The Extension of Rod-Coil Multiblock Copolymers and the Effect of the Helix-Coil Transition

TL;DR

This paper investigates how the extension elasticity of rod-coil multiblock copolymers varies under fixed and interconvertible architectures, highlighting the impact of helix-coil transitions on force-extension behavior.

Contribution

It introduces a theoretical analysis of the extension behavior of rod-coil copolymers considering both fixed and dynamic architectures, emphasizing the role of helix-coil transitions.

Findings

Quenched case shows a sharp slope change in force law.

Annealed case exhibits a sigmoid force law with a plateau.

Relevance to single molecule experiments on biopolymers and synthetic macromolecules.

Abstract

The extension elasticity of rod-coil mutliblock copolymers is analyzed for two experimentally accessible situations. In the quenched case, when the architecture is fixed by the synthesis, the force law is distinguished by a sharp change in the slope. In the annealed case, where interconversion between rod and coil states is possible, the resulting force law is sigmoid with a pronounced plateau. This last case is realized, for example, when homopolypeptides capable of undergoing a helix-coil transition are extended from a coil state. Both scenarios are relevant to the analysis and design of experiments involving single molecule mechanical measurements of biopolymers and synthetic macromolecules.