Capillary-driven plastic deformation in silver nanowires: finite element analysis of size-dependent mechanics and contact behaviours

Capillary forces, arising from surface tension and wetting interactions, play a crucial role in nanoscale material behavior, particularly during solvent evaporation in nanowire-based systems. In this study, capillary-induced deformation in silver nanowires is analyzed through a simplified two-step finite element model using ANSYS Static. The effects of these forces during the film formation and moisture treatment stages are investigated for silver nanowires with diameters of 25 nm, 40 nm, and 100 nm. Results show that smaller-diameter nanowires experience significantly higher capillary pressures, leading to greater plastic deformation despite their greater mechanical strength. In contrast, larger wires exhibit lower effective pressure due to reduced capillary efficiency, although the total capillary force is higher. The model contact angle after the film formation step allows for accurate estimation of capillary pressure during the moisture treatment step, enabling the calculation of final strain and stress distributions. Nanometer gaps between wires, which influence cold welding and contact resistance, are also quantitatively analyzed.