Silver-containing sol-gel coatings on textiles: antimicrobial effect as a function of curing treatment

Textiles coated with inorganic SiO(2) layers containing silver nanoparticles were prepared using the sol-gel process. The formation of silver particles was investigated as a function of curing treatment variables performed after the coating procedure. The formation of silver particles in nanometre scale was determined with transmission electron microscopy (TEM). The optical properties of coated textiles were investigated using UV/Vis-spectroscopy under arrangement of diffuse reflectance conditions, and the release of silver from coated textiles was determined with ICP-spectroscopy. Under the chosen conditions, the formation of embedded silver clusters requires a curing treatment at a minimum temperature of 150 degrees C. The silver-containing inorganic coatings inhibit the growth of fungi (Aspergillus niger) and bacteria (Bacillus subtilis and Pseudomonas putida) on the coated textiles. The antimicrobial effect depends more on the temperature used for curing treatment and less on the duration chosen for the treatment of textiles after coating. Conditions for application between 150 degrees C and 180 degrees C are commensurate with those used in commercial textile finishing, so the process presented here could be easily adapted to the production of textiles with antimicrobial effects.