New imidazolium ionic liquids as ecofriendly corrosion inhibitors for mild steel in hydrochloric acid (1 M): Experimental and theoretical approach

•Imidazolium ionic liquids [Imid-3PE] Br and [Imid-4PE] br were showing a good performance as corrosion inhibitors for mild steel.•A stable passive layer was formed on the mild steel surface.•[Imid-3PE] Br and [Imid-4PE] Br showed a good inhibition performance during the immersing time.•Molecular dynamics simulations were performed involving the experimental conditions.•The theoretical part was confirmed by the experimental findings.