A novel method for antimicrobial finishing of textile with inorganic nanoparticles by sonochemistry

This chapter reviews the research that has been done for the functionalization of textile with inorganic nanoparticles (Ag, CuO, ZnO, MgO, Al₂O₃) by sonochemical method. Sonochemistry is one of the most efficient techniques for creation of nanosized compounds. Ultrasonic waves in the frequency range of 20 kHz-1 MHz are the driving force for chemical reaction. The sonochemical reaction is dependent on the acoustic cavitation, which means creation, growing and explosion collapse of a bubble in the solution. Extreme conditions (temperature >5000 K, pressure >1000 atm and cooling rates >10⁹ K/sec) are developed when this bubble collapses, and that is the reason of break and formation of chemical bonds. The nanoparticles have been deposited on the surface of various fabrics (cotton, nylon, polyester) using ultrasound irradiation. This process produces a uniform coating of nanoparticles on surfaces with different functional groups. The coating can be performed by an in-situ process where the nanoparticles are formed and immediately thrown to the surface of the fabrics. This approach was used for Ag, ZnO and CuO. In addition, the sonochemical process can be used as a "throwing stone" technique, namely, previously synthesized nanoparticles will be placed in the sonication bath and sonicated in the presence of the fabric. This process has been shown with MgO and Al₂O₃ nanoparticles. The nanoparticles are thrown to the surface by the microjets and strongly adhered to the textile. This phenomenon was explained because of the local melting of the substrate due to the high rate and temperature of nanoparticles thrown at the solid surface by sonochemical microjets. The antibacterial activities of the nanocoated fabric composites were tested against Gram negative and Gram positive cultures. A significant bactericidal effect, even with low concentration of the nanoparticles, less than 1wt%, was demonstrated.