Estimation of Persistence Lengths of Semiflexible Polymers: Insight from Simulations

TL;DR

This paper uses Monte Carlo simulations to compare methods for estimating the persistence length of semiflexible polymers, analyzing model differences, external influences, and implications for experimental interpretation.

Contribution

It provides a comparative analysis of lattice models and discusses conditions for applying worm-like chain models to semiflexible polymers.

Findings

Different models yield varying persistence length estimates.

External conditions like solvent quality influence persistence length.

The scattering function analysis aids experimental data interpretation.

Abstract

The persistence length of macromolecules is one of their basic characteristics, describing their intrinsic local stiffness. However, it is difficult to extract this length from physical properties of the polymers, different recipes may give answers that disagree with each other. Monte Carlo simulations are used to elucidate this problem, giving a comparative discussion of two lattice models, the self-avoiding walk model extended by a bond bending energy, and bottle-brush polymers described by the bond fluctuation model. The conditions are discussed under which a description of such macromolecules by Kratky-Porod worm-like chains holds, and the question to what extent the persistence length depends on external conditions (such as solvent quality) is considered. The scattering function of semiflexible polymers is discussed in detail, a comparison to various analytic treatments is given, and an outlook to experimental work is presented.