Rechargeable Potent Anti‐Viral Cotton Grafted with a New Quaternized N‐Chloramine

Polymeric substrates can be endowed with antiviral properties by grafting N-chloramine precursors to the surface. These surfaces bind oxidative chlorine from a dilute chlorine bleach solution and are similarly recharged after depletion for reuse. Previously, enhanced antibacterial efficacy of quaternized N-chloramines compared to their neutral counterparts is reported. In this study, a new quaternized N-chloramine N-1-(3-methacrylamidopropyl)-N-1,N-1,N-10,N-10-tetramethyl-N-10-(2,2,6,6-tetramethylpiperidin-4-yl)decane-1,10-diaminium (MAMPIP) featuring two quaternary ammonium groups within the structure to boost the chlorination efficiency and achieve excellent antiviral efficacy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is reported. Antiviral fabrics are prepared by free-radical graft polymerization of MAMPIP, or copolymerization of MAMPIP with a comonomer (acrylamide or methacrylamide) onto cotton fabrics to achieve enhanced durability to re-chlorination. The poly(MAMPIP) grafted cotton, after chlorination, is highly effective against SARS-CoV-2 and achieves 4.59 log reduction (99.997%) after 5 min contact. Samples grafted with the copolymer of MAMPIP and acrylamide or methacrylamide are resistant to hydrolysis during re-chlorination and retain high active chlorine and antiviral activity after 5 cycles of re-chlorination (>3 log reduction after 10 min contact). Furthermore, the N-chloramine coatings show excellent stability after exposure to simulated daylight conditions under an accelerated weathering tester, and storage for 200 days at 21 degrees C, 65% RH. The resulting quaternized N-chloramine grafted cotton is a suitable platform for reusable antiviral textiles.