Molecular Dynamics Study of Stiffness in Polystyrene and Polyethylene

TL;DR

This study uses 3D Langevin Molecular Dynamics to compare the stiffness and structural properties of polystyrene and polyethylene, revealing how molecular structure and temperature influence their conformations.

Contribution

It provides new insights into how phenyl groups in polystyrene affect its stiffness and size compared to polyethylene, with temperature-dependent behavior analyzed.

Findings

Polystyrene has a larger mean radius than polyethylene due to phenyl groups.

Temperature increase causes both polymers to lengthen, with polystyrene consistently larger.

Stiffness behavior varies between short and long polymer chains.

Abstract

In this paper, we have studied polystyrene (PS) and polyethylene (PE) stiffness by 3-dimensional Langevin Molecular Dynamics simulation. Hard polymers have a very small bending, and thus, their end-to-end distance is more than soft polymers. Quantum dot lasers can be established as colloidal particles dipped in a liquid and grafted by polymer brushes to maintain the solution. Here by a study on molecular structures of PS and PE, we show that the principle reason lies on large phenyl groups around the backbone carbons of PS, rather than a PE with Hydrogen atoms. Our results show that the mean radius of PS random coil is more than PE which directly affects the quantum dot maintenance. In addition, effect of temperature increase on the mean radius is investigated. Our results show that by increasing temperature, both polymers tend to lengthen, and at all temperatures a more radius is predicted for PS rather than PE, but interestingly, with a difference in short and long chains. We show that stiffness enhancement is not the same at short and long polymers and the behavior is very different. Our results show a good consonance with both experimental and theoretical studies.