18-Mercaptooctadecanoic acid is widely used in the field of surface modification and nanotechnology. Its thiol group allows it to form strong bonds with gold and other metals, making it valuable for creating self-assembled monolayers (SAMs) on surfaces. These SAMs are utilized in biosensors to enhance sensitivity and specificity for detecting biomolecules. Additionally, it is employed in the development of functionalized nanoparticles for targeted drug delivery, where its long alkyl chain and carboxylic acid group facilitate the attachment of therapeutic agents. In material science, it is used to modify the surface properties of materials, improving their compatibility with other substances or enhancing their performance in specific applications. Its role in creating ordered molecular structures also makes it useful in the fabrication of electronic devices and coatings with tailored properties.