Effect of dispersants on rheology, dispersion stability, and sintering behavior of high-solid-content copper pastes

High-solid-content copper-based conductive pastes hold significant potential for application in printed electronics due to their low cost and excellent electrical conductivity. However, the inherent tendency to agglomerate and the insufficient dispersibility of glass powder significantly impair the paste’s rheological behavior and sintering quality. This study systematically investigates the effect of different dispersants—oleic acid (OA), polyethyleneimine (PEI), and polyvinylpyrrolidone (PVP)—on the dispersion behavior of glass powder and the overall performance of the copper paste. The results show that oleic acid significantly improves the dispersion of glass powder through interfacial adsorption and steric hindrance, leading to the lowest viscosity, highest stability, and smallest contact angle among the tested formulations. The copper film prepared using this formulation exhibits high density, superior conductivity (sheet resistance of 5.15 mΩ/sq), and strong adhesion (91.3%). This research provides a theoretical foundation and practical guidance for the design of highly dispersed copper paste with high solid content.