%0 Journal Article %J Adv. Mater. (Weinheim, Ger.)Advanced Materials (Weinheim, Germany) %D 1999 %T Electrodeposition of methylated sol-gel films on conducting surfaces. %A Shacham, Ronen %A Avnir, David %A Mandler, Daniel. %K indium tin oxide electrodeposition methylated polysiloxane sol gel film %K methylated polysiloxane sol gel film electrodeposition ITO gold surface %X An approach to sol-gel film formation is described, involving electrochem. control of pH near a conductive surface, in which methyltrimethoxysilane (MeTMOS) is deposited onto indium tin oxide (ITO) and Au surfaces. The method is based on a 2-step sol-gel prepn. procedure in which MeTMOS is first pre-hydrolyzed and then polycondensed. A const. neg. potential is applied to the electrode surface, increasing the concn. of hydroxyl ions, which act as a catalyst in the condensation process. This results in greater control over the deposition process and thus over film properties. [on SciFinder(R)] %B Adv. Mater. (Weinheim, Ger.)Advanced Materials (Weinheim, Germany) %I Wiley-VCH Verlag GmbH %V 11 %P 384 - 388 %8 1999/// %@ 0935-9648 %G eng %N 5 %0 Journal Article %J J. Phys. Chem. BJournal of Physical Chemistry B %D 1999 %T Studying Heterogeneous Catalysis by the Scanning Electrochemical Microscope (SECM): The Reduction of Protons by Methyl Viologen Catalyzed by a Platinum Surface. %A Selzer, Yoram %A Turyan, Iva %A Mandler, Daniel. %K catalysis SCEM redn proton electrogenerated methylviologen cation radical platinum %K hydrogen ion redn electrogenerated methylviologen cation radical platinum %K microscopy electrochem scanning heterogeneous catalysis hydrogen ion redn %X The feedback mode of the scanning electrochem. microscope (SECM) was used for studying a surface-catalyzed electron-transfer reaction. As a model system the authors examd. the redn. of protons by reduced N,N'-dimethyl-4,4'-bipyridinium, methylviologen radical cation, MV+•, catalyzed by a platinum surface. The exptl. configuration comprises a biased amalgamated Au ultramicroelectrode (UME) that approaches an unbiased Pt UME substrate of the same radius. MV+• that is electrochem. generated at the amalgamated UME is oxidized at the Pt surface as a result of reducing protons. This novel configuration permits the simultaneous measurement of the catalytic current and the mixed potential (open-circuit potential) attained at the Pt surface. The results are interpreted by an electrochem. model which was previously suggested; however, the authors' approach makes it possible to measure, for the 1st time, the current-potential relation predicted by the theory. The authors' results indicate that methylviologen behaves reversibly under all the exptl. conditions, and that the rate const. of hydrogen evolution, that is calcd., is in perfect agreement with previous reports. The significant advantages of the authors' approach are discussed as well as its applicability for studying other electrochem. systems. [on SciFinder(R)] %B J. Phys. Chem. BJournal of Physical Chemistry B %I American Chemical Society %V 103 %P 1509 - 1517 %8 1999/// %@ 1089-5647 %G eng %N 9 %0 Journal Article %J Electrochem. Commun.Electrochemistry Communications %D 1999 %T Comprehensive treatment of sphere-cap microelectrodes (SCMs) using digital simulations. %A Selzer, Yoram %A Mandler, Daniel. %K comprehensive treatment sphere cap microelectrode digital simulation %K finite difference method simulation steady state chronoamperometric behavior microelectrode %X The alternating direction implicit finite difference method (ADIFDM) was used to simulate the steady-state as well as the transient (chronoamperometric) behavior of sphere-cap microelectrodes (SCMs). The necessary steps to implement the ADIFDM for solving the rather complex geometry involved are described. The results for the steady-state behavior are in excellent agreement with a previously suggested anal. soln. making the ADIFDM an excellent tool to develop a comprehensive theory for SCMs. [on SciFinder(R)] %B Electrochem. Commun.Electrochemistry Communications %I Elsevier Science B.V. %V 1 %P 569 - 575 %8 1999/// %@ 1388-2481 %G eng %N 12 %0 Journal Article %J Adv. Mater. (Weinheim, Ger.)Advanced Materials (Weinheim, Germany) %D 1999 %T Electroless deposition of conducting polymers using the scanning electrochemical microscope. %A Borgwarth, Kai %A Rohde, Nils %A Ricken, Christoph %A Hallensleben, Manfred L. %A Mandler, Daniel %A Heinze, Jurgen. %K electropolymn bismethylpyrrolylthiophene scanning electrochem microscopy %K polybispyrrolylthiophene electroless deposition scanning electrochem microscopy %K scanning electrochem microscopy conducting polymer electroless deposition %X Electrochem. polymn. of 2',5'-bis(1-methylpyrrol-2-yl)thiophene (NSN) was carried out by scanning electrochem. microscopy, using Ru(bpy)33+ as oxidant for the polymn. process and for the ultramicroelectrode surface-distance probe. While this led to deposition of flat layers of polymer on a PMMA substrate, use of the weak oxidant IrCl62- gave sets of thin needles. Micrographs of the various patterns are shown (with resolns. of ≈ 15 μm) and the mechanism of polymn. is discussed. [on SciFinder(R)] %B Adv. Mater. (Weinheim, Ger.)Advanced Materials (Weinheim, Germany) %I Wiley-VCH Verlag GmbH %V 11 %P 1221 - 1226 %8 1999/// %@ 0935-9648 %G eng %N 14 %0 Journal Article %J Electrochim. ActaElectrochimica Acta %D 1999 %T Thiol self-assembled monolayers on mercury surfaces: the adsorption and electrochemistry of ω-mercaptoalkanoic acids. %A Muskal, Nechama %A Mandler, Daniel. %K self assembled monolayer mercury electrode adsorption electrochem mercaptoalkanoic acid %X The formation of self-assembled monolayers (SAMs) of ω-mercaptoalkanoic acids on a mercury surface under potential control was studied. Cyclic voltammetry and a.c. voltammetry were used for studying the different phases and transitions that the homologous series of these thiols form and undergo. The thiols are either physisorbed or chemisorbed depending on the applied potential and the transition between these two states occurs through a faradaic process. Also, the chemisorption of the thiols results in multilayer deposition when the thiol monolayer does not block electron transfer. Finally, the implications of this study to the formation and manipulation of SAMs of ω-functionalized alkanethiols on Hg are discussed. [on SciFinder(R)] %B Electrochim. ActaElectrochimica Acta %I Elsevier Science Ltd. %V 45 %P 537 - 548 %8 1999/// %@ 0013-4686 %G eng %N 4-5