AFM‐Based Single Molecule Force Spectroscopy of Polymer Chains: Theoretical Models and Applications

Abstract

In recent years, remarkable advances in research of the mechanical and structural properties of single polymer chains have been achieved thanks to atomic force microscope (AFM)‐based single molecule force spectroscopy (SMFS). This technique offers great possibilities to investigate the mechanical properties of a single polymer chain by static/dynamic force‐extension measurements at the mesoscale level. Data are analyzed with the help of appropriate theoretical models, such as statistical mechanics models for freely jointed chains (FJC) or worm‐like chains (WLC), which can well describe the moderate entropy‐controlled stretch of most polymers, and with semiclassical models, which are being modified using quantum mechanics principles to account for entropic and enthalpic contributions to stretching in the high‐force Hookean regime. In this article we review the theoretical models of single chain stretching, the latest progress in force‐extension measurements by static and dynamic AFM modes for polymer chains dispersed in different solvents and subjected to a force that may induce their conformational transformations, as well as relevant applications.