Smart Antibacterial Fabric Response to Sweat: Constructing Reversibly Switchable Surface by Zwitterionic Block Copolymers

Although various antibacterial fabrics have been extensively developed, smart antibacterial fabrics that can achieve stimulus responses have not been developed under high humidity conditions. In this study, a smart sweat-responsive antibacterial fabric has been designed by grafting zwitterionic PTMSPMA-<i>co</i>-PTMAO copolymer on cotton fabric (CF) to achieve "active attack" and "passive defense" against bacteria. It exhibits desirable antibacterial properties in both H₂O and dry environments with the killing rates against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i> reaching over 99.97%. Additionally, the fabric exhibits significant antiadhesion effects in sweat environments, with an antiadhesion rate above 99.95%. Various characterizations of PTMSPMA-<i>co</i>-PTMAO-CF reveal its smart responses in killing and antiadhesion of bacteria in high-humidity environments. In H₂O, the oxygen-containing anions in PTMSPMA-<i>co</i>-PTMAO-CF interact with H₂O via the hydrogen bond, exposing more -(CH₃)₂-N⁺ to kill the bacteria and enhance the "active attack." In sweat, ions (such as Na⁺ and Cl^-) will be electrically neutralized with the quaternary ammonium cations (-(CH₃)₂-N⁺) and oxygen-containing anions in PTMSPMA-<i>co</i>-PTMAO-CF, thereby significantly enhancing the antiadhesion and exhibiting "passive defense" in high-humidity environments. PTMSPMA<i>-co</i>-PTMAO-CF can also achieve reversible conversion of killing and antiadhesion, according to variations in the external environments. This study provides new insight on smart antibacterial fabrics in the fields of health monitoring, sports equipment, and medical protection.