Surfacefunctionalized

Surface-functionalized materials refer to surfaces whose chemistry has been deliberately modified to introduce functional groups, ligands, or reactive sites, while largely preserving bulk properties. The goal is to tailor interactions with surrounding media, enhance compatibility, or enable specific binding and catalysis. Functionalized surfaces can be modified covalently or through non-covalent interactions.

Common approaches include covalent attachment, surface grafting, and the formation of self-assembled monolayers. Silanization on oxide surfaces introduces organosilane groups; thiol-based self-assembled monolayers form on gold; and click chemistry provides selective, modular conjugation. Plasma or UV-ozone treatments can generate reactive groups for subsequent modification. Surface-initiated polymerization yields grafted polymers that alter steric, chemical, or wetting properties.

Materials that are frequently functionalized include silica, alumina, metals, polymers, carbon nanotubes, and graphene. Functional groups introduced span amine, carboxyl, hydroxyl, aldehyde, and hydrophobic moieties; ligands for bioconjugation (NHS esters, maleimide, biotin) enable selective binding of biomolecules or catalysts.

Characterization techniques such as X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR), contact angle measurements, atomic force microscopy (AFM), and ellipsometry verify surface composition, chemistry, and thickness. Applications cover biomedical implants and sensors, antifouling coatings, catalysis, and energy storage, where surface functionality improves biocompatibility, selectivity, or charge transfer.

Challenges include achieving uniform, scalable modification, ensuring long-term stability, avoiding unintended bulk changes, and addressing potential toxicity or environmental impact.