Mechanical characterization of nanopillars by atomic force microscopy

Mechanical characterization of nanopillars by atomic force microscopy

Angeloni, L. (TU Delft Micro and Nano Engineering)
Ganjian, M. (TU Delft Biomaterials & Tissue Biomechanics)
Nouri Goushki, M. (TU Delft Biomaterials & Tissue Biomechanics)
Mirzaali, Mohammad J. (TU Delft Biomaterials & Tissue Biomechanics)
Hagen, C.W. (TU Delft ImPhys/Microscopy Instrumentation & Techniques)
Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics)
Fratila-Apachitei, E.L. (TU Delft Biomaterials & Tissue Biomechanics)
Ghatkesar, M.K. (TU Delft Micro and Nano Engineering)

2021

Micro- and nano-patterns are gaining increasing attraction in several fields ranging from nanoelectronics to bioengineering. The mechanical properties of the nanostructures (nanopillars, nanotubes, nanowires, etc.) are highly relevant for many applications but challenging to determine. Existing mechanical characterization methods require mounting the testing setup inside a scanning electron microscope (SEM) and additional sample modification. Here, we propose two atomic force microscopy (AFM) methods, based on contact mode imaging (CMI) and force spectroscopy imaging (FSI), to determine the mechanical characteristics of individual micro- and nanopillars as fabricated, without using SEM. We present the working principles of both methods and two case studies on nanopillars fabricated by additive manufacturing methods: two-photon polymerization (2PP) and electron beam induced deposition (EBID). Various mechanical parameters were determined using CMI and FSI, respectively. For the 2PP nanopillars, we measured the stiffness (13.5 ± 3.2 N/m and 15.9 ± 2.6 N/m), the maximum lateral force (883.0 ± 89.5 nN and 889.6 ± 113.6 nN), the maximum deflection (64.2 ± 13.6 nm and 58.3 ± 14.24 nm), the failure stress (0.3 ± 0.03 GPa and 0.3 ± 0.02 GPa), and the adhesion force (56.6 ± 4.5 µN and 58.6 ± 5.2 µN). For the EBID nanopillars, we measured the failure stress (2.9 ± 0.2 GPa and 2.7 ± 0.4 GPa). The similar results obtained using both techniques confirmed the efficacy and consistency of the methods. The proposed methodologies have the potential of enabling otherwise impossible measurements particularly when the specimens need to be tested under wet conditions, such as patterns for mechanobiological studies.

Atomic force microscopy
Contact mode
Force spectroscopy
Nanomechanical characterization
Nanomechanics
Nanopillars

http://resolver.tudelft.nl/uuid:236620cf-1ecc-4f1c-83b8-0a9932907d90

https://doi.org/10.1016/j.addma.2021.101858

2214-8604

Additive Manufacturing, 39

Institutional Repository

journal article

© 2021 L. Angeloni, M. Ganjian, M. Nouri Goushki, Mohammad J. Mirzaali, C.W. Hagen, A.A. Zadpoor, E.L. Fratila-Apachitei, M.K. Ghatkesar