Dopamine-containing polyurethane was prepared by isocyanate chemistry and carbodiimide chemistry.In this polymer

polyurethane backbone was used to take the place of the protein polyamide chain and dopamine was appended to the polyurethane to mimic the strong adhesion of mussel adhesive proteins.It is possible to combine the unique adhesion of marine adhesive proteins with the designability

easy synthesis

and low cost of simple polymers.First

NCO terminated urethane prepolymer was synthesized from a polyether polyols and isophorone diisocyanate.Then the desired urethane-based prepolymer

together with dimethylol propionic acid was employed to synthesize carboxyl-containing polyurethane.Finally

mussel mimetic polyurethane was prepared using dopamine-HCl and carboxyl-containing polyurethane.The successful incorporation of dopamine with polyurethane was characterized by FTIR

1H-NMR and UV-Vis.FTIR showed the appearance of a shoulder peak 1656 cm-1 associated with the newly forming chemical bond amideⅠbetween —COOH in carboxylcontaining polyurethane and —NH2 in dopamine-HCl. 1H-NMR spectrum was also consistent with the structure of dopaminecontaining polyurethane.Chemical shifts in δ=7.4～8.0

6.3～6.7 and 8.5～9.0 are corresponding to hydrogens of newly forming chemical bond amide

aromatic hydrogens and phenolic hydrogens in catechol

respectively.The absorbance peak in UV-vis also implies the absence of catechol groups in the polymer.In the characterization of shear adhesive strength

we found that grafting dopamine to polyurethane by amide linkage greatly enhanced the adhesive strength.For the substrate of Fe

the adhesive strength has been improved by 30%

at about 5.2 MPa

which can be compared with mussel adhesive proteins.