ELECTRICAL PROPERTY CHANGES OF GNP HYBRID CONDUCTIVE INKS UNDER TORSIONAL LOADING ON FLEXIBLE COPPER SUBSTRATES

Abstract

This study investigated the effect of torsion cycles on the electrical properties of conductive materials at two different displacement levels (5 μm and 25 μm) to understand the changes in the material microstructure. The samples were studied using a controlled torsion method for 500 cycles, measuring resistance and resistivity, and the results were obtained before and after the test using the two-point probe technique. The results showed a significant increase in both parameters: at 5 μm, the average resistance increased by 7.6% (0.844 Ω to 0.908 Ω) with the resistivity increasing from 2.533×10⁻⁵ Ω·m to 2.725×10⁻⁵ Ω·m, while at 25 μm, the resistance increased from 0.867 Ω to 0.997 Ω and the resistivity increased from 2.600×10⁻⁵ Ω·m to 2.992×10⁻⁵ Ω·m (corresponding to a 15.4% increase). The statistical analysis performed showed an increase in the standard deviation after torsion, indicating variation in response between samples due to the non-uniformity of the microstructure. These findings demonstrate that torsional deformation not only significantly alters the electrical properties of materials, but also exhibits a magnitude-dependent effect, with larger effects observed at higher displacement levels. The implications of the study suggest the need for special consideration in applications of conductive materials that are subjected to torsional stress, especially in environments with cyclic loading. The data obtained provide a solid basis for modeling material durability in electromechanical engineering design and for future use in studies on flexible electronics.