Nickel-doped chitosan that gets stronger in water could replace some plastics
Feb 22nd 2026
IBEC researchers turned chitosan from shrimp shells into a biodegradable film that increases strength when wet, reaches plastic-grade performance, and can be produced in a near-zero-waste cycle.
- The team doped chitosan with nickel ions to create a biomaterial that becomes stronger on contact with water.
- Nickel ions stabilize reversible water-mediated bridges between polymer chains, enabling fast self-rearrangement that raises wet strength and toughness.
- Tensile strength of nickel-doped films was about 30 to 40 MPa, rising from 36.12±2.21 MPa when dry to 53.01±1.68 MPa when wet, comparable to some engineering plastics.
- Tested nickel concentrations ranged from 0.6 to 1.4 M, with roughly 0.8 M giving the largest wet-strength increase and 1 M or higher preserving strength while increasing toughness.
- Production uses an initial water immersion, 24-hour drying and re-wetting, and recovers expelled nickel for reuse to achieve nearly 100% nickel utilization across batches.
- A 1 m2 film supported 20 kg after 24 hours of immersion and a 244 x 122 cm film showed similar behavior, and about half the material biodegraded in garden soil after roughly four months.
- Likely near-term uses include agriculture, fishing and water-exposed packaging or coatings, while medical applications may be possible after further validation.
- The work was reported in Nature Communications and the team plans a 1000 m2 Barcelona facility for academia-industry collaboration opening in 2028.