Functional Fiber Membranes with Antibacterial Properties for Face Masks

Reusable face masks are an important alternative for minimizing costs of disposable and surgical face masks during pan-demics.Often complementary to washing,a prolonged lifetime of face masks relies on the incorporation of self-cleaning materials.The development of self-cleaning face mask materials requires the presence of a durable catalyst to deactivate contaminants and microbes after long-term use without reducing filtration efficiency.Herein,we generate self-cleaning fibers by functionalizing silicone-based(polydimethylsiloxane,PDMS)fibrous membranes with a photocatalyst.Coaxial electro-spinning is performed to fabricate fibers with a non-crosslinked silicone core within a supporting shell scaffold,followed by thermal crosslinking and removal of the water-soluble shell.Photocatalytic zinc oxide nanoparticles(ZnO NPs)are immo-bilized on the PDMS fibers by colloid-electrospinning or post-functionalization procedures.The fibers functionalized with ZnO NPs can degrade a photo-sensitive dye and display antibacterial properties against Gram-positive and Gram-negative bacteria(Escherichia coli and Staphylococcus aureus)due to the generation of reactive oxygen species upon irradiation with UV light.Furthermore,a single layer of functionalized fibrous membrane shows an air permeability in the range of 80-180 L/m^(2)s and 65%filtration efficiency against fine particulate matter with a diameter less than 1.0µm(PM_(1.0)).

Bioinspired cellulose-integrated MXene-based hydrogels for multifunctional sensing and electromagnetic interference shielding

Bioinspired hydrogels are complex materials with distinctive properties comparable to biological tissues.Their exceptional sensitivity to various external stimuli leads to substantial application potential in wearable smart devices.However,these multifaceted hydrogels are often challenging to be combined with pattern customization,stimulus responsiveness,self-healing,and biocompatibility.Herein,inspired by mussel secretions,a printable,self-healing,and biocompatible MXene-based composite hydrogel was designed and prepared by incorporating Ti3C2Tx MXene nanosheets into the hydrogel framework through the chelation of calcium ions(Ca2+)with polyacrylic acid and cellulose nanofibers at alkaline conditions.The biocompatible conductive hydrogel exhibited sensitivity(gauge factor of 2.16),self-healing(within 1 s),recognition,and adhesion,distinguishing it as an ideal candidate for wearable multifunctional sensors toward strain sensing,vocal sensing,signature detection,and Morse code transmission.Additionally,the multifunctional hydrogel manifested efficient electromagnetic interference shielding properties(reaching more than 30 dB at a thickness of 2.0 mm),protecting electronics and humans from electromagnetic radiation and pollution.Therefore,the presented work represents a versatile strategy for developing environmentally friendly conductive hydrogels,demonstrating the perspectives of intelligent hydrogels for multifunctional applications.