title: Apertureless near-field vibrational imaging of block-copolymer nanostructures with ultrahigh spatial resolution.
abstract: Nanodomains formed by microphase separation in thin films of the diblock copolymers poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) and poly(styrene-b-ethyleneoxide) (PS-b-PEO) were imaged by means of infrared scattering-type near-field microscopy. When probing at 3.39 mum (2950 cm(-1)), contrast is obtained due to spectral differences between the C--H stretching vibrational resonances of the respective polymer constituents. An all-optical spatial resolution better than 10 nm was achieved, which corresponds to a sensitivity of just several thousand C--H groups facilitated by the local-field enhancement at the sharp metallic probe tips. The results demonstrate that infrared spectroscopy with access to intramolecular dimensions is within reach.
authors.affiliation: Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin, Germany. raschke@mbi-berlin.de
authors.forename: Markus B
authors.initials: MB
authors.lastname: Raschke
authors.forename: Leopoldo
authors.initials: L
authors.lastname: Molina
authors.forename: Thomas
authors.initials: T
authors.lastname: Elsaesser
authors.forename: Dong Ha
authors.initials: DH
authors.lastname: Kim
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Knoll
authors.forename: Karsten
authors.initials: K
authors.lastname: Hinrichs