Preparation of barium sulfate/polymer hybrid nanoparticles from Bunte salt precursors

Barium sulfate suspensions are commonly used as contrast agents for improving the resolution of X-ray imaging. However, current limitations are rapid contrast washout and low stability in water. Polymer nanoparticles are synthesized by copolymerizing vinyl benzyl thiosulfate with methyl methacrylate in a miniemulsion by free-radical polymerization. BaSO₄ is then formed by the hydrolysis of thiosulfate-functionalized nanoparticles, leading to the production of sulfate ions, which react subsequently with Ba²⁺ in dispersion.