The high sensitivity at single molecule level of fluorescence correlation spectroscopy (FCS) enables measurements of charged polymer molecules at extreme dilution condition, which has been difficulty for conventional techniques as dynamic light scattering. By FCS, the conformation transition of single chain of polyelectrolytes is clearly exposed: the first-order conformation transition by pH of poly 2-vinylpyridine, the scaling analysis of polystyrene sulfonate shows a change from rod-like conformation to random coil conformation with the increase of the molecular weight. Photon count histogram (PCH) helps to determine the electric potential of single charged polymer molecules, explaining the important contribution of the counterion distribution: the breakdown of “counterion condensation.” FCS is a very important method for the study of charged polymers and bio-macromolecules.

Date Published: 22 February 2013
PDF: 8 pages
Proc. SPIE 8590, Single Molecule Spectroscopy and Superresolution Imaging VI, 859004 (22 February 2013); doi: 10.1117/12.2007679

Published in SPIE Proceedings Vol. 8590:
Single Molecule Spectroscopy and Superresolution Imaging VI
Jörg Enderlein; Ingo Gregor; Zygmunt Karol Gryczynski; Rainer Erdmann; Felix Koberling, Editor(s)