Intrinsic vulnerabilities to mechanical failure in nanoscale films

We use molecular simulations to explore how sample dimensions and interfacial properties impact some generic aspects of the mechanical and structural behavior of nanoconfined materials. Specifically, we calculate the strain-dependent properties of minimum-energy thin-film particle configurations (i.e., inherent structures) confined between attractive, parallel substrates. We examine how the relationship between the transverse strain and the stress tensor (the equation of state of the energy landscape) depends on the properties of the film and substrate. We find that both film thickness and film–substrate attractions influence not only the mechanical properties of thin films, but also the shape and location of the “weak spots” where voids preferentially form in a film as it is strained beyond its point of maximum tensile stress. The sensitivity of weak spots to film properties suggests that nanoscale materials may be intrinsically vulnerable to specific mechanisms of mechanical failure.