ERDC Determination of Nanomechanical Properties by Atomic Force Microscopy

The present film was created by the US Army Engineers Research and Development Center in Vicksburg, MS for their Environmental Consequences of Nanomaterials Focus Area. For a step-by-step guide of the characterization shown here, visit http://acwc.sdp.sirsi.net/client/en_US/search/asset/1041661. The following methods provide a guide to measure mechanical properties of materials by means of an atomic force microscope (AFM). Traditional nanoindentation measurements do not afford immediate complementary surface imaging to visualize the residual indent. This obstacle is overcome using AFM. By indenting a surface with a diamond-tipped, stiff cantilever, local nanoscopic materials properties may be deduced. Briefly, an appropriate AFM cantilever is calibrated to determine its deflection sensitivity and spring constant; it is then used as both an imager and indenter at the surface of material of interest. The load applied by the cantilever is accurately controlled by knowledge of the deflection sensitivity. The maximum applied load is mediated by the cantilever spring constant. Following data collection, image and force curve analyses are completed to determine projected indent areas and load/unload profiles. This yields materials properties that include the material hardness and the Young’s modulus along with corresponding surface topography.