Novel carboxylic functionalized ionic liquid grafted on carbonized polymer dots as highly efficient corrosion inhibitors

A one-step hydrothermal synthesis of ionic liquid grafted carbonized polymer dots (CPDs) from l-cysteine and carboxylic acid functionalized ionic liquid is presented. The obtained CPDs have been characterized by various methods, found multiples functional groups have been detected on the CPD surfaces from FT-IR and XPS and ¹³C NMR, and ionic liquid serves as both the reaction medium and the reaction precursor for the grafting, endows a charged surface and can prevent the aggregation of carbon dots, whose sizes are around 100 nm from HRTEM. The CPDs exhibit excellent corrosion inhibition efficiency of 94.07 % to carbon steel at 50 mg·L^-1 in 0.5 mol·L^-1 H₂SO₄ solution, and low surface roughness can be observed on the inhibited steel surface by SEM, and a mixed adsorption of CPD on steel surface, including chemisorption and physisorption, can be demonstrated by XPS, and finally molecular dynamic study shows that the parallel adsorption mode is preferred to ensure nice inhibiting efficiency. This work provides a promising preparation strategy for CPDs, with ionic liquid grafted, for effective corrosion inhibition. which ensures multiple surface adsorption sites.