Photocatalytic degradation of pesticides by nanofibrous membranes fabricated by colloid-electrospinning.

Photocatalytic degradation of organic pollutants is a promising way to clean wastewater. Herein, we develop and compare two processes for fabricating nanofibrous membranes with photocatalytic properties. Hybrid nanofibers are produced by colloid-electrospinning and composed of metal oxide nanoparticles on sintered SiO2 nanoparticles. The latter serves as support for the photocatalyst and preserves the structural integrity of nanofibers. Adsorption of metal salts on crosslinked polymer/SiO2 fibers followed by calcination allows for the obtention of fibers with large amounts of metal oxide. Nanofibrous membranes with supported ZnO, In2O3, or mixture of both, display photocatalytic activity upon UV irradiation. The membranes can degrade a dye and an organophosphate pesticide more effectively than membranes directly fabricated from the calcination of metal oxides.

Regulating Payload Release from Hybrid Nanocapsules with Dual Silica/Polycaprolactone Shells.

We describe a facile strategy to synthesize hybrid nanocapsules with an oil core for hindering interactions between payloads and silica shell. Polycaprolactone/silica nanocapsules are synthesized by an interfacial sol-gel process occurring simultaneously with internal phase separation of the polymer produced by a miniemulsion-solvent evaporation technique. The localization of the polycaprolactone in the nanocapsules is depending on the ratio between polymer and silica. Formation of hybrid nanocapsules is found to significantly hinder interactions of drugs such as ibuprofen and carbamazepine with the silica surface.

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 pandemics. 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 electrospinning 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 immobilized 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/m2s and 65% filtration efficiency against fine particulate matter with a diameter less than 1.0 µm (PM1.0). Supplementary Information: The online version contains supplementary material available at 10.1007/s42765-023-00291-7.