Fig. 5: Nano-Chemical Imaging and Spectroscopy of Single Polymer Chains.

a Schematic of the technological advances for acoustical mechanical suppression (AMS), which empowers chemical analysis with picometre-sensitivity by AFM-IR. (b, left) Morphology maps of bare HOPG in tapping mode in zero scan (top) and finite scan (bottom) by AMS AFM-IR (red-dashed box indicates area used for RMS calculation). (b, right) RMS noise of AFM-IR with and without AMS in tapping and contact modes; error bars represent sensitivity uncertainty and SE of three different areas within the same map. Single-chain χ-polymer nano-chemical analysis by AMS AFM-IR. c Morphology, IR amplitude, PLL frequency and PLL phase of a single polymer chain. d Morphological map of two single χ-polymer chains, with location of single-molecule IR spectrum indicated (cross). e Cross-sectional and deconvoluted polymer profiles at the cross location. f IR Spectra acquired on the single polymer chains showing characteristic S = O peaks (red cross, d). Single-Chains rac-polymer nano-chemical analysis by AMS AFM-IR. g Morphology map of an assembly of a few single rac-polymer chains. h Left: Hyperspectral 4D plot (x-y coordinates, z-axis wavenumber, colour scale absorption intensity) with slices at 1203, 1240, 1273 and 1320 cm⁻¹. Right: Two sets of representative spectra (background and polymer indicated by AFM probe). (i) Morphology map of another assembly of single rac-polymer chains. j Corresponding IR spectra from marked positions (shading represents SE). k Cross-sectional and deconvoluted polymer profiles.