SINGAPORE — While most people resign themselves to sweating in the tropics, a professor returning to Singapore after seven years abroad in cooler climes has been inspired to develop a material that can beat the heat.
When Assistant Professor Tan Swee Ching of the National University of Singapore (NUS) returned in 2014 from his last stop in Hong Kong, he found he was no longer acclimatized to the heat and humidity here.
“I figured if only we had something to lower the relative humidity, we wouldn’t need to turn on the air conditioner,” said the Materials Science and Engineering Department researcher.
Large amounts of moisture in the air, or humidity, on tropical islands like Singapore make it harder for sweat to evaporate, making temperatures warmer than they are.
Professor Tan’s concern about heat stress increased when the Covid-19 pandemic hit and he realized healthcare workers were enduring a felt temperature of around 64C when donning gear personal protective equipment at room temperature.
Citing a 2020 study, he noted that such suits often caused these workers to experience heat stress, leading to exhaustion and dizziness.
So he led a team of NUS researchers to develop a composite film that lowers temperatures felt to 40°C in protective suits by improving sweat evaporation.
Through trial and error over about eight months last year, the team created a non-toxic, moisture-retaining material made from a metal salt, rubber and several other chemicals.
To test the feasibility of applying the composite film in clothing, Home Team Science and Technology Agency (HTX) scientists helped incorporate the film into a protective suit and tested its effectiveness with a dummy that could move. and simulate human perspiration.
Through experiments, researchers have found that the suit can reduce humidity at peak performance for at least two hours.
At a press conference Thursday, March 24, researchers demonstrated the material’s cooling capabilities to increase sweat evaporation in a closed environment.
Journalists experienced what it felt like inside a suit fitted with the material by comparing the temperature difference between wearing a glove and placing the hand inside a box fitted with the film absorbing perspiration.
The material can be dried and reused at least 30 times, Professor Tan said.
The suit is also very energy efficient, compared to other materials, he added.
For example, silicone gel, typically used in food packaging to absorb fluids, can absorb 30% of its own weight in water and must be heated to 110°C to release the moisture.
On the other hand, the composite film can absorb its own weight in humidity and restore it when it is heated in the sun for two hours, or half an hour in the oven at 50°C.