The Interplay of Modulus, Strength, and Ductility in Adhesive Design Using Biomimetic Polymer Chemistry

Abstract

High‐performance adhesives require mechanical properties tuned to demands of the surroundings. A mismatch in stiffness between substrate and adhesive leads to stress concentrations and fracture when the bonding is subjected to mechanical load. Balancing material strength versus ductility, as well as considering the relationship between adhesive modulus and substrate modulus, creates stronger joints. However, a detailed understanding of how these properties interplay is lacking. Here, a biomimetic terpolymer is altered systematically to identify regions of optimal bonding. Mechanical properties of these terpolymers are tailored by controlling the amount of a methyl methacrylate stiff monomer versus a similar monomer containing flexible poly(ethylene glycol) chains. Dopamine methacrylamide, the cross‐linking monomer, is a catechol moiety analogous to 3,4‐dihydroxyphenylalanine, a key component in the adhesive proteins of marine mussels. Bulk adhesion of this family of terpolymers is tested on metal and plastic substrates. Incorporating higher amounts of poly(ethylene glycol) into the terpolymer introduces flexibility and ductility. By taking a systematic approach to polymer design, the region in which material strength and ductility are balanced in relation to the substrate modulus is found, thereby yielding the most robust joints.

State of the Art in the Development and Properties of Protein-Based Films and Coatings and Their Applicability to Cellulose Based Products: An Extensive Review

“…Although the adhesion mechanism is not completely known, glue proteins secreted by marine mussels bind strongly to all inorganic and organic surfaces in aqueous environments. Hence several papers were published in order to explain the peculiar properties of this kind of proteins and develop biomimetic adhesives or coatings by modifying synthetic polymers using moieties similar to DOPA, suitable for making films [246]. However, in this approach, natural proteins were not used up to now due to lack of protein availability, and for this reason recombinant approaches are currently under study.…”

Synthesis and Adhesive Property Study of a Mussel-Inspired Adhesive Based on Poly(vinyl alcohol) Backbone

“…Recently, Wilker and co‐workers synthesized a series of polystyrene‐based mussel‐inspired adhesives by the copolymerization of 3,4‐dimethoxybenzene ethylene and styrene, which showed excellent adhesive ability on metal, glass, and plastic substrates . Although significant achievements have been made in this area, however, the use of expensive raw materials, such as dopamine, 3,4‐dimethoxybenzaldehyde, and dopamine methacrylamide and the sophisticated preparation steps seriously limited their practical application …”

“…Mussel byssus proteins (Mfps), a group of proteins secreted from mussel byssus being rich in catecholic amino acid, 3,4-dihydroxyphenyl-l-alanine (DOPA), are well known for their strong adhesive properties at wet/underwater conditions. [1][2][3] Scientific studies have shown that DOPA plays a key role for the strong adhesion, due to the formation of (2 of 9) 1700206 achievements have been made in this area, however, the use of expensive raw materials, such as dopamine, [22] 3,4-dimethoxybenzaldehyde, [23] and dopamine methacrylamide [24] and the sophisticated preparation steps [25] seriously limited their practical application. [26] In previous work, we had developed a simple and efficient method to synthesis a poly(vinyl alcohol) (PVA)-based biomimetic polymer with pendent catechol groups via a one-step acetal formation reaction from two cheap commercially available materials: PVA and 3,4-dihydroxybenzaldehyde, which could act as hot curing adhesives and exhibited excellent bonding strength.…”

A Simple Strategy to Achieve Mussel‐Inspired Highly Effective Antibacterial Coating

“…Mussel-inspired catechol chemistry opens a versatile approach to build functional materials for surface modification due to their fascinating chemical properties, such as outstanding adhesive properties, strong metal-chelation abilities, and redox characteristics. [1][2][3][4][5][6][7][8][9][10][11][12] These biomimetic materials form functional coatings on the surface of a wide range of substrates. [13][14][15][16][17] Among these coatings, antibacterial coating is very important and has been extensively studied, since the demand to free the surfaces from bacteria attaching and proliferating continues to increase, especially for biomedical devices.…”