Stability-enhanced polydopamine coatings on solid substrates by iron(III) coordination

Polydopamine (pDA), a mussel-inspired polymer, has been extensively utilized in various areas because of its versatile and multifunctional properties. However, the poor chemical stability of pDA under harsh reaction conditions has hampered its wider applicability, and therefore, enhancement of its chemical stability is required. In this study, we report a facile method for enhancing the chemical stability of pDA layers. The simple immersion of pDA-coated substrates in an iron chloride solution resulted in the production of pDA layers complexed with Fe III , and these layers showed highly enhanced stability even in the presence of a strong alkali (1 M NaOH).