Plastic has become a permanent fixture in modern life—and that’s exactly the problem. Designed for convenience, it clogs oceans, chokes marine life, and lingers in ecosystems for centuries. Even when it breaks down, it often becomes microplastics that infiltrate food chains. Despite efforts like recycling, bans, and biodegradable alternatives, microplastic pollution remains an overwhelming challenge.

But scientists may have discovered a promising new approach: a type of plastic that doesn’t stick around. A study published in Science introduces “supramolecular plastics,” materials that dissolve safely into saltwater. These plastics are strong, versatile, and designed to disappear when exposed to the ocean. The material could help address one of the world’s most persistent environmental problems.

“With this new material, we have created a new family of plastics that are strong, stable, recyclable, can serve multiple functions, and importantly, do not generate microplastics,” said Takuzo Aida at the RIKEN Center for Emergent Matter Science.

Make biodegradable plastic

This new plastic is made using two key components. The first, sodium hexametaphosphate, is commonly used in food products and cleaning agents. The second, guanidinium sulfate, is a salt-based compound. When these two are mixed in water, they create a dense, interlinked network held together by molecular forces called “salt bridges.” Once this network forms, it can be dried and shaped into plastic films, molds, or even complex 3D-printed objects.

These plastics are built from two surprisingly common components: sodium hexametaphosphate, found in food and detergents, and guanidinium sulfate, a salt-based compound. When dissolved in water, they form a dense molecular network held together by salt bridges. Once dried, the material can be molded into films, containers, or even 3D-printed shapes.

Here’s the magic: in saltwater, those molecular bonds are disrupted. The network disintegrates back into its harmless building blocks—substances that marine bacteria can digest. In tests, thin films dissolved in hours; thicker pieces in just a few days.

Unlike many biodegradable plastics, which only break apart under industrial conditions or after lengthy exposure to heat, this plastic responds to the very environment it is most likely to end up in—the ocean. Even outside the sea, it is designed to decompose gradually, guaranteeing it doesn’t contribute to long-term waste. When buried in soil, for example, it naturally breaks down into organic compounds, unlike conventional plastics.

Also, the new material is non-toxic and non-flammable—meaning no CO2 emissions—and can be reshaped at temperatures above 120°C like other thermoplastics.

Good quality material

The plastics aren’t just eco-friendly; they’re also strong and versatile.

“While the reversable nature of the bonds in supramolecular plastics have been thought to make them weak and unstable, our new materials are just the opposite,” Aida said.

Tests showed that it performs as well as many traditional plastics, with the durability to hold up under heat and pressure. Its ability to be reused or recycled also sets it apart. The researchers demonstrated a process to dissolve and recover its key components, which can be used to create new plastics. This approach makes the material a candidate for supporting a circular economy, where waste is minimized, and materials are continuously repurposed.

The potential for this type of plastic is massive. Aside from 3D printing and medial materials, everyday items like food packaging and single-use containers, not to mention the biggie—plastic shopping bags—could be made from it.

While the science behind supramolecular plastics is innovative to say the least, bringing this material into widespread use will require time and investment. Manufacturing systems must be adapted to produce it commercially, and industries that rely on traditional plastics will need to see its value. Costs and durability in extreme conditions will need further testing, and policymakers must step in to encourage its adoption.

Still, the discovery represents an important shift in how plastics are imagined and designed. By creating materials useful for a finite time and then disappearing without harm, scientists are rethinking the very nature of waste.