Diffusive Adhesives for Water-Rich Materials: Strong and Tunable Adhesion Beyond the Interface

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Adhering water-rich materials (hydrogels, tissues) is challenging due to limited adhesive-substrate contact.
• Current adhesives exhibit weak and non-adjustable adhesion, primarily at the interface.

Purpose of the Study:

• To develop a novel class of diffusive adhesives (DAs) for enhanced adhesion to water-rich substrates.
• To achieve strong, tunable, and non-covalent adhesion by maximizing adhesive-substrate contact.

Main Methods:

• DAs composed of hydrogel matrices with preloaded water-soluble monomers and crosslinkers were designed.
• Monomers and crosslinkers diffused into water-rich substrates upon contact.
• In-situ polymerization and crosslinking formed an interpenetrating network, binding the adhesive and substrate.

Main Results:

• The developed DAs achieved high adhesion strength and toughness, comparable to leading natural and artificial adhesives.
• Adhesion strength was precisely tunable by controlling the diffusion profile.
• The method achieved strong adhesion without requiring covalent bonding between the adhesive and substrate.

Conclusions:

• Diffusive adhesives offer a promising strategy for robust adhesion to challenging water-rich materials.
• The tunable nature of DAs opens possibilities for precise control over adhesion strength.
• Potential applications are significant in biological and medical fields, particularly for hydrogels and tissue adhesion.