Robust and Versatile Coatings Engineered via Simultaneous Covalent and Noncovalent Interactions

Abstract

Interfacial modular assembly has emerged as an adaptable strategy for engineering the surface properties of substrates in biomedicine, photonics, and catalysis. Herein, we report a versatile and robust coating (pBDT-TA), self-assembled from tannic acid (TA) and a self-polymerizing aromatic dithiol (i.e., benzene-1,4-dithiol, BDT), that can be engineered on diverse substrates with a precisely tuned thickness (5-40 nm) by varying the concentration of BDT used. The pBDT-TA coating is stabilized by covalent (disulfide) bonds and supramolecular (π-π) interactions, endowing the coating with high stability in various harsh aqueous environments across ionic strength, pH, temperature (e.g., 100 mM NaCl, HCl (pH 1) or NaOH (pH 13), and water at 100 °C), as well as surfactant solution (e.g., 100 mM Triton X-100) and biological buffer (e.g., Dulbecco's phosphate-buffered saline), as validated by experiments and simulations. Moreover, the reported pBDT-TA coating enables secondary reactions on the coating for engineering hybrid adlayers (e.g., ZIF-8 shells) via phenolic-mediated adhesion, and the facile integration of aromatic fluorescent dyes (e.g., rhodamine B) via π interactions without requiring elaborate synthetic processes.