Optical Near Field Spectroscopy
Non destructive characterization of polymer-polymer interfaces by optical near field spectroscopy
Usually, buried polymer - polymer interfaces can not be characterized by linear vibrational spectroscopic methods without destroying the sample. Since the interface layer is extremely thin the bulk materials cover molecular interactions between the polymers. The sensitivity of linear spectroscopic methods such as infrared or Raman is not high enough for the weak signals of the interface layer.
Optical near-field excitations on metallic nanoparticle-based structures can be used to enhance the weak signals of the interface layer. When such metallic nanoparticles are embedded in the polymer-polymer interface local molecular vibrations will be enhanced. The both well known techniques, surface enhanced infrared absorption (SEIRA) and surface enhanced Raman scattering (SERS), can be used for a characterization of the interface on a molecular level without influence of the bulk material.
In this research project we investigate strategies for an optimized embedding of metallic nanoparticles in polymer-polymer interfaces as well as for highly sensitive plasmonic structures. First results demonstrate that the space between nanoparticles gives rise to spectroscopic "hot spots" with a strong enhancement of the signals.
Fig. Scheme for interface analysis with non-linear optical spectroscopy
- Vilnius University, Lithuania, Department of General Physics and Spectroscopy
- Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Klinisches Sensoring und Monitoring