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Scientists at Tomsk State University (TSU) have developed a technology for producing a new class of woven sorbent materials. These fabrics can absorb harmful substances from the air, self-clean under the influence of sunlight, and be used to monitor human health, as reported by the website of the Russian Ministry of Science and Higher Education.
“The difference in our approach is that we do not apply the material to the fabric but grow it directly within the fabric. This allows us not only to increase the content of the metal-organic framework (MOF) to 10–25 per cent in such a composite material but also to anchor it more firmly within the fabric’s structure,” explained Valeriya Lobanova, a student at TSU’s Faculty of Chemistry and one of the study’s authors.
Metal-organic frameworks (MOFs) are a class of materials that have not yet found widespread application: they are free-flowing, and their porous structure is not fully utilised. Russian scientists have managed to resolve some of these issues.
Chemists at TSU have obtained a Russian Federation patent for a method of immobilisation – the reliable incorporation of MOF particles into the fabric structure. A precursor is introduced into the fabric, from which the material self-assembles at elevated temperatures in water or an organic solvent with the aid of linker molecules. Nanoscale MOF particles form on the surface of the fibres and in the inter-fibre space, ensuring high stability.
The scientists used cotton and polyethylene terephthalate (lavsan, polyester) as the base materials. They are currently working with a wider range of fabrics.
The researchers tested three types of polymers. One of them (Cu-HKUST) imparted sorption properties to the fabric for gaseous pollutants. Another type not only absorbs harmful and hazardous pollutants but also neutralises them through catalytic degradation. The third type (MIL-100(Fe)) demonstrated photocatalytic activity, in other words, the breakdown of organic compounds under the influence of sunlight. It was used to purify water of phenol (an organic compound used in the production of plastics, antiseptics, medicines and dyes) at room temperature and proved effective. This material was successfully synthesised at room temperature, which simplifies its production.
According to the authors, the materials obtained can be used for water purification and the creation of smart fabrics capable of absorbing harmful substances or odours, and then self-cleaning under the action of sunlight or soft ultraviolet light.
MOF nanoparticles incorporated into the fabric can act as drug capsules for treating skin conditions, monitor exposure levels to harmful factors in industrial settings, and help gather information on the state of people and the environment.
Parallel research into functional fabrics is also underway in other BRICS countries.
For instance, Iranian researchers have incorporated antibacterial nanoparticles directly into the structure of polyester fibres, reports Mehr News Agency, a partner of TV BRICS. This method has preserved the material’s durability and imparted antibacterial properties to it. The nanoparticles disrupt the biological activity of microorganisms, preventing their growth and reproduction. The material is also resistant to fungal growth. The fabric has been tested in accordance with Iranian national standards and has demonstrated effectiveness against Staphylococcus aureus and Klebsiella pneumoniae, reducing the microbial load by at least 99 per cent. It is proposed that this fabric be used to produce, for example, seat covers for public transport, children’s clothing, workwear, and bedding.
The Indian Institute of Technology (IIT) in Guwahati has developed a self-cleaning, electrically conductive textile that converts electricity and sunlight into heat, according to the university’s website. Silver nanowires (100,000 times thinner than a human hair) have been applied to the cotton fabric, providing heating at low voltage without the risk of electric shock. A water-repellent coating, modelled on the lotus leaf, protects the material from oxidation, moisture and dirt. The fabric maintains a temperature of 40–60 degrees Celsius for over 10 hours and can be used in clothing for working in cold conditions, for heat therapy for arthritis, and as well for heating water or accelerating chemical reactions.
Chinese scientists have developed a self-cleaning polymer coating for fabrics that allows dirt, grease and bacteria to be removed simply by rinsing with water, without the use of washing powder, according to Vietnam News Agency (VNA), a partner of TV BRICS. The coating is created by alternately spraying two compounds, which form a dense moisturising layer on the fabric’s surface. Unlike previous technologies, the cleaning effectiveness of this coating does not depend on the presence of light and does not diminish during the drying process. Tests have shown that such fabric retains its properties after more than 100 wash cycles, and the new technology reduces water and electricity consumption by approximately 82 per cent.