Written by Shatarupa Majumdar
“Imagine wearing a fabric that keeps you cool in the scorching sun without consuming any energy. Sounds like a dream, right? But thanks to radiation cooling technology, this is now a reality.
What is radiative cooling fabric?
Radiative cooling is an innovative, sustainable solution that utilizes the reflectivity function of fibers to cool the human body. By reflecting sunlight, these fabrics provide a cooling effect without relying on energy. Researchers have been exploring this domain, and we’ll delve into the findings.
Notable research and technology behind radiative textile materials
One such notable study focuses on Polylactic acid fibers (PLA fibers), also known as corn fibers, derived from starch-based biomass like corn and potato. PLA fibers boast impressive properties: non-toxic, antibacterial, biodegradable, flame-retardant, and biocompatible. They’re also gentle on skin and durable.
In this research, PLA serves as the base material. The fabric undergoes a unique treatment: one side is modified with hydrophilic agents and titanium dioxide (TiO2), while the other side is treated with MXene and coated with polydimethylsiloxane (PDMS) to prevent oxidation.
TiO2 is a white solid that is insoluble in water. It has a wide range of applications, including paint and sunscreen. Titanium dioxide (TiO2) can be applied to fabrics to provide UV protection, self-cleaning properties, and durability. By blocking UV-A and UV-B radiation, TiO2 protects skin from harmful sun exposure, while its photocatalytic activity helps break down stains and odors. TiO2-treated fabrics are suitable for various applications, including outdoor clothing, sportswear, and protective clothing, offering benefits such as enhanced performance, comfort, and extended lifespan, making it a valuable addition to various fabric-based products.
MXenes are a class of 2D inorganic compounds consisting of atomically thin layers of transition metal carbides, nitrides, or carbonitrides. They are known for accepting various hydrophilic terminations. First discovered in 2011 at Drexel University, MXenes were named by combining "MX" (from MAX phases) with "ene"; similar to graphene. Along with MBenes, MXenes are a significant area of research in materials science.
PDMS, a silicone polymer, enhances fabric properties with benefits like water repellency, durability, and thermal regulation. By creating a hydrophobic surface, PDMS makes fabrics water-resistant, while improving resistance to wear and tear. Its passive daytime radiative cooling properties reflect solar radiation and emit heat, making it ideal for outdoor clothing, sportswear, and protective clothing, where water repellency, breathability, and thermal regulation are essential.
On further study, tests reveal that the resulting functional PLA fabric possesses excellent UV resistance, favourable air permeability, high sunlight reflectivity on the TiO2-treated side while the MXene side exhibits superior photochemical conversion capabilities. Thus providing effective cooling on the treated sides.
Another notable study was conducted and was incorporated with an advanced radiative cooling fiber membrane. This innovative membrane uses a unique combination of materials and technology to achieve impressive cooling properties.
The membrane consists of: PHBV (poly(3-hydroxybutyrate-co-3-hydroxyvalerate)): A biodegradable matrix with multiple absorption peaks in the atmospheric window, and SiO2 nanoparticles: Embedded within the membrane to enhance Mie scattering and selective emission. The membrane is created using electrospinning technology, resulting in a micro-nano-multistage architecture. This material upholds a number of Properties, including:
- High solar reflectivity (0.95): This reflects most of the sun’s radiation.
- High emissivity (0.89): Efficiently emits heat in the atmospheric window.
- Cooling performance: With a Cooling temperature of 4.85 °C lower than ambient. Temperature differential of 12.8 °C relative to human skin. Average cooling power of 64.05 W/m2. And Peak cooling power of 91.75 W/m2.
- Mechanical properties: The mechanical properties include Elongation at break: 151% (high flexibility) and Water contact angle: 124.5° (hydrophobic).
This advanced membrane is suitable for personal wearable cooling fabrics, offering a promising solution for thermal management in various applications.
Learn more about radiative material in textiles and how it works.
Conclusion
In conclusion, the innovative applications of radiation cooling technology in fabrics have shown promising results, offering a sustainable solution for personal cooling. The studies on PLA fibers treated with TiO2, MXene, and PDMS, as well as the advanced radiative cooling fiber membrane, demonstrate impressive properties and performance.
These materials and technologies have the potential to revolutionize the textile industry, providing comfortable, durable, and eco-friendly fabrics for various applications. As research continues to advance, we can expect to see more innovative solutions for thermal management, enhancing our daily lives and promoting a more sustainable future.
Related Article: Properties of Cotton Fibre (Physical, Chemical, and Technical Properties)
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