Cooperativity of Catechols and Amines in High‐Performance Dry/Wet Adhesives

Abstract

The outstanding adhesive performance of mussel byssal threads has inspired materials scientists over the past few decades. Exploiting the amino‐catechol synergy, polymeric pressure‐sensitive adhesives (PSAs) have now been synthesized by copolymerizing traditional PSA monomers, butyl acrylate and acrylic acid, with mussel‐inspired lysine‐ and aromatic‐rich monomers. The consequences of decoupling amino and catechol moieties from each other were compared (that is, incorporated as separate monomers) against a monomer architecture in which the catechol and amine were coupled together in a fixed orientation in the monomer side chain. Adhesion assays were used to probe performance at the molecular, microscopic, and macroscopic levels by a combination of AFM‐assisted force spectroscopy, peel and static shear adhesion. Coupling of catechols and amines in the same monomer side chain produced optimal cooperative effects in improving the macroscopic adhesion performance.

Two Faces of Amine–Catechol Pair Synergy in Underwater Cation−π Interactions

“…The synergy between flanking Lys and Dopa has been frequently studied, suggesting that their synergy promotes underwater adhesion via salt displacement, water displacement, energy dissipation, and entropy compensation . Additionally, the amine–catechol synergy has been studied not only for theoretical models but also for designing practical pressure-sensitive adhesives that could be used in both dry and wet conditions . In this work, we, for the first time, tried to investigate how the proximity of amines and catechols affects cation−π interactions using a nanomechanical tool.…”

“…46 Additionally, the amine−catechol synergy has been studied not only for theoretical models but also for designing practical pressuresensitive adhesives that could be used in both dry and wet conditions. 47 In this work, we, for the first time, tried to investigate how the proximity of amines and catechols affects cation−π interactions using a nanomechanical tool. Unexpectedly, we observed an antisynergetic effect of the Lys−Dopa pair on underwater cation−π interactions using synthetic simple peptides: Dopa with flanking Lys had weaker cation−π interactions than Dopa with separated Lys (Figure 3a).…”

Bioinspired pressure-sensitive adhesive: evaluation of the effect of dopamine methacrylamide comonomer as a general property modifier using molecular dynamics simulation

“…Our simulation ndings conrmed and claried the mechanism of hydrogen bonds formation for cohesive strength improvement resulting from DMA comonomer. 14,15 Mechanical properties Three methods including (1) static, (2) uctuation formula, and (3) dynamics are used to calculate mechanical properties using molecular dynamics results. 45 In this study, the static procedure was used to determine mechanical properties.…”

“…Tiu et al 14 reported that DMA comonomer improved the adhesion strength of poly( n -butyl acrylate- co -acrylic acid) copolymer to different organic and metal surfaces. Furthermore, they showed 15 that a combination of catechol and amino acid in a side group led to the highest improvement in the performance of the adhesive based on copolymers of poly( n -butyl acrylate- co -acrylic acid) in the peeling, static shear and atomic force spectroscopy tests. As a different approach, effect of hydroxyl and hydrogen group groups on the adhesion of liquid to substrate have been discussed in literature 16,17 by using fluorosilanes on the substrate.…”

Instant and Strong Underwater Adhesion by Coupling Hygroscopicity and In Situ Photocuring

“…Many marine organisms such as mussels, sandcastle worms, and barnacles, can firmly anchor themselves to surfaces that are routinely covered with the undesired hydration layer . This fascinating underwater adhesion is largely attributed to their proteinaceous secretions containing special chemical functionalities such as 3,4-dihydroxyphenyllalanine (DOPA). , DOPA, due to its benzene ring connecting two neighboring hydroxy groups, allows for various noncovalent and covalent interactions with diverse surfaces even in the presence of hydration layer. , With this excellent surface affinity/adaptability, myriad DOPA-containing polymeric adhesives with favorable underwater adhesion have been developed. − Additional chemical functionalities such as hydrophobicity and positive charges (cations) are often incorporated with DOPA to assist repelling the hydration layer. − Although this mussel-inspired dehydrating strategy can bestow synthetic adhesives with strong underwater adhesion, the intrinsic tendency to oxidation undermines the robustness of DOPA-based adhesives. , …”