Research on the modification of ink by introducing silver and SiO ₂ @Ag composite nanoparticles

Abstract Silver nanoparticles (AgNPs) possess outstanding properties such as high electrical conductivity, high thermal diffusivity, and low-temperature sintering. These advantages make composite coatings utilizing AgNPs as conductive fillers widely applicable. In this work, silver nitrate (AgNO 3 ) was reduced by glucose with a chemical reduction method, and then reduced silver was chemically plated onto SiO 2 powder surfaces, successfully synthesizing SiO 2 @Ag core–shell structures. Subsequently, this core–shell material was mixed with silver nanopowder, resin, ink, and solvent to form a composite conductive coating, which was then cured into a film at 140°C. Test results demonstrate that the cured conductive coating exhibits a balanced set of properties: an electrical resistivity of 49 Ω·cm, which is acceptable for keypad applications, a hardness of 141.2 HV, a tensile stress of 3.2 MPa at maximum load, an elastic modulus of 0.3 MPa, a thermal diffusivity maintained at 0.1 cm 2 s −1 , and good adhesion (rated 4B per ASTM D3359). This coating, which integrates conductivity, mechanical strength, and good compatibility with substrates, shows broad application potential in areas such as printed circuits, new energy devices, and electronic keypads.