Person: Vicente Gómara, Adrián
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Vicente Gómara
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Adrián
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Ingeniería
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InaMat2. Instituto de Investigación en Materiales Avanzados y Matemáticas
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0000-0002-9099-5851
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811477
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Publication Open Access Icephobic and anticorrosion coatings deposited by electrospinning on aluminum alloys for aerospace applications(MDPI, 2021) Vicente Gómara, Adrián; Rivero Fuente, Pedro J.; García, Paloma; Mora, Julio; Carreño, Francisco; Rodríguez Trías, Rafael; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; IngenieríaAnti-icing or passive strategies have undergone a remarkable growth in importance as a complement for the de-icing approaches or active methods. As a result, many efforts for developing icephobic surfaces have been mostly dedicated to apply superhydrophobic coatings. Recently, a different type of ice-repellent structure based on slippery liquid-infused porous surfaces (SLIPS) has attracted increasing attention for being a simple and effective passive ice protection in a wide range of application areas, especially for the prevention of ice formation on aircrafts. In this work, the electrospinning technique has been used for the deposition of PVDF-HFP coatings on samples of the aeronautical alloy AA7075 by using a thickness control system based on the identification of the proper combination of process parameters such as the flow rate and applied voltage. In addition, the influence of the experimental conditions on the nanofiber properties is evaluated in terms of surface morphology, wettability, corrosion resistance, and optical transmittance. The experimental results showed an improvement in the micro/nanoscale structure, which optimizes the superhydro-phobic and anticorrosive behavior due to the air trapped inside the nanotextured surface. In addi-tion, once the best coating was selected, centrifugal ice adhesion tests (CAT) were carried out for two types of icing conditions (glaze and rime) simulated in an ice wind tunnel (IWT) on both as-deposited and liquid-infused coatings (SLIPs). The liquid-infused coatings showed a low water adhesion (low contact angle hysteresis) and low ice adhesion strength, reducing the ice adhesion four times with respect to PTFE (a well-known low-ice-adhesion material used as a reference).Publication Open Access Icephobic coating based on novel SLIPS made of infused PTFE fibers for aerospace application(MDPI, 2024) Vicente Gómara, Adrián; Rivero Fuente, Pedro J.; Rehfeld, Nadine; Stake, Andreas; García, Paloma; Carreño, Francisco; Mora, Julio; Rodríguez Trías, Rafael; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1929The development of slippery surfaces has been widely investigated due to their excellent icephobic properties. A distinct kind of an ice-repellent structure known as a slippery liquid-infused porous surface (SLIPS) has recently drawn attention due to its simplicity and efficacy as a passive ice-protection method. These surfaces are well known for exhibiting very low ice adhesion values (τice < 20 kPa). In this study, pure Polytetrafluoroethylene (PTFE) fibers were fabricated using the electrospinning process to produce superhydrophobic (SHS) porous coatings on samples of the aeronautical alloy AA6061-T6. Due to the high fluorine–carbon bond strength, PTFE shows high resistance and chemical inertness to almost all corrosive reagents as well as extreme hydrophobicity and high thermal stability. However, these unique properties make PTFE difficult to process. For this reason, to develop PTFE fibers, the electrospinning technique has been used by an PTFE nanoparticles (nP PTFE) dispersion with addition of a very small amount of polyethylene oxide (PEO) followed with a sintering process (380 °C for 10 min) to melt the nP PTFE together and form uniform fibers. Once the porous matrix of PTFE fibers is attached, lubricating oil is added into the micro/nanoscale structure in the SHS in place of air to create a SLIPS. The experimental results show a high-water contact angle (WCA) ≈ 150° and low roll-off angle (αroll-off) ≈ 22° for SHS porous coating and a decrease in the WCA ≈ 100° and a very low αroll-off ≈ 15° for SLIPS coating. On one hand, ice adhesion centrifuge tests were conducted for two types of icing conditions (glaze and rime) accreted in an ice wind tunnel (IWT), as well as static ice at different ice adhesion centrifuge test facilities in order to compare the results for SHS, SLIPs and reference materials. This is considered a preliminary step in standardization efforts where similar performance are obtained. On the other hand, the ice adhesion results show 65 kPa in the case of SHS and 4.2 kPa of SLIPS for static ice and <10 kPa for rime and glace ice. These results imply a significant improvement in this type of coatings due to the combined effect of fibers PTFE and silicon oil lubricant.Publication Open Access Setting a comprehensive strategy to face the runback icing phenomena(Elsevier, 2023) Mora, Julio; García, Paloma; Carreño, Francisco; González, Miguel; Gutiérrez, Marcos; Montes, Laura; Rico, Victor J.; López-Santos, Carmen; Vicente Gómara, Adrián; Rivero Fuente, Pedro J.; Rodríguez Trías, Rafael; Larumbe, Silvia; Acosta, Carolina; Ibáñez-Ibáñez, Pablo; Corozzi, Alessandro.; Raimondo, Mariarosa; Kozera, Rafal; Przybyszewski, Bartlomiej; González-Elipe, Agustín R.; Borrás, Ana; Redondo, Francisco; Agüero, Alina; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2The development of anti-icing robust surfaces is a hot topic nowadays and particularly crucial in the aeronautics or wind energy sectors as ice accretion can compromise safety and power generation efficiency. However, the current performance of most anti-icing strategies has been proven insufficient for such demanding applications, particularly in large unprotected zones, which located downstream from thermally protected areas, may undergo secondary icing. Herein, a new testing methodology is proposed to evaluate accretion mechanisms and secondary icing phenomena through, respectively, direct impact and running-wet processes and systematically applied to anti-icing materials including commercial solutions and the latest trends in the state-of-the-art. Five categories of materials (hard, elastomeric, polymeric matrix, SLIPS and superhydrophobic) with up to fifteen formulations have been tested. This Round-Robin approach provides a deeper understanding of anti-icing mechanisms revealing the strengths and weaknesses of each material. The conclusion is that there is no single passive solution for anti-ice protection. Thus, to effectively protect a given real component, different tailored materials fitted for each particular zone of the system are required. For this selection, shape analysis of such a component and the impact characteristics of water droplets under real conditions are needed as schematically illustrated for aeronautic turbines.Publication Open Access Novel design of superhydrophobic and anticorrosive PTFE and PAA + B - CD composite coating deposited by electrospinning, spin coating and electrospraying techniques(MDPI, 2022) Vicente Gómara, Adrián; Rivero Fuente, Pedro J.; Urdiroz Urricelqui, Unai; García, Paloma; Mora, Julio; Palomares, F. Javier; Rodríguez Trías, Rafael; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2A superhydrophobic composite coating consisting of polytetrafluoroethylene (PTFE) and poly(acrylic acid)+ β-cyclodextrin (PAA + β-CD) was prepared on an aluminum alloy AA 6061T6 substrate by a three-step process of electrospinnig, spin coating, and electrospraying. The electrospinning technique is used for the fabrication of a polymeric binder layer synthesized from PAA + β-CD. The superhydrophilic characteristic of the electrospun PAA + β-CD layer makes it suitable for the absorption of an aqueous suspension with PTFE particles in a spin-coating process, obtaining a hydrophobic behavior. Then, the electrospraying of a modified PTFE dispersion forms a layer of distributed PTFE particles, in which a strong bonding of the particles with each other and with the PTFE particles fixed in the PAA + β-CD fiber matrix results in a remarkable improvement of the particles adhesion to the substrate by different heat treatments. The experimental results corroborate the important role of obtaining hierarchical micro/nano multilevel structures for the optimization of superhydrophobic surfaces, leading to water contact angles above 170°, very low contact angle of hysteresis (CAH = 2°) and roll-off angle (αroll−off < 5°). In addition, a superior corrosion resistance is obtained, generating a barrier to retain the electrolyte infiltration. This study may provide useful insights for a wide range of applications.Publication Open Access Integración de inteligencia artifical en un sistema embebido para medidas optoeléctricas(2016) Vicente Gómara, Adrián; Elosúa Aguado, César; Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación; Telekomunikazio eta Industria Ingeniarien Goi Mailako Eskola TeknikoaEste proyecto consiste en la implementación de una red neuronal en el sistema embebido PIC 16F877A de la familia Microchip para realizar medidas de absorción óptica y clasificar distintas muestras. Gracias a algoritmo de la red se puede identificar el tipo de muestra que se está analizando a partir de la medición de la absorbancia para tres longitudes de onda (rojo, verde y azul). El sistema en conjunto se ha integrado en una placa de circuito impreso (PCB), simplificando la circuitería y componentes propuestos en un diseño previo. El código se ha programado en C y se ha optimizado para utilizar los recursos de memoria disponibles en el PIC, haciendo un uso eficiente de los mismos. El tiempo de ejecución es lo suficientemente bajo como para poder realizar la medida y clasificación de la muestra en pocos segundos, por lo que se puede considerar un sistema a tiempo real. Los resultados obtenidos animan a la mejora del prototipo desarrollado para su aplicación en la prácticaPublication Open Access Etched and nanocoated single-mode multimode single-mode (SMS) fibers for detection of wind turbine gearbox oil degradation(IEEE, 2019) Del Villar, Ignacio; Goñi Carnicero, Jaime; Vicente Gómara, Adrián; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua, 2017/PI044The application of an etching process in a single-mode multimode single-mode (SMS) fiber allows monitoring the change of refractive index of wind turbine gearbox oil due to temperature and degradation with a limitation at short temperatures, where the transmission and attenuation bands in the optical spectrum fade. The application of a black tin oxide nanocoating solves this issue and allows tuning the refractive index region where the sensitivity is maximum. The SMS was designed for operating at short wavelengths, where the setup is less expensive. The experimental results were contrasted with a theoretical analysis developed with FIMMWAVE, which allowed understanding better the phenomena involved in the experiments.Publication Open Access Electrospinning technique as a powerful tool for the design of superhydrophobic surfaces(IntechOpen, 2020) Rivero Fuente, Pedro J.; Vicente Gómara, Adrián; Rodríguez Trías, Rafael; Ingeniería; Ingeniaritza; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1929The development of surface engineering techniques to tune-up the composition, structure, and function of materials surfaces is a permanent challenge for the scientific community. In this chapter, the electrospinning process is proposed as a versatile technique for the development of highly hydrophobic or even superhydrophobic surfaces. Electrospinning makes possible the fabrication of nanostructured ultrathin fibers, denoted as electrospun nanofibers (ENFs), from a wide range of polymeric materials that can be deposited on any type of surface with arbitrary geometry. In addition, by tuning the deposition parameters (mostly applied voltage, flow rate, and distance between collector/needle) in combination with the chemical structure of the polymeric precursor (functional groups with hydrophobic behavior) and its resultant viscosity, it is possible to obtain nanofibers with highly porous surface. As a result, functionalized surfaces with water-repellent behavior can be implemented in a wide variety of industrial applications such as in corrosion resistance, high efficient water-oil separation, surgical meshes in biomedical applications, or even in energy systems for long-term efficiency of dye-sensitized solar cells, among others.Publication Open Access The role of the fiber/bead hierarchical microstructure on the properties of pvdf coatings deposited by electrospinning(MDPI, 2021) Vicente Gómara, Adrián; Rivero Fuente, Pedro J.; Rodríguez Trías, Rafael; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1929Among the various polymeric options employed for the deposition of electrospun coat-ings, poly(vinylidene fluoride) (PVDF) has been widely investigated thanks to its excellent mechanical properties, high chemical resistance, and good thermal stability. In this work, the electrospin-ning technique is used for the fabrication of functional PVDF fibers in order to identify and evaluate the influence of the experimental conditions on the nanofiber properties in terms of optical trans-mittance, wettability, corrosion resistance, and surface morphology. Some of these properties can play a relevant role in the prevention of ice formation in aircrafts. According to this, a matrix of 4 × 4 samples of aluminum alloy AA 6061T6 was successfully coated by controlling two operational input parameters such as the resultant applied voltage (from 10 up to 17.5 KV) and the flow rate (from 800 up to 1400 µL/h) for a fixed polymeric precursor concentration (15 wt.%). The experimental results have shown a multilevel fiber-bead structure where the formation of a fiber mesh directly depends on the selected operational parameters. Several microscopy and surface analysis techniques such as confocal microscopy (CM), field emission scanning electron microscopy (FE-SEM), UV/vis spectroscopy, and water contact angle (WCA) were carried out in order to corroborate the morphology, transmittance, and hydrophobicity of the electrospun fiber composite. Finally, the corrosion behavior was also evaluated by electrochemical tests (Tafel curves measurement), show-ing that the presence of electrospun PVDF fibers produces a relevant improvement in the resultant corrosion resistance of the coated aluminum alloys. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Publication Open Access Lossy mode resonance sensors based on nanocoated multimode-coreless-multimode fibre(Elsevier, 2020) Vicente Gómara, Adrián; Santano Rivero, Desiree; Zubiate Orzanco, Pablo; Urrutia Azcona, Aitor; Del Villar, Ignacio; Ruiz Zamarreño, Carlos; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA26In this work it is proved the ability to obtain lossy mode resonances (LMRs) in the transmission spectrum with multimode-coreless-multimode fibre optic structure coated with tin oxide on the coreless segment. The devices were characterized as a function of the surrounding medium refractive index and sensitivities of 7346.93 nm/RIU and 708.57 nm/RIU were attained for the first and the second LMR respectively. As an application proof of this technology, one of the devices was biofunctionalized and used for detecting goat anti-mouse IgG in concentrations ranging from 1 to 40 mg/L, with a limit of detection of 0.6 mg/L. This proves the ability of this simple structure to be used for biological, chemical or environmental applications.Publication Open Access Modeling experimental parameters for the fabrication of multifunctional surfaces composed of electrospun pcl/zno-nps nanofibers(MDPI, 2021) Rivero Fuente, Pedro J.; Fuertes Bonel, Juan Pablo; Vicente Gómara, Adrián; Mata Ruiz, Álvaro; Monteserín, María; Rodríguez Trías, Rafael; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PJUPNA1929In this work, a one-step electrospinning technique has been implemented for the design and development of functional surfaces with a desired morphology in terms of wettability and corrosion resistance by using polycaprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs). The surface morphology has been characterized by confocal microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle (WCA), whereas the corrosion resistance has been evaluated by Tafel polarization curves. Strict control over the input operational parameters (applied voltage, feeding rate, distance tip to collector), PCL solution concentration and amount of ZnO NPs have been analyzed in depth by showing their key role in the final surface properties. With this goal in mind, a design of experiment (DoE) has been performed in order to evaluate the optimal coating morphology in terms of fiber diameter, surface roughness (Ra), water contact angle (WCA) and corrosion rate. It has been demonstrated that the solution concentration has a significant effect on the resultant electrospun structure obtained on the collector with the formation of beaded fibers with a higher WCA value in comparison with uniform bead-free fibers (dry polymer deposition or fiber-merging aspect). In addition, the presence of ZnO NPs distributed within the electrospun fibers also plays a key role in corrosion resistance, although it also leads to a decrease in the WCA. Finally, this is the first time that an exhaustive analysis by using DoE has been evaluated for PCL/ZnO electrospun fibers with the aim to optimize the surface morphology with the better performance in terms of corrosion resistance and wettability.