Real‐Time Imaging of the Coil‐Globule Transition of Single Adsorbed Poly(2‐vinylpyridine) Molecules

Summary: We applied scanning force microscopy to study, in real time, the mobility and reorganisation of single poly(2‐vinylpyridine) molecules that were adsorbed on mica and exposed to vapours of ethanol or water. The macromolecules adopted a compact globular conformation in ethanol‐saturated vapour and extended to a surface‐bound two‐dimensional coil in water‐saturated vapour. Hence, reversible coil‐to‐globule conformational transitions of flexible polymer chains were directly visualized with unique molecular resolution. Left: individual P2VP molecules on mica compacted by exposure to ethanol vapour, right: the same macromolecules extended in water vapour. image Left: individual P2VP molecules on mica compacted by exposure to ethanol vapour, right: the same macromolecules extended in water vapour.