Ordered Nanostructures on a Hydroxylated Aluminum Surface through the Self-Assembly of Fatty Acids

Liaščukienė, Irma; Aissaoui, Nesrine; Asadauskas, Svajus; Landoulsi, Jessem; Lambert, Jean-François

doi:10.1021/la2051542

Cited by 26 publications

(36 citation statements)

References 47 publications

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“…much higher than that of IRO without AW additives. The likely explanation could be that the lack of chemical inertness in IRO (whose ester linkages easily decompose upon exposure to metal oxides even without any tribochemical influence), its increased polarity and possibly the factors discussed elsewhere interfered with some of the processes needed for ZDDP to generate durable tribofilms …”

Section: Resultsmentioning

confidence: 99%

Tribological effects of Cu, Fe and Zn nano-particles, suspended in mineral and bio-based oils

et al. 2015

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Many studies focus on nanoparticles as lubricity additives but overlook the fact that wear produces nanosized debris during the field use. In order to simulate the fine metal contaminants, which are the most widespread in various field applications, prefabricated Fe, Cu and Zn nanoparticles were used. Their 0.01–1% suspensions in vegetable and mineral oils with or without ZDDP and ashless AW package were tested on four‐ball AW under 150‐N load. Tribological effects of nanoparticles were not significant in formulations without AW additives. However, nanoFe addition produced notable lubricity improvement in already excellently performing rapeseed formulation with ZDDP, while such addition reduced performance of the ashless AW pack. Results show that metal nanoparticles can play both positive and negative roles on additive effectiveness and nanosized contaminants can significantly affect the lubricant performance. Copyright © 2015 John Wiley & Sons, Ltd.

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Section: Resultsmentioning

confidence: 99%

Tribological effects of Cu, Fe and Zn nano-particles, suspended in mineral and bio-based oils

et al. 2015

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“…32 This process produces an aluminum oxyhydroxide (with a pseudoboehmite structure) 36,37 thin film on the surface, enabling the substrate to be used in adsorption experiments. 32 The coordination of carboxylic acids to alumina derivatives is well-known, 42−46 and we expected that squaramic derivatives could coordinate pseudo-boehmite interfaces in a similar mode. The activated substrates were subsequently treated with the selected squaramic acid 1–4 suspended in heptane (see Experimental Section).…”

Section: Resultsmentioning

confidence: 99%

“…The aluminum substrates were activated following a previously described methodology. 32 The square (1 × 1 cm) plates were polished via an electrolytic process by using a TenuPol-5 (Struers) apparatus [5 °C, 40 V, HClO 4 (60%)]. The disklike (2.5 cm 2 ) plates were mechanically polished by using successively SiC paper (#600 and #1200 grain size) and diamond particle suspensions (3 and 1 μm, Buehler).…”

Section: Methodsmentioning

confidence: 99%

Surface Modification of Pseudoboehmite-Coated Aluminum Plates with Squaramic Acid Amphiphiles

et al. 2019

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The functionalization of interfaces has become very important for the protection or modification of metal (metal oxides) surfaces. The functionalization of aluminum is particularly interesting because of its relevance in fabricating components for electronic devices. In this work, the utilization of squaramic acids for the functionalization of aluminum substrates is reported for the first time. The physicochemical properties of the interfaces rendered by n-alkyl squaramic acids on aluminum metal substrates coated with pseudoboehmite [Al(O)x(OH)y] layers are characterized by contact angle, grazing-angle Fourier-transform infrared spectroscopy, atomic force microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and matrix-assisted laser desorption ionization time-of-flight. Moreover, we could confirm the squaramic functionalization of the substrates by diffuse reflectance UV–vis spectroscopy, which cannot be used for the characterization of UV–vis-inactive substrates such as carboxylates and phosphonates, commonly used for coating metallic surfaces. Remarkably, the results of sorption experiments indicate that long-chain alkyl squaramic acid desorbs from activated-aluminum substrates at a reduced rate compared to palmitic acid, a carboxylic acid frequently used for the functionalization of metal oxide surfaces. Theoretical calculations indicate that the improved anchoring properties of squaramic acids over carboxylates are probably due to the formation of additional hydrogen bonding interactions on the interface. Accordingly, we propose N-alkyl squaramic acids as new moieties for efficient functionalization of metal oxides.

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“…43 Recently, this protocol has been used to investigate the mechanism of self-assembly of fatty acids on an Al oxy-hydroxide surface. 44 After surface polishing and prior to the hydroxylation treatment, surface characterization, based on PM-IRRAS analysis, revealed the dominating presence of a band at about 950 cm À1 (Fig. S1a, ESI †), which can be attributed to the Al-O-Al stretching vibration of the amorphous aluminum oxide layer.…”

Section: Nanoscale Organization Of the Al Oxide Layermentioning

confidence: 99%

Direct AFM force mapping of surface nanoscale organization and protein adsorption on an aluminum substrate

Landoulsi

Duprès

2013

Phys. Chem. Chem. Phys.

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We investigate the nanoscale organization of a superficially hydroxylated Al substrate and its effect on subsequent protein adsorption using atomic force microscopy (AFM). For this purpose we used a mode which allows a direct mapping of a variety of surface properties (adhesion, elasticity, dissipation, etc.) to be probed simultaneously with topographical images. The hydroxylation treatment leads to a drastic modification of the surface morphology, owing to the formation of AlOOH compounds. In air, AFM images revealed the formation of regular nanorod-like structures randomly distributed, inducing the appearance of nanoporous domains on the surface. In buffer solution, prior to the adsorption of proteins, the surface nanoscale organization is preserved, mainly due to the chemical stability of AlOOH compounds under these conditions. The adsorption of proteins on the obtained nanostructured surface was performed using either a globular (β-lactoglobulin) or a fibrillar (collagen) protein and by modulating the adsorbed amount through the incubation time or the concentration of proteins in solution. At low amounts, collagen adsorbs on the whole surface without preferential localization. The surface topography remains similar to the bare surface, while significant changes were evidenced on adhesion and elasticity maps. This is due to the fact that the surface became adhesive and less stiff, owing to the presence of a soft and hydrated protein layer. By contrast, β-lactoglobulin tends to diffuse into the nanoporous domains, leading to their filling up, and the surface is blurred with a thick and dense protein layer upon increasing the amount of adsorbed molecules. Our findings demonstrate the interest in using AFM for surface mapping to investigate the mechanism of protein adsorption at the nanoscale on materials with high surface roughness.

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Ordered Nanostructures on a Hydroxylated Aluminum Surface through the Self-Assembly of Fatty Acids

Cited by 26 publications

References 47 publications

Tribological effects of Cu, Fe and Zn nano-particles, suspended in mineral and bio-based oils

Tribological effects of Cu, Fe and Zn nano-particles, suspended in mineral and bio-based oils

Surface Modification of Pseudoboehmite-Coated Aluminum Plates with Squaramic Acid Amphiphiles

Direct AFM force mapping of surface nanoscale organization and protein adsorption on an aluminum substrate

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