The aim of the work discussed in this paper was to characterize adsorbed self-assembled monolayers on different metal oxide substrates with angle-resolved XPS measurements. The substrates used were silicon wafers (100) coated with 300 nm Al, Ta, or Ti. They were coated with acids by immersing them in an ethanol solution. The orientation of long-chain organic acids adsorbed on metal oxides has been successfully identified by angle-resolved XPS. On Al, Ta, and Ti substrates, C(11) chains are orientated in the right manner, i.e. with the phosphonic group at the bottom and the thiophene group on top. The orientations of the C(2) and C(6) chains are not clear. The thickness of the layers could be obtained by using Tougaard nanostructure analysis, and it shows monolayers. A model of the chemical bonds between the phosphonic group and the metal could be developed from the chemical shift. For titanium, all three P-O bonds bind to the metal substrate, whereas only the P-O(H) bond binds to the metal on aluminium and tantalum.
Aggregate formation of modified pyrroles was investigated in water and water/ethanol mixtures by means of light scattering for novel reactive single-chain alkyl phosphonate containing pyrrole units. The influence of concentration, pH, temperature and organic solvents on the evolution of the vesicle size is discussed. Longchain alkyl phosphonates functionalized with pyrrole units form stable vesicles in water solutions. Lowering of the pH value results in a partial protonation of the phosphonate groups and in less electrostatic repulsion between the anionic groups, leading to larger vesicle diameters and higher tendency to aggregate. Addition of ethanol, as well as increase in temperature cause an increase in the aggregate size due to better solubility of alkyl phosphonates. The reactive vesicles are extremely interesting templates for oxidative polymerisation of pyrrole and they can provide the formation of novel particles based on conjugated polymers. Koninklijke Brill NV, Leiden, 2008
A new class of compounds, !-(thiophen-3-yl) alkyl phosphonic acids, was used to link conductive polythiophene layers and several metal oxide substrates. In general, the adhesion between polythiophene lms and metal substrates is insuf cient for technical and microelectronic applications. The use of adhesion promoters between the substrate and the polymer enables the formation of a strongly bonded composite. Adhesive compounds were synthesized which contained a phosphonic acid group attached to the substrate and a thienyl group for surface polymerization with thiophene monomers. The properties of these created adhesion promoters were characterized on several substrates by contact angle measurements and IR investigations. First successful attempts were made to obtain a structured polymer surface via micro-contact printing.
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