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Polymer Brushes

Surface architectures with distinct properties

polymer brush

Schematic representation of a polymer brush.

The term "polymer brush" was coined by deGennes to describe an architecture in which polymer chains are terminally tethered to a surface at a very high denisty (anchoring density is much smaller than coil dimensions). Due to this overcrowding the chains stretch perpendicular to the surface until the loss of possible conformations (loss in entropy) balances the enthalpic gain of segment dilution. The situation is illustrated in the image to the right in a somewhat simplified way as the chains are drawn invidually as if there would be no overlap.

The best way to realize such an architecture is to grow the chains directly at the surface of the substrate. This approach is called grafting from polymerization or surface-initiated polymerization. In a first step, the surface is decorated with an monolayer of an initiator which can then be used to "grow a lawn" of polymer molecules. Using this approach we are able to create monolayers of a variety of polymers with a thickness between a few nanometers and a few micrometers. The properties of the layers can be readily adjusted by choosing an appropriate monomer.

Example projects:

Polyelectrolyte Brushes

pel brush (schematic)

Polyelectrolyte Brushes are surface architectures with rather special properties. Their swelling behavior is unique and shows strong and often times unespected dependencies on pH and ionic strength of the medium.

 

 

Mixed Polymer Brushes

mixed polymer brush (schematic)

Blockcopolymer brushes or mixed polymer brushes combine two immiscible polymers in very close proximity. Phase seggregation is limited to nano scales and can be switched using selective or non-selective solvents.

Brush Degradation

140124-scheibelein-irtg-grahical-plot.png

Polymer brushes are intrinsically meta-stable architectures. In contact with solvent they experience a strong osmotic pressure forcing them to swell strongly. Most uncharged brushes easily withstand this force, yet for many charged polymer brushes the swelling leads to a drag on the chains that is stronger than chemical bonds. Catastrophic degrafting is often times the result.

 

Gradient Surfaces

gradient brush

Combining surface-initiated polymerization with interference lithography provides means to generate topological gradients on the nanoscale.

 

Selected publications:

  • Lomadze,N.; Kopyshev,A.; Rühe, J.; Santer, S.
    Light-Induced Chain Scission in Photosensitive Polymer Brushes
    Macromolecules, 44, 2011, 7372-7377
  • Schuh, C.; Rühe, J.
    Penetration of Polymer Brushes by Chemical Nonidentical Free Polymers
    Macromolecules, Vol 44, 2011, 3502-3510
  • Schuh, C.; Lomadze,N.; Rühe, J.; Kopyshev,A.; Santer, S.
    Photomechanical Degrafting of Azo-Functionalized Poly(methacrylic acid) (PMAA) Brushes
    J. Phys. Chem. B, 115, 2011, 10431–10438
  • Schuh, C.; Santer, S.; Prucker, O.; Rühe, J.
    Polymer Brushes with Nanometer-Scale Gradients
    Advanced Materials, Vol. 21, 2009, 1-5
  • Raghuraman, G. K.; Rühe, J.; Dhamodharan, R.,
    Grafting of PMMA brushes on titania nanoparticulate surface via surface-initiated conventional radical and
    J Nanopart Res, Vol 10, 2008, 415-427
  • Santer, S., Kopyshev, A., Donges, J., Rühe, J., Jiang, X., Zhao, B., Müller, M.
    Memory of Surface Patterns in Mixed Polymer Brushes: Simulation and Experiment
    Langmuir, Vol. 23 (1), 2007, 279 - 285
  • Akgun, B., Lee, D. R., Kim, H., Zhang, H., Prucker, O., Wang, J., Rühe, J., Foster, M.D.
    Self-Affine Surfaces of Polymer Brushes
    Macromolecules, Vol 40, 2007, 6361-6369
  • Murata, H., Prucker, O., Rühe, J.
    Synthesis of Functionalized Polymer Monolayers from Active Ester Brushes
    Macromolecules, Vol. 40, 2007, 5497 - 5503
  • Munirasu, S., Rühe, J., Dhamodharan, R.
    Ambient temperature ATRP of benzyl methacrylate as a tool for the synthesis of block copolymers with styrene
    Journal of Polymer Science Part a-Polymer Chemistry, Vol. 44, 2006, 2848-2861
  • Santer, S., Kopyshev, A., Donges, J., Yang, H.-K., Rühe, J.
    Dynamically Reconfigurable Polymer Films: Impact on Nanomotion
    Advanced Materials, Vol. 18, 2006, 2359-2362
  • Santer, S., Kopyshev, A., Yang, H.-K., Rühe, J.
    Local composition of nanophase-separated mixed polymer brushes
    Macromolecules, Vol. 39, 2006, 3056-3064
  • Kim, H., Foster, M. D., Rühe, J.
    Surface fluctuations of polymer brushes probed by diffuse X-ray scattering
    Polymer, 46/7, 2005, 2331-2337
  • Zhang H., Rühe J.
    Swelling of Poly(methacrylic acid) Brushes: Influence of Monovalent Salts in the Environment
    Macromolecules, 2005, 4855-4860
  • Biesalski, M., Johannsmann, D., Rühe, J.
    Electrolyte-induced collapse of a polyelectrolyte brush

    Journal of Chemical Physics, Vol. 120, 2004, 8807-8814
  • Konradi, R., Rühe, J.
    Interaction of Poly(methacrylic acid) Brushes with Metal Ions: An Infrared Investigation
    Macromolecules, Vol. 37, 2004, 6954-6961
  • S. Santer (Prokhorova), J. Rühe
    Motion of nano-objects on polymer brushes
    Polymer, 2004, pp.8279
  • Bunjes, N., Paul, S., Habicht, J., Prucker, O., Rühe, J., Knoll, W.
    On the swelling behavior of linear end-grafted polystyrene in methanol/toluene mixtures
    Colloid and Polymer Science, Vol. 282, 2004, 939-945
  • Rühe, J., Ballauff, M., Biesalski, M., Dziezok, P., Gröhn, F., Johannsmann, D., Houbenov, N., Hugenberg, N., Konradi, R., Minko, S., Motornov, M., Netz, R. R., Schmidt, M., Seidel, Ch., Stamm, M., Stephan, T., Usov, D., Zhang, H.
    Polyelectrolyte Brushes
    Schmidt, M. (Ed.), Polyelectrolytes with Defined Molecular Architecture I, Vol. 165:79-150, Springer Verlag, Berlin, 2004, 71
  • Biesalski, M., Rühe, J.
    Tailoring the Change Density of Surface-Attached Polyelectrolyte Brushes
    Macromolecules, Vol. 37, 2004, 2196-2202
  • Prokohova, S. , Kopyshev, A., Ramakrishnan, A., Zhang, H., Rühe, J.
    Can polymer brushes induce motion of nano-objects?
    Nanotechnology, 2003, 1098-1108
  • Zhang, H., Rühe, J.
    Interaction of strong polyelectrolytes with surface-attached polyelectrolyte brushes-polymer brushes as substrates for the layer-by-layer deposition of polyelectrolytes
    Macromolecules, Vol. 36, 2003, 6593
  • S.A. Prokhorova, A. Kopyshev, A. Ramakrishnan, H. Zhang, H., J. D. Jeyaprakash S. Samuel, J. Rühe
    Organization of Silica Nanoparticles on Diblock-Copolymer and Mixed Brushes
    Polymer Preprints, 2003, pp.453
  • Zhang, H. , J., Rühe,
    Polyelectrolyte Multilayers on Weak Polyelectrolyte Brushes
    Macromol. Chem., Rapid Commun., Vol. 24, 2003, 576-579
  • Biesalski, M., Rühe, J.
    Synthesis of a poly(p-styrenesulfonate) brush via surface- initiated polymerization
    Macromolecules, Vol. 36, 2003, 1222-1227
  • Ramakrishnan, A., Dhamodharan, R., Rühe, J.
    Controlled growth of PMMA brushes on silicon surfaces at room temperature
    Macromolecular Rapid Communications, Vol. 23, 2002, 612-616
  • Jung, D. H., Park, I. J., Choi, Y. K., Lee, S. B., Park, H. S., Rühe, J.
    Perfluorinated polymer monolayers on porous silica for materials with super liquid repellent properties
    Langmuir, Vol. 18, 2002, 6133-6139
  • Jeyaprakash, J. D., Samuel, S., Dhamodharan, R., Rühe, J.
    Polymer brushes via ATRP: Role of activator and deactivator in the surface-initiated ATRP of styrene on planar substrates
    Macromolecular Rapid Communications, Vol. 23, 2002, 277-281
  • Biesalski, M., Rühe, J.
    Scaling laws for the swelling of neutral and charged polymer brushes in good solvents
    Macromolecules, Vol. 35, 2002, 499-507
  • Biesalski, M., Johannsmann, D., Rühe, J.
    Synthesis and swelling behavior of a weak polyacid brush
    Journal of Chemical Physics, Vol. 117, 2002, 4988-4994
  • Benmouna, F., Peng, B., Gapinski, J., Patkowski, A., Rühe, J., Johannsmann, D.
    Dynamic light scattering from liquid crystal polymer brushes swollen in a nematic solvent
    Liquid Crystals, Vol. 28, 2001, 1353-1360
  • Chen, X. H., Tolbert, L. M., Henderson, C. L., Hess, D. W., Rühe, J.
    Polymer pattern formation on SiO2 surfaces using surface monolayer initiated polymerization
    Journal of Vacuum Science & Technology B, Vol. 19, 2001, 2013-2019
  • Rühe, J.
    Polymerization to Control Interfacial Properties
    Encyclopedia of Materials: Science and Technology, Elsevier Science Ltd., 2001, 7213-7218
  • Gelbert, M., Biesalski, M., Rühe, J., Johannsmann, D.
    Collapse of polyelectrolyte brushes probed by noise analysis of a scanning force microscope cantilever
    Langmuir, Vol. 16, 2000, 5774-5784
  • Rühe, J., Knoll, W.
    Functional Polymer Brushes
    Ciferri, A. (Ed.), Supramolecular Polymers, Marcel Dekker, New York, 2000, 565-613
  • Peng, B., Rühe, J., Johannsmann, D.
    Homogeneously aligned liquid-crystal polymer brushes
    Advanced Materials, Vol. 12, 2000, 821-824
  • Biesalski, M., Johannsmann, D., Rühe, J.
    Neutral and charged polymer brushes at solid surfaces
    Macromolecular Symposia, Vol. 145, 1999, 113-124
  • Peng, B., Johannsmann, D., Rühe, J.
    Polymer brushes with liquid crystalline side chains
    Macromolecules, Vol. 32, 1999, 6759-6766
  • Biesalski, M., Rühe, J.
    Preparation and characterization of a polyelectrolyte monolayer covalently attached to a planar solid surface
    Macromolecules, Vol. 32, 1999, 2309-2316
  • Biesalski, M., Rühe, J., Johannsmann, D.
    Segment density profiles of polyelectrolyte brushes determined by Fourier transform ellipsometry
    Journal of Chemical Physics, Vol. 111, 1999, 7029-7037
  • Biesalski, M., Rühe, J.
    Swelling of a polyelectrolyte brush in humid air
    Langmuir, Vol. 16, 1999, 1943-1950
  • Habicht, J., Schmidt, M., Rühe, J., Johannsmann, D.
    Swelling of thick polymer brushes investigated with ellipsometry
    Langmuir, Vol. 15, 1999, 2460-2465
  • Rühe, J., Yano, R., Lee, J. S., Koberle, P., Knoll, W., Offenhausser, A.
    Tailoring of surfaces with ultrathin polymer films for survival and growth of neurons in culture
    Journal of Biomaterials Science-Polymer Edition, Vol. 10, 1999, 859-874
  • Laschitsch, A., Bouchard, C., Habicht, J., Schimmel, M., Rühe, J., Johannsmann, D.
    Thickness dependence of the solvent-induced glass transition in polymer brushes
    Macromolecules, Vol. 32, 1999, 1244-1251
  • Gelbert, M., Roters, A., Schimmel, M., Rühe, J., Johannsmann, D.
    Viscoelastic spectra of soft polymer interfaces obtained by noise analysis of AFM cantilevers
    Surface and Interface Analysis, Vol. 27, 1999, 572-577
  • Roters, A., Schimmel, M., Rühe, J., Johannsmann, D.
    Collapse of a polymer brush in a poor solvent probed by noise analysis of a scanning force microscope cantilever
    Langmuir, Vol. 14, 1998, 3999-4004
  • Prucker, O., Rühe, J.
    Mechanism of radical chain polymerizations initiated by azo compounds covalently bound to the surface of spherical particles
    Macromolecules, Vol. 31, 1998, 602-613
  • Prucker, O., Schimmel, M., Tovar, G., Knoll, W., Rühe, J.
    Microstructuring of molecularly thin polymer layers by photolithography
    Advanced Materials, Vol. 10, 1998, 1073-+
  • Prucker, O., Rühe, J.
    Synthesis of poly(styrene) monolayers attached to high surface area silica gels through self-assembled monolayers of azo initiators
    Macromolecules, Vol. 31, 1998, 592-601
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