Ozonolysis Is the Primary Cause of UV Photooxidation of Alkanethiolate Monolayers at Low Irradiance

Zhang, Yumo; Terrill, Roger H.; Tanzer, T. A.; Bohn, Paul W.

doi:10.1021/ja9714853

Cited by 110 publications

(143 citation statements)

References 28 publications

Supporting

Mentioning

134

Contrasting

Unclassified

Order By: Relevance

“…This stands in contrast to the degradation mode of alkanethiol SAMs, where the degradation initiates preferentially at the defect sites and oxidation of headgroups produce large amount of solvent-labile species that remain on the surface. 3 All these results suggest that the headgroups in alkylsiloxane SAMs have negligible reactivity. The difference can be explained by the different chemical reactivity of the two systems.…”

Section: Active Agentsmentioning

confidence: 94%

“…The contact angle measurements indicate that the hydrophobic CH 3 and CH 2 groups (contact angle ∼ 110°) are converted to hydrophilic groups such as CHO, OH, and COOH (contact angle ∼ 0°6 8 ) during degradation (Figure 2). However, even after 30 min of degradation, when half of the CH 2 groups are lost, according to FTIR (Figure 4), the contact angle still has not dropped to zero.…”

Section: Preferential Reactive Sites In the Ch Chainsmentioning

confidence: 99%

“…3 The reactivity of alkanethiol SAMs has been attributed to the thiolate headgroups, which are prone to oxidation. 3 Even the alkyl chains can degrade under harsh conditions, e.g., under photo or electron irradiation. [4][5][6] Knowledge of SAM photoreactivity may help to design and prepare more stable SAMs for technological applications.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mechanism of UV Photoreactivity of Alkylsiloxane Self-Assembled Monolayers

McArthur

Borguet

2005

J. Phys. Chem. B

View full text Add to dashboard Cite

A molecular level understanding of the photoreactivity of self-assembled monolayers (SAMs) becomes increasingly important as the spatial resolution starts to be limited by the size of the resist and the spatial extent of the photochemical reactions in photoresist micropatterning. To this end, a number of surface characterization techniques were combined to understand the reactive agents, reactive sites, kinetics, and reaction pathways in the UV photoreactivity of octadecylsiloxane (ODS) SAMs. Quantitative analysis of our results provides evidence that ground state atomic oxygen is the primary reactive agent for the UV degradation of ODS SAMs. UV degradation, which follows zero-order kinetics, results in the scission of alkyl chains instead of the siloxane headgroups. Our results suggest that the top of the ODS SAMs is the preferential reactive site. Using a novel, highly surface sensitive technique, fluorescence labeling of surface species, we identified the presence of submonolayer quantities chemical functional groups formed by the UV degradation. These groups are intermediates in a proposed mechanism based on hydrogen abstraction.

show abstract

Section: Active Agentsmentioning

confidence: 94%

Section: Preferential Reactive Sites In the Ch Chainsmentioning

confidence: 99%

See 1 more Smart Citation

Mechanism of UV Photoreactivity of Alkylsiloxane Self-Assembled Monolayers

McArthur

Borguet

2005

J. Phys. Chem. B

View full text Add to dashboard Cite

show abstract

“…The SAM can separate the analyte of interest from interfering analytes and bring it closer to the nanostructured surface, analogous to the use of a stationary phase in high-performance liquid chromatography. Although SAMs have been useful for many applications, thermal desorption (70,71) and photooxidation (72)(73)(74) can result in defects in the coatings and thermodynamically unstable substrates (75).…”

Section: Surface-enhanced Raman Spectroscopy Sensingmentioning

confidence: 99%

Surface-Enhanced Raman Spectroscopy

Stiles

Dieringer

Shah

et al. 2008

Annual Rev. Anal. Chem.

2,801

2,323

View full text Add to dashboard Cite

The ability to control the size, shape, and material of a surface has reinvigorated the field of surface-enhanced Raman spectroscopy (SERS). Because excitation of the localized surface plasmon resonance of a nanostructured surface or nanoparticle lies at the heart of SERS, the ability to reliably control the surface characteristics has taken SERS from an interesting surface phenomenon to a rapidly developing analytical tool. This article first explains many fundamental features of SERS and then describes the use of nanosphere lithography for the fabrication of highly reproducible and robust SERS substrates. In particular, we review metal film over nanosphere surfaces as excellent candidates for several experiments that were once impossible with more primitive SERS substrates (e.g., metal island films). The article also describes progress in applying SERS to the detection of chemical warfare agents and several biological molecules. 601

show abstract

“…Zhang et al have shown that ultraviolet (UV) irradiation also results in the formation of sulphonates on the surface, the oxidation product of the sulphur end of the thiol [122]. The extent of oxidation is dependent on the alkane chain length, the shorter-chain alkanethiols being oxidized more rapidly.…”

Section: Stability Of the Monolayermentioning

confidence: 99%