The Fabrication Of Core-Shell Conductive Particles By Dopamine-Assisted Functionalization

Core-shell composite nanoparticles is a material that coating second material on polymer or organic material in nano or micron size by various of physical and chemical methods with good optical properties, particle stability, catalytic activity and so on. Metallization core-shell particles used to be the fillers for conductive materials. Dopamine is secreted by mussels’ protein adhere to wet surface and now it widely used as effective modified material for secondary reaction such as electroless plating, layer by layer self-assemble, covered reaction and so on. The polydopamine was resulted by dopamine self-polymerization in an alkaline aqueous solution.In this research, we used dopamine as modified coating layer to fabrication metallization core-shell particles. The products used as the filler for conductive materials and the fabricate method is simple, non-toxic and high efficiency. The details are as followings:(1) A novel method of fabrication of micro-particles with multilayer structure was proposed. Polystyrene micro-spheres were used as the substrates. Novel polystyrene/poly(dopamine)/gold (from inner to outer) conductive micro-particles were first synthesized by the functionalization of the polystyrene micro-spheres with poly(dopamine), followed by electroless gold-plating. These PS/PDA/Au micro-particles were then coated with a epoxy vinyl resin layer by biomimetic poly(dopamine) coating to form core/shell-structured particles, with polystyrene/poly(dopamine)/gold core and poly(dopamine)/epoxy vinyl resin shell (denoted as PS/PDA/Au/PDA/Epoxy Vinyl Resin). The overall procedure is nonroxic, controllable, simple and inexpensive and this multilayer core/shell micro-particle shows its structural advantages of conductive property by gold plating core and insulating property by epoxy vinyl resin layer outside. These multilayer core/shell micro-particles used as micro-filler for anisotropic conductive films(ACF). The fillers were insulation at room temperature and showed conductive property with the broken of epoxy vinyl resin layer when ACF applied pressure at high temperature.(2) The production of SiO2/PDA/Ag particles was realized by polydopamine modification and new type electroless plating.We studied the industrial production conditions for fabrication of SiO2/PDA/Ag particles. Respectively, by changing the experimental conditions and the feeding amount, greatly reduce the cost of experimental preparation cost as well as the time cost. Through our reasearch, we found out that the best experimental condition is make sure the temperature is 50℃, under this condition we can produce 100g SiO2 in 4h. In order to study the experimental condition for semi-solid preparing method, we reduce the volume of reaction solutions, that we can produce 10g SiO2 by 1h in 5ml solution. According to the modification by dopamine, these SiO2 particles can deposit silver layer by electroless plating.