• Dr. Anton Kiriy
• Vera Bocharova
• Prashant Sinha
• Constantin Demedinok

Miniaturization has become a driving force in different areas of technology including microelectronics, microfluidics, sensor technology or biotechnology. With new and emerging techniques (scanning probe microscopies, optical tweezers, etc.) it recently has become possible to study in more detail the nanoscopic regime thus opening a complete new area of science.

It offers the unique possibility to control and manipulate single polymer molecules to achieve particular functions at molecular scale. In this way one may reach the ultimate smallest scale where macroscopic functions can be scaled down, while however new aspects will arise.

Polymer chemistry offers a fascinating world of structures of different architecture, composition and functionality. Utilization of single polymer molecules as templates, constitutes a highly promising strategy to generate nanoparticles of desired size, shape, location, with specific properties. Like macroscopic objects, single molecules of polyelectrolyte (PE) can be stretched and aligned under external forces (e.g., centrifugal or capillary forces, electric or shear fields) and can be immobilized onto surfaces by simple procedures like casting or printing.

We found that PE single molecules of various architectures can be mineralized in different conformations that constitutes the route to nanoparticles of desired shape (including wire-shaped and star-shaped), size and composition (including metallic, magnetic and semiconductive nanoparticles).

• fabrication of random copolymer, block-copolymer and polymeric supramolecular object based on polyelectrolyte molecules
• orientation of PE molecules with shear forces
• mineralization of single PE molecules and fabrication of nanoparticles of dedicated shape
• manipulation with nanoobject and positioning nanoparticles
• fabrication of nanodevices

In acidic water PS forms collapsed core stabilized by protonated P2VP arms. After metallization of PS₇-P2VP₇ deposited from acidic aqueous solution with fully extended P2VP arms the Pd...PS₇-P2VP₇ nanocomposite appears in the good resolved star-shaped conformation (see Figs).

It is well known that mixing of stoichoimetric amounts of K₄Fe(CN)₆ and FeCl₃ leads to microscopic particles of PB (Fe₄[Fe(CN)₆]₃) which precipitate from solution. We developed a simple method to produce surfactant-free water-soluble negatively charged PB nanoclusters stabilized by excess of HCF-anions. Specifically, we found out that mixing of diluted solution of FeCl₃ with excess of K₄Fe(CN)₆ solution leads to clear deep-blue dispersions. The attachment of PB clusters occurs selectively and homogeneously along whole PC chain and significantly improves both the topography (Figure a- c, e-f) and the phase AFM images (Figure d). The distance between adjacent clusters depends on the diameter of PB clusters and usually equal to 10-20 nm. Histogram (g, h) presents the size distribution of the PB clusters.

One-dimensional nanostructures of conductive polymers (CPs) have attracted a great interest as building blocks for future miniatuarized nanoelectronic devices and highly sensitive chemical or biological sensors. Most of methods to CP nanowires involve chemical or electrochemical oxidative polycondensation in “hard templates” (such as zeolites, track- etched polymeric membranes, and porous alumina), or “soft templates” (surfactant micelles, or liquid crystalline phases). However, for various applications CP nanowires must be properly integrated into circuits, therefore at least one additional step, such as a release of the nanowires from the templates or/and their positioning in the device, is required.

We have developed a simple chemical route to conductive polypyrrole (Ppy) nanowires by the grafting of Ppy from isolated synthetic polyelectrolyte molecules. The location and length of the synthesized Ppy nanowires are defined by the location and length of adsorbed single-molecule templates. Diameter of the nanowires varies from few nanometers to hundreds of nanometers and can be adjusted by polycondensation time and concentration of reagents. The dc conductivity of individual Ppy nanowires approaches the conductivity of Ppy in the bulk (~1 S/cm). This result opens broad opportunities for fabrication of electronic devices and sensors at molecular level.

• Nanoscale Electronic Devices via Templating Supramolecular Polyelectrolytes (NEDSPE)
  
  • Funds:
    • DFG
    • EUROCORES
    • SONS

• Prof. Karl Leo,
  TU Dresden
• Prof. Sergiy Minko
  Clarkson University
• Prof. Costas Tsitsilianis
  University of Patras
• Prof. R. Jerome,
  Univerity of Liège, Belgium
• Prof. Siegmar Roth,
  Max Planck Institute for Solid State Research, Stuttgart, Germany
• Dr. Vojislav Krstic,
  Laboratoire Nationale des Champs Magnétique Pulsés - CNRS
• Dr. Hartmut Vinzelberg, Dr. Ingolf Mönch,
  Leibniz Institute for Solid State and Materials Research, Dresden, Germany
• Prof. Nikos Hadjichristidis,
  Laboratory of Industrial Chemistry University of Athens, Greece
• Dr. Helmut Schlaad,
  Max Planck Institute of Colloids and Interfaces Potsdam-Golm, Germany
• Dr. Christophe Detrembleur,
  Universite der Liege, Belgium
• Dr. Paul Simon,
  Max-Planck-Institut for Chemical Physics of Solids, Dresden, Germany
• Prof. Dr. Kenneth A. Dawson,
  University College Dublin, Ireland