Electrical Resistance Behavior of Printed Ag Nanowire Electrode Lines Under Transverse Tensile Strain

Printed stretchable interconnects may experience tensile deformation perpendicular to the direction of current flow, but their electrical response under transverse loading remains insufficiently understood. In this study, dispenser-printed silver nanowire (Ag NW) line electrodes on polydimethylsiloxane were subjected to transverse tensile strains of 10-40% for 10 stretching-release cycles. Ten specimens were tested at each strain level. Resistance was measured in situ, and deformation-induced changes in the Ag NW network were examined using optical microscopy and field-emission scanning electron microscopy (FESEM). To distinguish the effects of macroscopic deformation from changes in network connectivity, the measured resistance was compared with geometric predictions based on Poisson-induced shortening of the printed line. At 10% strain, the stretched-state resistance closely followed the geometric prediction and remained nearly unchanged during cycling. At 20% strain, the resistance increased progressively with repeated cycling and local cracks were observed, whereas the first-cycle deviation from the geometric reference remained small relative to the specimen-to-specimen variation. At 30% and 40% strain, the measured resistance clearly exceeded the geometric reference in both the stretched and released states. After 10 cycles at 40% strain, the corresponding relative resistances reached 1.369 and 1.736, respectively. FESEM observations showed that conductive nanowire bridges remained across locally cracked regions at 20% strain, whereas crack penetration into the line interior and local pathway loss were observed at 30% strain. These results indicate an intermediate response at 20% strain and a clear transition to a network-damage-dominated response at 30% strain.