Arsonic Acid Self‐Assembled Monolayers Protect Oxide Surfaces from Micronewton Nanomechanical Forces

Abstract

The development of new surface coatings is critical for combating wear and increasing the device lifetime in microelectromechanical systems (MEMS). Here, a class of arsonic acid self‐assembled monolayers (SAMs) is reported that form readily on oxide substrates including silicon oxide, borosilicate glass, and titanium oxide. Monolayers are easily prepared using a straightforward soaking technique, which is amenable to large‐scale commercial applications. Monolayer formation on borosilicate glass and titanium oxide is characterized using infrared spectroscopy. Monolayers on borosilicate glass, native silicon oxide and titanium oxide are evaluated with contact angle measurements, as well as wear measurements using nanoscratching experiments. On titanium oxide and borosilicate glass, monolayers prepared from hexadecylarsonic acid provide significantly greater surface protection than surfaces reacted under similar conditions with hexadecylphosphonic acid, a common modifying agent for oxide substrates.

Local Light-Induced Modification of the Inside of Microfluidic Glass Chips

“…Conversely, photolithographic methods rely on and are limited so far by the absorption of light by both the glass and the reagents. As a result, commonly used glass modification chemistries such as silane-, phosphonic acid-, arsonic acid-, and catechol-based approaches do not allow the local modification of discrete areas with fine details or unusual geometries on the inside of a glass microchannel by means of single-step photolithography . In contrast, the photochemical attachment of alkenes has allowed the local formation of densely packed, stable organic monolayers with reactive functional groups on exposed surfaces. , Because the reaction is photochemical in nature, it enables local modification of the inside of a glass microchannel and, for example, the subsequent local attachment of fragile, biologically active materials, such as DNA–enzyme hybrids.…”

Organic Arsenicals as Functional Motifs in Polymer and Biomaterials Science

“…Organic arsenicals with a single arsonic acid group have been employed as surface active ligands for the formation of 2D self‐assembled monolayers (SAMs), and for the 3D modification of the Fe 3 O 4 nanoparticles . Alkyl arsonic acids have been shown to be versatile and robust ligands for the formation of SAMs at oxide surfaces including titanium oxide and silicon oxide . The alkyl arsonates were more reactive than the related alkyl phosphonates, which was exemplified by the formation of alkyl arsonate SAMs at the surface of borosilicate glass which was not possible with alkyl phosphonates.…”

“…Likewise, inorganic metal-AsO n @SiO 2 composite nanoparticles have been developed for improved cellular uptake and pH-dependent release of therapeutic As 2 O 3 . [112][113][114] Organic arsenicals with a single arsonic acid group have been employed as surface active ligands for the formation of 2D self-assembled monolayers (SAMs), [115] and for the 3D modification of the Fe 3 O 4 nanoparticles. [116] Alkyl arsonic acids have been shown to be versatile and robust ligands for the formation of SAMs at oxide surfaces including titanium oxide and silicon oxide.…”

“…[116] Alkyl arsonic acids have been shown to be versatile and robust ligands for the formation of SAMs at oxide surfaces including titanium oxide and silicon oxide. [115] The alkyl arsonates were more reactive than the related alkyl phosphonates, which was exemplified by the formation of alkyl arsonate SAMs at the surface of borosilicate glass which was not possible with alkyl phosphonates. SAMs were characterized by drop-shape analysis (water contact angle), Fourier-transform infrared spectroscopy (FT-IR), and nanoscratching measurements to determine small-scale mechanical properties.…”

Mild Photochemical Biofunctionalization of Glass Microchannels

“…The localized functionalization of silicon oxide and glass surfaces with organic functional molecules is crucial for a wide range of advanced applications of glass-based biohybrid materials. − Most surface modifications on glass make use of silane chemistry, − although other molecule-to-surface linkages such as phosphonic acid, arsonic acid, and catechol-based have also been used. While these oxygen-based anchor groups have proven their value for thermal anchoring reactions, they are incompatible with single-step photolithographic patterning.…”