Langmuir-Blodgett (LB) monomolecular layers of alkylhydroxamic acids and alkylphosphonic acids on copper and iron substrates have been studied by X-ray photoelectron spectroscopy (XPS) and sum-frequency vibrational spectroscopy. According to the XPS results, the structures of the hydroxamic acid and phosphonic acid Langmuir-Blodgett films are very similar: the thickness of the layer of the hydrocarbon tails is typically 1.9-2.1 nm, while the layer of headgroups is about 0.3-0.35 nm thick. The tilt angle of the carbon chains is estimated to be 20-30 degrees with respect to the sample surface normal, and the molecules are connected to the substrate via their headgroups. Analysis of the P 2p and N 1s lines indicates the presence of deprotonated headgroups. The substrate Cu 2p line includes a component which can be assigned to Cu(2+) ions in a thin Cu(OH)(2) layer. The deposition of LB layers led to significant decrease of the hydroxide-related signal, which indicates that binding of the headgroups to the surface is accompanied by the elimination of water molecules. The sum-frequency spectra also clearly indicate that well-ordered monolayers can be formed by the Langmuir-Blodgett technique. Since the non-resonant background from the metal substrates renders the analysis of the spectra more difficult, model system samples on glass were prepared. It was found that the alkyl chains of the adsorbed acids predominantly adopt the all-trans conformation and form an ordered structure. Upper limits for the mean tilt angle of the terminal methyl groups are approximately 10-20 degrees.

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Protective nanolayers of alkyl hydroxamic acids deposited on a copper surface as a Langmuir -Blodgett lm (LB) or as a self assembled molecular layer (SAM) were studied in acidic and neutral sodium chloride and sodium sulphate solutions. The LB lm deposition and SAM formation on copper substrate were followed by a surface visualisation technique and by contact angle measurement. Following exposure to aggressive electrolytes the anticorrosion abilities of the monolayers and multilayers were characterised by image analysis, by the roughness of the copper surface, and by an electrochemical method.CEST/2120

Langmuir-Blodgett (LB) nanolayers of alkyl hydroxamic and phosphonic acids on glass, iron and copper surfaces were studied in the presence of different, corrosion relevant micro-organisms. The quality of monomolecular and multimolecular LB layers was characterised by dynamic contact angle measurement, atomic force microscopy and the sum frequency vibration technique. The inhibition efficiency of microbial adhesion and biofilm formation, which was analysed by the surface visualising technique, epifluorescence microscopy and microbiological methods, increased with layer thickness. There were some differences in the blocking activity of the two amphiphiles (octadecylphosphonic acid C18P and octadecanoyl hydroxamic acid C18N) applied in LB films. Their repellent activity did not differ in cooling water but, in the presence of Acidithiobacillus ferrooxidans, the C18N nanolayer inhibited the biofilm formation much better.

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