This Cotton Repels Water and Sun

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Washing loads of clothes and getting a sunburn have never been particularly enjoyable experiences. However, scientists have developed a coating for cotton fibers that could not only lighten your laundry load, but protect your skin from the sun's harmful ultraviolet rays.

Using the water-repellent and UV-blocking functions of zinc oxide nanorods, researchers from Northeast Normal University in China created a coating for textiles that not only mimicks the water-repelling nature of the lotus leaf, but was found to have a UV protection factor (UPF) of 101.51, double the highest possible rating.

Previous experiments have created self-cleaning, UV-repellent fabrics through a surface application of titanium dioxide and zinc oxide films. But when team leader Lingling Wang and the rest of the research team modified cotton textiles with zinc oxide nanorods and dumbell-shaped zinc oxide crystallites, they found the material could potentially block a wider range of UV rays.

However, doing so meant carefully suppressing the photoactivity of zinc oxide, which reacts with sunlight in a way that compromises the water repellant nature of the nanorods. So they coated the nanorods with with a silica shell that not only effectively blocks the photoactivity of zinc oxide, but helps it retain hydrophobicity.

The scientists believe this technology will be useful in the surface modification of cotton textiles, creating durable, multifunctional fabrics with enhanced superhydrophobic and UV-ray blocking properties.

Photo: Lingling Wang