Dissecting atomic interweaving friction reveals the orbital overlap repulsion and its role in the integrity of woven nanofabrics in composites

Abstract

Strong and stable woven formations are a type of promising structure for regulating external forces in hybrid material systems with desired electro/thermomechanical properties. The strength of the knitted composite structures relies on the distribution of stress over a cohesive network of nanoribbons/fabrics, whose integrity is dependent upon an underlying mechanism of stabilization through friction that keeps the nanoribbons/fabrics in their place. Herein, we uncover a new molecular-level friction mechanism in interwoven composite structures, where the extreme pulling speed causes instant orbital overlap, which creates additional resisting interfacial shear strength that delays the collapse of the woven structure. Our theoretical analysis of atomic woven two-dimensional materials (e.g., graphene, MXene, black phosphorus, and layered double hydroxide) conducted through molecular dynamics simulations and density functional theory calculations help break up this force between the atomic interactions and a repulsive force residing within the forced orbital overlap at the edges of the sliding and the confining nanosheets. Our results depict the robustness of the epoxy-weave interface considering the presence of imperfections within the woven formation. The detailed dissection of the friction within the woven formations provides new insight into its crucial role in preserving the post-failure integrity of woven composites. This knowledge will help us understand the physical behavior of knots and weaves as reinforcements at the atomic scale and further realize the potential of nanofabrics for bottom-up ultimate design.