Regensburg 2022 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 17: Poster 2
CPP 17.37: Poster
Dienstag, 6. September 2022, 11:00–13:00, P2
Dynamic Origin of the Entropic Force on a Semi-Confined Chain — •Rodrique Badr1, Lama Tannoury2, and Leonid Klushin3 — 1Johannes Gutenberg University, Mainz, Germany — 2Martin Luther University, Halle-Wittenberg, Germany — 3American University of Beirut, Beirut, Lebanon
Thermodynamics predicts that the free energy of confinement
| F=B |
|
for a chain confined in a tube with thin and thick walls is the same in both cases. This equivalence implies that the force acting to eject the chain from semi-confinement is also the same. Thermodynamics, however, does not explain the dynamical origin of the force, but one can understand the force as originating from contacts with the surface of the boundary. Intuition suggests that the thin boundary should amount to fewer contacts and thus lead to a smaller ejection force when compared to the case of a thick boundary. Using coarse-grained molecular dynamics (MD) simulations, we support and validate the thermodynamic prediction that the magnitude of the ejection force is the same for different thicknesses of the boundary.
The forces are also found to be in good agreement with the scaling laws
predicted by the thermodynamic approach. Finally, the results from our MD simulations provide an explanation of the origin of this equivalence of entropic forces, through the analysis of the radial distribution of contributions from the boundary to the ejection force.