Figure 26.

Nanofabrication-related implications on mechanical properties. (a) shows an SEM side-view of a Pt-C tetrapod fabricated via 3D FEBID on SiO₂. The upper part is a truncated AFM tip, which allows dynamic compression of such nanoarchitectures. The latter is shown in (b), where unexpected twisting effects were stochastically found. The SEM top view image in (c) reveals slight mismatches in the merging zone by left/right-handed displacements in the sub-10 nm regime (see arrows). (d) shows a finite-element simulation during vertical compression, including the aforementioned displacement as shown in the red-framed inset. This mismatch, although small, induce the twisting effect, which clearly shows the high demands on spatial precision during 3D nanofabrication. (e) shows another tetrapod structure in an SEM side view, in which the non-straight branches become evident. For further studies, Δα was defined as indicated in blue. Then, this parameter was varied in finite-element simulations, while vertical stiffnesses were calculated as shown in (f) and further validated by experiments (see ref [128]). As evident, even a small Δα of 5° implies a four-fold decrease in stiffness, which decays quickly with larger Δα. As for the upper row, these experiments reveal the high demands on nanofabrication to fully exploit the intended mechanical properties. Images were reproduced with permission from reference [128].