Triple functions of polyaniline in situ coated on silver powders for high-performance electrically conductive pastes

Abstract

Silver powders, with high electrical conductivity, as the conductive fillers of electrically conductive adhesives have been widely investigated in the fields of microelectronic packaging. Herein, polyaniline (PANI)-coated silver powders were successfully fabricated via a facile chemical reduction, followed by the polymerization of aniline. The PANI plays triple functions to synergistically improve the performance of electrically conductive pastes as follows: (1) The aniline-coated silver particles are used as an ideal dispersant to substitute polyvinyl pyrrolidone and polyethylene glycol in the preparation strategy of silver powders; (2) The polymerization of aniline plays a surface modifier role instead of silane coupling agents to prepare silver-based conductive adhesives with homodisperse silver powders; (3) The high conductivity of PANI could reduce the contact resistance between silver powders and decrease the electrical resistivity of conductive adhesive films significantly. As a result, the PANI coats silver powders (pH = 3) show a decreased electrical resistivity of conductive adhesive films of 4.24×10−5 Ω·cm with the shear resistance of 9.06 MPa and the sheet resistance of 10.6 mΩ.sq−1. This work provides an efficient way to controllably synthesize PANI-coated silver powders for high-performance electrically conductive pastes.