New Brush Copolymers as an Effective Dispersant for Stabilizing Concentrated Suspensions of Silver Nanoparticles

• Published in: Langmuir Vol. 36; no. 13; pp. 3377 - 3385
• Main Authors: Chao, Tsung-Ming, Hsieh, Ta-Li, Chang, Shinn-Jen, Chang, Cha-Wen, Li, Chia-Chen
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 07.04.2020
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/acs.langmuir.0c00361

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.