Marine Bioinspired Underwater Contact Adhesion

Area of Science:

• Biomaterials Science
• Adhesion Science
• Marine Biology

Background:

• Marine organisms like mussels and barnacles exhibit strong wet adhesion.
• Mussel adhesion primarily relies on catechol moieties, but barnacles utilize non-catecholic aromatic residues.
• Previous synthetic biomimetic adhesives focused on catechol-based strategies.

Purpose of the Study:

• To investigate the wet adhesion properties of copolymerized acrylate films.
• To mimic the key functionalities found in barnacle cement proteins and mussel foot proteins (mfps).
• To explore non-catecholic aromatic residues for enhanced wet adhesion.

Main Methods:

• Synthesized copolymerized acrylate films incorporating aromatic (catecholic and non-catecholic), cationic, anionic, and nonpolar residues.
• Measured initial wet contact adhesion using a probe tack testing apparatus with a flat-punch geometry.
• Evaluated adhesion in deionized water and artificial seawater across different pH levels.

Main Results:

• An optimized bio-inspired copolymer film demonstrated wet contact adhesion of ~15.0 N/cm(2) in deionized water and ~9.0 N/cm(2) in artificial seawater.
• Adhesion strength was up to 150 times greater than commercial pressure-sensitive adhesive tapes.
• Maximum wet contact adhesion was observed around pH 7.

Conclusions:

• Bio-inspired copolymer films incorporating barnacle cement functionalities show significant wet adhesion.
• The findings challenge the sole reliance on catechols for wet adhesion and highlight non-catecholic residues.
• The developed adhesive shows promise for biomedical applications due to its strong performance at neutral pH.