Single Molecules of Polymers


Single molecules of polymers are the objects, which study opens new possibilities to collect important information for polymer and colloidal science. Understanding of the behavior of single polymer chains in solutions and in adsorbed state is crucial for adsorption processes, chromatography and other separation methods, design and applications of new advanced materials and technologies such as drug delivery systems, sensors, responsive materials, catalysts, miniaturized devices, lab-on-chip and microfluidic technologies.

Polymer single molecules are studied in our group using the recent advances in atomic force microscopy (AFM). AFM, as one of the major constitutive parts of scanning probe microscopy (SPM), allows for the visualization of fine conformational details of polymer molecules under air atmosphere and under liquid medium. Recently, we have succeeded in a high resolution visualization of single chains of synthetic polymers on mica surface in situ under aqueous solutions. This experience allowed us to compare the conformations of polymer chains on the mica substrate using samples prepared in different conditions and also in applied electrical field. We obtain information about equilibrium conformations of the adsorbed polymer molecules under aqueous solutions:

Video 1. Polymer single molecule imaging under liquid medium.

and in air after the slow drying in the atmosphere at 99% humidity, as well as, after fast drying by nitrogen stream or spin-coating for "frozen" conformations of polymer molecules:

Video 2. Preparation of single molecule sample for AFM-imaging under air.

A 2D Single Molecule Software was developed in our group for the processing of recorded images of single polymer molecules. "2D Single Molecule Software" is a freeware available upon request.


Major Directions:

Single molecules under aqueous medium

Single MoleculesSingle Molecule
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)

Single Molecule Adsorption
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

Single Molecules; Slow Drying
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)

Single Molecules; Fast Drying
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)

Group co-operates with:
Publications on Topic (review titles are marked blue):
  1. Koestner, R.; Roiter, Y.; Kozhinova, I.; Minko, S. AFM Imaging of Adsorbed Nafion Polymer on Mica and Graphite at Molecular Level. Langmuir 2011, ACS Just Accepted Manuscript (Published on Web: July 7, 2011). Details
  2. Koestner, R.; Roiter, Y.; Kozhinova, I.; Minko, S. The Effect of Local Charge Distribution on Graphite Surface on Nafion Polymer Adsorption as Visualized at Molecular Level. Journal of Physical Chemistry C 2011, ACS Just Accepted Manuscript (Published on Web: July 1, 2011). Details
  3. Roiter, Y.; Trotsenko, O.; Tokarev, V.; Minko, S. Single Molecule Experiments Visualizing Adsorbed Polyelectrolyte Molecules in the Full Range of Mono- and Divalent Counterion Concentrations. Journal of the American Chemical Society 2010, 132(39), 13660-13662. Details
  4. Trotsenko, O.; Roiter, Y.; Minko, S. Structure of salted and discharged globules of hydrophobic polyelectrolytes adsorbed from aqueous solutions. Journal of Polymer Science, Part B: Polymer Physics 2010, 48(14), 1623-1627. Details
  5. Roiter, Y.; Ornatska, M.; Rammohan, A. R.; Balakrishnan, J.; Heine, D. R.; Minko, S. Interaction of Lipid Membrane with Nanostructured Surfaces. Langmuir 2009, 25(11), 6287-6299. Details
  6. Roiter, Y.; Minko, S. Responsive behavior of single polymer molecules: visualization with AFM. PMSE Preprints 2008, 99, 545.
  7. Roiter, Y.; Minko, S. Adsorption of Polyelectrolyte versus Surface Charge: in Situ Single-Molecule Atomic Force Microscopy Experiments on Similarly, Oppositely, and Heterogeneously Charged Surfaces (Invited paper). Journal of Physical Chemistry B 2007, 111(29), 8597-8604. Details
  8. Roiter, Y.; Minko, S. Single molecules of polymers: AFM imaging under liquid medium. Polymer Preprints 2007, 48(2), 522-523.
  9. Roiter, Y.; Jaeger, W.; Minko, S. Conformation of single polyelectrolyte chains vs. salt concentration: Effects of sample history and solid substrate (Invited paper). Polymer 2006, 47(7), 2493-2498. Details
  10. Roiter, Y.; Minko, S. AFM Single Molecule Experiments at the Solid-Liquid Interface: In Situ Conformation of Adsorbed Flexible Polyelectrolyte Chains. Journal of the American
    Chemical Society
    2005, 127(45), 15688-15689. Details
  11. Lupitskyy, R.; Roiter, Y.; Tsitsilianis, C.; Minko, S. From Smart Polymer Molecules to Responsive Nanostructured Surfaces. Langmuir 2005, 21(19), 8591-8593. (Heteroarm star co-polymer) Details
  12. Minko, S.; Roiter, Y. AFM single molecule studies of adsorbed polyelectrolytes. Current Opinion in Colloid & Interface Science 2005, 10(1-2), 9-15. Details
  13. Roiter, Y.; Minko, S. Adsorbed polyelectrolyte single molecules: AFM visualization under liquid. PMSE Preprints 2005, 93, 717.
  14. Minko, S.; Kiriy, A.; Gorodyska, G.; Sheparovych, R.; Lupitskiy, R.; Tsitsilianis, C.; Stamm, M. Conformation of Polymer Molecule via Atomic Force Microscopy. ACS Symposium Series 2005, 897(Applications of Scanned Probe Microscopy to Polymers, edited by Batteas, James D.; Michaels, Chris A.; Walker, Gilbert C.), 207-223. Details
  15. Kiriy, A.; Gorodyska, G.; Kiriy, N.; Sheparovych, R.; Lupytsky, R.; Minko, S.; Stamm, M. AFM Imaging of Single Polycation Molecules Contrasted with Cyanide-Bridged Compounds. Macromolecules 2005, 38(2), 501-506. Details
  16. Kiriy, A.; Gorodyska, G.; Kiriy, N.; Sheparovych, R.; Lupytsky, R.; Minko, S.; Stamm, M. AFM Imaging of Single Polycation Molecules Contrasted with Cyanide-Bridged Compounds. Macromolecules 2005, 38(2), 501-506. Details
  17. Voronov, A.; Minko, S.; Shulga, A.; Pefferkorn, E. Non-equilibrium adsorption at solid/liquid interfaces from polyelectrolyte solutions. Colloid and Polymer Science 2004, 282(9), 1000-1007. Details
  18. Minko, S.; Kiriy, A.; Gorodyska, G.; Lupitskyy, R.; Tsitsilianis, C.; Stamm, M. Conformational transitions visualized in single polyelectrolyte molecule AFM experiments. Polymer
    Preprints
    2004, 45(2), 258. pdf version
  19. Kiriy, A.; Gorodyska, G.; Minko, S.; Stamm, M. Cyanide-bridged compounds as contrasting agents for AFM imaging of single polycation molecules. Polymer Preprints 2004, 45(1), 486-487. pdf version
  20. Kiriy, A.; Bocharova, V.; Gorodyska, G.; Minko, S.; Stamm, M. Assembling of Prussian blue nanoclusters along single polyelectrolyte molecules. PMSE Preprints 2004, 90, 593-594. pdf version
  21. Tsitsilianis, C.; Bossard, F.; Sfika, V.; Stavrouli, N.; Kiriy, A.; Gorodyska, G.; Stamm, M.; Minko, S. Multifunctional double hydrophilic triblock copolymer in solution and on surface. PMSE Preprints 2004, 90, 368-369. pdf version
  22. Kiriy, A.; Gorodyska, G.; Minko, S.; Stamm, M.; Tsitsilianis, C. Single Molecules and Associates of Heteroarm Star Copolymer Visualized by Atomic Force Microscopy. Macromolecules 2003, 36(23), 8704-8711. Details
  23. Kiriy, A.; Gorodyska, G.; Minko, S.; Tsitsilianis, C.; Jaeger, W.; Stamm, M. Chemical Contrasting in a Single Polymer Molecule AFM Experiment. Journal of the American
    Chemical Society
    2003, 125(37), 11202-11203. Details
  24. Kiriy, N.; Jähne, E.; Adler, H.-J.; Schneider, M.; Kiriy, A.; Gorodyska, G.; Minko, S.; Jehnichen, D.; Simon, P.; Fokin, A. A.; Stamm, M. One-Dimensional Aggregation of Regioregular Polyalkylthiophenes. Nano Letters 2003, 3(6), 707-712. Details
  25. Kiriy, A.; Gorodyska, G.; Minko, S.; Tsitsilianis, C.; Stamm, M. Atomic force microscopy visualization of single star copolymer molecules. PMSE Preprints 2003, 88, 233-234. pdf version
  26. Gorodyska, G.; Kiriy, A.; Minko, S.; Tsitsilianis, C.; Stamm, M. Reconformation and Metallization of Unimolecular Micelles in Controlled Environment. Nano Letters 2003, 3(3), 365-368. Details
  27. Kiriy, A.; Gorodyska, G.; Minko, S.; Jaeger, W.; Štěpánek, P.; Stamm, M. Cascade of Coil-Globule Conformational Transitions of Single Flexible Polyelectrolyte Molecules in Poor Solvent. Journal of the American Chemical Society 2002, 124(45), 13454-13462. Details
  28. Minko, S.; Gorodyska, G.; Kiriy, A.; Jaeger, W.; Stamm, M. Visualization of single polyelectrolyte molecules. PMSE Preprints 2002, 87, 185-186. pdf version
  29. Minko, S.; Kiriy, A.; Gorodyska, G.; Stamm, M. Single Flexible Hydrophobic Polyelectrolyte Molecules Adsorbed on Solid Substrate: Transition between a Stretched Chain, Necklace-like Conformation and a Globule. Journal of the American Chemical Society 2002, 124(13), 3218-3219. Details
  30. Minko, S.; Voronov, A.; Pefferkorn, E. Oscillation Phenomenon at Polymer Adsorption. Langmuir 2000, 16(20), 7876-7878. Details
  31. Voronov, A.; Pefferkorn, E.; Minko, S. Adsorption of Protonated Poly(vinylpyridine) on Silica. Correlation between Interfacial Conformation and Colloid Stability. Macromolecules 1998, 31(18), 6387-6389. Details