Abstract
A new class of monodisperse water-soluble nanogels was prepared by a simple and green method. Semi-interpenetrating nanogels based on poly (vinyl alcohol), PVA, and poly(acrylic acid), PAA, nanoparticles. PAA was prepared by crosslinking of acrylic acid (AA) in the presence of hydroxypropylcellulose (HPC), N, N-methylenebisacrylamide (MBA) as a crosslinker and potassium peroxydisulfate (KPS) as redox initiator system. PVA nanoparticles were prepared by crosslinking in divinyl sulfone via changing the water and acetone compositions. PVA/PAA nanogel was prepared using epichlorohydrin as crosslinker. The structure and morphology of the nanogel was characterized by Fourier transform infrared spectroscopy (FTIR), transmission and scanning electron microscopy (TEM and SEM). The particle size of the prepared nanogel was determined by dynamic light scattering (DLS) measurements. The corrosion protection effect of PVA/PAA nanogel on the steel surface in 1M HCl solution was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Polarization curves indicate that PVA/PAA nanogel is a mixed type inhibitor affecting both cathodic and anodic corrosion currents. The diameter of the capacitive loop increases substantially with increasing PVA/PAA nanogel concentration indicating that the corrosion resistance of steel has been enhanced significantly. The investigated inhibitor has shown good inhibition efficiency in 1 M HCl. The inhibition efficiency, calculated from impedance results showed the same trend as those obtained from potentiodynamic polarization measurements.