Research news

Author of the image: Asst. Prof. Jelena Vasiljević

Publish Date: 24.03.2021

Category: Interdisciplinary research, Our contribution to sustainable development goals

Sustainable development goals: 3 Good health and well-being, 9 Industry, innovation and infrastructure (Indicators)

In the time of cutting-edge and constantly evolving technologies, we can combine knowledge with imagination, or mimick unique natural phenomena to create completely new and exciting protective textile materials. 

The natural self-cleaning surface of the lotus leaf thus inspired us to develop a cotton fabric, the surface of which acts as a repellent for water and oil-based dirt. This self-cleaning surface property is called the “lotus effect”, whereby water forms spherical droplets that roll-off the surface at extremely low angles and collect particles of dirt along the way. The “lotus effect” is the result of a special hierarchical dual-scale micro/nano structured rough surface with a very low energy. Such a rough, low-energy surface has low adhesion to various molecules and prevents interactions between the surface of the cotton fabric and liquids, as well as pathogens, such as bacteria, fungi and potentially viruses. Therefore, this extraordinary cotton fabric has an additional protective property – a passive antimicrobial (antipathogenic) activity. Today, low-adhesion surfaces that minimise the adsorption of pathogenic bacteria, fungi, and viruses are extremely important in creating an effective tool for preventing and controlling the spread of deadly diseases. Another quality of this cotton fabric is frost protection, since it prevents the accumulation of ice on the surface.

Our research group, which includes researchers from the Textiles and Ecology programme group at the Faculty of Natural Sciences and Engineering, headed by Prof. Barbara Simončič, and researchers from the Coating Development Group of the Department for Materials Chemistry at the National Institute of Chemistry, headed by Asst. Prof. Ivan Jerman, succeeded in designing a self-cleaning protective cotton fabric using the environmentally friendly sol-gel process for the production of silica-based materials. We were able to develop cotton fibres with a low-energy, hierarchical surface roughness by using silicon dioxide nanoparticles coated with a protective water- and oil-repellent polymer film of nano-dimensional thickness. The molecule that ensures the functionality of the protective film thus obtained is an organic-inorganic hybrid precursor, whose special structure allows us to create an elastic film on the fibres, which has side functional groups that are oriented away from the surface of the fibres. The latter can be used to impart water and oil repellency to textiles, while also providing an opportunitty for the development of additional protective properties, such as antipathogenic activity, which destroys pathogenic microorganisms, as well as  flame retardancy and increased thermal stability, which provide protection against flame and heat.

The challenge of achieving multifunctional properties also motivated us to design a multifunctional superhydrophobic, highly oleophobic, antimicrobial and flame retrdant protective polymer film on the cotton fabric. Its structure includes perfluorinated chains to impart water and oil repellency, phosphorus and nitrogen groups for flame retardancy, and quaternary ammonium groups for antimicrobial activity. In achieving this, it was extremely important that all functional organic groups could interact without interfering with each other.

CottonAuthor of the image: Asst. Prof. Jelena Vasiljević

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