Nanoscale Materials Analysis using AFM-IR

L. Gong
3M Company,
United States

Keywords: spectroscopy, characterization, nano-infrared, AFM


Nano-infrared spectroscopy is an exciting new field which bridges the long-existing gap of unambiguous chemical analysis with a nanoscale spatial resolution – it extends the chemical analysis using IR to the realm of nano, which could never be achieved with conventional infrared instruments due to the limit set by optical diffraction. Among the many rapidly emerging techniques in this field, Atomic force microscopy – Infrared spectroscopy (AFM-IR) stands out because of its extraordinary spectral sensitivity, great correlation to bulk IR transmission spectra, and exceptional versatility & robustness especially on polymeric material systems. AFM-IR is a hybrid technique that combines the fine spatial resolution of AFM with the exceptional chemical analysis capability of infrared. It is s a technique based on photothermal induced resonance (PTIR) effect, that the tip of a gold-coated AFM probe is used to locally detect the thermal expansion in a sample resulting from the absorption of IR radiation. As a result, AFM-IR can simultaneously provide the topological, phase and chemical mapping at a spatial resolution of 20 nm. It can also collect local nano-IR spectra covering the mid-IR region. This presentation reviews several strategic applications of the AFM-IR technique in the critical analysis of real-world nanoscale materials and the significance of these results, which largely facilitates the fundamental understanding of the materials systems.