Loading Biomass-Derived Coatings on Carbon Steel Using Layer-by-Layer Self-Assembly: An Undergraduate Laboratory for Teaching Sustainable Metal Corrosion Prevention Strategy

Metal corrosion is a common electrochemical process that can result in serious safety risks and property damage. Teaching students how to prevent metal corrosion in undergraduate experiments might help them become more adept at applying their chemical knowledge to solving real-world problems. In this work, we report a novel multidisciplinary electrochemical experiment that uses biomass-derived tannic acid (TA) and chitosan (CS) as anticorrosive compounds. TA and CS are alternately deposited on the surface of a carbon steel sheet to form a supramolecular coating by using a molecular Layer-by-Layer (LbL) self-assembly technique. The polarization curves of the samples before and after coating are measured, and the corrosion potential (E_corr) and corrosion current (I_corr) obtained by a Tafel extrapolation method are used to determine the corrosion protection efficiency. The use of TA and CS avoids the environmental hazards connected with traditional inorganic chromium and organic polymer anticorrosive coatings and teaches the notion of sustainability to students in chemistry experiments. Additionally, students do a practical study using their basic knowledge to investigate how different LbL situations affect corrosion protection. Furthermore, since the simplified experimental activity can be conducted at home, a larger audience is reached to help introduce and promote green corrosion protection.