Abstract:
Inspired by the adhesion between mussels and rocks, a series of hydrogels composed of poly3-(methacrylamido)propyl trimethylammonium chloride polyacrylamide dopamine (PMPTCDMA) and poly vinyl benzenesulfonic acid sodium salt hydrate (PNaSS) based on charge interaction were prepared. Without introducing covalent bond or coordination bond, opposite charge interaction was adopted in the PNaSS/PMPTCDMA hydrogels system. The cationic polyelectrolyte, PMPTCDMA, being simulated the proteins secreted by mussels, similarly contains abundant positive charges and catechol residues. The anionic polyelectrolyte, PNaSS, imitates the rocks with negative charged surfaces. The mechanical performance of the obtained PNaSS/PMPTCDMA hydrogels could be tuned with the content of catechol and water. The PNaSS/PMPTCDMA hydrogels exhibit high stretch performance and robust adhesion property. After being soaked with saline, the hydrogels reached high tensile fracture stress of 1.89 MPa. Besides, the shear strength of adhesion on glass slides increased to 6.17 MPa, which is almost three times stronger than the origin value (1.58 MPa), revealing a comparable performance to commerical adhesives. The mussel-inspired polyelectrolyte hydrogels were promising for the adhesion of devices underwater, or in humid environments.