Angle-dependent peeling behavior of compliant nanofilms on planar substrates

Abstract

The peeling of compliant nanofilms from supporting substrates is essential in mechanical exfoliation techniques, biomimetic adhesives, and nanoelectromechanical systems. Prior to the steady state, the peeling force typically increases in the initial stage and then decreases nonlinearly in the transition stage. However, existing mechanics models rarely capture the effects of the film’s tensile stiffness and peeling angle on these two stages, particularly the initial peeling stiffness and peak peeling force. Though extending a recent model (Yuan et al., 2024) by accurately incorporating the film’s in-plane deformation and arbitrary peeling angle, this work establishes a comprehensive large-deformation model using the energy-variational method. The proposed model effectively predicts the entire peeling process across different peeling angles and is validated by molecular dynamics simulations. For relatively large peeling angle, the film’s tensile stiffness exhibits minor effect on the peeling behavior. The influences of the peeling angle on the peeling process, peeling stiffness, and peak peeling force are analyzed in detail. Through dimensional analysis, an explicit scaling relation for the peak peeling force is derived, accounting for system parameters such as peeling angle, film stiffness, structural parameters, and interfacial properties. This work provides a comprehensive model for the peeling behavior of nanofilm-substrate systems, offering new insights into the atomic-scale interface mechanics of two-dimensional materials.