Oxidación electroquímica de los isómeros del aminofenol en medio ácido. Caracterización de los polímeros formados

Memoria para optar al grado de suficiencia investigadora del programa de doctorado “Ciencia de Materiales”. Tutores: José Luis Vázquez Picó y Emilia Morallón NúñezResumen de los resultados obtenidos durante el estudio de la oxidación electroquímica de los isómeros del aminofenol, y la caracterización de los materiales poliméricos obtenidos.Ministerio de Ciencia y Tecnología (MAT 2001-1007); Generalitat Valenciana (GV01-313

Electrochemical treatment of aluminium alloy 7075 in aqueous solutions of imidazolium phosphonate and phosphate ionic liquids and scratch resistance of the resultant materials

The abilitiy of 1-ethyl-3-methylimidazolium ethylphosphonate ([ImPhosphonate]) and 1-ethyl-3-methylimidazolium diethylphosphate ([ImPhosphate]) ionic liquids (ILs) to interact with anodized Al7075 T6 aluminium alloy has been studied via electrochemical techniques under different applied potentials, inside and outside the passivation regions. SEM, EDX and XPS analysis have been used to study the composition of the surface coatings. The abrasion resistance after treatment with the ILs has been studied by scratch tests under progressive load, and compared with the performance of the unprotected material and the anodized alloy. While conventional anodization only improves the abrasion resistance of Al7075 in a 30%, the maximum reduction of the penetration depth, 86% with respect to Al7075 and 79% with respect to the anodized alloy, is obtained for the material treated with [ImPhosphonate] at 1 V, in the passivation region. Under these conditions, a phosphorus-containing alumina layer is formed. Applied voltages outside the passivation region for each IL activate the dissolution of the alumina layer and reduce abrasion resistance, not only with respect to the anodized material, but also with respect to the unprotected alloy.This work received the financial support of the Ministerio de Economía y Competitividad (MINECO, Spain) and the EU FEDER Program (Grant MAT2014-55384-P), and the Fundación Séneca, Agencia de Ciencia y Tecnología de la Región de Murcia for a “Ayuda a las Unidades y Grupos de Excelencia Científica de la Región de Murcia (Programa Séneca 2014)” (Grant 19877/GERM/14)

Antiwear performance of ionic liquid+graphene dispersions with anomalous viscosity-temperature behavior

New dispersions of few-layers graphene (G) in 1-ethyl-3-methylimidazolium ([EMIM]) ionic liquids (ILs) with dicyanamide ([DCA]) or bis(trifluoromethylsulfonyl)imide ([TFSI]) anions have been obtained by mechanical mixing and sonication. IL+0.5 wt% G dispersions show constant viscosity values from 357K (for IL = [EMIM][DCA]) or from 385K (for IL = [EMIM][TFSI]) to 393K. IL + G dispersions with G > 0.5 wt% show linear viscosity increases with increasing temperature, from 306K (for [EMIM][DCA]+1 wt%G) and from 330K to 393K (for [EMIM][TFSI]+0.75 wt%G and [EMIM][TFSI]+1 wt%G). Addition of graphene improves the poor wear reducing performance of [EMIM][DCA], and prevents surface damage on steel when added to [EMIM][TFSI]. Graphene increases the load-carrying ability of ILs, forms a surface layer on the sliding path and retains wear debris, preventing the formation of large abrasive particles.Ministerio de Economía, Industria y Competitividad (MINECO, Spain), EU FEDER Program (Grant # MAT2017-85130-P) Este trabajo es resultado de la actividad desarrollada en el marco del Programa de Ayudas a Grupos de Excelencia de la Región de Murcia, de la Fundación Séneca, Agencia de Ciencia y Tecnología de la Región de Murcia (Grant # 19877/GERM/15) M.D. Avilés ha recibido una beca del MINECO (BES-2015-074836)

Protic ammonium bio-based ionic liquid crystal lubricants

Bis(2-hydroxyethyl) ammonium stearate (DES) protic ionic liquid crystal (PILC) has been added in 1 wt% and 2 wt% proportion to di-bis(2-hydroxyethyl) ammonium succinate (DSU) protic ionic liquid (PIL) to obtain (DSU+1%DES) and (DSU+2%DES) lubricant blends. The new blends are non-Newtonian fluids with liquid crystalline domains. Addition of (DES) PILC to (DSU) PIL reduces running-in friction coefficient in more than 70% and prevents surface damage, decreasing wear rate in more than one order of magnitude. Optical profilometry, optical and scanning electron microscopy (SEM), energy dispersive (EDX) and X-ray photoelectron spectroscopy (XPS) have been used to analyze surfaces after the tribological tests.This research was funded by Spanish Ministerio de Ciencia e Innovación, Agencia Estatal de Investigación (AEI) , and the European Union FEDER Program (Grant # MAT2017–85130-P ). “Este trabajo es resultado de la actividad desarrollada en el marco del Programa de Ayudas a Grupos de Excelencia de la Región de Murcia, de la Fundación Seneca, Agencia de Ciencia y Tecnología de la Región de Murcia (Grant # 19877/GERM/15 )”

Rheological study of new dispersions of Carbon Nanotubes in the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide

Dispersions of three different types of carbon nanotubes in a 1 wt.% proportion in the low viscosity 1-ethyl-3-methylimidazolium ([EMIM][DCA]) ionic liquid have been obtained. The neat ionic liquid presents Newtonian behavior, but the addition of carbon nanotubes increases the viscosity with respect to [EMIM][DCA] in the following order: Single-Walled Carbon Nanotubes (SWCNTs) > aligned Multi-Walled Carbon Nanotubes (aligned-MWCNTs) > Multi-Walled Carbon Nanotubes (MWCNTs), and the resulting fluids show non-Newtonian behavior. SWCNTs and MWCNTs dispersions present shear thinning with increasing shear rate, but a shear thickening effect for aligned-MWCNTs at intermediate shear rate values at room temperature has been observed. This effect disappears at 100 ºC. The thermal response of the viscosity of [EMIM][DCA] and the CNTs-IL dispersions can be fitted to the Arrhenius model. For[EMIM][DCA] and the dispersion with MWCNTs the viscous behavior prevails at low frequencies, with a cross point at a critical frequency value which decreases with increasing temperature. However, the dispersions of SWCNTs and aligned-MWCNTspresent storage modulus values higher than loss modulus in the whole range of frequency.The authors acknowledge the Ministerio de Economía, Industria y Competitividad (MINECO, Spain), the EU FEDER Program (Grants # MAT2014-55384-P and # MAT2017-85130-P), and Fundación Séneca - Agencia de Ciencia y Tecnología de la Región de Murcia “Ayuda a las Unidades y Grupos de Excelencia Científica de la Región de Murcia (Programa Séneca 2014)” (Grant # 19877/GERM/14), for financial support. M.D. Avilés acknowledges a research fellowship (Grant # BES-2015-074836) to MINECO

Physicochemical characterisation of graphene-ammonium lactate ionic liquid nanofluid.

A new series of nanofluids based on graphene dispersed in 2-hydroxyethylammonium lactate (ML) ionic liquid was developed. Concentrations of 0.1, 0.5 and 1 wt% of graphene were studied and these dispersions were stable after 2 months. Raman spectra showed a strong interaction between ML and graphene. The effect of the concentration of graphene and temperature on the viscoelastic behaviour and conductivity of the nanofluids was studied. An unexpected decrease in the viscosity was found with a low concentration of graphene due to the suppression of hydrogen bonding of the ionic liquid. Shear thinning effects appeared with higher concentrations of graphene and Ostwald and Herschel-Bulkley equations were used to describe the steady-state viscosity results. Creep-recovery tests were also performed, and the data were fitted to a complex Burgers model for the nanofluid with 1 wt% of graphene, with a 47 % of elastic response. The complexity of the model was related to the presence of different molecular arrangements in the nanofluid. An enhancement of the conductivity was observed with increasing values of the graphene concentration. The effect of temperature on viscosity and electrical conductivity was successfully modelled by using both Vogel-Fulcher-Tammann and Power Law equations. Electrochemical characterisation at room temperature was also carried out, finding an irreversible oxidation at 1 V only for the highest concentration (1 wt%). The concentration of percolation was estimated in the range of 0.5 to 1 wt% of graphene.The authors acknowledge the financial support of Ministerio de Economía y Competitividad and Agencia Estatal de Investigación (MINECO and AEI, Spain), EU-FEDER (MAT2017-85130-P, and PID2021-122169NB) and the Fundación Seneca, Agencia de Ciencia y Tecnología de la Región de Murcia (‘Ayuda a las Unidades y Grupos de Excelencia Científica de la Región de Murcia’; Grant # 19877/GERM/15). P.M. M.-R. is grateful to Fundación Séneca for FPI research grant (21574/FPI/21)

Los músculos artificiales son motores eléctricos que sienten las condiciones de trabajo

Los actuadores de bicapa polipirrol-DBS-CI04-//polímero no conductor se comportan como dispositivos electro-quimio-mecánicos. Esto supone que al estar controlado su movimiento de flexión por una reacción electroquímica, cualquier magnitud fisica o química que afecte al equilibrio químico, modificará su comportamiento a través de la energía eléctrica consumida durante la actuación, como por ej emplo la corriente aplicada o la temperatura. Esta característica convierte a estos dispositivos en sensores de las condiciones ambientales y actuadores simultáneamente.Centro Universitario de la Defensa. Escuela de Turismo de Cartagena. Escuela Técnica Superior de Ingeniería Industrial UPCT. Escuela Técnica Superior de Ingeniería de Telecomunicación (ETSIT). Escuela de Ingeniería de Caminos y Minas (EICM). Escuela de Arquitectura e Ingeniería de Edificación (ARQ&IDE). Parque Tecnológico de Fuente Álamo. Navantia. Campus Mare Nostru

Influencia de distintos parámetros en la reacción de oxidación del polipirrol

La velocidad de la reacción a la que se produce la oxidación de uno de los polímeros conductores más estudiados, como es el polipirrol, ha sido investigada mediante técnicas electroquímicas modificando distintos parámetros: electro lito, disolvente y e5pesor de la película, variando en cada estudio tan sólo uno de ellos. A partir de estos valores de velocidad, y siguiendo la ecuación de la cinética química ha sido posible hallar el valor de los coeficientes cinéticos para cada uno de los disolventes y aniones empleados, así como las energías de activación para los distintos espesores. Los resultados obtenidos muestran cómo varía la velocidad de reacción con cada uno de los parámetros anteriores.Asociación de Jóvenes Investigadores de Cartagena, (AJICT). Universidad Politécnica de Cartagena. Escuela Técnica Superior de Ingeniería Industrial UPCT, (ETSII). Escuela Técnica Superior de Ingeniería Agronómica, (ETSIA), Escuela Técnica Superior de Ingeniería de Telecomunicación (ETSIT). Escuela de Ingeniería de Caminos, Canales, y Puertos y de Ingeniería de Minas, (EICM). Fundación Séneca, Agencia Regional de Ciencia y Tecnología. Parque Tecnológico de Fuente Álamo. Grupo Aquilin