Electrochemical properties of biopolymers in strong acid and application in displacement sensor

Abstract

The electrochemical properties of thin films of two derivatives of the biopolymer hydroxypropyl methylcellulose (HPMC), namely, hydroxypropyl methylcellulose phthalate (HPMCP) and hydroxypropyl methylcellulose acetate succinate (HPMCAS), in a strongly acidic environment were studied. The corrosion resistance of HPMC-derivative-coated high-speed steel (HSS) was evaluated using electrochemical impedance spectroscopic measurements and potentiodynamic polarization. The results of Nyquist plots and Tafel polarization showed that HPMCP and HPMCAS have different corrosion resistance properties. HPMCP helps form oxide compounds with the HSS surface, and HPMCAS synthesizes new compounds on the surface with water, thus increasing the corrosion resistance pathways. In this study, derivatives of biopolymers are used to create an ecologically friendly and anticorrosion coating to protect the surface of HSS and to provide an anticorrosion mechanism in a strong acid environment.