There is a critical need for new efficient solutions to purify and disinfect water from source to point-of-use, especially for the water contaminated by pathogenic microbes. Traditional disinfection technologies are chemically intensive and limited, either by biofouling or by the irreversible consumption of disinfectants. Herein, we present a scalable methodology to create biocidal and rechargeable nanofibrous membranes (BNF membranes) by combining N-halamine antimicrobial agent with electrospun nanofibers. Our method allows intrinsically rechargeable N-halamine moieties to covalently incorporate into nanofibers with high biocidal activity and durability. The resulting BNF membranes exhibit integrated properties of high porosity, large surface area, robust mechanical strength, super hydrophilicity, rechargeable chlorination capability (>3000 ppm), and high bactericidal efficacy (99.9999% contact-killing), which enabled the BNF membranes effectively disinfect bacteria-contained water by direct filtration, with promising high durability and fluxes (10000 L m −2 h −1 ). The successful synthesis of BNF membranes also provides a versatile platform for exploring the antimicrobial N-halamine materials in a self-supporting, structurally adaptive, and nanofibrous form.

Pathogenic microbial contamination from microbial adhesion and subsequent formation of the biofilm on surfaces of plastic food packaging materials, especially with robust resistance to antimicrobial agents, is a major reason for the outbreak of foodborne infections. Conventional strategies in controlling the contaminations are significantly limited either by biofouling or by the irreversible consumption of antimicrobial agents. Herein, we report a robust methodology to create rechargeable biocidal poly­(vinyl alcohol-co-ethylene) films (SBMA@HAF films) with antifouling function via chemically incorporating both N-halamine (HAF) and zwitterionic moieties [[2-(methacryloyloxy)­ethyl]­dimethyl-(3-sulfopropyl)­ammonium hydroxide (SBMA)]. The promise of the design exhibits three features to defeat bacterial contaminations: (i) zwitterionic moieties can effectively reduce bacterial attachment onto the films, (ii) N-halamine with robust rechargeable biocidal activity can rapidly kill any attached bacteria, and (iii) any inactivated bacterial debris can be easily released to avoid biofilm formation due to the superhydrophilicity of the zwitterions. The resulting SBMA@HAF films exhibit integrated properties of high transparency, robust mechanical property, great hydrophilicity, ease of chlorine recharging (>250 ppm), long-term stability, high biocidal efficacy (>99.9999% via contact killing), and promising antifouling functions, which enable the SBMA@HAF films to serve as a biocidal material in food packaging applications.

Antimicrobial polymeric films that are both mechanically robust and function renewable would have broad technological implications for areas ranging from medical safety and bioengineering to foods industry; however, creating such materials has proven extremely challenging. Here, a novel strategy is reported to create high-strength N-halamine incorporated poly(vinyl alcohol-co-ethylene) films (HAF films) with renewable antimicrobial activity by combining melt radical graft polymerization and reactive extrusion technique. The approach allows here the intrinsically rechargeable N-halamine moieties to be covalently incorporated into polymeric films with high biocidal activity and durability. The resulting HAF films exhibit integrated properties of robust mechanical strength, high transparency, rechargeable chlorination capability (>300 ppm), and long-term durability, which can effectively offer 3-5 logs CFU reduction against typical pathogenic bacterium Escherichia coli within a short contact time of 1 h, even at high organism conditions. The successful synthesis of HAF films also provides a versatile platform for exploring the applications of antimicrobial N-halamine moieties in a self-supporting, structurally adaptive, and function renewable form.

Embedding medical and hygiene products with regenerable antimicrobial functions would have significant implications for limiting pathogen contaminations and reducing healthcare-associated infections. Herein, we demonstrate a scalable and industrially feasible methodology to fabricate chlorine rechargeable melt-blown polypropylene (PP) nonwoven fabrics, which have been widely used in hygienic and personal protective products, via a combination of a melt reactive extrusion process and melt-blown technique. Methacrylamide (MAM) was employed as a precursor of halamine monomers and covalently grafted onto the PP backbone to form polypropylene-grafted methacrylamide (PP-g-MAM), which could be chlorinated, yielding biocidal acyclic halamines. Subsequently, the resultant PP-g-MAM was manufactured into nonwoven fabrics with varying fiber diameters by adjusting the hot air flowing speed during the melt-blowing process. The chlorinated nonwoven fabrics (PP-g-MAM-Cl) exhibited integrated properties such as a robust mechanical property, good thermal stability, high chlorination capability (>850 ppm), and desirable chlorine rechargeability. More importantly, such chlorinated nonwoven fabrics showed a promising antibacterial and antiviral efficiency, achieving 6 log CFU reduction of bacteria (both Escherichia coli O157: H7 and Listeria innocua) and 7 log PFU reductions of a virus (T7 bacteriophages) within 15 and 5 min of contact, respectively, revealing great potential to serve as a reusable antimicrobial material for medical protection applications.

Protein separation materials that are both selective and effective could have wide applications in fields of bioengineering and pharmaceutical industry. However, preparation of such materials has proven to be extremely challenging. Herein, we present a scalable methodology to prepare carboxyl group functionalized nanofibrous membranes (SFNM) by combining sustainable silk and electrospinning. The naturally abundant silk is thus reconstructed into nanofibrous membranes with tunable surface functions. The resultant SFNMs exhibit integrated properties of ultrathin fiber diameter (125 nm), larger surface area (14 m2 g–1), high porosity, superhydrophilicity, and negatively charged fiber surface, which can reversibly adsorb lysozyme with a robust capacity of 710 mg g–1 and high durability, matching well with the requirements for purifying protein solutions. The fabrication of such fascinating materials may provide new insights into the design and development of multifunctional separation membranes for various applications.