TEHRAN -- A simple and cost-effective method for coating glass wool fibers by silver nanoparticles was proposed by Iranian researchers at Sharif University of Technology.

"Top-down fabrication techniques, which are employed in the synthesis of metal nanomaterials (like laser sputtering), are classified as expensive procedures," Nafiseh Sharifi, Ph.D. student at Sharif University of Technology, explained. "Regarding the surface tension between glass fibers and the silver coating, silver nano-islands would be formed upon a bed of glass wool via a low-cost method," he added.

Since glass fibers possess high surface-to-weight fractions, they are widely used in air purification systems. On the other hand, silver nanoparticles are effective antibacterial agents. As a consequence, integrating these two properties would result in an efficient bacteria-eliminating package.

In the research work, a uniform coating over a substrate of glass wool was formed thorough a chemical method in which silver complexes are reduced over the glass wool surface. Afterwards, silver nano-islands were shaped over the bed by gradual heating.

The initial concentration of the raw materials as well as the heating temperature can considerably affect the morphology of nano-islands.

Sharifi also found the optimized values for these two factors so that a maximum separation among the islands exists while the islands would not diffuse towards the bed.