Polarization parameters for the corrosion of mild steel in 0.5 M HCl without and with various concentrations of MISB molecules.

Inhibitor	C (mM)	E corr (mV per SCE)	β a (μA cm−2)	β c (mV dec−1)	i corr (μA cm−2)	IE%	θ
Blank		−445	70.6	114.8	1130
MISB	8.56 × 10−3	−522	69.2	107.8	462.0	59.21	0.60
	17.10 × 10−3	−545	164.7	146.3	229.0	79.83	0.80
	25.70 × 10−3	−525	72.3	76.4	173.0	84.78	0.83
	34.20 × 10−3	−541	132.6	152.1	97.0	91.51	0.92