dc.description.abstract |
[eng] 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−visinactive 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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