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

Abstract 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 N¹‐(3‐methacrylamidopropyl)‐N¹,N¹,N¹⁰,N¹⁰‐tetramethyl‐N¹⁰‐(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 °C, 65% RH. The resulting quaternized N‐chloramine grafted cotton is a suitable platform for reusable antiviral textiles.