Characterization of self-assembled carboxylate monolayers and multilayers at copper and silver.

摘要

A variety of chemically modified surfaces were constructed by the self-assembly method via chemisorption onto evaporated metal films. Monolayer films, self-assembled from solution, include n-alkanoic acids, CH(sub 3)(CH(sub 2))(sub n)COOH, and n-perfluoroalkanoic acids, CF(sub 3)(CF(sub 2))(sub n)COOH, on copper, and n-alkanethiolates, C(sub H)3(CH(sub 2))(sub n)SH on copper. Monolayer films were obtained from the gas phase, a newly developed technique, for n-alkanoic acids on silver, and n-alkanethiolates on silver and gold. Multilayer films obtained by self-assembly from the gas phase include n-alkanoic acids at copper and silver and perfluoroacids at copper. Carboxylic acid terminated interfaces were formed by the self-assembly of the bifunctional mercaptoacids, HS(CH(sub 2))(sub n)COOH, via the thiol moiety, at gold. These interfaces were derivatised with copper by deposition of a thin metal overlayer. The monolayer and multilayer films were characterized by optical ellipsometry, contact angle measurements, atomic force and scanning tunneling microscopies, and infrared reflection spectroscopy. Comparisons were made to properties of analogous bulk compounds. These techniques were, used to determine the properties of these films such as composition, orientation, defectiveness, molecular ordering and environment, and hydrophobicity and reactivity.