Opportunity
Conventional fabrics and non-woven materials, widely used in products like clothing, filtration media, and personal protective equipment (PPE) such as face masks, are predominantly passive. They rely on physical filtration or electrostatic adherence to capture pollutants and microorganisms but lack active self-cleaning or self-disinfecting capabilities. This limitation necessitates frequent replacement, poses risks of secondary contamination from accumulated pathogens, and contributes to environmental waste. Existing attempts to create active fabrics, such as those incorporating titanium dioxide or zinc oxide photocatalysts, are inadequate. Titanium dioxide is only effective under ultraviolet (UV) light, which is a small fraction of the solar spectrum and often unavailable indoors. Zinc oxide-based materials can release cytotoxic Zn²⁺ ions, causing skin irritation and inflammation. Furthermore, most current active fabrics are not biodegradable, leading to persistent environmental pollution after disposal. There is a clear and pressing need for a safe, effective, and environmentally friendly fabric that can actively neutralize threats under common light conditions while being comfortable and sustainable.
Technology
This patent addresses the aforementioned problems by inventing a self-cleaning fabric based on advanced, wide-spectrum responsive photocatalysts integrated into a nanofibre matrix. The core innovation lies in the use of specifically engineered photocatalysts: a thermally-treated zeolitic imidazolate framework-8 (ZIF-8-T) in nanoparticle form or a carbon-doped SSZ-13 zeolite in microparticle form. Thermal treatment of ZIF-8 modifies its ligand structure, significantly enhancing its photocatalytic activity, light absorption range (extending into visible and infrared spectra), and stability while reducing Zn²⁺ ion release and associated cytotoxicity. For the zeolite, controlled calcination under a mixed gas atmosphere dopes carbon into the framework, which narrows the bandgap, facilitates electron transfer, and suppresses charge carrier recombination, thereby activating visible-light responsiveness. These photocatalyst particles are uniformly loaded onto ultrathin, electrospun carbon-based nanofibres (made from materials like polyvinylidene fluoride (PVDF) or biodegradable polylactic acid (PLA)/polybutylene adipate terephthalate (PBAT)) to form the fabric. When exposed to a broad spectrum of light (from about 200 nm to 800 nm, encompassing UV, visible, and IR), the photocatalyst generates reactive oxygen species that rapidly decompose and inactivate harmful microorganisms (bacteria, viruses) and degrade organic pollutants on the fabric's surface. The fabric can be laminated with a biodegradable non-woven inner layer to create multi-layered self-cleaning articles like face masks, combining active disinfection with high particulate filtration.
Advantages
- Broad-Spectrum Photocatalytic Activity: Effective under UV, visible, and near-infrared light, enabling functionality indoors under ambient light and outdoors in sunlight.
- High Efficacy and Rapid Action: Demonstrates excellent disinfection performance, inactivating up to 100% of E. coli bacteria within 30 minutes under visible light.
- Reduced Cytotoxicity and Enhanced Safety: The thermal treatment of ZIF-8 and the carbon doping of zeolite minimize the release of harmful metal ions (e.g., Zn²⁺), making the fabric safer for prolonged skin contact.
- High Filtration Efficiency: The electrospun nanofibre structure provides excellent filtration of fine particulate matter (e.g., ~97.7-99.5% efficiency against PM2.5) and microorganisms.
- Environmental Sustainability: Utilizes biodegradable polymer options (PLA, PBAT) for both the nanofibre and supporting non-woven layer, promoting degradability and reducing plastic waste.
- Comfort and Breathability: The ultrathin, porous fabric structure ensures good air permeability and wearer comfort.
- Versatile Fabrication: The electrospinning process allows for the simultaneous formation of nanofibres and loading of photocatalysts, enabling scalable production.
Applications
- Personal Protective Equipment (PPE): Face masks, surgical masks, respirators, and protective clothing for healthcare, industrial, and public use.
- Medical and Healthcare Textiles: Hospital curtains, bed linens, staff uniforms, and wound dressings.
- Air Filtration Systems: Filters for HVAC systems, air purifiers, vacuum cleaners, and personal fans.
- Consumer and Home Textiles: Self-cleaning clothing, tablecloths, curtains, upholstery, wallpapers, and tents.
- Specialized Filtration: Water treatment filters and membranes for degrading organic pollutants.
- Industrial and Outdoor Applications: Protective covers, sunshades, and geo-textiles.
