Pitcher Plant Inspires A More Slippery Package

by Rudy Sanchez on 08/21/2018 | 3 Minute Read

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The pitcher plant is a carnivorous plant that feeds on insects by luring them and trapping them in a special digestive liquid. In order for their prey to fall into this liquid trap, these plants have developed a surface on their leaves making them slippery when moistened by condensation or nectar.The specialized leaves of the pitcher plant partly served as inspiration for a new packaging breakthrough coming out of Virginia Tech. In a paper published by Scientific Reports, researchers describe a process that wicks common edible oils like cottonseed into extruded plastics that are commonly used in food packaging (polyethylene and polypropylene). Until now, the process to make a slippery liquid-infused porous surface (SLIPS) used fluorine and silicone-based materials and complex manufacturing methods that made their commercial applications impractical and cost-prohibitive. This new technique is compatible with inexpensive food oils, making the process commercially viable.

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The oils use the inherent roughness of these polymers, so no additional coatings or special techniques need to be used. The polymers are impregnated with oil using a roller, and they stick to the plastic due to the roughness of the material.“[The] slippery periphery on the pitcher plant actually inspired our product,” said lead study author Ranit Mukherjee.The study used ketchup, yogurt and water to test the process: its application in food and pharmaceutical packages would reduce waste and make more of the product available to consumers. According to the Food and Agriculture Organization of the United Nations, in industrialized nations, approximately 40% of food is wasted at the retail and consumer level. Some of this waste is attributable to the last remaining bit of consumable product you can’t squeeze out of a bottle or packet. By using this kind of super-wicking plastic, more food is dispensed with even less thrown away.Sure, leftover ketchup might seem trivial but imagine what's left over in the 11 billion packets Heinz sells every year that ends up in the garbage because it sticks to the inside of the package.

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"We had two big breakthroughs," according to Jonathan Boreyko, Assistant Professor of Biomedical Engineering and Mechanics and the study's co-author. "Not only are we using these hydrocarbon-based polymers that are cheap and in high demand, but we don't have to add any surface roughness, either. We actually found oils that are naturally compatible with the plastics, so these oils are wicking into the plastic itself, not into a roughness we have to apply."For all the technological marvels that surround us and transform daily life, scientists and engineers are still drawing inspiration from the engineering found in nature. Just as Swiss engineer George de Mestral modeled Velcro from the hooks found on the cockle-burs that would stick to his clothes and dog’s fur while out hiking, so too engineers like Mukherjee and Boreyko are modeling this new packaging design from the pitcher plant.Who can say what flora or fauna will inspire the next technical breakthrough?

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