The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
Aalto

Flow and Conductivity Properties of Comb-Shaped Self-Organized Supramolecules

Riikka Mäki-Ontto née Mäkinen

Dissertation for the degree of Doctor of Philosophy to be presented with due permission for public examination and debate in Auditorium F1 at Helsinki University of Technology (Espoo, Finland) on the 23rd of November, 2001, at 12 o'clock noon.

Overview in PDF format (ISBN 951-22-5696-7)   [2880 KB]
Dissertation is also available in print (ISBN 951-22-5733-5)

Abstract

Structures, which are significantly smaller than e.g. in the present day microelectronics, are pursued in nanotechnology. Structures near molecular level can be constructed for example by imitating biological systems where self-organization and molecular recognition are used to form supramolecules.

In this work hierarchically self-organized supramolecular nanostructured materials are constructed with peculiar conductivity behavior. The structures are, as such, not macroscopically aligned and therefore the conductivity is isotropic throughout the macroscopic sample.

Two types of supramolecular materials are studied under an oscillatory shear flow in order to find routes towards macroscopically oriented hierarchical structures. The first type consists of 20 - 50 Å lamellar structure due to self-organization of comb-shaped supramolecules. The second structure is a hierarchically self-organized, i.e. lamellar-within-lamellar structure, where there are structures at two length scales, i.e. at 20 - 50 Å and 200 - 1000 Å. Shear flow conditions allowing optimal macroscopic order were identified. Finally, macroscopically aligned protonically conducting material is presented, which shows globally tridirectional conductivity with anisotropic hopping conductivity.

Asymmetric structures i.e. lamellae-within-cylinders are also briefly studied and a method is found to achieve mesoporous materials with polymer brushes at the walls of emptied cylinders. The brushes can be used to tailor the functionalities of the pores.

The results of this work show that materials, which are relatively simple to produce, allow tailored macroscopic properties due to their aligned self-organized nanoscale structures.

This thesis consists of an overview and of the following 6 publications:

  1. J. Ruokolainen, R. Mäkinen, M. Torkkeli, R. Serimaa, T. Mäkelä, G. ten Brinke, O. T. Ikkala, Switching Supramolecular Polymeric Materials with Multiple Length Scales, Science 1998, 280, 557-560.
  2. O. Ikkala, J. Ruokolainen, R. Mäkinen, M. Torkkeli, R. Serimaa, T. Mäkelä, and G. ten Brinke, Electrical Switching Based On Dimensionality Transitions in Nanostructured Polymers, Synthetic Metals 1999, 102, 1498-1501. © 1999 Elsevier Science. By permission.
  3. R. Mäkinen, J. Ruokolainen, O. Ikkala, K. de Moel, G. ten Brinke, W. De Odorico, and M. Stamm, Orientation of Supramolecular Self-Organized Polymeric Nanostructures by Oscillatory Shear Flow, Macromolecules, 2000, 33, 3441-3446. © 2000 American Chemical Society. By permission.
  4. K. de Moel, R. Mäki-Ontto, M. Stamm, G. ten Brinke, and O. Ikkala, Oscillatory Shear Flow Induced Alignment of Lamellar Melts of Hydrogen Bonded Comb Copolymer Supramolecules, Macromolecules 2001, 34, 2892-2900. © 2001 American Chemical Society. By permission.
  5. R. Mäki-Ontto, K. de Moel, E. Polushkin, G. Alberda van Ekenstein, G. ten Brinke, and O. Ikkala, Tridirectional protonic conductivity in soft materials, Report TKK-F-A809 2001, submitted to Advanced Materials. © 2002 WILEY-VCH Verlag. By permission.
  6. R. Mäki-Ontto, K. de Moel, W. de Odorico, J. Ruokolainen, M. Stamm, G. ten Brinke, and O. Ikkala, "Hairy Tubes": Mesoporous Materials Containing Hollow Self-Organized Cylinders with Polymer Brushes at the Walls, Advanced Materials, 2001, 13, 117-121. © 2001 WILEY-VCH Verlag. By permission.

Keywords: oscillatory shear flow, macroscopic orientation, protonic conductivity, mesoporous materials, hierarchical structures

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© 2001 Helsinki University of Technology

Last update 2011-05-26