Mono-disperse submicron silver powder for conductive elastomer

The synthesis of superfine silver powder with good dispersity is of great significance for accelerating the development of high-end electronics and photovoltaic products. Herein, a kind of quasi-spherical submicron silver powder prepared by the introduction of gelatin during silver ions reduction is reported. The optimal scheme is determined that the initial pH of gelatin solution is 3 and the mass of gelatin (M_w 50,000—70,000) is 10% of silver nitrate, leading to a mono-disperse silver powder with regular morphology and average particle size of 0.5 µm. In addition, the prepared silver powder can be further combined with polydimethylsiloxane (PDMS) to form a stretchable conductive elastomer (PDMS/Ag elastomer). In unstretched state, the minimum sheet resistance of the elastomer can reach 66 Ω/□ without annealing treatment. Even when the elongation reaches 100%, it still exhibits good conductivity with a sheet resistance of only 13 kΩ/□. The comprehensive performance, mainly referring to stretching and conductivity, is comparable to that of some flexible conductive materials involving silver nanowire or nanocarbon. Thus, this study will demonstrate a new class of silver powder with a potential in flexible electronics.