The utility of an infrared scanning near-field microscope in the characterization of the mesoscale structure of thin film polymer blends is demonstrated. This unique IR microscope souples the nanoscale spatial resolution of scanning probe microscopy with the chemical specificity of vibrational spectroscopy. This powerful combination allows the in situ mapping of chemical functional groups with subwavelength spatial resolution. Key features of this instrument include broad tunability and bandwidth, parallel spectral detection for high image acquistion rates and IR transparent, near-field aperture probes. Near-field spectral images of a thin film of polystyrene/poly (ethyl acrylate) acquired in the C-H stretching region are used to benchmark the chemical imaging capabilities of this microscope. Analysis of the near-field infrared spectra yields information about the nanoscale chemical morphology of this sample that is consistent with results from previous chemical modification/AFM studies. Finally, the relative contributions of scattering and absorption to the overall near-field transmission (extinction) contrast in these images are discussed.
Citation: Handbook of Vibrational Spectroscopy
Pub Type: Journals
chemical imaging, infrared microscopy, infrared spectroscopy, near-field mcirosocpy, nsom, polymer blends