On the importance of boundary conditions on nanomech

Nanomechanical bending behavior and elastic modulus of silver nanowires 65140 nm suspended across silicon microchannels were investigated using digital pulsed force mode DPFM atomic force microscopy through coincident imaging and force profi领. Deflection profiles analyzed off-line demonstrate the role of bending nanowire shape and symmetry in experimentally determining boundary conditions, eliminating the need to rely on isolated midpoint bending measurements and the usual assumptions for supported-end behavior. Elastic moduli for as-prepared silver nanowires ranged from 80.4±5.3 to 96.4±12.8 GPa, which met or exceeded the literature values for bulk silver. The calculated moduli were based on classic mode领, both with one-dimensional analytical solutions and three-dimensional finite element analysis. Mode领 results indicate that the classic models are accurate as long as the boundary conditions are not arbitrarily assumed but directly confirmed by data analysis. DPFM also facilitated the experimental determination of sample gauge lengths from images and bending profiles.