Photochemical Covalent Attachment of Alkene-Derived Monolayers onto Hydroxyl-Terminated Silica

Abstract

The functionalization of optically transparent substrates is of importance, for example, in the field of biosensing. In this article, a new method for modification of silica surfaces is presented that is based on a photochemical reaction of terminal alkenes with the surface. This yields highly hydrophobic surfaces, which are thermally stable up to at least 400 degrees C. The formed monolayer provides chemical passivation of the underlying surface, according to studies showing successful blocking of platinum atomic layer deposition (ALD). The reaction is photochemically initiated, requiring light with a wavelength below 275 nm. X-ray photoelectron spectroscopy and infrared spectroscopy studies show that the alkenes initially bind to the surface hydroxyl groups in Markovnikov fashion. At prolonged reaction times (>5 h), however, oligomerization occurs, resulting in layer growth normal to the surface. The photochemical nature of the reaction enables the use of photolithography as a tool to constructively pattern silica surfaces. Atomic force microscopy shows that the features of the photomask are well transferred. The newly developed method can complement existing patterning methods on silica that are based on soft lithography.

Modular Functionalization of Electrodes by Cross‐Coupling Reactions at Their Surfaces

“…Chemically modified surfaces have been at the center of research interests in the past decades due their many applications in areas such as electrocatalysis,1, 2 corrosion protection,3 molecular electronics,4, 5 integrated circuits,6, 7 information storage,7, 8 and sensing 5, 9, 10…”

Local Probe Oxidation of Self-Assembled Monolayers on Hydrogen-Terminated Silicon

“…Local probe oxidation can, in principle, be used for site-selective surface modifications 4 to obtain surface functionalities that can otherwise only be obtained upon the patterned deposition of functionalized self-assembled monolayers (SAMs). 5,6 Such organic monolayers are usually used as resist materials in local probe oxidation experiments. 7,8 Sagiv and coworkers introduced the concept of electrooxidative patterning of the monolayer itself.…”

Biofunctionalization of a “Clickable” Organic Layer Photochemically Grafted on Titanium Substrates

“…27,33 To minimize the possible photochemical oxidation, this process was conducted in a N 2 glovebox. Successful modification of the Ti substrate was confirmed by analyzing the chemical composition, thickness, and wettability of the TMG-C10 grafted surfaces.…”

“…Similar results were reported for the photografting of alkenes on other hydroxyl-terminated substrates. 33,39 …”