Turning nature’s design into a paint that could cool the future

Borrowing a trick from nature, Hong Kong start-up i2Cool has developed an electricity-free solution to keep us cool as global temperatures rise.

Summer heat can be insufferable, especially in tropical regions. When no amount of water, ice cream or cool air from fans can prevent you getting drenched in sweat, switching on the air conditioning can feel like the only quick fix. Yet these machines are costly to run – and, over time, they trap us in a vicious cycle, as they emit more greenhouse gases that speed up climate change.

In Hong Kong, technology start-up i2Cool has developed a cooling solution that doesn’t need electricity – a paint that forms a coating of polymers and nanoparticles on the walls and roofs of buildings. By reflecting back most of the sunlight and radiating heat away, the coating can reduce surface temperatures by up to 42 degrees Celsius, lowering indoor temperatures and reducing the need for air conditioning.

This technology was inspired by the hair structure of the Saharan silver ant, which helps keep the ant’s body temperature cool even in extreme heat above 70 degrees Celsius, according to Martin Zhu, the co-founder and CEO of i2Cool. He developed the paint while studying for his PhD at the City University of Hong Kong with his co-founder and then supervisor, Edwin Tso, the associate dean of the university’s School of Energy and Environment.

The pair decided to shift from academia to starting their own venture after seeing promising results from tests conducted on a campus rooftop. “When I read the lab results and realised how much energy we could save, I knew sustainable technology like this would be a necessity,” recalls Martin, who was recognised as a Gen.T Leader of Tomorrow in 2025.

Since it was introduced in 2022, i2Cool’s paint has been applied in more than 500 locations, including the Hong Kong Coliseum and Dubai Mall, the Middle Eastern city’s largest shopping centre. Martin says the product has helped clients cut energy consumption by between 30 and 50 per cent and, as of late 2025, it has reduced carbon emissions equivalent to planting more than 850,000 trees.

Jiao Jiao Zhang, Head of Portfolio Coverage, Hong Kong, HSBC Innovation Banking, says she is struck by how Martin and his team turned an observation of nature into a commercial innovation. She also points to the paint’s clear value in improving energy efficiency, an area she believes is increasingly being prioritised by governments and businesses around the world.

Given that this paint has such potential, Jiao Jiao believes that her team, which supports start-ups and high-growth companies across Greater China, can help maximise i2Cool’s impact. Launched in June 2023, HSBC Innovation Banking is a dedicated proposition offering specialised services and financing solutions for the global innovation ecosystem. Leveraging the bank’s extensive global network and expertise, its portfolio coverage team provides a comprehensive suite of services – including venture lending, global expansion support, strategic advisory and capital-raising – to support companies at every stage of their growth journey.

With a presence in Hong Kong and mainland China, i2Cool is now scaling up manufacturing and expanding further into Southeast Asia, Europe and the Middle East to serve high-heat markets. “I see i2Cool becoming the global standard for passive cooling,” Martin says. “We want to expand our product range and make our cooling technology accessible everywhere, so future generations can live on a cooler, healthier planet.”

That determination to make a difference in the world is shared by many emerging entrepreneurs. Reflecting on her experience in supporting founders through milestones such as funding rounds and public listings, Jiao Jiao says, “Innovation changes human life. I’m privileged to contribute to the growth stories of the next generation by incubating visionary ideas and turning them into real-world impact.”

By standing behind visionaries like i2Cool, HSBC Innovation Banking is empowering pioneering companies to shape the future.