Molecular modifications at metal surfaces provide powerful means to control ion-induced interactions and corrosion processes. Using in-operando SFA measurements, surface analysis, and simulations, we demonstrate how hydration and ion specificity govern electromechanical adhesion between functionalized interfaces. In parallel, microstructured thiol monolayers on copper reveal how molecular films modulate corrosion mechanisms and promote protective, oriented oxide layers. Together, these approaches offer new perspectives for understanding surface processes at the atomic and molecular scale and for enhancing the durability of functional materials.