Speaker
Description
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.
