Open Access
An antibacterial submicron fiber mat with in situ synthesized silver nanoparticles
(Wiley, 2012) Rivero Fuente, Pedro J.; Urrutia Azcona, Aitor; Goicoechea Fernández, Javier; Rodríguez, Yoany; Corres Sanz, Jesús María; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
This work presents an alternative approachfor fabricating electrospun submicron highly hydrophilicfiber mats loaded with silver nanoparticles. These fiber matsshow a high efficient antibacterial behavior, very attractivefor applications like wound healing and skin regenerationprocesses. The fabrication method is divided in two steps.First, poly(acrylic acid) (PAA) and b-cyclodextrin (b-CD)submicron fibers were electrospun and further stabilizedusing a thermal treatment, yielding stable hydrogel-likefibers with diameters ranging from 100 nm up to severalmicrons. In the second step, silver ions were loaded into thefibers and then reduced to silver nanoparticles in-situ. Theelectrospinning parameters were adjusted to achieve thedesired properties of the fiber mat (density, size) and after-wards, the characteristics of the silver nanoparticles(amount, size, aggregation) were tuned by controlling thesilver ion loading mechanism. Highly biocide surfaces wereachieved showing more than 99.99% of killing efficiency.The two-step process improves the reproducibility and tun-ability of the fiber mats. To our knowledge, this is the firsttime that stable hydrogel fibers with a highly biocide behav-ior have been fabricated using electrospinning.
Open Access
Optical sensors based on lossy-mode resonances
(Elsevier Science, 2017) Matías Maestro, Ignacio; Ascorbe Muruzabal, Joaquín; Acha Morrás, Nerea de; López Torres, Diego; Zubiate Orzanco, Pablo; Sánchez Zábal, Pedro; Urrutia Azcona, Aitor; Socorro Leránoz, Abián Bentor; Rivero Fuente, Pedro J.; Hernáez Sáenz de Zaitigui, Miguel; Elosúa Aguado, César; Goicoechea Fernández, Javier; Bariáin Aisa, Cándido; Corres Sanz, Jesús María; Ruiz Zamarreño, Carlos; Arregui San Martín, Francisco Javier; Del Villar, Ignacio; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC
Open Access
Humidity sensor based on a long-period fiber grating coated with a hydrophobic thin film
(2010) Urrutia Azcona, Aitor; Rivero Fuente, Pedro J.; Goicoechea Fernández, Javier; Arregui San Martín, Francisco Javier; Matías Maestro, Ignacio; Ingeniaritza Elektrikoa eta Elektronikoa; Institute of Smart Cities - ISC; Ingeniería Eléctrica y Electrónica
In this work it is proposed a novel fiber optic humidity sensor based on a functionally coated long-period fiber grating (LPG). The coating is composed of tetraorthosilicate matrix functionalized with perfluorooctyltriethoxysilane and its fabrication was performed by the sol-gel technique using a dip coating process using the LPG as substrate. This technique allows to fabricate sensitive films in a fast and simple way compared to other overlay fabrication techniques. The fabricated sensor was tested in a programmable temperature and climatic chamber. Relative humidity (RH) was varied in range from 20%RH to 80%RH at room temperature. The results showed a smooth exponential-like wavelength shift of the LPG attenuation band.
Open Access
Multifunctional protective PVC-ZnO nanocomposite coatings deposited on aluminum alloys by electrospinning
(MDPI, 2019) Iribarren Zabalegui, Álvaro; Rivero Fuente, Pedro J.; Berlanga Labari, Carlos; Larumbe Abuin, Silvia; Miguel, Adrián; Rodríguez Trías, Rafael; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PRO-UPNA 18 (6107)
This paper reports the use of the electrospinning technique for the synthesis of nanocomposite micro/nanofibers by combining a polymeric precursor with hydrophobic behavior like polyvinyl chloride (PVC) with nanoparticles of a corrosion inhibitor like ZnO. These electrospun fibers were deposited on substrates of the aluminum alloy 6061T6 until forming a coating around 100 m. The effect of varying the different electrospinning deposition parameters (mostly applied voltage and flow-rate) was exhaustively analyzed in order to optimize the coating properties. Several microscopy and analysis techniques have been employed, including optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Water contact angle (WCA) measurements have been carried out in order to corroborate the coating hydrophobicity. Finally, their corrosion behavior has been evaluated by electrochemical tests (Tafel curves and pitting potential measurements), showing a relevant improvement in the resultant corrosion resistance of the coated aluminum alloys.
Open Access
Nuevos enfoques metodológicos y docentes para la mejora del aprendizaje en el área de Ciencia de Materiales e Ingeniería Metalúrgica
(SM, 2021) Rivero Fuente, Pedro J.; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
Uno de los principales retos de la enseñanza universitaria es saber motivar e incentivar el aprendizaje de los estudiantes. La utilización de modalidades educativas a distancia garantiza una formación flexible y facilita la autonomía en el aprendizaje. En este trabajo se presenta la implantación y la evolución de la asignatura online Functional Coatings en el ámbito de la Ingeniería que ha tenido una excelente acogida por parte de los estudiantes debido a la diversidad de los materiales y su alto grado de novedad.
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; Ingeniería
Anti-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).
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, PJUPNA1929
The 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.
Open Access
Modelización y estudio experimental y mediante CFD de un ventilador para alumnos de Grado en Ingeniería Mecánica y de Tecnologías Industriales
(Dykinson, 2021) Fuertes Bonel, Juan Pablo; Torres Salcedo, Alexia; Rivero Fuente, Pedro J.; Armañanzas Goñi, Javier; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
El trabajo planteado en esta comunicación tiene como principales objetivos por un lado, el conocimiento del funcionamiento un ventilador y por el otro, el empleo de softwares propios del diseño (CAD) y de la Mecánica de Fluidos (CFD). Con esto, se busca que el alumno amplíe y afiance sus conocimientos de una máquina fluidomecánica vista en el aula y también, que aprecie la importancia que tiene en ingeniería el trabajo multidisciplinar. Se ha escogido un ventilador, ya que por un lado, su modelización en CAD es más sencilla frente a otras máquinas hidráulicas, como puede ser una bomba centrífuga, y por el otro, porque dentro de las asignaturas de los distintos grados, el estudio del ventilador se realiza en menor profundidad, que el de las máquinas hidráulicas. El trabajo del alumno consta de tres partes diferenciadas: experimentación, diseño y simulación mediante CFD. En la experimentación, el objetivo es que el alumnado pueda manipular un ventilador en el laboratorio contrastando lo visto en teoría con la realidad, y que mediante una toma de datos establecida previamente, se familiarice con su funcionamiento. El siguiente paso consiste en diseñar en CAD la máquina y de esta manera, que puedan poner en práctica lo aprendido en asignaturas anteriores, en cuanto a diseño en CAD se refiere. Por último, y como complemento a las clases sobre CFD, que se imparten en la asignatura donde está programado este trabajo, se pide que el alumnado sea capaz de simular el funcionamiento del ventilador experimentado.
Open Access
Hydrophobic and corrosion behavior of sol-gel hybrid coatings based on the combination of TiO2 NPs and fluorinated chains for aluminum alloys protection
(MDPI, 2018) Rivero Fuente, Pedro J.; Maeztu Redin, Juan Deyo; Berlanga Labari, Carlos; Miguel, Adrián; Rodríguez Trías, Rafael; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, Navarre-PRO-UPNA18-6107-FRRRIO
In this work, layers of a sol-gel hybrid matrix doped with metal oxide nanoparticles (TiO2 NPs) have been deposited on flat samples of AA6061-T6 aluminum alloy using the dip-coating technique, with the aim of obtaining coatings with better anti-corrosive and hydrophobic properties. Two different organic modified silica alkoxides, namely 3-(glycidyloxypropyl)trimethoxysilane (GPTMS) and methyltriethoxysilane (MTEOS), have been used for an adequate entrapment of the metal oxide nanoparticles. In addition, a fluorinated metal-alkoxide precursor has also been added to the hybrid matrix in order to improve the hydrophobic behavior. The experimental results corroborate that the presence of these TiO2 NPs play an important role in the development of the sol-gel hybrid coatings. The water contact angle (WCA) measurements, as well as pencil hardness tests indicate that TiO2 NPs make a considerable increase in the resultant hydrophobicity possible, with better mechanical properties of the coatings. The coating thickness has been measured by cross-section scanning electron microscopy (SEM). In addition, a glow discharge optical emission spectroscopy (GD-OES) analysis has been carried out in order to corroborate the adequate entrapment of the TiO2 NPs into the sol-gel coatings. Finally, potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) have been performed in order to evaluate the corrosion resistance of the coatings. All the results provide insights into the efficacy of the developed sol-gel hybrid coatings for anticorrosive purposes with good mechanical properties.
Open Access
Layer-by-layer assembly as a powerful nanofabrication technique for the design of antimicrobial surfaces in the textile industry
(Taylor & Francis, 2022) Rivero Fuente, Pedro J.; Ingeniería; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2
In this work, the fabrication of multilayer structures has been presented by using the layer-by-layer (LbL) nanoassembly technique with the aim to prevent the bacterial adhesion, pathogen colonization, or even contact-killing bacteria. The use of this nanofabrication technique is of great interest because the resultant thickness of the films can be perfectly controlled as a function of the electrostatic attraction between positive and negative charged compounds. In addition, this technique shows a great versatility because it can be implemented to a wide variety of substrates with any shape and composition (i.e., polymers, composites, medical devices, metallic substrates) without using any expensive equipment. In some cases, the polyelectrolytes can play a dual role for preparing multilayer antimicrobial surfaces. The first one is that most of them can be used for embedding active compounds, which can be released in a further step, while the second one, controlling the pH of the dipping cationic polyelectrolyte solutions can induce the presence of higher protonated charges in the outer surface, which 256can act as a better effective antimicrobial activity. Finally, a perspective in detail of these different approaches will be deeply analyzed against different bacterial strains.