Passivation of aluminum with alkyl phosphonic acids for biochip applications

Attavar, Sachin; Diwekar, Mohit; Linford, Matthew R.; Davis, Mark; Blair, Steve

doi:10.1016/j.apsusc.2010.05.041

Cited by 40 publications

(29 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The first is present in the two samples that had not ‘seen’ the F plasma: the Al‐0s and NP‐0s samples. These two spectra show a peak at approximately 75.7 eV, which is known in the literature to correspond to the oxidized aluminum in aluminum oxide . The similarity of the spectra of these two samples implies that deposition of NP does not substantially perturb the aluminum substrate.…”

Section: Resultsmentioning

confidence: 61%

“…Here, we report an XPS and ToF‐SIMS analysis of untreated and NP‐coated aluminum surfaces that were exposed for different amounts of time to the products of a fluoroalkane + oxygen plasma. As noted, NP adsorbs to native aluminum oxide through its phosphonate groups to form a corrosion inhibiting layer . XPS was of central importance in this work because (i) it is nondestructive in nature, (ii) its data interpretation is relatively straightforward, (iii) it gives quantitative compositions from the upper approximately 10 nm of materials, and (iv) it informs regarding the chemical environment (oxidation states) of elements vis‐à‐vis chemical shifts .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fluorine plasma treatment of bare and nitrilotris(methylene)triphosphonic acid (NP) protected aluminum: an XPS and ToF-SIMS study

Madaan

Diwan

Linford

2014

Surf. Interface Anal.

Self Cite

View full text Add to dashboard Cite

Nitrilotris(methylene)triphosphonic acid (NP) is a technologically important molecule that has been used for years as a corrosion inhibitor and/or adhesion promoter on aluminum and other metal surfaces. However, to the best of our knowledge, the detailed surface characterization of NP adsorbed on aluminum, or on any other surface, has not been reported. Herein, we report an X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of a series of untreated and NP-coated aluminum substrates that were exposed to the downstream products of a fluoroalkane + oxygen plasma for different amounts of time (from 0 to 20 s). As indicated by P 2p, N 1s, Al 2p, O 1s, and F 1s narrow scans, even a 4-s plasma treatment significantly damages the NP protective layer and converts the native aluminum oxide into aluminum oxyfluoride. Heat treatment of the fluorine plasma-treated samples in the air substantially converts the aluminum oxyfluoride back to aluminum oxide, while similar heating under vacuum results in little change to the materials. A slow loss of fluorine from the samples occurs over the course of weeks when they are stored in the air. A ToF-SIMS analysis reveals sets of signals that are consistent with no surface treatment, NP treatment, or fluorine plasma treatment. A principal component analysis of the negative ion ToF-SIMS spectra from the samples shows the expected differentiation of the samples.

show abstract

Section: Resultsmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Fluorine plasma treatment of bare and nitrilotris(methylene)triphosphonic acid (NP) protected aluminum: an XPS and ToF-SIMS study

Madaan

Diwan

Linford

2014

Surf. Interface Anal.

Self Cite

View full text Add to dashboard Cite

show abstract

“…It was reported that an anodized aluminum surface coated with fluorinated alkyl phosphonic acids showed higher contact angles for water and organic liquids in comparison with the alkylsilanes with the same alkyl groups, although the reason was not clarified . Although there are some advantages of phosphonic acids for formation of SAMs on aluminum and several studies on phosphonic acid‐based SAMs on aluminum have been carried out, the formation of SAMs has not been fully understood. Recent in situ analysis revealed island growth of phosphonic acid molecules on aluminum oxide, suggesting that a monolayer is not always formed.…”

Section: Introductionmentioning

confidence: 99%

Observation of self‐assembled layers of alkyl phosphonic acid on aluminum using low‐voltage scanning electron microscopy and AFM

Sato

Fujii

Tsuji

et al. 2013

Surface & Interface Analysis

View full text Add to dashboard Cite

Self-assembled alkyl phosphate layers have been formed on a flat, anodized aluminum substrate in dilute ethanol solution containing 2 wt% n-tetradecylphosphonic acid (TDP) and examined by low-voltage scanning electron microscopy as well as atomic force microscopy and X-ray photoelectron spectroscopy. Locally, multi-layered alkyl phosphate films have been formed on aluminum, being clearly observed by a low-voltage scanning electron microscope operated at less than 1 kV. Atomic force microscopy observations disclosed that bilayers of tetradecylphosphonic acid are stacked on the substrate to form multilayers. The present study revealed that the uniform self-organized monolayer is not always formed readily on an oxidized aluminum surface.

show abstract

“…Self‐assembled monolayers (SAMs) have numerous applications, including for surface passivation, biological sensors, electronic devices, and lubrication . Some of the most studied SAM components include the silanes, which effectively bind to silica surfaces, the alkanethiols, which form monolayers on gold, alkanes and alkenes, which bind to hydrogen‐terminated and scribed (bare) silicon, and the phosphonic acids, which adhere well to metal oxides, including alumina, iron oxide, tantalum oxide, silicon oxide, copper oxide, titania, zirconia, niobium oxide, and indium tin oxide . Phosphonates form the most densely packed monolayers on alumina reported .…”

Section: Introductionmentioning

confidence: 99%

Layer‐by‐layer deposition of nitrilotris(methylene)triphosphonic acid and Zr(IV): an XPS, ToF‐SIMS, ellipsometry, and AFM study

Diwan

Singh

Hurley

et al. 2015

Surface & Interface Analysis

Self Cite

View full text Add to dashboard Cite

Layer-by-layer assemblies consisting of alternating layers of nitrilotris(methylene)triphosphonic acid (NTMP), a polyfunctional corrosion inhibitor, and zirconium(IV) were prepared on alumina. In particular, a nine-layer (NTMP/Zr(IV)) 4 NTMP stack could be constructed at room temperature, which showed a steady increase in film thickness throughout its growth by spectroscopic ellipsometry up to a final thickness of 1.79 ± 0.04 nm. At higher temperature (70°C), even a two-layer NTMP/Zr(IV) assembly could not be prepared because of etching of the alumina substrate by the heated Zr(IV) solution. XPS characterization of the layer-bylayer assembly showed a saw tooth pattern in the nitrogen, phosphorus, and zirconium signals, where the modest increases and decreases in these signals corresponded to the expected deposition and perhaps removal of NTMP and Zr(IV). Time-of-flight secondary ion mass spectrometry (ToF-SIMS) confirmed the attachment of the NTMP molecule to the surface through PO À , PO 2 À , PO 3 À , and CN À signals. Increasing attenuation of the Al signal from the substrate after deposition of each layer was observed by both XPS and ToF-SIMS. Essentially complete etching of the alumina by the heated Zr(IV) solution was confirmed by spectroscopic ellipsometry, XPS, and ToF-SIMS. Atomic force microscopy revealed that all the films were smooth with R q roughness values less than 0.5 nm.

show abstract

Passivation of aluminum with alkyl phosphonic acids for biochip applications

Cited by 40 publications

References 31 publications

Fluorine plasma treatment of bare and nitrilotris(methylene)triphosphonic acid (NP) protected aluminum: an XPS and ToF-SIMS study

Fluorine plasma treatment of bare and nitrilotris(methylene)triphosphonic acid (NP) protected aluminum: an XPS and ToF-SIMS study

Observation of self‐assembled layers of alkyl phosphonic acid on aluminum using low‐voltage scanning electron microscopy and AFM

Layer‐by‐layer deposition of nitrilotris(methylene)triphosphonic acid and Zr(IV): an XPS, ToF‐SIMS, ellipsometry, and AFM study

Contact Info

Product

Resources

About