Helical configurations of elastic rods in the presence of interfacial traction

Abstract

The Kirchhoff thin elastic rod models are always the important basis to explore the configuration mechanism of the flexible structures in both the macroscopic and microscopic scale. As a continuum model of DNA, a thin elastic rod subjected to interfacial interactions is used to investigate the helical equilibrium configuration of DNA in salt solution. In this paper, the Kirchhoff’s equations in the presence of interfacial traction and the free energy density functions of different configurations are studied. The transition formula of the free energy between B-DNA and ZDNA is obtained, and the results show that the free energy of the transition is mainly determined by the salt concentration, which agrees well with the experimental data.

Keywords

interfacial energy / static Kirchhoff’s equations / helical configuration / ionic concentration / B-DNA to ZDNA transition

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