Bacterial exopolysaccharides for corrosion resistance on low carbon steel

Corrosion is a global issue that affects safety and economics. There is an increasing demand for bio-based polymers for industrial applications and production of polymers by micro-organisms is especially attractive. This work reports on the electrochemical and physical properties of exopolysaccharides produced from lactic acid bacteria and their suitability as anti-corrosive coatings. Bacterial exopolysaccharide coatings protected low carbon steel from corrosion by reducing ionic diffusion rates and maintaining a relatively passive metal-coating interface. The data suggest the kinetics of film deposition are fast (<5 min) and there is little excess (loosely bound) material when hydrated. Measurements show thin (50 nm) coatings that when exposed to water exhibit self-repairing phenomenon. The corrosion protection offered by the coatings is reported as the corrosion rate calculated from the corrosion current obtained by electrochemical impedance and polarization spectroscopy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45032. © 2017 Wiley Periodicals, Inc.