Atom transfer radical polymerization (ATRP) is a technique for synthesizing polymers with well-defined structures and controlled molecular weights. It involves the addition of a small amount of a catalyst to a mixture of monomers, initiators, and solvents, which then enables the controlled growth of polymers. ATRP has become a widely used method in polymer synthesis due to its ability to produce polymers with specific properties and functionalities. This research area has applications in various fields including materials science, biomedicine, and nanotechnology.