C. Phillips, Q. Hu, C. Li, M. Wagner, P. De Wolf
Bruker Nano,
United States
Keywords: SPM, AFM, gated measurements, nanochemical spectroscopy, AFM-IR
Summary:
Nanoscale infrared (nano-IR) microscopy enables label-free chemical imaging and spectroscopy at the nanometer scale by combining atomic force microscopy (AFM) with infrared radiation. AFM-IR has been used to explore the nanoscale chemical origins of biological processes including Amyloid Beta aggregation and bone calcification [1]. Over the years, AFM-IR has been developed further through coupling with different AFM imaging modes: the original photothermal induced resonance mode and the recently developed surface sensitive technique are based on contact mode, while Tapping AFM-IR is built on tapping mode [2]. Peak Force Tapping based Peak Force infrared (PFIR) microscopy [3] later joined as an additional AFM-IR mode. All these nano-IR variations inherit the advantages and limitations of their respective AFM base mode. In this work, we focus on the capabilities offered by a force curve-based AFM-IR-related approach, with improved signal-to-noise and deconvolution of signal origin with the addition of a gated output. We discuss (1) the capability to perform simultaneous multimodal imaging collecting both mechanical properties such as elastic modulus together with chemical information, (2) methods to understand and decouple artifacts induced by variations in mechanical properties from the AFM-IR data, and (3) the control of gate width and positioning to gain new material insights. [1] A. Catarina V. D. dos Santos, N. Hondl, V. Ramos-Garcia, J. Kuligowski, B. Lendl, G. Ramer, ACS Meas. Sci. Au. 3, 5, 301–314, (2023). [2] J. Mathurin, A. Deniset-Besseau, D. Bazin, E. Dartois, M. Wagner, A. Dazzi, J. Appl. Phys. 131, 010901 (2022). [3] L. Wang, H. Wang, X. Xu, Chem. Soc. Rev. 51, 5268 (2022).