Embodiments of this invention relate to adhesives, and more particularly to biomimetic heteropolymer adhesive compositions. Certain embodiments relate to biomimetic terpolymer adhesive compositions including dopamine methacrylamide, 3,4-dihydroxyphenylalanine, or 3,4-dihydroxystyrene, mimicking moieties found in marine mussel adhesive proteins. In some embodiments, elastic moduli of the adhesives are preferably selected to match the elastic moduli of the substrates to minimize stress concentrations, to increase the ductility of the adhesive-substrate system, or both.