Robust and recoverable dual cross‐linking networks in pressure‐sensitive adhesives

Abstract Pressure‐sensitive adhesives (PSAs) demand the ability to simultaneously improve toughness and adhesion. However, these requirements of PSAs have remained a great challenge because robust and recoverable characteristics are usually contradictory properties of PSAs. Dual cross‐linking networks developed by incorporating dynamic noncovalent bonds into chemical cross‐linking networks have the potential to mitigate these requirements in a wide variety of applications including adhesives, hydrogels, and elastomers. Herein, a facile approach to achieve dual cross‐linking networks of acrylic PSAs with excellent mechanical properties and high‐adhesive performance that integrate physically cross‐linked networks into chemically cross‐linked networks is proposed. Diurethane acrylic monomer‐pentaerythritol ethoxylate (DAM‐PEEL) groups were introduced into the acrylic PSA system through photopolymerization. The PSA/DAM‐PEEL dual cross‐linking networks led to the development of the chemically cross‐linked networks for both PSA and DAM via covalent bonds and the physically cross‐linked networks between the amide groups of DAM and the hydroxyl groups of PEEL via hydrogen bonds. Consequently, the PSA/DAM‐PEEL dual cross‐linking networks were able to simultaneously improve the modulus and stretchability. This design strategy for developing dual cross‐linking networks of materials could offer potential applications for various adhesive‐related applications.