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Replacing Plastic with Sustainable Biosynthetic Substitutes

Team from the University of Science and Technology of China (USTC) develops a transparent nacre-inspired nanocomposite film, constructed from sustainable naturally occurring ingredients from living bacteria.

More than 380 million tonnes of plastic are produced globally every year, these non-biodegradable materials usually end up as waste, polluting our natural environments. Over 40 percent of plastic produced is used for manufacturing films for packaging. Usage of these plastic films for bags and food wrappers typically are not recycled and will persist in the environment for hundreds of years.

Pollution caused by plastic film waste is becoming one of the most prominent environmental issues due to increase in consumerism and rapid production of disposable plastic film products. Under normal conditions, a single plastic bag can be broken down into 1.75 million microscopic fragments. These fragments of microplastics however, still pose danger to polluting our environment and have also been found in many species of fish, shrimp, and birds.

To mitigate the environmental impact of disposable plastics, a team led by Professor Yu Shuhong from USTC have recently formulated a sustainable alternative to plastic. This novel material is made from ingredients produced by living bacteria to create a transparent nacre-inspired nanocomposite film. Fabrication of this film was through a one-step process known as aerosol-assisted biosynthesis. This novel fermentation process combined nanomaterial deposition and nanoscale assembly with bacterial secretion process to achieve advancing strength and transparency.

The combination of clay nanosheets and bacterial cellulose gives this biosynthetic film substantial mechanical strength with a nacre-inspired structure, improving strength and transparency of the film.

The team was able to create to film to possess multiple intriguing macroscopic properties, including unique optical and mechanical properties. Special optical performance was demonstrated by combining high optical transmittance and high optical haze, which is essential for efficient light management in optoelectronic devices. This property of the biosynthetic film shows its potential to be used as a plastic substitute in light management.

Flexibility of the new material was also shown as it could be folded into a desired shape with no visible damage after unfolding. Its extremely low thermal expansion coefficient and high maximum service temperature also demonstrates its thermal stability. The research team also see promise in the potential of large-scale production of this sustainable nacre-inspired composite film for commercial use. [APBN]