A Self-Cleaning Hydrophobic Polymeric Coating Material with Switchable Heavy Metal-Binding Ability

Abstract

Addressing rising environmental and technological challenges demand the development of innovative multifunctional polymeric coatings with integrated surface and chemical functionalities. In this study, a hydrophobic copolymer, poly(dodecyl acrylate-r-tert-butyl methacrylate) [poly(DA-r-TBMA)], was rationally designed and synthesized to have pronounced hydrophobicity and self-cleaning properties. Long dodecyl side chains and sterically bulky tert-butyl substituents work together to minimize surface free energy, resulting in a lotus leaf-like coating with high water contact angles and efficient surface pollutant removal by rolling water droplets. Poly(DA-r-TBMA) was converted into poly(DA-r-MAA) by selective acid-catalyzed hydrolysis of the tert-butyl ester groups. This post-polymerization modification adds dangling carboxylic acid functionalities to the polymer backbone, boosting its attraction to dangerous heavy metal ions like Pb2+ and Cd2+ via coordination and electrostatic interactions. As a result, the pristine copolymer serves as a long-lasting self-cleaning protective layer, while its hydrolyzed derivative functions as an effective heavy metal-binding agent. Overall, this work provides a sustainable polymer design technique that can be used for both environmental cleanup and surface protection.