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Two common anti-UV materials: nano titanium dioxide (TiO2) and nano zinc oxide (ZnO)

Nano zinc oxide (ZnO) and nano titanium dioxide (TiO2) are two commonly-used oxide materials for UV resistance.

 

They have special optical and chemical properties at the nanoscale, making them important candidates in the field of UV resistance.

 

  1. Nanozinc oxide (ZnO), as an excellent ultraviolet shielding agent, shows good ultraviolet absorption properties in the ultraviolet spectrum range. It has high transmittance and excellent optical properties, so it is widely used in the preparation of anti-UVcoatings, fabrics and other products as it has a shielding effect on both UVA (long wave 320 ~ 400nm) and UVB (medium wave 280 ~ 320nm).

 

  1. Nanotitanium dioxide(TiO2)has excellent chemical stability, thermal stability and non-migration, strong achromatic and hiding power, low corrosiveness, good dispersibility, and is non-toxic, odorless and non-irritating, safe to use, and also has the function of sterilization and deodorization.

 

More importantly, nano titanium dioxide can not only absorb ultraviolet rays, but also emit and scatter ultraviolet rays, so it has strong UV resistance. Compared with the same dose of organic anti-UV agents, its absorption peak in the ultraviolet region is higher. Moreover, nano TiO2 has a blocking effect on both medium-wave and long-wave ultraviolet rays, unlike organic anti-UV agents that only have a shielding effect on medium-wave or long-wave ultraviolet rays. Researchers add light shielding agents, light stabilizers, etc. to achieve photoaging resistance of polymer material products, and rutile-type nano TiO2 is non-toxic and odorless to ultraviolet light UVA (315 ~ 400 nm) and UVB (280 ~ 315 nm) ) have a very good shielding effect, do not decompose or discolor after absorbing ultraviolet light, and have excellent stability and durability.

 

  1. The combined use of zinc oxidenano and titanium dioxide nano is also a common anti-UV strategy. Their combined use can give full play to their respective advantages and improve the anti-ultraviolet effect.

Since a single oxide absorbs ultraviolet light in a limited wavelength range, the preparation of UV-resistant nanocomposite oxides has attracted increasing attention from researchers.

For example, nano titania mainly has good absorption performance at 280~350nm, but its absorption at 350~400nm is weak. Although nano ZnO’s short-wave absorption performance is not as good as nano TiO2, it can provide very broad-spectrum protection and inhibit UVA.

The experimental results were found through the ultraviolet absorption spectrum of pure TiO2 and nano ZnO/TiO2 composite particles: at the same concentration, the ultraviolet transmittance of the system containing nano-TiO2 in the 280 ~ 322nm band is only 1%, and the ultraviolet transmittance in the 322 ~ 351nm band is only 1%. The transmittance is 1%~15%, the ultraviolet transmittance in the 351~400nm band is 15%~46%, and its ultraviolet transmittance in the 322~400nm band shows a linear upward trend; while the ultraviolet transmittance of nano-ZnO/TiO2 composite particles in the range of 280-351nm band is always 15%, and the transmittance in the 351 ~ 400nm band is only 15%-18%, the increase in ultraviolet transmittance is not significant.

It can be seen that the UV shielding performance of nano-TiO2 below 351nm is higher than that of nano-ZnO/TiO2, while above 351nm, the UV-shielding performance of nano-ZnO/TiO2 is much higher than nano-TiO2. Although the absorption of nano-ZnO/TiO2 in the UVB region is not as good as that of nano TiO2, its blocking effect on long-wave UVA is better than that of nano-TiO2. It can also be seen that the ultraviolet transmittance of the composite particles in the entire UVB and UVA bands is very small, always below 15%, knowing that this composite particle has a strong ability to shield ultraviolet rays.

 

To sum up, nano zinc oxide and nano titanium dioxide play an important role in the field of UV resistance. Their excellent performance and wide application make them key ingredients in protective products, providing effective protection for people’s health and safety.

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Antibacterial Mechanism and Use of Zinc Oxide Nanoparticles

Nano zinc oxide ZNO is a new type of multifunctional fine inorganic material. Due to the miniaturization of particles, nano zinc oxide powder produces surface effects, small size effects, quantum effects and macro quantum tunneling effects that are not available in bulk materials. It exhibits many special properties, such as non-toxic, non-migrating, fluorescent, piezoelectric, antibacterial and deodorizing, absorbing and scattering ultraviolet rays, etc. Due to the abundant sources of ZnO raw materials and low prices, while zinc is also a mineral element necessary for the human body, nano-ZnO has become one of the hotspots in the research of inorganic antibacterial agents.

Nano-zinc oxide also has many new uses in the field of science and technology, such as manufacturing gas sensors, phosphors, antibacterial materials, ultraviolet shielding materials, varistors, image recording materials, piezoelectric materials, pressure-sensitive materials, varistors, high-efficiency roughness, and magnetism. Materials and plastic films, etc.

There are two antibacterial mechanisms of nano-zinc oxide ZNO:

Photocatalytic antibacterial mechanism. That is, nano-zinc oxide can decompose negatively charged electrons in water and air under the irradiation of sunlight, especially ultraviolet light, while leaving positively charged holes, which can stimulate oxygen change in the air. It is active oxygen, and it oxidizes with a variety of microorganisms, thereby killing the bacteria.

The antibacterial mechanism of metal ion dissolution is that zinc ions will gradually be released. When it comes into contact with the bacteria, it will combine with the active protease in the bacteria to make it inactive, thereby killing the bacteria.

The antibacterial finishing and research on cotton fabrics by nano-zinc oxide and ordinary zinc oxide found that the antibacterial effect of nano-zinc oxide is the result of two antibacterial mechanisms of photocatalysis and metal ion elution. Nano-zinc oxide has antibacterial properties against Staphylococcus aureus Stronger than E. coli, the smaller the size of the nanoparticles, the stronger the photocatalytic effect.

The practical applications of nano-zinc oxide ZNO in antibacterial and anti-ultraviolet functions are summarized as follows:

The field of daily necessities

Applications in apparel, such as sweatshirts, blouses, uniforms, trousers, professional wear, swimwear and children’s wear. It is also used in industry and decoration, such as: advertising cloth, outdoor decoration cloth and so on.

Professional hygiene

For medical use, the antibacterial polyester staple fiber of nano-zinc oxide can be blended with cotton to make hospital bed sheets, surgical gowns, doctor work clothes, patient clothes, etc. For civilian use, it can be used in the food industry and various bedding, furniture cloth, decorative cloth, etc., sterile surgical gowns, sterile masks, sanitary covering materials, etc.

Fields of outdoor work

The anti-ultraviolet properties of nano-zinc oxide make it can be used to produce all kinds of parasols, curtains, transportation tarps and all kinds of tent cloths.

If you need to use nano zinc oxide powder for your application, please contact us.