CuO-Ag Nanocomposite Powders for Antimicrobial Applications

Silver based nanoparticles as antimicrobial agents are well documented. Incorporation of a small amount of  silver nanoparticles in CuO matrix  is a cost effective  away to make antimicrobial properties.  The material ions  are prone to come in contact with pathogens and virus  due to presence of charge molecules. The S-S bonds, proteins and  RNA/DNA  break due to metal ion interaction and oxidation stress of metal. 

Copper based nanoparticles of ~ 20 nm have been prepared by a Flame Spray Pyrolysis (FSP) processing facility and a stable nanoparticle suspension of the nanoparticles is prepared by optimizing the solid loading and pH.  Uniform coating of the aqueous nanoparticles suspension is achieved on the cotton  fabric with good adhesion using a suitable binder. The coated fabric exhibited an efficacy > 99.9% against gram positive and negative bacteria. The efficacies of these fabrics are reported ≥99.2% and≥ 99.997%   against SARS-CoV-2  (CCMB)  and H1N1 (BUREAU VERITAS), respectively (ISO 18184). Masks having different designs such as single layer, double layers , triple and four layers with nanoparticle coated fabric as outer layer have been  prepared by Industrial partner M/s. Resil Chemicals Pvt. Ltd., Benguluru, at large scale. These masks were tested as per the different  standards at SITRA, Coimbatore. The four layers mask exhibited bacterial filtration efficiency ≥ 99.7% (ASTM F2101), particulate filtration efficiency at 0.3 microns : ≥ 99.3 (ASTM F 2299/F2299M-03: 2017) and breathability: 61.2 Pa/cm2 (EN 14683: 2019).  The mask was found to  Splash resistance and water repellent and classified as class 1  in flammability test.  Dermatological test /Skin sensitization test was carried out as per ISO 10993 Part 23:2021 (E) and found to  be safe to skin and body. Leaching of particles from  the mask is  less than allowed limit  with  8h  exposure with flow rate of 28.5 l/min.  Function of self-disinfection  up to 30 washes  is tested.