The inhibition of corrosion of S30403 stainless steel by a naturally occurring catecholic polymer

Corrosion measurements based on cyclic potentiodynamic polarization indicate that a catecholic mussel adhesive protein adsorbed on to S30403 stainless steel coupons confers significant corrosion inhibition on the metal compared with other adsorbates tested. This inhibition is concentration dependent, with a maximum measured concentration effect occurring at a 1.0 mg/ml solution concentration. This effect results in a reduction of weight loss of more than 50% in both the polarization measurements and in acidic ferric chloride measurements for 72 h. A synthetic analog of the mussel protein with a bottle brush configuration, instead of the tandem linear array of decapeptide repeats characteristic of the natural protein, showed no inhibitory effect on the corrosion of stainless steel samples. This suggests that the molecular configuration of the natural protein may be as important as its functional chemistry in the inhibition of corrosion of S30403 stainless steel.