A seawater-assisted self-healing metal–catechol polyurethane with tunable mechanical properties

Recently, self-healing polymers have been one of the most intriguing academic fields due to the fact that they can increase their service lives and reduce the amount of waste. Here we designed and synthesized a novel telechelic polyurethane with dopamine (DA) end groups that are coordinated with Ca 2+ to form dynamic non-covalent bonds. The tensile stress of the designed polyurethanes increases with increase in the amount of metal cation added, while the strain at break slightly decreases. Rheological tests show that the ionic coordination between Ca 2+ and catechol can dynamically break and recombine under the stimulation of seawater, endowing the polymer with superior self-healing properties (up to 84% based on toughness). Therefore, the seawater-triggered self-healable, super tough polyurethane presented here is very intriguing as it has many potential applications especially in the marine environment. © 2019 Society of Chemical Industry