Aqueous electrochemical synthesis of stable silver metal nanoparticles onto a chitosan matrix on stainless steel

Silver nanoparticles are formed through an environmentally-benign electrochemically-driven method on type 304 stainless steel electrodes, with potential energy and biomedical applications. An electrochemically-deposited initial layer of chitosan strongly adheres to the passive layer formed on the 304 stainless steel electrodes. Electrochemical deposition from a subsequent silver nitrate solution forms nanoparticles in the size range of 10 to 200 nm depending on processing parameters, in situ, rapidly and at room temperature. The overall coating has been shown to possess mechanical cohesiveness, flexibility, and durability, including remarkable stability with atmospheric exposure (both of the matrix and the nanoparticles contained within). Infrared and UV-vis spectroscopies, synchrotron X-ray absorption, and electron microscopy have been used to characterize the materials and indicate that chitosan provides protection from environmental degradation (as well as promotes formation of the nanoparticles).