Dopamine-Induced Surface Functionalization for the Preparation of Al–Ag Bimetallic Microspheres

A novel method for the preparation of highly conductive silver-plated aluminum (Al) microspheres was demonstrated. The surface of the aluminum microspheres was functionalized by a bioinspired polydopamine (PDA) coating. Electroless plating of silver was then carried out on the functionalized aluminum microspheres. An aqueous solution of silver nitrate is used as silver precursor and glucose is used as reducing reagent. The overall procedure is fast, simple, nontoxic, and controllable. The surface compositions and the crystalline structure of the modified aluminum microspheres were studied by x-ray photoelectron spectroscopy (XPS) and x-ray diffraction, respectively. XPS results show that the Al-PDA surfaces were successfully deposited with polydopamine and were ready for electroless deposition of silver. Scanning electron microscopy (SEM) was used to study the morphology of the Al–Ag bimetallic particles. SEM results show that the silver-plated aluminum core–shell microspheres have a continuous, uniform, and compacted silver layer. The as-prepared Ag/Al particles possess high electrical conductivity.