Structure-controlled Nanomaterial Synthesis using Surfactant-assisted Ball Milling- A Review

The applications of nanoparticles have been tremendously increased in the field of targeted drug release, gene silencing, therapeutics, industrial and environmental catalysis, water purification and optoelectronics. These are because of their versatile sizes and shapes, large specific surface area with convenient surface properties, high chemical reactivity, physical affinity and optical, electrical and magnetic properties. However, the synthesis of nanoparticles with controlled nano/microstructures and desired surface properties has been remaining a challenging task. Various approaches have been proposed for the commercial production of nanostructured particles from solid bulk materials. Chemical methods for the synthesis of controlled structure nanoparticles from rare-earth solid compounds have showed limited success in terms of yield, purity and cost. Recently, surfactant assisted high energy ball milling has been exploited for the synthesis of various nanomaterials, nanograins and nanocomposites from solid state. Self-assembled structures of surfactants act as cationic, anionic or charge neutral lubricants to control the nano/microenviroment of the nanostructured materials, producing nanoparticles with improved dispersion. In high-energy ball milling, plastic deformation, cold-welding and fracture predominantly contribute to bring a change in size, shape and nano/microenvironment of nanoparticles. In this review, we have systematically presented the basic concept and applications of surfactant assisted mechanical milling for the synthesis of various nanomaterial, nanocomposite and nanoparticles. Keywords: Ball milling, bulk materials, cold-welding, micro/nanostructured materials, plastic deformation, surfactant assisted mechanical milling.