16. Nanopatterning of Photosensitive Polymer Films

  1. Prof. Dr. Wolfgang Knoll5 and
  2. Prof. Dr. Rigoberto C. Advincula6
  1. Zouheir Sekkat1,2,3,4,
  2. Hidekazu Ishitobi3,
  3. Mamoru Tanabe4,
  4. Tsunemi Hiramatsu4 and
  5. Satoshi Kawata3,4

Published Online: 7 JUN 2011

DOI: 10.1002/9783527638482.ch16

Functional Polymer Films: 2 Volume Set

Functional Polymer Films: 2 Volume Set

How to Cite

Sekkat, Z., Ishitobi, H., Tanabe, M., Hiramatsu, T. and Kawata, S. (2011) Nanopatterning of Photosensitive Polymer Films, in Functional Polymer Films: 2 Volume Set (eds W. Knoll and R. C. Advincula), Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany. doi: 10.1002/9783527638482.ch16

Editor Information

  1. 5

    AIT Austrian Institute of Technology GmbH, Donau-City-Straße 1, 1220 Vienna, Austria

  2. 6

    University of Houston, Department of Chemistry, Department of Chemical and Biomolecular Engineering, 136 Fleming Bldg., Houston, TX 77204-5003, USA

Author Information

  1. 1

    MAScIR INANOTECH ENSET Optics and Photonics Laboratory Rabat, Morocco

  2. 2

    Hassan II Academy of Science and Technology Rabat, Morocco

  3. 3

    RIKEN Nanophotonics Laboratory 2-1 Hirosawa Saitama Wako 351-0198, Japan

  4. 4

    Osaka University Department of Applied Physics Yamada-oka 2-1 Osaka Suita 565-0871, Japan

Publication History

  1. Published Online: 7 JUN 2011
  2. Published Print: 20 APR 2011

ISBN Information

Print ISBN: 9783527321902

Online ISBN: 9783527638482

SEARCH

Keywords:

  • nanopatterning;
  • photosensitive polymer films;
  • near-field nanofabrication;
  • two-photon patterning;
  • nanofabrication

Summary

We review our work on nanopatterning of azo-polymer films. Nanoscale polymer movement is induced by a tightly focused laser beam in an azo-polymer film just at the diffraction limit of light. The deformation pattern that is produced by photoisomerization of the azo dye is strongly dependent on the incident laser polarization and the longitudinal focus position of the laser beam along the optical axis. The anisotropic nanofluidity of the polymer film and the optical gradient force played important roles in the light-induced polymer movement. We explored the limits of the size of the photoinduced deformation, and we found that the deformation depends on the laser intensity and the exposure time. The smallest deformation size achieved was 200nm in full width of half-maximum; a value that is nearly equal to the size of the diffraction-limited laser spot. Furthermore, a nanoprotrusion was optically induced on the surface of the films, beyond the limit of light diffraction, by metal-tip-enhanced near-field illumination. A silver-coated tip was located inside the diffraction limited spot of a focused laser beam (460 nm), and an enhanced near-field, with a 30-nm light spot, was generated in the vicinity of the tip due to localized surface plasmons. The incident light intensity was carefully regulated to induce surface nanodeformation by such a near-field spot. A nanoprotrusion with 47 nm full width of half-maximum and 7nm height was induced. The protrusion occurs because the film is attracted toward the tip end during irradiation. At the top of the protrusion, an anisotropic nanomovement of the polymer occurs in a direction nearly parallel to the polarization of the incident light, and suggests the existence at the tip end of not only a longitudinal, that is, along the tip long axis, but also a lateral component of the electric field of light. The azo-polymer film helps map the electric field in the close vicinity of the tip. We also report on two-photon patterning of the films. Exposure of azo-polymer films, which absorb in the visible range (λmax = 480 nm), to 920nm irradiation leads to polarization dependent patterning that are associated with polymer nanomovement caused by photoselective two-photon cis[LEFT RIGHT ARROW]trans isomerization, while irradiation at 780nminducesmultiphoton bleaching of the azo chromophore. These wavelengths hit the bleaching and isomerization pathways in the chromophore, respectively.