Self-cleaning bioplastics repel liquid and dirt
The innovative plastic developed at RMIT University repels liquids and dirt – just like a lotus leaf – then breaks down rapidly once in soil. RMIT Ph.D. researcher Mehran Ghasemlou, the lead author of the study published in Science of the Total Environment, said the new bioplastic was ideal for fresh food and takeaway packaging.
“Plastic waste is one of our biggest environmental challenges but the alternatives we develop need to be both eco-friendly and cost-effective, to have a chance of widespread use,” Ghasemlou said. “We designed this new bioplastic with large-scale fabrication in mind, ensuring it was simple to make and could easily be integrated with industrial manufacturing processes.”
Ghasemlou said nature was full of ingeniously-designed structures that could inspire researchers striving to develop new high-performance and multifunctional materials. “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,” he 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 heating or complicated equipment and would be simple to upscale to a roll-to-roll production line, Ghasemlou said.
Naturally compostable
While biodegradable plastics are a growing market, not all bioplastics are equal. 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.
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,” Adhikari said. “Through our bio-inspired engineering that mimics the ‘lotus effect’, we have delivered a highly-effective starch-based biodegradable plastic.”
Ghasemlou is currently working with a bioplastic company, which is evaluating further development of these novel water-repellent materials. The RMIT research team is keen to collaborate with other potential partners on commercial applications for bioplastic.
