Biomimetic underwater adhesives based on IL-mediated coacervation

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomimetic Engineering

Background:

• Developing underwater adhesives with rapid solidification, robust adhesion, durability, and conductivity is challenging.
• Mussel adhesive proteins provide inspiration for creating advanced underwater glues.

Purpose of the Study:

• To synthesize a coacervation-derived glue with integrated rapid solidification, robust adhesion, durability, and conductivity for underwater applications.
• To investigate the influence of ionic liquid structure on coacervation and underwater adhesion properties.

Main Methods:

• Synthesized a glue using histidine and tryptophan mimetic polymers and ionic liquids (ILs).
• Incorporated benzene, imidazole, and benzotriazolium motifs into the polymer for water-driven coacervation.
• Studied the effect of IL hydrophilicity and polymer affinity on coacervation and adhesion.

Main Results:

• Achieved instant coacervation and robust underwater adhesion by optimizing IL structure and polymer affinity.
• Demonstrated glue effectiveness on diverse surfaces and in various environments (saline, acidic, alkaline solutions).
• The adhesive exhibited anti-freezing properties down to -40 °C and conductivity, enabling strain sensing.

Conclusions:

• The coacervation-derived glue successfully integrates rapid solidification, robust underwater adhesion, durability, and conductivity.
• Ionic liquid structure plays a critical role in tuning coacervation and adhesion performance.
• This biomimetic approach offers new strategies for designing high-performance underwater adhesives for marine engineering and soft electronics.