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The requirements for textiles differ greatly depending on the area of application, whereby it often does not remain with only one required functionality. For example, in the field of functional clothing or protective clothing/PPE, it is necessary to protect the textile’s wearers from UV radiation. At the same time, self-cleaning effects offer certain advantages in that field. In addition, an antimicrobial effect in functional clothing can reduce the formation of unpleasant odors, and in PPE – especially in the healthcare sector – can contribute to the interruption of the chain of infection. One way to achieve these 3 desired functions in just one finishing step is to immobilize titanium dioxide (TiO2). However, TiO2 is viewed critically for application in the textile sector due to a REACH listing. Another disadvantage is that it only takes effect under UV radiation and is therefore not suitable for indoor use. Alternatively, photocatalysts such as doped zinc oxides (ZnO) can be used, which also exhibit catalytic activity through activation by visible light, which can lead to the killing of microorganisms and the degradation of organic soiling.
Energy consumption by air-conditioning is expansive and leads to the emission of millions of tons of CO2 every year. A promising approach to circumvent this problem is the reflection of solar radiation: Rooms that would not heat up by irradiation will not need to be cooled down. Especially, transparent conductive metal oxides exhibit high infrared (IR) reflectivity and are commonly applied as low-emissivity coatings (low-e coatings). Indium tin oxide (ITO) coatings are the state-of-the-art application, though indium is a rare and expensive resource. This work demonstrates that aluminum-doped zinc oxide (AZO) can be a suitable alternative to ITO for IR-reflection applications. AZO synthesized here exhibits better emissivity to be used as roofing membrane coatings for buildings in comparison to commercially available ITO coatings. AZO particles forming the reflective coating are generated via solvothermal synthesis routes and obtain high conductivity and IR reflectivity without the need of any further post-thermal treatment. Different synthesis parameters were studied, and their effects on both conductive and optical properties of the AZO nanoparticles were evaluated. To this end, a series of characterization methods, especially 27Al-nuclear magnetic resonance spectroscopy (27Al-NMR) analysis, have been conducted for a deeper insight into the particles’ structure to understand the differences in conductivity and optical properties. The optimized AZO nanoparticles were coated on flexible transparent textile-based roofing membranes and tested as low-e coatings. The membranes demonstrated higher thermal reflectance compared with commercial ITO materials with an emissivity value lowered by 16%.
The pH value of the human skin is not in the neutral range but is slightly acidic with values of – depending on the body part – 3.5 to 6. This provides a suitable habitat for the commensal skin floral but has a killing effect on some pathogenic micro-organisms and an inactivating effect on some viruses. This protective acid mantle of the skin thus represents a first external protective layer against infestation by pathogens. An appropriate surface pH on textiles can help to minimize the transmission of pathogens through the clothing of healthcare workers while at the same time not exerting a negative influence on the skin’s own flora. In addition, the colonization of e.g. bed linen by pathogenic microorganisms can be reduced. This can also have a positive influence on bacteria-associated odor formation on functional clothing.
The pH value of the human skin is not in the neutral range but is slightly acidic with values of – depending on the body part – 3.5 to 6. This provides a suitable habitat for the commensal skin floral but has a killing effect on some pathogenic micro-organisms and an inactivating effect on some viruses. This protective acid mantle of the skin thus represents a first external protective layer against infestation by pathogens. An appropriate surface pH on textiles can help to minimize the transmission of pathogens through the clothing of healthcare workers while at the same time not exerting a negative influence on the skin’s own flora. In addition, the colonization of e.g. bed linen by pathogenic microorganisms can be reduced. This can also have a positive influence on bacteria-associated odor formation on functional clothing.