Chemical modification of gold surface via UV-generated aryl radicals derived 3,5-bis(trifluoromethyl)phenyl)iodonium salt

Abstract

In recent years, iodonium salts emerged as a unique novel class of compounds for surface modification by electrografting. Herein, we demonstrated that 3,5-bis(trifluoromethyl)phenyl)iodonium salt (IS-(CF3)2) can be applied for the modification of surfaces via generation of aryl radicals through activation by UV light, without the addition of any photoinitiators. The thickness of the organic layer was found to be close to the size of an organic radical. The as-prepared structures were characterized by XPS, wettability, Raman spectroscopy and AFM measurements. The formation of close to monomolecular layer on the surface was proved by three independent methods (AFM, XPS, and ellipsometry). UV-generated aryl radicals can also be used for simple one-step surface patterning with organic functional groups. In our contribution, we developed a convenient and easy-to-handle approach for the grafting of modified patterns. The application of IS-(CF3)2 allows controlling the distribution of surface-modified area via the application of the lithographic mask. The proposed strategy offers advantages such as strong covalent bonding of aryl radical, easiness of experimental procedure in combination with the possibility to control surface architecture.