Berlin 2005 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 31: Polymer physics: special techniques
CPP 31.1: Vortrag
Mittwoch, 9. März 2005, 09:45–10:00, TU C130
Scattering-type near-field infrared microscopy of selforganized nanodomains of diblock copolymers — •M. B. Raschke1, L. Molina1, K. Hinrichs2, D. H. Kim3, and W. Knoll3 — 1Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin — 2ISAS - Institute for Analytical Sciences, D-12489 Berlin — 3Max-Planck-Institut für Polymerforschung, D-55128 Mainz
The expansion of scattering-type scanning near-field optical microscopy (s-SNOM) into the infrared spectral region currently emerges as a promising technique due to its ability to achieve all-optical resolution down to the several nanometer range in combination with the chemical sensitivity provided by infrared spectroscopy. Here, we have performed a nanometer scale surface analysis and identification of domains formed by phase separation of the diblock copolymers polystyrene-b-polyvinylpyridine (PS-b-P2VP) and polystyrene-b-polyethyleneoxide (PS-b-PEO). This has been achieved by means of non-interferometric IR-scattering detection based on epi-illumination of sharp Au-coated cantilever tips in a noncontact atomic force microscopy configuration. Probing at 3.39 µm (2950 cm−1) contrast is obtained due to differences in the spectral position of the C–H stretch vibrational resonances for the two polymer constituents and their local density. The mechanism of the near-field tip-sample coupling by vibrational resonances responsible for the imaging contrast has been deduced and can be modelled based on the dielectric functions of the polymer compounds measured by spectroscopic ellipsometry.