Ambivalent Adhesives: Combining Biomimetic Cross-Linking with Antiadhesive Oligo(ethylene glycol)

Abstract

Oligo(ethylene glycol) (OEG) and poly(ethylene glycol) (PEG) exhibit several desirable properties including biocompatibility and resistance to fouling by protein adsorption. Still needed are surgical glues and orthopedic cements, among several other materials, that display similar traits. However the very lack of interactions with other molecules that prevents toxicity and fouling also makes adhesion elusive. In work described here the cross-linking chemistry of marine mussel adhesive is combined with OEG to make a family of terpolymers. The effect of polymer composition upon bulk adhesion was examined. High strength bonding was found with a subset of the polymers containing appreciable OEG content. These structure-property insights may help the design of new materials for which the properties of OEG and high strength adhesion are both being sought.

Mussel‐Inspired Alternating Copolymer as a High‐Performance Adhesive Material Both at Dry and Under‐Seawater Conditions

“…[ 1 ] Although the actual mechanism for the strong adhesion of mfps has yet to be clarified precisely, it is widely accepted that 3,4‐dihydroxyphenylalanine (DOPA), a noncanonical amino acid, plays an important role in such excellent adhesive properties through both oxidative crosslinking [ 2,3 ] and metal ion chelation processes. [ 4,5 ] Thus, up to now, great efforts have been made to incorporate DOPA or catechol groups in a broad range of designed polymers to get mussel‐inspired adhesives, which showed good bonding performances both at dry and underwater conditions. These polymers were generally named as “catechol‐functionalized polymers” (CFPs).…”

“…[ 6 ] Wilker et al synthesized poly[(3,4‐dihydroxystyrene)‐ co ‐styrene] via anionic polymerization method, which achieved a bonding strength of 11 MPa on aluminum by using CaCO 3 particles as reinforcing materials. [ 7 ] Subsequently, they also incorporated the CFPs with poly(lactic acid) [ 8–10 ] or pendant oligo(ethylene glycol) moieties [ 4 ] to produce biodegradable/biocompatible adhesives with good dry‐state bonding strength. Wan et al synthesized catechol‐functionalized poly(vinyl alcohol) via esterification reactions [ 11 ] and acetal formation reactions, [ 12 ] exhibiting bonding strengths of 4.0 MPa on glass and 14.9 MPa on stainless steel, respectively.…”

The Chemistry behind Catechol‐Based Adhesion

“…Several studies report optimum catechol contents between these extremes,close to 10-15 mol %. [85,87,107] This parameter is also strongly dependent on the molecular weight of the polymer (Figure 8). [100] Overall, lowmolecular-weight species have better mobility and, therefore, provide better wetting for enhanced interaction with the surface.…”

“…However,c ovalent cross-linking is ac ommonly followed approach in synthetic catechol-based materials.A sageneral trend, al arger catechol content results in greater cohesion forces.H owever,t here is al imit;a ne xcess of catechol may result in excessive cohesion forces,thereby generating arigid material with fewer adhesive surface interactions.I nm arine mussels, [7,82] optimum DOPAa mounts range from 3t o3 0% of the total amino acid content, [83] with an average of close to 10 mol %. [84,85] Based on this observation, several groups focused on the synthesis of catechol-based adhesive materials with optimised catechol contents. [86][87][88][89][90][91] Mussel-inspired biomimetic polymers have been mainly prepared from polyesters, [88,89] polyamides, [92] polyacrylates, [93][94][95][96] polyethylene glycols, [16,[97][98][99] polyoxetanes, [87,91] polystyrenes [86,100] polypeptides, [101][102][103] and polysaccharides.…”

Rheology of nitrile rubber with hybrid crosslinked network composed of covalent bonding and hydrogen bonding

“…4 Recently, many smart supermolecular materials with transient network by physical crosslinking have been reported, 4,13,20,21,[23][24][25] and they could present some special properties, such as self-healing, 12,13,15,20,26 stimuli responsiveness, 22,27,28 toughness 29,30 and adhesive. [31][32][33] Transient network in polymers has been investigated since 1990s. [34][35][36][37][38] In particular, the relaxation behavior of transient network was studied and several constitutive models were proposed on the basis of Maxwell model and Boltzmann superposition principle.…”