Crack quasi-healing in films of vertically aligned 1D nanostructures: Impact of compliance in a 1D geometry

We study nanostructured films made of helical nanowires and nanosprings, which provide remarkable mechanical behavior. When subjected to wetting and drying processes, these films crack like most coatings. However, beyond the great ability of these films to shrink, the cracks partially close when these films are no longer mechanically stressed. While for conventional coatings about 20 % of the crack opening is relieved, more than 80 % of the crack opening is relieved in films of nanosprings when the film is unloaded. We show here that this quasi-reversibility is related to (i) the high compliance of the material, (ii) the low energy consumed by plasticity, and (iii) the high deformability of the film components, e.g., the nanosprings. These results are compared to the case of usual particulate films.& nbsp;Published under an exclusive license by AIP Publishing.