11-Phosphonoundecanoic acid is primarily used in surface modification and material science applications. It is often employed as a functionalizing agent to create self-assembled monolayers (SAMs) on metal oxides, particularly for improving the adhesion and corrosion resistance of coatings. This compound is also utilized in the development of biocompatible surfaces for medical devices, where its phosphonic acid group enables strong binding to metal surfaces while the long carbon chain provides hydrophobic properties. Additionally, it finds use in the preparation of advanced materials, such as nanoparticles and nanocomposites, where it acts as a stabilizer or linker to enhance material performance. Its ability to form stable bonds with surfaces makes it valuable in catalysis and sensor technology as well.