Membrane-based mechanical characterization of screen-printed inks: Deflection analysis of ink layers on polyimide membranes

Measurements of Young's modulus and residual stresses of screen-printed ink layers using a bulge test on coated polyimide-based membranes are proposed in this work. The applied bulge test monitors the deflection of membranes under pressure with interferometry. The obtained Young's modulus ranges from 6 to 8 GPa for a carbon blend-based ink and is around 12 GPa for a silver nanoparticle ink. These values are compared with standard nanoindentation and show good agreement. Besides, the residual stresses range from −4 to 8 MPa for the carbon blend-based ink, while the silver ink is measured around −10 MPa. The use of the membrane-based method underlines the influence of exact deposition and curing conditions on the ink film material properties. The impact of the substrate on the ink layer properties, such as the thickness and its uniformity, is discussed, especially with regard to the heat treatment of the membrane.