A team of chemistry researchers from the University of Sydney Nano Institute has developed nanostructured surface coatings that have anti-fouling properties without using any toxic components.
The researchers estimate that the increased drag on ship hulls due to biofouling costs the shipping industry in Australia alone $A320m ($254m) a year and billions worldwide.
The team have developed coatings that use nanowrinkled surfaces inspired by carnivorous plants which they claim delays degradation by marine fouling.
Leader of the research team, associate professor Chiara Neto, said: “We are keen to understand how these surfaces work and also push the boundaries of their application, especially for energy efficiency. Slippery coatings are expected to be drag-reducing, which means that objects, such as ships, could move through water with much less energy required.”
The new materials were tested tied to shark netting in Sydney’s Watson Bay, showing that the nanomaterials were efficient at resisting biofouling in a marine environment.
The research has been published in ACS Applied Materials & Interfaces.
The new coating uses nanowrinkles inspired by the carnivorous Nepenthes pitcher plant. The plant traps a layer of water on the tiny structures around the rim of its opening. This creates a slippery layer causing insects to aquaplane on the surface, before they slip into the pitcher where they are digested.
Nanostructures utilise materials engineered at the scale of billionths of a metre – 100,000 times smaller than the width of a human hair. Associate Professor Neto’s group at Sydney Nano is developing nanoscale materials for future development in industry.
Biofouling can occur on any surface that is wet for a long period of time, for example aquaculture nets, marine sensors and cameras, and ship hulls. The slippery surface developed by the Neto group stops the initial adhesion of bacteria, inhibiting the formation of a biofilm from which larger marine fouling organisms can grow.