  The behavior of nanostructures under high strain-rate conditions has been
object of theoretical and experimental investigations in recent years. For
instance, it has been shown that carbon and boron nitride nanotubes can be
unzipped into nanoribbons at high velocity impacts. However, the response of
many nanostructures to high strain-rate conditions is still not completely
understood. In this work we have investigated through fully atomistic reactive
(ReaxFF) molecular dynamics (MD) simulations the mechanical behavior of carbon
(CNS) and boron nitride nanoscrolls (BNS) colliding against solid targets at
high velocities,. CNS (BNS) nanoscrolls are graphene (boron nitride) membranes
rolled up into papyrus-like structures. Their open-ended topology leads to
unique properties not found in close-ended analogues, such as nanotubes. Our
results show that the collision products are mainly determined by impact
velocities and by two impact angles, which define the position of the scroll
(i) axis and (ii) open edge relative to the target. Our MD results showed that
for appropriate velocities and orientations large-scale deformations and
nanoscroll fracture can occur. We also observed unscrolling (scrolls going back
to quasi-planar membranes), scroll unzipping into nanoribbons, and significant
reconstruction due to breaking and/or formation of new chemical bonds. For
particular edge orientations and velocities, conversion from open to
close-ended topology is also possible, due to the fusion of nanoscroll walls.
