  Super-compressible foam-like carbon nanotube films have been reported to
exhibit highly nonlinear viscoelastic behaviour in compression similar to soft
tissue. Their unique combination of light weight and exceptional electrical,
thermal and mechanical properties have helped identify them as viable building
blocks for more complex nanosystems and as stand-alone structures for a variety
of different applications. In the as-grown state, their mechanical performance
is limited by the weak adhesion between the tubes, controlled by the van der
Waals forces, and the substrate allowing the forests to split easily and to
have low resistance in shear. Under axial compression loading carbon nanotubes
have demonstrated bending, buckling8 and fracture9 (or a combination of the
above) depending on the loading conditions and on the number of loading cycles.
In this work, we partially anchor dense vertically aligned foam-like forests of
carbon nanotubes on a thin, flexible polymer layer to provide structural
stability, and report the mechanical response of such systems as a function of
the strain rate. We test the sample under quasi-static indentation loading and
under impact loading and report a variable nonlinear response and different
elastic recovery with varying strain rates. A Bauschinger-like effect is
observed at very low strain rates while buckling and the formation of permanent
defects in the tube structure is reported at very high strain rates. Using
high-resolution transmission microscopy
