Microwave-assisted process for silver/silica sol application onto cotton fabrics

Abstract

Silica sols modified with a silver compound are applied onto textile substrates to realize its antibacterial properties. As textile substrates, cotton fabrics are used. The liquid sol recipes are applied by a padding process onto the textiles. Afterwards, a microwave-assisted heating process is applied for drying of the silica sol coating and to form elementary silver nanoparticles. The microwave process is done in a closed autoclave system with process temperatures in the range of 80–140 °C. The process duration is only 5 min short, compared to traditional hydrothermal processes. The coating forming process is strongly determined by the applied process temperature, probably due to boiling and evaporation processes. Lower process temperatures and temperature development used lead to a regular distribution of the silica sol coating on the textile substrates. All prepared coated samples exhibit significant antibacterial properties against the bacteria S. aureus and E. coli. The antibacterial effectiveness increases as a function of silver content and with increasing process temperature of the microwave process. This first experimental set-up can act as first proof-of- concept for effective and fast functionalization of substrates by using microwave technology.