Collision-induced adhesion behavior and mechanism for metal particle and graphene

Micro- and nano-scale collisions exhibit extraordinary behavior compared to the common macroscopic collisions. Understanding the size-dependent collision behavior and the relevant mechanism is of great significant for molecular movement, drug delivery, and the design of novel anti-collision materials. In this work, we explore the comprehensive impact dynamics of metal projectiles on graphene by using molecular dynamics simulations. It has been discovered that in addition to the normal penetration and rebound behaviors, ultrasoft two-dimensional materials can also capture impacting metal projectiles, i.e., the adhesion behavior. This abnormal behavior is primarily attributed to the dissipation of kinetic energy during impact, which leads to the weak rebounded kinetic energy relative to the interactions between the impacting objects. Additionally, in the case of finite-sized graphene, the projectile may receive additional energy from the reflected cone wave at the boundary to escape the adhesion. This phenomenon is referred to as adhesion-rebound behavior. We present the phase diagrams illustrating the impact behaviors under various conditions such as projectile stiffness, impact velocity, graphene size, projectile sizes, and projectile density. This work provides an insight into the multiscale collision phenomena and an instructive strategy for the design of transfer printing, collision protection, etc.