An electrochemical quartz crystal microbalance study on polymerization of oligo-p-phenylenes

Boosting Electrocatalyzed Hydrogen Evolutions with Electropolymerized Thiophene Substituted CoIIICorroles

Herein, a A3 type and a A2B type meso-thiophene-substituted CoIIIcorroles are prepared and the electronic structures are investigated. Interestingly, these two CoIIIcorroles are facilely polymerized under electrochemical conditions, and are...

Electrochemical deposition of poly(trans-[RuCl2(4-vinylpyridine)4]) and its reductive desorption: cyclic voltammetry and electrochemical quartz crystal microbalance studies

The electropolymerization of trans-[RuCl(2)(vpy)(4)](vpy = 4-vinylpyridine) on Au or Pt electrodes was studied by cyclic voltammetry and the electrochemical quartz crystal microbalance (EQCM) technique. Cyclic voltammetry of the monomer in DMSO on Au shows reductions at -2.0 and -2.2 V. Potential cycling over the first wave leads to polymer formation; however, scanning over the second wave leads to desorption of the polymer. These observations were confirmed by EQCM measurements which also revealed a high polymerization efficiency. Electrolysis, EQCM and XPS measurements showed that desorption was associated with substitution of chloride ligands by DMSO when the polymer was in a highly reduced state. The film also showed reversible mass changes due to the oxidation and accompanying ingress of charge-balancing anions and solvent into the film. Measurements on the dried films revealed that large quantities of solvent are trapped in the film during the electropolymerization process.

An EQCM Study of the Electropolymerization of Benzene in an Ionic Liquid and Ion Exchange Characteristics of the Resulting Polymer Film

The direct electropolymerization of benzene dissolved in the ionic liquid 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate was studied at room temperature applying the electrochemical quartz-crystal microbalance technique. Analysis of the damping changes showed that the Sauerbrey equation could be applied for data evaluation. In the polymer, every third to fourth benzene ring carried a positive charge in the oxidized state. During electropolymerization, some ionic liquid was absorbed in the growing polymer. The redox behavior was characterized by wide peaks typical for conducting polymers. Charge neutrality of the polymer during redox cycling was maintained by anion and cation exchange with the ionic liquid. With increasing scan rate, cation exchange became more and more important.

Radical Intermediates in Electrochemical Polymer-Forming Reactions

The role of organic radicals in the formation of functional polymers, in particular intrinsically conducting polymers, is reviewed. New results recently obtained with in situ spectroscopic methods illustrating the influence of the molecular structure of monomers (aniline and substituted anilines) in the behaviour of radical intermediates are presented. The stabilising influence of substituents at various positions of the aniline molecule is evaluated and compared based on conceivable structures of reaction intermediates.