Scientists just made an all-silk cooling textile that reflects 94.8% of sunlight and lowers skin temperature by 4.3 °C

Imagine a shirt that makes you cooler than regular clothes, without batteries, chemicals, or plastic. That’s precisely what a team of researchers from Tsinghua University did with a new kind of silk fabric engineered at the nanoscale.

According to a study, ‘Sustainable all-silk textiles for personal thermal management,’ published in Nature Sustainability by Xun-En Wu, Yingying Zhang, and colleagues, the researchers have developed a silk nanotextile, or SilkNT, made entirely of silk, without synthetic polymers or toxic additives. In lab tests, skin covered with SilkNT was 4.3°C cooler than skin covered with traditional silk fabric. Maintaining that kind of temperature difference passively through a hot day would be meaningful for anyone who spends time outdoors in summer.

What makes this fabric work differently
According to the same Nature Sustainability study, the fabric is made by twisting together regenerated silk nanofibres and regular silk yarn using a Fermat-spiral twist, a geometric pattern seen in nature, such as the spiral pattern of seeds in a sunflower. This creates a layered, hierarchical structure within the fabric on a microscopic scale.


It’s important architecturally because of how it handles sunlight. According to the study, SilkNT has a solar reflectance of 94.8%, meaning that almost all incoming solar radiation is reflected rather than absorbed as heat. The fabric also has reduced UV absorption, at only 8.19%, which is a significant improvement over normal silk.

The cooling effect comes from a process called radiative cooling. Your body constantly emits infrared heat, and a well-designed fabric can channel that heat outward through a specific atmospheric window, effectively using the sky as a heat sink. According to the Nature Sustainability study, this is due to the hierarchical architecture and intrinsic optical properties of silk, which enable this without added nanoparticles or synthetic coatings.

Why existing cooling fabrics have a problem
That’s where the sustainability angle comes in. Most high-performance cooling textiles developed in recent years are based on synthetic polymers, such as nanoporous polythene or polyoxymethylene, or embed metal oxide nanoparticles into the fiber for optical performance. Both these approaches have real environmental and health risks.

According to a study published in Environmental Science and Pollution Research by Carney Almroth and colleagues, synthetic textiles shed plastic microfibers when washed, fibers that eventually enter wastewater systems, accumulate in oceans, and have been found in food chains and marine organisms. The researchers tested shedding on several synthetic fabrics and found that all shed microfibers, with some shedding thousands of fibers per wash.

Nanoparticles embedded in cooling fabrics bring a separate concern. According to a Nature Sustainability study, there are serious risks to environmental and human health, including microplastic shedding and nanoparticle toxicity, which limit the widespread use of synthetic cooling textiles. SilkNT doesn’t suffer from either of those problems because it contains only silk.

Previous research, and how is SilkNT different
Researchers have been working on radiative-cooling textiles for several years. According to a 2023 study, ‘An all-weather radiative human body cooling textile,’ published in Nature Sustainability by Wu et al. , a polyoxymethylene nanotextile was developed that achieved efficient radiative cooling both outdoors and indoors: cooling the body by 0.5 to 8.8°C compared to typical textiles depending on conditions. It was a remarkable technical feat, but polyoxymethylene remains a synthetic plastic.

SilkNT takes a very different approach: instead of designing a new synthetic material with optical properties similar to those of nature, it starts with a natural material and manipulates the structure at the nanoscale. The outcome, as reported in the 2026 Nature Sustainability study, is a fabric that also exhibits outstanding biodegradability, recyclability, and biocompatibility, as verified through extensive experimental characterization and life-cycle assessment.

What this could mean going forward
Humans have been using silk for thousands of years. It’s biodegradable, it’s well tolerated on the skin, and it doesn’t leave a trail of plastic particles every time it’s washed. SilkNT’s research suggests these time-proven characteristics can be combined with advanced optical engineering to achieve cooling results that rival those of materials engineered from scratch in a laboratory.

Researchers describe SilkNT as a proof of concept for a new engineering approach to cooling textiles, one with a tiny ecological footprint. It remains to be seen whether this can be done at a commercial scale and at affordable prices. But as heatwaves become more intense and frequent across the US and globally, the demand for passive, wearable cooling solutions will only grow. It’s a good place to start with a fabric that keeps you cooler, is made from a natural biodegradable material, and creates no microplastic pollution in the process.