High-resolution and large dynamic range nanomechanical mapping in tapping-mode atomic force microscopy

Abstract

High spatial resolution imaging of material properties is an important task for the continued development of nanomaterials and studies of biological systems. Time-varying interaction forces between the vibrating tip and the sample in a tapping-mode atomic force microscope contain detailed information about the elastic, adhesive, and dissipative response of the sample. We report real-time measurement and analysis of the time-varying tip-sample interaction forces with recently introduced torsional harmonic cantilevers. With these measurements, high-resolution maps of elastic modulus, adhesion force, energy dissipation, and topography are generated simultaneously in a single scan. With peak tapping forces as low as 0.6 nN, we demonstrate measurements on blended polymers and self-assembled molecular architectures with feature sizes at 1, 10, and 500 nm. We also observed an elastic modulus measurement range of four orders of magnitude (1 MPa to 10 GPa) for a single cantilever under identical feedback conditions, which can be particularly useful for analyzing heterogeneous samples with largely different material components.

Multi-modal analysis on the intermittent contact dynamics of atomic force microscope

“…In [44] polystyrene (E 2 ¼4 GPa) and highly oriented pyrolytic graphite (E 2 ¼5 Gpa) [44], their a 4 's are 18.7 and 23.4, respectively.…”

Scientific basis of nanotechnology, implications for the food sector and future trends

“…Simultaneously to topography, phase (scale ¼ 30 deg), adhesion, peak force, dissipation, and elastic modulus (scale ¼ 5 GPa) were recorded (Berquand et al, 2009). based technique which allows one to perform the quantitative characterization of mechanical parameters of soft samples (mainly, elastic modulus, tip-sample adhesion force and tip-sample dissipation) with nanometrical lateral resolution (Sahin & Erina, 2008;Sahin, Magonov, Su, Quate, & Solgaard, 2007). Also, thermal characterization at the nanoscale has been performed on caramel using SThM (Morton et al, 2003).…”

The implementation and the performance analysis of the multi-channel software-based lock-in amplifier for the stiffness mapping with atomic force microscope (AFM)

“…As in most cases the tip-sample interactions can be described with the DMT (Derjagin, Muller, Toropov) model [11,12], it can be easily shown that the dynamics of the tapping of the tip against the surface is related to the stiffness of the sample (Fig. 1).…”

“…2). Although originally such cantilevers were used in much more complex [12][13][14], the mapping of surface's stiffness by utilizing the higher harmonic of the cantilever's torsional oscillation was successfully performed by Sahin [6]. It allowed observation of the changes of the PS and PMMA polymer film changes while the temperature increased.…”