Silver nanopowders (nano-Ag) have extremely high surface energy and are generally difficult to have an effective dispersant for their dispersion stabilization. This study proposes two brush copolymers that show a strong preference for adsorption on the nano-Ag surface via their backbone, while their side chains extend into the dispersion solvent for particle stabilization. After adding only 5 wt % (based on the mass of nano-Ag) of the proposed dispersants, the nano-Ag particles can be stably suspended without settling for at least 2 months. Besides, 5 wt % of these dispersants can well stabilize at least 40 wt % nano-Ag dispersed in di(ethylene glycol) ethyl ether, which is a common solvent for conductive inks and pastes. For applications, a thin film cast using the dispersed nano-Ag shows greatly improved surface flatness as compared to that made without the dispersant, and a low electrical resistivity of 2 × 10 −5 Ω cm is obtained after the film is annealed at 170 °C for 20 min.

Silver (Ag) nanoparticle has extremely high surface energy and it is difficult to find an efficient dispersant to prevent its agglomeration in suspensions. A new brush copolymer, succinic anhydride modified epoxy‐amine poly[(propylene oxide)‐co‐(ethylene oxide)]‐grafted polymer (EPOA), which can efficiently disperse concentrated aqueous suspensions of Ag nanoparticles is revealed. The dispersion efficiency of EPOA for the dispersion of a 60 nm‐Ag nanoparticles in aqueous suspension is studied by measuring its sedimentation and rheological behavior, and the results are compared with those of a commercially available dispersant, ammonium poly(acrylic acid) (PAA‐NH4). Interactions between the dispersants and the Ag nanoparticles are characterized by zeta potential and adsorption analyses. Theoretical calculations are conducted to clarify the adsorption and the dominant dispersion stabilization mechanisms of the dispersants. Compared with PAA‐NH4, EPOA obtains a higher stable suspension of Ag nanoparticles with less significant sedimentation over 1 month. The dispersion homogeneity of the suspension remains excellent even at an extremely high solid loading of 30–40 wt%. According to adsorption analysis, it is suggested that both EPOA and PAA‐NH4 adsorb via single‐point attachment through the carboxyl group on the Ag surface. Based on theoretical calculations, the Ag nanoparticles are better stabilized by EPOA via an electrosteric dispersion mechanism.