Surface Modification of As-Prepared Silver-Coated Silica Microspheres through Mussel-Inspired Functionalization and Its Application Properties in Silicone Rubber

A mussel-inspired functionalization method was developed to improve the dispersibility and compatibility of silver-coated silica (SiO₂/Ag) microspheres in silicone rubber matrix; at the same time, the high conductivity of the microspheres was maintained. The poly(dopamine) (PDA) layer was deposited on SiO₂/Ag surface by spontaneous polymerization of dopamine. The SEM images showed that the SiO₂/Ag/PDA microspheres are uniformly distributed and firmly integrated with silicone rubber. The PDA layers effectively improved the interfacial interaction between fillers and rubber matrix. The electrical resistivity of the SiO₂/Ag/PDA/MVQ composites can be well controlled by adjusting the dopamine deposition time. Due to the favorable dispersibility and compatibility of the SiO₂/Ag/PDA in the rubber matrix, the composites exhibited a dramatic increase in tensile strength (47%) and maintained their low electrical resistivity of 8.3 × 10^-3 ω·cm in the meanwhile at dopamine deposition time of 8 h. This approach can be extended to modify other particles to improve their compatibility in matrix.