New Lotus-Inspired Plastic Could Solve Many Environmental Problems

Using the lotus leaf as inspiration, researchers develop a self-cleaning, environmentally friendly bioplastic.
lotus leaf holding water

Researchers have invented a durable, sustainable, and biodegradable, self-cleaning bioplastic inspired by the lotus leaf and its self-cleaning properties.

The new material, created at RMIT University in Melbourne, Australia, repels liquids and dirt, much like a lotus leaf, is biodegradable and can be used for composting.

A new way to make bioplastic

According to RMIT Ph.D. researcher Mehran Ghasemlou, principal author of the paper published in Science of the Total Environment, this novel bioplastic is suitable for fresh food, takeout packaging etc.

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Plastic waste is one of our biggest environmental challenges,” Ghasemlou said, “but the alternatives we develop need to be both eco-friendly and cost-effective, to have a chance of widespread use.”

“We created this new bioplastic with large-scale fabrication in mind, making sure it was easy to develop and incorporate into industrial production processes.”

Nature, according to Ghasemlou, is rich in cleverly built structures that might inspire researchers working on new high-performance and multifunctional materials.

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“We’ve created a novel sort of bioplastic that exactly balances both strength and degradability by replicating the incredibly water-repellent structure of lotus leaves,” he added.

Bioplastic is created using inexpensive and readily accessible basic components such as starch and cellulose to keep production costs low and facilitate fast biodegradability.

According to Ghasemlou, the manufacturing method does not require heating or sophisticated equipment. It would be simple to scale up mass production.

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Degrades in soil

While the market for biodegradable plastics is booming, not all bioplastics are created equal. Industrial methods and high temperatures are required to break down most biodegradable or compostable polymers.

Trials have shown that the novel bioplastic degrades organically and fast in soil without use of recycling machines or chemicals.

“There are big differences between plant-based materials — just because something is made from green ingredients doesn’t mean it will easily degrade,” Ghasemlou explained.

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“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.”

Lotus-inspired structures

Lotus leaves are known for having some of the most water-repellent surfaces on the planet and are virtually impervious to dirt.

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The key is in the surface structure of the leaf, which is made up of small pillars capped with a waxy covering.

Any water that falls on the leaf stays a droplet, rolling away with the assistance of gravity or the wind. As the drops run along the leaf, they pick up debris and keep the leaf clean.

The RMIT team of science and engineering experts synthesized a plastic consisting of starch and cellulose nanoparticles to create the lotus-inspired substance.

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This bioplastic surface was imprinted with a pattern that resembles the structure of lotus leaves, then protected with a layer of PDMS, a silicon-based organic polymer.

According to tests, the bioplastic not only successfully repels liquids and dirt, but it also keeps its self-cleaning capabilities after being attacked with abrasives and subjected to heat, acid, and ethanol.

Professor Benu Adhikari, the corresponding author, stated that the design addresses significant limitations of starch-based polymers.

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“Starch is one of the most promising and versatile natural polymers, but it is relatively fragile and highly susceptible to moisture,” Adhikari explained.

“Through our bio-inspired engineering that mimics the ‘lotus effect,’ we have delivered a highly-effective starch-based biodegradable plastic.”

Ghasemlou is presently collaborating with a bioplastics firm to develop these new water repellent polymers further. On commercial applications for bioplastic, the RMIT research team is eager to engage with other possible partners.

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According to the researchers, most compostable or biodegradable plastics today must undergo industrial processes and be subjected to high temperatures to degrade. On the other hand, their bioplastic does not requires only naturally present bacteria in the soil.

“Biodegradation of novel bioplastics made of starch, polyhydroxyurethanes, and cellulose nanocrystals in the soil environment” and “Robust and Eco-Friendly Superhydrophobic Starch Nanohybrid Materials with Engineered Lotus Leaf Mimetic Multiscale Hierarchical Structures” were published in Science of The Total Environment and ACS Applied Materials & Interfaces, respectively.

Final thought

If this bioplastic is as promised, it will be a remarkable achievement. It is an essential step for the future of our planet. No acids, no high temps…just nature. But we’ll wait and see if it works as well as it did in the lab.

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