RESUMEN
The first electrochemical series in a deep eutectic solvent (DES) is described. Speciation resulting from the unusual chemistry of the choline chloride based DES is used to explain both similarities and differences from aqueous media. We give examples of how these differences can be exploited in technologically important systems.
RESUMEN
Electropolymerized films of the functionalized pyrrole, pentafluorophenyl-3-(pyrrol-1-yl)propionate (PFP), were reacted with a solution-phase nucleophile, ferrocene ethylamine. This reaction was chosen as a model representative of a postdeposition modification of the polymer membrane's properties. For the first time, a nondestructive method for direct chemical analysis of the reaction profile within the electrodeposited polymer membrane after nucleophilic substitution is presented. This was achieved through the application of in situ neutron reflectivity with supplementary analytical information concerning the film's chemical composition obtained from XPS, FT-IR, and electrochemical measurements. The results presented illustrate how, for a partially reacted film resulting from a short reaction time, the extent of reaction with ferrocene ethylamine is not homogeneous throughout the thickness of the film, but occurs predominantly at the polymer/solution interface. We show that the progress of the reaction within the polymer film is limited by the transport of reacting species in the dense regions of the membrane that are furthest from the solution interface. The data do not fit an alternative model in which there is spatially homogeneous progression of the reaction front throughout the bulk of the thin film polymer. Guided by the neutron reflectivity measurements, suitable modifications were made to the electrodeposition method to prepare films whose architecture resulted in faster rates of reaction.
RESUMEN
In this paper, we explore the role that polymer conductivity and functionality play in determining the nature of molecular recognition at artificial polymer interfaces, as evidenced by electron transfer with the small redox protein, cytochrome c. The relationship is investigated electrochemically using cyclic voltammetry in order to assess the degree of molecular recognition between the biological molecule and carboxyl-functionalized beta-substituted poly(thiophenes) and poly(pyrroles), as well as a co-polymer matrix of these derivatives. In the latter case, the co-polymer film was analysed quantitatively using X-ray photoelectron spectroscopy, and it was found that its composition did not reflect the initial molar ratios of the monomers prior to electrodeposition.