• Polyethylenimine (PEI) with three different epoxies were evaluated as potential corrosion inhibitors. • The corrosion resistance performances of PEIs were revealed with several electrochemical tests. • SEM and AFM show extraordinary surface adsorption performances by PEIs. • Linear PEI showed better corrosion protection as compared to branched PEI. Polyethylenimine (branched and linear) cross-linked coatings were studied for Low Carbon Steel (LCS) corrosion protection in 2 M sulfuric acid corrosive media. Three epoxies namely 4,4′-methoxy (N,N-diglycidyl anisole) (ER1), 4,4′-methylene (N,N-diglycidyl aniline) (ER2), and Diglycidyl 1,2-cyclohexanedicarboxylate (ER3) have been used to produce different cross-linked coating materials with polyethylenimine branched (PEIB) and polyethylenimine linear (PEIL). Our aim was to investigate and find the best surface protective materials among the studied crosslinked polymers. Weight-loss, potentiodynamic polarization techniques including electrochemical impedance spectroscopy were used to conclude the corrosion inhibition behavior of the cross-linked polymeric coatings in 2 M H 2 SO 4 solution. Electrochemical analysis suggested that the sample PEIL-ER3 (cross-linked polymer) has better corrosion inhibition performance as compared to the other studied samples. After assessment of the electrochemical investigation, the inhibitory action of PEIB-ER1, PEIB-ER2, PEIB-ER3, PEIL-ER1, PEIL-ER2, and PEIL-ER3 at 303 K was found to be approximately 68%, 79%, 89%, 72%, 84%, and 92%, respectively. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) revealed that the substrate coated with PEIL-ER3 showed less corroded surfaces as compared to the substrates coated with the other studied samples. Fourier Transform Infrared Spectroscopy-Attenuated Total Reflection (FTIR-ATR) investigated the surface characterization of the LCS. The obtained results verify the surface adsorption of the LCS by the studied cross-linked polymer materials.