Feature Article

Preparation and magnetoviscosity of nanotube ferrofluids by viral scaffolding and ALD on porous templates

  1. Zhenyu Wu1,
  2. Robert Zierold2,
  3. Anna Mueller3,
  4. S. Emil Ruff3,
  5. Chenchen Ma1,
  6. Abid A. Khan4,
  7. Fania Geiger3,
  8. Bernd A. Sommer3,
  9. Mato Knez5,
  10. Kornelius Nielsch2,*,
  11. Alexander M. Bittner4,6,*,
  12. Christina Wege3,*,
  13. Carl E. Krill III1,*

Article first published online: 7 SEP 2010

DOI: 10.1002/pssb.201046208

Issue

physica status solidi (b)

physica status solidi (b)

Special Issue: Nanowires and nanotubes: From controlled synthesis to functions

Volume 247, Issue 10, pages 2412–2423, October 2010

Additional Information

How to Cite

Wu, Z., Zierold, R., Mueller, A., Ruff, S. E., Ma, C., Khan, A. A., Geiger, F., Sommer, B. A., Knez, M., Nielsch, K., Bittner, A. M., Wege, C. and Krill, C. E. (2010), Preparation and magnetoviscosity of nanotube ferrofluids by viral scaffolding and ALD on porous templates. Phys. Status Solidi B, 247: 2412–2423. doi: 10.1002/pssb.201046208

Author Information

  1. 1

    Institute of Micro and Nanomaterials, Ulm University, Albert-Einstein-Allee 47, 89081 Ulm, Germany

  2. 2

    Institute of Applied Physics, University of Hamburg, Jungiusstraße 11, 20355 Hamburg, Germany

  3. 3

    Institute of Biology, University of Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany

  4. 4

    CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia – San Sebastian, Spain

  5. 5

    Max Planck Institute of Microstructure Physics, Am Weinberg 2, 06120 Halle, Germany

  6. 6

    IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain

*Phone: +49 40 42838 6521, Fax: +49 40 42838 3589

Publication History

  1. Issue published online: 28 SEP 2010
  2. Article first published online: 7 SEP 2010
  3. Manuscript Accepted: 3 AUG 2010
  4. Manuscript Revised: 30 JUL 2010
  5. Manuscript Received: 23 APR 2010

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Keywords:

  • atomic layer deposition;
  • ferrofluids;
  • nanotubes;
  • synthesis;
  • templates;
  • tobacco mosaic virus

Abstract

Current models for magnetoviscosity suggest that replacing the spherical nanoparticles of a conventional ferrofluid with magnetic nanotubes would lead to a stronger field-induced viscosity enhancement and a much-improved stability against shear thinning – two important parameters for technological exploitation of the magnetoviscous effect. We report the development of positive and negative templating strategies for the synthesis of magnetic nanotubes out of a variety of materials. Our positive template is Tobacco mosaic virus (TMV) – in natural form or genetically engineered to express specific surface chemistries and lengths – which we exploit as a template for the electroless deposition (ELD) of nanosized clusters of nickel and as a scaffold for magnetic particles in a conventional ferrofluid. Our negative templating strategy employs porous anodic aluminum oxide (AAO) as a substrate for the atomic layer deposition (ALD) of a conformal coating of iron oxide, offering precise control over the length and wall thickness of the resulting nanotubes. Both strategies were scaled up to produce the mass quantities of uniform-aspect-ratio nanotubes that are needed for macroscopic ferrofluid volumes. The magnetoviscosity of these “nanotube ferrofluid” samples was studied as a function of applied magnetic field and shear frequency, and a particularly strong effect was found to be induced by viral scaffolding.

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