Evaluation of Effective Factors on the Dispersibility and Electrical Conductivity of Water-Based Inks Containing Carbon Black

Water-based conductive inks have emerged as environmentally friendly alternatives to solvent-based systems, offering reduced volatile organic emissions and improved safety. Carbon black, a cost-effective non-metallic conductor, is widely employed in such formulations; however, simultaneously achieving good dispersibility and high electrical conductivity remains challenging due to the opposing influences of its structural and surface properties. This study examines the dispersibility and conductivity of inks prepared with three carbon black grades (N-550, N-330, and N-234) supplied by Iran Carbon Company. Ink pastes were formulated using acrylic resin, a polymeric dispersant, and bead milling. While all inks demonstrated excellent stability under high-speed centrifugation, they exhibited distinct rheological and colorimetric behaviors. Scanning electron microscopy and electrical resistance measurements revealed that inks containing N-234 achieved the highest conductivity, attributed to its complex microstructure and large specific surface area that promote percolation network formation. The surface resistance in ink containing N-234 is about nine times lower than in ink containing N-550. These findings highlight that selecting carbon black with high structure and surface area, combined with optimized dispersants and mixing conditions, enables the concurrent realization of stable dispersions and enhanced electrical performance. This work provides valuable insights for the design of sustainable water-based conductive inks for printed electronics and antistatic coatings.