Scientists at Shanghai Jiao Tong University have used nature-inspired solutions to tackle a common modern problem: extreme heat in cities. Their work, featured in the Biomimetics Journal, introduces an environmentally sustainable solution— a diatomite-based Radiative Cooling Coating (RCC). This innovative material, derived from the fossilised remains of diatoms, tiny aquatic organisms, promises to revolutionise the way we cool our buildings and vehicles, reducing the reliance on traditional, energy-intensive air conditioning systems.
At the heart of this technology is diatomite, known for its intricate porous structure, which, when combined with a naturally derived binder, methylcellulose, forms a potent duo capable of reflecting sunlight and dissipating heat. This unique blend results in a coating that significantly reduces surface temperatures, offering up to 7 degrees Celsius (12.6 degrees Fahrenheit) of cooling on sunny days, and maintaining impressive performance even under cloudy conditions with a reduction of 6.5 degrees Celsius (11.7 degrees Fahrenheit).
(a) Left: ordinary house. Right: House with cooling paint.
(b) Schematic illustration of a coating based on diatomaceous earth, methylcellulose, and water.
What distinguishes this RCC is its effectiveness as well as its unwavering dedication to sustainability. By eschewing harmful organic compounds in favour of safe, abundant natural materials, the researchers have positioned diatomite as not only an effective cooling agent but also a resource-efficient option. China’s vast reserves of diatomite, estimated in the millions of tons, underscore the scalability and environmental friendliness of this approach.
The versatility of the diatomite-based coating is remarkable. It can be applied to a diverse array of surfaces including metals, wood, and plastics, making it suitable for a wide spectrum of applications from architectural structures to automotive exteriors. Rigorous testing, including thermal cycling and UV accelerated aging trials, attest to the coating’s resilience and longevity, ensuring it can withstand both the test of time and the elements.
The RCC’s design principle is a masterclass in simplicity and effectiveness, steering clear of the toxic and costly processes typically associated with conventional coatings. Instead, it leverages the natural scattering capabilities of diatomite particles to efficiently reflect sunlight. The micro-nanostructure of diatomite not only scatters sunlight but also enhances the coating’s emissivity in the mid-infrared spectrum, crucial for promoting radiative cooling by allowing surfaces to emit heat into outer space, thereby circumventing the sun’s warming effects.
This diatomite based RCC epitomises the innovative spirit of the Shanghai Jiao Tong University team, offering a sustainable solution to cooling needs by mimicking nature’s own heat management strategies. This approach heralds a new era of sustainable urban development, emphasising the need to incorporate environmentally responsible materials and methods to tackle the challenges of contemporary life.
As cities worldwide struggle with higher temperatures and the environmental effects of traditional cooling methods, this diatomite-based innovation stands out as a ray of hope.It exemplifies the principles of biomimicry, demonstrating how nature-inspired solutions can foster sustainable advancements for societal and environmental benefit. The transition from the microscopic legacy of diatoms to cutting-edge cooling technology is a vivid testament to the untapped potential of nature’s ingenuity in addressing humanity’s most pressing challenges, paving the way for a cooler, greener future without the burden of a heavy carbon footprint.