Lateral proton diffusion rates along stearic acid monolayers
UNSPECIFIED (2000) Lateral proton diffusion rates along stearic acid monolayers. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 122 (11). pp. 2597-2602. ISSN 0002-7863Full text not available from this repository.
Proton in-plane lateral diffusion rates in Langmuir monolayers have been measured as a function of surface coverage, with a sensitivity not possible previously, using scanning electrochemical microscopy (SECM) operating in the induced desorption mode. With this approach an acidic monolayer, spread at the air/water interface, is deprotonated locally, by reducing protons in solution to hydrogen at an ultramicroelectrode probe, which drives the acid dissociation reaction. In turn, this creates a proton diffusion gradient in the solution and at the interface, and the transport-limited current flowing at the electrode provides a measure of the rates of diffusion in these two environments. Measurements on stearic acid monolayers at the air/water interface clearly show that in-plane lateral proton diffusion occurs, but the diffusion coefficient depends critically on the physical state of the monolayer, and is at most only ca. 15% of the magnitude in bulk solution.
|Item Type:||Journal Article|
|Subjects:||Q Science > QD Chemistry|
|Journal or Publication Title:||JOURNAL OF THE AMERICAN CHEMICAL SOCIETY|
|Publisher:||AMER CHEMICAL SOC|
|Date:||22 March 2000|
|Number of Pages:||6|
|Page Range:||pp. 2597-2602|
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