Polymer Composition and Substrate Influences on the Adhesive Bonding of a Biomimetic, Cross-Linking Polymer

Abstract

Hierarchical biological materials such as bone, sea shells, and marine bioadhesives are providing inspiration for the assembly of synthetic molecules into complex structures. The adhesive system of marine mussels has been the focus of much attention in recent years. Several catechol-containing polymers are being developed to mimic the cross-linking of proteins containing 3,4-dihydroxyphenylalanine (DOPA) used by shellfish for sticking to rocks. Many of these biomimetic polymer systems have been shown to form surface coatings or hydrogels, however bulk adhesion is demonstrated less often. Developing adhesives requires addressing design issues including finding a good balance between cohesive and adhesive bonding interactions. Despite the growing number of mussel mimicking polymers, there has been little effort to generate structure-property relations and gain insights on what chemical traits give rise to the best glues. In this report, we examined the simplest of these biomimetic polymers, poly[(3,4-dihydroxystyrene)-co-styrene]. Pendant catechol groups (i.e., 3,4-dihydroxystyrene) were distributed throughout a polystyrene backbone. Several polymer derivatives were prepared, each with a different 3,4-dihyroxystyrene content. Bulk adhesion testing showed where the optimal middle ground of cohesive and adhesive bonding resides. Adhesive performance was benchmarked against commercial glues as well as the genuine material produced by live mussels. In the best case, bonding was similar to cyanoacrylate “Krazy” or “Super” glue. Performance was also examined using low (e.g., plastics) and high (e.g., metals, wood) energy surfaces. Adhesive bonding of poly[(3,4-dihydroxystyrene)-co-styrene] may be the strongest of reported mussel protein mimics. These insights should help us to design future biomimetic systems, thereby bringing us closer to development of bone cements, dental composites, and surgical glues.

Bioinspired dopamine-conjugated polyaspartamide as a novel and versatile adhesive material

“…When this coating was subjected to a macroscopic load, effective transfers of mechanical stress from the metal matrix to the polymer cement improved the strength of conventional PMMA cements bonded to titanium and aluminum. Matos-Pérez et al [23] presented a structure-property study on the simplest mimic of mussel adhesive proteins. They synthesized a series of poly(3,4-dihydroxystyrene-costyrene) by varying the 3,4-dihydroxystyrene content to test the effect of this content on the bulk adhesion of the material on aluminum substrates.…”

Synthesis and adhesive property study of polyoxetanes grafted with catechols via Cu(I)-catalyzed click chemistry

“…Since free-catechol containing polymers might adhere to the column to make GPC results unauthentic [22], the molecular weights of the final catechol-containing polyoxetanes were estimated from the GPC results of the unmodified polyoxetanes. As can be seen from the results, the five adhesive polymers have similar molecular weights (w19 kDa for M n ).…”

Nanospherical arabinogalactan proteins are a key component of the high-strength adhesive secreted by English ivy

“…To evaluate the behavior of the prepared adhesive composites, the adhesion strength of this reconstructed adhesive was examined by both the lap joint shear strength test and the tensile strength test, two strategies that have been extensively applied to quantitatively assess bioadhesives (Fig. 6A) (42,43,(57)(58)(59). The variation in shear strength of the prepared adhesive constructs was monitored over time to reflect the curing progress.…”

“…ELISA screening test was also performed at the CCRC, using a method as previously described (90). Tensile test was conducted to evaluate the reconstructed ivy-mimetic adhesive composites, according to the standard procedure (ASTM D1002) as previously reported (42,43,(57)(58)(59), with slight modification. More detailed materials and methods are available in SI Materials and Methods.…”