Effect of processing conditions on the electromechanical behaviour of inkjet-printed multimaterial electronics under tensile strain

Multimaterial additive-manufactured electronics (AME) via inkjet printing enable the seamless integration of dielectric and conductive materials, yet the electromechanical behaviour of such structures under applied stress remained a critical knowledge gap. This study systematically investigated how key printing parameters—specifically trace width, thickness, and printing orientation—influenced the mechanical and electrical performance of co-printed Ag-nanoparticle/acrylate components. Specimens were fabricated using a Dragonfly AME system and subjected to custom tensile testing coupled with Digital Image Correlation and continuous electrical monitoring. A Design of Experiments approach combined with analysis of variance quantified the effects of geometric factors.The results demonstrated that, while macroscopic mechanical properties were mainly governed by the dielectric matrix, the electrical response showed a strong dependence on printing parameters. The critical onset strain proved most sensitive to printing orientation, decreasing from approximately 4% at \((0^{\circ})\) to 1.5% at \((90^{\circ})\), while the post-cracking degradation rate was dictated by trace cross-sectional area. Conversely, the gauge factor exhibited high stability with variations below 8%, indicating it was a process-independent property. Thermal characterisation identified Tg and the operational limit temperature, beyond which the storage modulus decreased significantly. These quantitative insights enabled the development of guidelines for AME components, which were applied to fabricate a multilayer 3D-printed strain gauge that showed excellent linearity (\((R^2=0.99)\)) relative to commercial benchmarks. This work established a systematic methodology for designing reliable AME devices that integrate sensing capabilities with structural integrity.