Mechanical Enhancement of Bioinspired Polydopamine Nanocoatings

Inspired by the catechol and amine rich adhesive proteins of mussels, polydopamine (pDA) has become one of the most widely employed methods for functionalizing material surfaces, powered in part by the versatility and simplicity of pDA film deposition that takes place spontaneously on objects immersed in an alkaline aqueous solution of dopamine monomer. Despite the widespread adoption of pDA as a multifunctional coating for surface modification, it exhibits poor mechanical performance. Attempts to modify the physical properties of pDA by incorporation of oxidizing agents, crosslinkers or carbonization of the films at ultra-high temperatures have been reported; however, improving mechanical properties with mild post-treatments without sacrificing the functionality and versatility of pDA remains a challenge. Here, we demonstrate thermal annealing at a moderate temperature (130 ˚C) as a facile route to enhance mechanical robustness of pDA coatings. Chemical spectroscopy, x-ray scattering, molecular force spe...