Dissolving plastic: Japan's invention could save our oceans

Researchers in Japan have developed a plastic that dissolves in seawater within hours, offering a potential solution for the modern-day scourge of ocean pollution and wildlife harm. The new supramolecular plastic was co‑developed by the University of Tokyo and the RIKEN Center for Emergent Matter Science. Lead researcher Takuzo Aida explains that it is made by combining two ionic monomers to form a salt bond, which keeps it strong and flexible. The trick is that the material is highly sensitive to salt: when it comes into contact with salt, it breaks down into its original raw materials, which bacteria can then decompose, ultimately returning to the environment as safe substances. Tests in salt solutions similar to seawater showed the plastic dissolving in about two to three hours, depending on size and thickness, and it also works in soil, though a little slower. A small piece of the plastic decomposed after about 200 hours. Many existing biodegradable plastics do not break down fully, leaving behind microplastics—fragments less than one‑fifth of an inch in size—that are found everywhere, including in the human brain, arteries, and other organs. In 2020, an estimated 2.7 million tonnes of plastic entered the environment, and plastic pollution is set to triple by 2040, adding up to 37 million metric tons of waste to the oceans each year. The new material is still in development, but Aida hopes it will prove useful for the packaging industry and become a safe, sustainable substitute. The amount of plastic produced is increasing every year, and reducing that growth would be a meaningful contribution.