Characterisation of antiviral agents on textiles for the killing of Covid-19

Recent events due to the Coronavirus (Covid-19) pandemic have led to increased interest in personal protective equipment (PPE). Antiviral activity in PPEs has become desirable in the wake of the Covid-19 pandemic due in 2020 due to the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus. This work aims to characterise morphological and surface properties of fabrics enhanced with known antiviral agents for PPE application. The Textilise™ process, a modified textile padding technique, was utilised to incorporate antiviral agents into the fabric matrix. Silver (Ag), silver liposome (Ag LP) and silane coupled quaternary ammonium cation (QS) as a selection of metal, metal-organic and inorganic-organic based agents respectively. Superwhite (SW) and cream coloured cotton/polyester fabric blends selected as the substrate were coated via the pad-dry-cure method. Bromophenol blue (BPB) test followed by UV-Vis was found to be a useful qualitative indicator for chemical concentration on the fabric surface. A linear relationship between increasing antiviral NP content and decreasing BPB absorbance was found. Detection of QS, Ag and Ag LP modified fabrics was achievable at concentrations as low as 200 µg/g, 17.53 µg/g and 9.22 µg/g respectively for SW fabrics. The NP content was determined by acid assisted microwave digestion followed by induced coupled plasma spectroscopy. Affinity of agents to fabrics was determined by the Langmuir and Freundlich adsorption isotherms. Both isotherms suggested improved adsorption for cream fabrics, but the heterogeneous assumptions of the Freundlich isotherms are more appropriate for agent/fabrics systems. Electron microscopy revealed Ag LP and QS presence on samples. Ag LP particles formed a uniform distribution on fibre. QS agglomerates were present on textiles surfaces and in between individual fibres largely attributed to overtreatment. X-ray photoelectron spectroscopy confirmed the elemental composition of Ag 3d, Si 2p and N 1s bands on modified fabrics. Electrokinetic analysis successfully alterations in the surface zeta potential due to the varying degrees of agent finishing. These results are advantageous and can be considered safety and quality by design systems.