromolecules under applied forces. Using molecular dynamics, we examined how constant and periodic forces affect polymer chain conformations in dilute solutions, modeled for good and poor solvents. We systematically calculated the projection of the end-to-end vector in the force direction as a function of the applied force. This analysis led to the construction of force-extension diagrams, which revealed conformational transitions of polymers from a globular state to an extended chain. Analysis of hysteresis loops for periodic forces showed that longer force periods allowed more time for the system to respond, resulting conformational reorganization. These results were compared with analytical solutions of the Rouse model under periodic perturbation and scaling laws, providing a valuable benchmark and deeper insight into the observed dynamics. We also characterized the relationship between dissipated energy and the frequency of the applied sinusoidal stretching force. These findings provide new insights into the mechanical behavior of polymer chains under oscillatory forces, enhancing our understanding of their dynamic properties and potential applications.
Keywords: molecular dynamics; polymer physics; force spectroscopy; oscillatory force