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| Format: | Artículo científico |
| Language: | en |
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Sociedade Brasileira de Física
2004
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| Online Access: | https://www.redalyc.org/articulo.oa?id=46434110 |
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Table of Contents:
- Water at interfaces and its influence on the electrical properties of adsorbed films Osvaldo N. Oliveira Antonio Riul Vitor B. P. Leite Física, Astronomía y Matemáticas This paper discusses water at interfaces with emphasis on the electrical properties of adsorbed films. Two issuesare addressed, namely adsorption of organic molecules at the air/water interface in Langmuir monolayers andthe influence of adsorbed water on the electrical properties of nanostructured organic films deposited onto solidsubstrates. In Langmuir monolayers the focus will be on the interaction of the adsorbed molecules with theunderlying water, particularly with regard to the surface potential and lateral conductance of the monolayers.It will be shown that these electrical measurements are extremely sensitive to small changes in the subphase,including trace amounts of impurities. Phase transitions due to structuring of the monolayer will be discussedat the light of theoretical models that deal with proton transfer along the monolayers. Attempts will be made toconnect the interpretation at the molecular level with experimental findings from techniques such as Brewsterangle microscopy and fluorescence microscopy, which provide information at the mesoscopic or microscopicscale. The gradient of the dielectric constant for water at the monolayer interface is inferred from modeling themonolayer surface potential in terms of the dipole moments of the molecules. For deposited films, the discussionwill be centered on the electrical properties of nanostructured films produced with either the Langmuir-Blodgett(LB) or the layer-by-layer (LBL) methods. The strong effects from adsorbed water will be presented, withmention to sensor applications where the extreme sensitivity of the electrical properties to water is exploitedand to doping of a conducting polymer induced by X-ray irradiation. 2004 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46434110 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.1 Vol.34