Scientists Create Self-Cleaning Bioplastic Inspired by Lotus

This picture shows farmer Nguyen Van Khoa harvesting lotus flowers on a pond in Hanoi. (AFP)
This picture shows farmer Nguyen Van Khoa harvesting lotus flowers on a pond in Hanoi. (AFP)
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Scientists Create Self-Cleaning Bioplastic Inspired by Lotus

This picture shows farmer Nguyen Van Khoa harvesting lotus flowers on a pond in Hanoi. (AFP)
This picture shows farmer Nguyen Van Khoa harvesting lotus flowers on a pond in Hanoi. (AFP)

A research team at the Royal Melbourne Institute of Technology (RMIT) have developed a self-cleaning bioplastic that is eco-friendly and ideal for fresh food and takeaway packaging.

The new plastic is inspired by the nature full of ingeniously designed structures that could inspire researchers striving to develop new high-performance and multifunctional materials, reported the team in their study published March 8 in the journal Science of The Total Environment.

Plastic waste is one of our biggest environmental challenges but the alternative this team developed is both eco-friendly and cost-effective. "We've replicated the phenomenally water-repellent structure of lotus leaves to deliver a unique type of bioplastic that precisely combines both strength and degradability," lead author Mehran Ghasemlou said.

The bioplastic is made from cheap and widely available raw materials -- starch and cellulose -- to keep production costs low and support rapid biodegradability.

The fabrication process does not require complicated equipment and would be simple to upscale to a roll-to-roll production line, Ghasemlou said.

While biodegradable plastics are a growing market, most biodegradable or compostable plastics require industrial processes and high temperatures to break them down.

The new bioplastic does not need industrial intervention to biodegrade, with trials showing it breaks down naturally and quickly in soil. "There are big differences between plant-based materials -- just because something is made from green ingredients doesn't mean it will easily degrade," Ghasemlou said.

"We carefully selected our raw materials for compostability and this is reflected in the results from our soil studies, where we can see our bioplastic rapidly breaks down simply with exposure to the bacteria and bugs in soil. Our ultimate aim is to deliver packaging that could be added to your backyard compost or thrown into a green bin alongside other organic waste, so that food waste can be composted together with the container it came in, to help prevent food contamination of recycling,” he explained.

The researchers inspired their new bioplastic from the always immaculate lotus leaf renowned for having some of the most water-repellent surfaces on earth and are almost impossible to get dirty.

The secret lies in the leaf's surface structure, which is composed of tiny pillars topped with a waxy layer. Any water that lands on the leaf remains a droplet, simply rolling off with the help of gravity or wind. The droplets sweep up dirt as they slide down, keeping the leaf clean.

To make their lotus-inspired material, the RMIT team of science and engineering researchers first synthetically engineered a plastic made of starch and cellulosic nanoparticles. The surface of this bioplastic was imprinted with a pattern that mimics the structure of lotus leaves, then coated with a protective layer of PDMS, a silicon-based organic polymer.

Tests show the bioplastic not only repels liquids and dirt effectively, but also retains its self-cleaning properties after being scratched with abrasives and exposed to heat, acid and ethanol. Corresponding author, Professor Benu Adhikari, said the design overcomes key challenges of starch-based materials.

"Starch is one of the most promising and versatile natural polymers, but it is relatively fragile and highly susceptible to moisture. By mimicking the 'lotus effect', we have delivered a highly effective starch-based biodegradable plastic," Adhikari said.

Ghasemlou is currently working with a bioplastic company, which is evaluating further development of these novel water repellant materials to start the commercial applications of the bioplastic.



Berliners Jump into the Spree River to Show It’s Clean Enough for Swimming 

People swim in the river Spree to demand the lift of the hundred years old swimming ban at the river in front of the Berlin Cathedral and the TV Tower in Berlin, Germany, Tuesday, June 17, 2025. (AP)
People swim in the river Spree to demand the lift of the hundred years old swimming ban at the river in front of the Berlin Cathedral and the TV Tower in Berlin, Germany, Tuesday, June 17, 2025. (AP)
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Berliners Jump into the Spree River to Show It’s Clean Enough for Swimming 

People swim in the river Spree to demand the lift of the hundred years old swimming ban at the river in front of the Berlin Cathedral and the TV Tower in Berlin, Germany, Tuesday, June 17, 2025. (AP)
People swim in the river Spree to demand the lift of the hundred years old swimming ban at the river in front of the Berlin Cathedral and the TV Tower in Berlin, Germany, Tuesday, June 17, 2025. (AP)

A century after the city of Berlin banned swimming in the Spree River because it was so polluted it could make people sick, there's a push by swimmers to get back into the water.

Around 200 people jumped into the slow-moving, greenish water Tuesday to show that it's not only clean enough, but also lots of fun to splash and swim in the Mitte neighborhood along the world-famous Museum Island.

A group calling itself Fluss Bad Berlin, or River Pool Berlin, has been lobbying for years to open the meandering river for swimmers again.

“For 100 years now, people have not been allowed to swim in the inner-city Spree and we no longer think this is justified, because we can show that the water quality is usually good enough to go swimming during the season,” said Jan Edler, who is on the board of Fluss Bad Berlin and helped organize Tuesday's swim-in.

To circumvent the ban, the group registered their collective swim event as an official protest.

Standing on a little staircase that leads down to the Spree canal, which flows around the southern side of the island, Edler stressed that “we want the people to use the Spree for recreation again.”

He pointed to the fact that the river has been cleaned up thoroughly, and that the water quality has improved in the last decade and is constantly being monitored.

Even city officials in the central Mitte district of Berlin say they'd be interested in introducing river swimming again in 2026.

“There are still many things that need to be clarified, but I am optimistic that it can succeed,” district city councilor Ephraim Gothe told German news agency dpa recently.

Supporters of lifting the swimming ban also point at Paris, where the Seine River was opened up for swimmers for the Olympic Games last year and will be opened this summer for Parisians. Swimming there had been banned since 1923.

In Vienna, too, water lovers can splash into the Danube River canal, in the Swiss city of Basel they can bathe in the Rhine, and in Amsterdam there are some designated areas where people can plunge into the canals.

Only in Berlin, swimming has been continuously prohibited in the Spree since May 1925, when the German capital closed all traditional river pools because the water was deemed too toxic. Some of those pools weren't only used for recreational swimming, but were a place for poor people to wash themselves if they didn't have bathrooms at home.

These days, the water is clean on most days, except when there's heavy rain, which leads to some water pollution.

Allowing swimmers to dive into the river would also mean loosening the historical monument protection on some parts of the riverbanks to install easy access ways to the water and places for lifeguards.

Another problem is the busy boat traffic on the Spree that could endanger swimmers. However, for the time being, the Fluss Bad Berlin group only wants to open up nearly 2-kilometer-long (just over a mile-long) canal where there's no boat traffic.

For what it's worth, the German capital, a city of 3.9 million, could definitely need more places where people can cool off in the summer as regular outdoor pools tend to be hopelessly overcrowded on hot summer days.

“The cities are getting hotter,” Edler said. “It's also a question of environmental justice to create offers for people who just can’t make it out of the city when it’s so hot and can enjoy themselves in the countryside.”