RMIT engineers develop water-repellent bioplastic inspired by the lotus leaf

A new Australian-developed material using biophilic design could help cut back on plastic pollution.

Engineers at RMIT University have developed a compostable, water-repellent bioplastic that could be used as an alternative to regular plastics. The team took inspiration from the lotus leaf, which naturally repels water and other contaminants, to design the material. Chemical and food engineer Professor Benu Adhikari says the threat of plastic pollution was a key motivator for the project.

“Microplastics are everywhere,” he told create. “I am always thinking about how we can create packaging materials that are safe to use in contact with food but can be composted or naturally degraded when discarded.”

The bioplastic’s key innovation is twofold: it is both biodegradable and fully water-resistant. A key consideration for the researchers was the threat to the environment posed by single-use plastic that does not biodegrade.

They also considered how material that allows water vapour to seep through proves ineffective for storing food.

“All food has a moisture content,” Adhikari said. “Purely starch-based packaging is ineffective because if the packaging material comes into contact with the food, then it easily dissolves.”

The innovation mimics the “lotus effect”, in which water and contaminants are repelled from sticking to a surface.

“The lotus leaf has a really interesting function because of its unique microstructure: [a layer of microscopic] pillars and a waxy coating on top,” said PhD researcher Mehran Ghasemlou. “If you place a droplet of water on the surface, it will easily reject it.”