The Polymer Society of Korea

Deng Limin (카이스트)

Deng Limin (카이스트)

이정용 (KAIST)

영우빈 (KAIST)

Inspired by the red sea star’s fibrinolytic healing, we developed a polyurethane (DSFPU-3) with rapid underwater self-healing at ambient conditions. It integrates dual hydrophobic units—fluorinated hard segments and alkyl-chain soft segments—to repel water and protect dynamic bonding sites. Tandem dynamic covalent bonds (disulfide and imine) enable fast bond exchange and healing. DSFPU-3 shows excellent mechanical properties (tensile strength 4.2 MPa, toughness 17.9 MJ·m⁻³) and retains integrity after 4 days underwater. Optical and 3D microscopy confirm surface scratches heal fully within 12 hours at room temperature, with 98% mechanical recovery and a healing rate over 33.33 μm/h. Rheology and scratch-depth decay analysis support the self-healing mechanism. This approach offers a pathway to design high-performance underwater self-healing polymers for bioelectronics, soft robotics, and implants.