title: Electrophoretic assembly of naturally occurring humic substances as thin films.
abstract: Polydisperse humic acid thin films on optically transparent electrodes (OTEs) have been prepared by electrophoretic deposition from a solution of Suwanee River humic acid (SHA) in ethanol/acetonitrile. The thickness of the film and the rate of deposition of SHA are dependent on the applied voltage and the concentration of the solution. Tapping-mode atomic force microscopy (TM-AFM) confirms the assembly of SHA aggregates on the electrode surface. The ability of these thin films to incorporate redox-active species such as ferrocene from solution is demonstrated by cyclic voltammetry experiments. A linear dependence of the peak current for the oxidation of ferrocene as a function of scan rate indicates that the ferrocene is incorporated into the humic membrane.
authors.affiliation: Department of Chemistry, Indiana University Northwest, Gary, Indiana 46408, USA. kvinod@iun.edu
authors.forename: K
authors.initials: K
authors.lastname: Vinodgopal
authors.forename: Vaidyanathan
authors.initials: V
authors.lastname: Subramanian
authors.forename: Sheila
authors.initials: S
authors.lastname: Carrasquillo
authors.forename: Prashant V
authors.initials: PV
authors.lastname: Kamat
mesh_terms: D004563:Electrochemistry; D004566:Electrodes; D004784:Environmental Monitoring; D006812:Humic Substances / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008962:Models, Theoretical; D055095:Optics and Photonics; D014867:Water / Q000737:chemistry
chemical_list: D006812:Humic Substances; D014867:Water