Single molecules under aqueous medium
Figure 1. Single polymer molecule images recorded using a MultiMode microscope equipped with a fluid cell. A sharp coil-to-globule transition of a poly(2-vinylpyridine)
molecule upon pH change has been observed in this AFM images. (Roiter, Y.; Minko, S.
J. Am. Chem. Soc. 2005,
127(45), 15688-15689.
Details)
Figure 2. Single molecules adsorbed on mica at lower pH values (recorded
in situ). The fraction of uncovered mica surface descreases as the quantity of surface negative charges reduces and quantity of positive charges increases. Thus, positively charged polyelectrolyte prefer to adsorb only to the areas enriched with remaining negative charges, avoiding the rest of mica. (Roiter, Y.; Minko, S. (
Invited paper).
Journal of Physical Chemistry B 2007,
111(29), 8597-8604.
Details)
AFM images of polymer single molecules recorded in air
Figure 4. Polymer single molecules recorded in air after slow drying of samples at 99% humidity. Images were produced in the course of the
sample history study for poly(methacryloyloxyethyl dimethylbenzylammonium chloride) (PMB). Samples were prepared from 0.5 mg/L PMB solutions
without salt (a) and containing trisodium orthophosphate: (b) 4 mM; (c) 8 mM; and (d) 24 mM. Molecules were able to equilibrate
on the surface at slow sample drying, however, their radius of gyration decreased significantly with salt addition.
(Roiter, Y.; Jaeger, W.; Minko, S. (
Invited Paper)
Polymer 2006,
47(7), 2493-2498.
Details)
Figure 5. Single molecules recorded in air after fast drying of samples by spin-coating. Samples were prepared from 0.5 mg/L PMB solutions
without salt (a) and containing trisodium orthophosphate (24 mM) leading to the formation of PMB compact globules in solution.
Molecules were "frozen" or trapped in the conformation resembling their conformation in the solution.
(Roiter, Y.; Jaeger, W.; Minko, S. (
Invited Paper)
Polymer 2006,
47(7), 2493-2498.
Details)