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Characterization of contact angle hysteresis on soft surfaces is sensitive to the measurement protocol and might present adventitious time-dependencies. Contact line dynamics on solid surfaces is altered by the surface chemistry, surface roughness and/or surface elasticity. We observed a “slow” spontaneous relaxation of static water sessile drops placed on elastic surfaces. This unexpected drop motion reveals unresolved equilibrium configurations that may affect the observed values of contact angle hysteresis. Drop relaxation on deformable surfaces is partially governed by a viscoelastic dissipation located at the contact line. In this work, we studied the natural relaxation of water drops formed on several smooth PDMS surfaces with different elastic moduli. We monitored in time the contact angle and contact radius of each drop. For varying the initial contact angle, we used the growing-shrinking drop method. We postulate that the so-called “braking effect”, produced by the surface deformability, affects the contact line velocity and in consequence, the contact angle measurements. We conclude that the wetting properties of elastic surfaces should be properly examined with reliable values of contact angle measured after drop relaxation.
Pablo F. Ibáñez-Ibáñez; Francisco J. Montes Ruiz-Cabello; Miguel A. Cabrerizo-Vílchez; Miguel A. Rodríguez-Valverde. Contact line relaxation of sessile drops on PDMS surfaces: A methodological perspective. Journal of Colloid and Interface Science 2020, 589, 166 -172.
AMA StylePablo F. Ibáñez-Ibáñez, Francisco J. Montes Ruiz-Cabello, Miguel A. Cabrerizo-Vílchez, Miguel A. Rodríguez-Valverde. Contact line relaxation of sessile drops on PDMS surfaces: A methodological perspective. Journal of Colloid and Interface Science. 2020; 589 ():166-172.
Chicago/Turabian StylePablo F. Ibáñez-Ibáñez; Francisco J. Montes Ruiz-Cabello; Miguel A. Cabrerizo-Vílchez; Miguel A. Rodríguez-Valverde. 2020. "Contact line relaxation of sessile drops on PDMS surfaces: A methodological perspective." Journal of Colloid and Interface Science 589, no. : 166-172.
Aluminum-magnesium (Al-Mg) alloy and aluminum-coated steel (aluminized steel) are typically used for the manufacturing of baking trays and molds. For these applications, these materials must be modified to develop release and hydrophobic properties. With this aim, the bare substrates are typically coated with low-surface energy materials such as fluoropolymers, elastomers, or sol-gel layers. In this work, some alternative strategies to prepare these functional surfaces are presented. We used three-step processes involving (i) micro-texturing, (ii) nano layer deposition through immersion and electrodeposition, and (iii) hydrophobization. The raw substrates were sanded or sandblasted at the micro scale, accordingly. Texturization at the nano scale was achieved with a cerium layer formed by electrodeposition or solution immersion. The cerium layers were hydrophobized with fatty acids. The wetting properties of the samples were studied with tilting-plate and bouncing drop methods. We measured the surface roughness of the samples by contact profiling and analyzed their surface morphology using a field emission scanning electron microscope (FESEM). The elemental chemical composition of the samples was analyzed by energy-dispersive X-ray spectroscopy (EDX). The wettability results indicated that the best performance for the Al-Mg substrates was reached by sandblasting and later immersion in a cerium nitrate solution. For aluminized steel substrates, the best results were obtained with both electrodeposition and immersion methods using a cerium chloride solution.
Guillermo Guerrero-Vaca; Miguel A. Rodríguez-Valverde; Pedro Castilla-Montilla; Francisco Alguacil-Salamanca; Óscar Rodríguez-Alabanda; Pablo E. Romero; Esther Molero-Romero; F. Javier Montes Ruiz-Cabello; F. Montes Ruiz-Cabello. Superhydrophobic Cerium-Based Coatings on Al-Mg Alloys and Aluminized Steel. Coatings 2019, 9, 774 .
AMA StyleGuillermo Guerrero-Vaca, Miguel A. Rodríguez-Valverde, Pedro Castilla-Montilla, Francisco Alguacil-Salamanca, Óscar Rodríguez-Alabanda, Pablo E. Romero, Esther Molero-Romero, F. Javier Montes Ruiz-Cabello, F. Montes Ruiz-Cabello. Superhydrophobic Cerium-Based Coatings on Al-Mg Alloys and Aluminized Steel. Coatings. 2019; 9 (12):774.
Chicago/Turabian StyleGuillermo Guerrero-Vaca; Miguel A. Rodríguez-Valverde; Pedro Castilla-Montilla; Francisco Alguacil-Salamanca; Óscar Rodríguez-Alabanda; Pablo E. Romero; Esther Molero-Romero; F. Javier Montes Ruiz-Cabello; F. Montes Ruiz-Cabello. 2019. "Superhydrophobic Cerium-Based Coatings on Al-Mg Alloys and Aluminized Steel." Coatings 9, no. 12: 774.
Evaporating salty droplets are ubiquitous in nature, in our home and in the laboratory. Interestingly, the transport processes in such apparently simple systems differ strongly from evaporating “freshwater” droplets since convection is partly inverted due to Marangoni stresses. Such an effect has crucial consequences to the salt crystallization process and to the deposits left behind. In this work we show unprecedented measurements that, not only confirm clearly the flow inversion, but also elucidate their impact on the distribution of nonvolatile solutes. Contrary to what has been often reported in the literature, such a flow reversal does not prevent the formation of ring-shaped stains: particles accumulate at the contact line driven solely by the interfacial flow. We can therefore conclude that the classical “coffee-stain effect” is not the only mechanism that can generate ring-shaped stains in evaporating droplets.
Alvaro Marin; Stefan Karpitschka; Diego Noguera-Marín; Miguel A. Cabrerizo-Vílchez; Massimiliano Rossi; Christian J. Kähler; Miguel A. Rodríguez Valverde. Solutal Marangoni flow as the cause of ring stains from drying salty colloidal drops. Physical Review Fluids 2019, 4, 041601 .
AMA StyleAlvaro Marin, Stefan Karpitschka, Diego Noguera-Marín, Miguel A. Cabrerizo-Vílchez, Massimiliano Rossi, Christian J. Kähler, Miguel A. Rodríguez Valverde. Solutal Marangoni flow as the cause of ring stains from drying salty colloidal drops. Physical Review Fluids. 2019; 4 (4):041601.
Chicago/Turabian StyleAlvaro Marin; Stefan Karpitschka; Diego Noguera-Marín; Miguel A. Cabrerizo-Vílchez; Massimiliano Rossi; Christian J. Kähler; Miguel A. Rodríguez Valverde. 2019. "Solutal Marangoni flow as the cause of ring stains from drying salty colloidal drops." Physical Review Fluids 4, no. 4: 041601.
Fluoropolymer-based coatings are widely used for release applications. However, these hydrophobic surfaces do not reveal a significantly low adhesion. Water repellency incorporated to fluoropolymer coatings might enhance their release performance. In this work, we focused on the surface texturing of a well-known polytetrafluoroethylene (PTFE)-based coating. We explored as texturing routes: sanding, sandblasting and laser ablation. We examined the surface roughness with white light confocal microscopy and the surface morphology with environmental scanning electron microscopy (ESEM). Water-repellent fluoropolymer coatings were reproduced in all cases, although with different degree, parametrized with bounces of water drops (4–5 μL). Laser ablation enabled the lowest adhesion of coatings with 24 ± 2 bounces. This result and the current development of laser patterning for industry assure the incipient use of laser ablation for release coatings.
Guillermo Paz-Gómez; Juan Carlos Del Caño-Ochoa; Oscar Rodríguez Alabanda; Pablo E. Romero; Miguel Cabrerizo-Vílchez; Guillermo Guerrero; Miguel Angel Rodríguez-Valverde; Paz- Gómez; Caño- Ochoa; Rodríguez- Alabanda; Cabrerizo- Vílchez; Guerrero- Vaca; Rodríguez- Valverde. Water-Repellent Fluoropolymer-Based Coatings. Coatings 2019, 9, 293 .
AMA StyleGuillermo Paz-Gómez, Juan Carlos Del Caño-Ochoa, Oscar Rodríguez Alabanda, Pablo E. Romero, Miguel Cabrerizo-Vílchez, Guillermo Guerrero, Miguel Angel Rodríguez-Valverde, Paz- Gómez, Caño- Ochoa, Rodríguez- Alabanda, Cabrerizo- Vílchez, Guerrero- Vaca, Rodríguez- Valverde. Water-Repellent Fluoropolymer-Based Coatings. Coatings. 2019; 9 (5):293.
Chicago/Turabian StyleGuillermo Paz-Gómez; Juan Carlos Del Caño-Ochoa; Oscar Rodríguez Alabanda; Pablo E. Romero; Miguel Cabrerizo-Vílchez; Guillermo Guerrero; Miguel Angel Rodríguez-Valverde; Paz- Gómez; Caño- Ochoa; Rodríguez- Alabanda; Cabrerizo- Vílchez; Guerrero- Vaca; Rodríguez- Valverde. 2019. "Water-Repellent Fluoropolymer-Based Coatings." Coatings 9, no. 5: 293.
Evaluation of superhydrophobic (SH) surfaces based on contact angle measurements is challenging due to the high mobility of drops and the resolution limits of optical goniometry. For this reason, some alternatives to drop-shape methods have been proposed such as the damped-oscillatory motion of ferrofluid sessile drops produced by an external magnetic field. This approach provides information on surface friction (lateral/shear adhesion) from the kinetic energy dissipation of the drop. In this work, we used this method to compare the low adhesion of four commercial SH coatings (Neverwet, WX2100, Ultraever dry, Hydrobead) formed on glass substrates. As ferrofluid, we used a maghemite aqueous suspension (2% v/v) synthesized ad hoc. The rolling magnetic drop is used as a probe to explore shear solid–liquid adhesion. Additionally, drop energy dissipates due to velocity-dependent viscous stresses developed close to the solid–liquid interface. By fitting the damped harmonic oscillations, we estimated the decay time on each coating. The SH coatings were statistically different by using the mean damping time. The differences found between SH coatings could be ascribed to surface–drop adhesion (contact angle hysteresis and apparent contact area). By using this methodology, we were able to grade meaningfully the liquid-repelling properties of superhydrophobic surfaces.
Angelica Goncalves Dos Santos; Francisco Javier Montes-Ruiz Cabello; Fernando Vereda; Miguel A. Cabrerizo-Vilchez; Miguel A. Rodriguez-Valverde. Oscillating Magnetic Drop: How to Grade Water-Repellent Surfaces. Coatings 2019, 9, 270 .
AMA StyleAngelica Goncalves Dos Santos, Francisco Javier Montes-Ruiz Cabello, Fernando Vereda, Miguel A. Cabrerizo-Vilchez, Miguel A. Rodriguez-Valverde. Oscillating Magnetic Drop: How to Grade Water-Repellent Surfaces. Coatings. 2019; 9 (4):270.
Chicago/Turabian StyleAngelica Goncalves Dos Santos; Francisco Javier Montes-Ruiz Cabello; Fernando Vereda; Miguel A. Cabrerizo-Vilchez; Miguel A. Rodriguez-Valverde. 2019. "Oscillating Magnetic Drop: How to Grade Water-Repellent Surfaces." Coatings 9, no. 4: 270.
In this work, we studied the wettability of hydrophobic surfaces fabricated with three different materials (PTFE, PDMS and paraffin wax) over a wide range of roughness. We estimated the Advancing, Receding and Most-Stable contact angles and we identified the transition from a homogeneous wetting regime (Wenzel) to a hybrid wetting regime (Cassie-Baxter). Using a modified Cassie-Baxter equation which considers the chemical heterogeneity of the samples, we were able to determine the solid area fraction within the contact area. This way, we designed a methodology to identify the superhydrophobic degree of rough-hydrophobic surfaces.
F.J. Montes Ruiz-Cabello; M.A. Cabrerizo-Vílchez; Miguel Angel Rodriguez-Valverde. Evaluation of the solid-liquid contact area fraction of drops deposited on rough surfaces beyond the Wenzel regime. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2019, 568, 455 -460.
AMA StyleF.J. Montes Ruiz-Cabello, M.A. Cabrerizo-Vílchez, Miguel Angel Rodriguez-Valverde. Evaluation of the solid-liquid contact area fraction of drops deposited on rough surfaces beyond the Wenzel regime. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2019; 568 ():455-460.
Chicago/Turabian StyleF.J. Montes Ruiz-Cabello; M.A. Cabrerizo-Vílchez; Miguel Angel Rodriguez-Valverde. 2019. "Evaluation of the solid-liquid contact area fraction of drops deposited on rough surfaces beyond the Wenzel regime." Colloids and Surfaces A: Physicochemical and Engineering Aspects 568, no. : 455-460.
Wettability of solid surfaces is mostly probed with sessile drops rather than bubbles because this method is readily followed out. This recurrent use may lead to a misleading connection of certain phenomena to the hydrophobicity/hydrophilicity of materials. For instance, the Cassie-Baxter regime and the wicking effect are generally associated only to hydrophobic and hydrophilic surfaces, respectively. However, the same phenomenology should be observed when air bubbles (underwater conditions) in contact with solid surfaces are used instead. In particular, one might expect that rough-hydrophilic surfaces become superaerophobic due to the appearance of a hybrid dewetting regime, like the Cassie-Baxter regime described for rough-hydrophobic surfaces. Otherwise, rough-hydrophobic surfaces might become superaerophilic due to air-wicking. To elucidate this issue, in this work, we analyzed the wettability of surfaces with very different intrinsic contact angle and roughness degree. The analysis was performed with both Sessile Drop and Captive Bubble methods. Our results with captive bubbles for rough-hydrophilic surfaces revealed phenomena only explained by the occurrence of a transition from the Wenzel regime to an “inverse” Cassie-Baxter regime. In addition, our results with captive bubbles for rough-hydrophobic surfaces showed evidences of air percolation through the interconnected asperities. This effect reminds the wicking effect reproduced on rough-hydrophilic surfaces, responsible for superhydrophilicity.
Carmen Lucía Moraila; F. Javier Montes Ruiz-Cabello; Miguel Cabrerizo-Vílchez; Miguel Ángel Rodríguez-Valverde. Wetting transitions on rough surfaces revealed with captive bubble experiments. The role of surface energy. Journal of Colloid and Interface Science 2018, 539, 448 -456.
AMA StyleCarmen Lucía Moraila, F. Javier Montes Ruiz-Cabello, Miguel Cabrerizo-Vílchez, Miguel Ángel Rodríguez-Valverde. Wetting transitions on rough surfaces revealed with captive bubble experiments. The role of surface energy. Journal of Colloid and Interface Science. 2018; 539 ():448-456.
Chicago/Turabian StyleCarmen Lucía Moraila; F. Javier Montes Ruiz-Cabello; Miguel Cabrerizo-Vílchez; Miguel Ángel Rodríguez-Valverde. 2018. "Wetting transitions on rough surfaces revealed with captive bubble experiments. The role of surface energy." Journal of Colloid and Interface Science 539, no. : 448-456.
The manufacturing of polyurethane foam is a process of great industrial importance in the automotive and furniture sector. The operation of demolding is the most delicate, since the foam sticks firmly to the walls of the mold onto which it has spread. In order to avoid the use of demolding agents, the proposal is to coat the inside of the molds with non-stick coatings. In this work, three types of different coatings were studied: fluoropolymers, ceramics, and elastomers. After carrying out different tests in the laboratory, two fluoropolymer coatings (PFA (perfluoroalkoxy) and PTFE (polytetrafluoroethylene)) were selected for a test at the industrial level and, after 1500 cycles of demolding, it was experimentally proven that the PFA coating is the most adequate for the use studied.
Francisco Sánchez-Urbano; Guillermo Paz-Gómez; Óscar Rodríguez-Alabanda; Pablo E. Romero; Miguel Cabrerizo-Vílchez; Miguel Ángel Rodríguez-Valverde; Guillermo Guerrero-Vaca. Non-Stick Coatings in Aluminium Molds for the Production of Polyurethane Foam. Coatings 2018, 8, 301 .
AMA StyleFrancisco Sánchez-Urbano, Guillermo Paz-Gómez, Óscar Rodríguez-Alabanda, Pablo E. Romero, Miguel Cabrerizo-Vílchez, Miguel Ángel Rodríguez-Valverde, Guillermo Guerrero-Vaca. Non-Stick Coatings in Aluminium Molds for the Production of Polyurethane Foam. Coatings. 2018; 8 (9):301.
Chicago/Turabian StyleFrancisco Sánchez-Urbano; Guillermo Paz-Gómez; Óscar Rodríguez-Alabanda; Pablo E. Romero; Miguel Cabrerizo-Vílchez; Miguel Ángel Rodríguez-Valverde; Guillermo Guerrero-Vaca. 2018. "Non-Stick Coatings in Aluminium Molds for the Production of Polyurethane Foam." Coatings 8, no. 9: 301.
Several ways to produce superhydrophobic metal surfaces are presented in this work. Aluminum was chosen as the metal substrate due to its wide use in industry. The wettability of the produced surface was analyzed by bouncing drop experiments and the topography was analyzed by confocal microscopy. In addition, we show various methodologies to measure its durability and anti-icing properties. Superhydrophobic surfaces hold a special texture that must be preserved to keep their water-repellency. To fabricate durable surfaces, we followed two strategies to incorporate a resistant texture. The first strategy is a direct incorporation of roughness to the metal substrate by acid etching. After this surface texturization, the surface energy was decreased by silanization or fluoropolymer deposition. The second strategy is the growth of a ceria layer (after surface texturization) that should enhance the surface hardness and corrosion resistance. The surface energy was decreased with a stearic acid film. The durability of the superhydrophobic surfaces was examined by a particle impact test, mechanical wear by lateral abrasion, and UV-ozone resistance. The anti-icing properties were explored by studying the ability to repeal subcooled water, freezing delay, and ice adhesion.
F.J. Montes Ruiz-Cabello; Pablo F. Ibáñez Ibáñez; Guillermo Paz-Gomez; Miguel Cabrerizo-Vilchez; Miguel Angel Rodriguez-Valverde. Fabrication of Superhydrophobic Metal Surfaces for Anti-Icing Applications. Journal of Visualized Experiments 2018, e57635 -e57635.
AMA StyleF.J. Montes Ruiz-Cabello, Pablo F. Ibáñez Ibáñez, Guillermo Paz-Gomez, Miguel Cabrerizo-Vilchez, Miguel Angel Rodriguez-Valverde. Fabrication of Superhydrophobic Metal Surfaces for Anti-Icing Applications. Journal of Visualized Experiments. 2018; (138):e57635-e57635.
Chicago/Turabian StyleF.J. Montes Ruiz-Cabello; Pablo F. Ibáñez Ibáñez; Guillermo Paz-Gomez; Miguel Cabrerizo-Vilchez; Miguel Angel Rodriguez-Valverde. 2018. "Fabrication of Superhydrophobic Metal Surfaces for Anti-Icing Applications." Journal of Visualized Experiments , no. 138: e57635-e57635.
Miguel Ángel Fernández-Rodríguez; Sahar Rahmani; Chris K.J. Yu; Miguel Ángel Rodríguez-Valverde; Miguel Ángel Cabrerizo-Vílchez; Charnelle A. Michel; Joerg Lahann; Roque Hidalgo-Álvarez. Synthesis and interfacial activity of PMMA/PtBMA Janus and homogeneous nanoparticles at water/oil interfaces. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2018, 536, 259 -265.
AMA StyleMiguel Ángel Fernández-Rodríguez, Sahar Rahmani, Chris K.J. Yu, Miguel Ángel Rodríguez-Valverde, Miguel Ángel Cabrerizo-Vílchez, Charnelle A. Michel, Joerg Lahann, Roque Hidalgo-Álvarez. Synthesis and interfacial activity of PMMA/PtBMA Janus and homogeneous nanoparticles at water/oil interfaces. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2018; 536 ():259-265.
Chicago/Turabian StyleMiguel Ángel Fernández-Rodríguez; Sahar Rahmani; Chris K.J. Yu; Miguel Ángel Rodríguez-Valverde; Miguel Ángel Cabrerizo-Vílchez; Charnelle A. Michel; Joerg Lahann; Roque Hidalgo-Álvarez. 2018. "Synthesis and interfacial activity of PMMA/PtBMA Janus and homogeneous nanoparticles at water/oil interfaces." Colloids and Surfaces A: Physicochemical and Engineering Aspects 536, no. : 259-265.
The analysis of wetting properties of superhydrophobic surfaces may be a difficult task due to the restless behavior of drops on this type of surfaces and the limitations of goniometry for high contact angles. A method to validate the performance of superhydrophobic surfaces, rather than standard goniometry, is required. In this work, we used bouncing drop dynamics as a useful tool to predict the water repellency of different superhydrophobic surfaces. From bouncing drop experiments conducted over a wide range of superhydrophobic surfaces, we found that those surfaces with a proper roughness degree and homogeneous chemical composition showed higher water-repellency. We also conducted a drop condensation study at saturating conditions aimed to determine whether there is direct correlation between water repellency and condensation delay. We found that the drop condensation process is strongly related to the surface topography, as well as the intrinsic wettability. The condensation is promoted on rough surfaces but it is delayed on intrinsically hydrophobic surfaces. However, the differences found in condensation delay between the superhydrophobic surfaces explored in this study cannot be justified by their chemical homogeneity nor their efficiency as water repellent surfaces, separately.
F. Javier Montes Ruiz-Cabello; Pablo F. Ibáñez-Ibáñez; J. Francisco Gómez-Lopera; José Martínez-Aroza; Miguel Cabrerizo-Vílchez; Miguel A. Rodríguez-Valverde. Testing the performance of superhydrophobic aluminum surfaces. Journal of Colloid and Interface Science 2017, 508, 129 -136.
AMA StyleF. Javier Montes Ruiz-Cabello, Pablo F. Ibáñez-Ibáñez, J. Francisco Gómez-Lopera, José Martínez-Aroza, Miguel Cabrerizo-Vílchez, Miguel A. Rodríguez-Valverde. Testing the performance of superhydrophobic aluminum surfaces. Journal of Colloid and Interface Science. 2017; 508 ():129-136.
Chicago/Turabian StyleF. Javier Montes Ruiz-Cabello; Pablo F. Ibáñez-Ibáñez; J. Francisco Gómez-Lopera; José Martínez-Aroza; Miguel Cabrerizo-Vílchez; Miguel A. Rodríguez-Valverde. 2017. "Testing the performance of superhydrophobic aluminum surfaces." Journal of Colloid and Interface Science 508, no. : 129-136.
A successful methodology for obtaining hybrid films which allow thermal triggering and continuous, irreversible, control of their hydrophilicity/hydrophobicity nature was developed. Two types of poly(dimethylsiloxane)-silica ([email protected]) films were prepared for that purpose: A hydrophilic film in which the thermal treatment causes an irreversible gradual increase of hydrophobicity; and a hydrophobic film that turns more hydrophilic upon thermal treatment. The opposite directionality of the change is dictated by the film substrate, on which the same hybrid is deposited. In both cases the thermal treatment induced a phase separation which caused the change in hydrophobicity. The magnitude of change in hydrophilicity/hydrophobicity is continuously controllable in both types of films by either the temperature or heating time. The films were characterized before and after heating by a variety of methods, including contact angle (CA) measurements with the sessile drop and the tilting plate methods, and by X-ray photoelectron spectroscopy (XPS) analysis. A thorough kinetic study was carried out, following the progress of the changes in the wettability property of the surfaces. The kinetics analyses proved that the changes in the wettability in all cases are due to phase separation processes, the directionality of which is determined by the treatment of the substrate on which the films are deposited. By monitoring the change of wettability (ΔCA) at various temperatures, an Arrhenius plot was obtained from which the activation energy and Arrhenius pre-exponential factor for the phase separation were derived, corroborating the proposed mechanism. To the best of our knowledge, this is the first use of phase separation behavior of a hybrid film in order to apply irreversible, thermally controllable change of surface wettability, tailored to proceed in opposite directions, and the first kinetic study of such a process.
Noam Ralbag; Francisco Javier Montes Ruiz-Cabello; Miguel Ángel Rodríguez Valverde; Vitaly Gutkin; Ruthy Sfez; David Avnir. Continuous thermal control of hydrophilicity/hydrophobicity changes of hybrid films and of their directionality: Kinetics and substrate effects. Journal of Colloid and Interface Science 2017, 505, 692 -702.
AMA StyleNoam Ralbag, Francisco Javier Montes Ruiz-Cabello, Miguel Ángel Rodríguez Valverde, Vitaly Gutkin, Ruthy Sfez, David Avnir. Continuous thermal control of hydrophilicity/hydrophobicity changes of hybrid films and of their directionality: Kinetics and substrate effects. Journal of Colloid and Interface Science. 2017; 505 ():692-702.
Chicago/Turabian StyleNoam Ralbag; Francisco Javier Montes Ruiz-Cabello; Miguel Ángel Rodríguez Valverde; Vitaly Gutkin; Ruthy Sfez; David Avnir. 2017. "Continuous thermal control of hydrophilicity/hydrophobicity changes of hybrid films and of their directionality: Kinetics and substrate effects." Journal of Colloid and Interface Science 505, no. : 692-702.
Particles adsorbed at liquid interfaces are commonly used to stabilise water-oil Pickering emulsions and water-air foams. The fundamental understanding of the physics of particles adsorbed at water-air and water-oil interfaces is improving significantly due to novel techniques that enable the measurement of the contact angle of individual particles at a given interface. The case of non-aqueous interfaces and emulsions is less studied in the literature. Non-aqueous liquid-liquid interfaces in which water is replaced by other polar solvents have properties similar to those of water-oil interfaces. Nanocomposites of non-aqueous immiscible polymer blends containing inorganic particles at the interface are of great interest industrially and consequently more work has been devoted to them. By contrast, the behaviour of particles adsorbed at oil-oil interfaces in which both oils are immiscible and of low dielectric constant (ε < 3) is scarcely studied. Hydrophobic particles are required to stabilise these oil-oil emulsions due to their irreversible adsorption, high interfacial activity and elastic shell behaviour.
Miguel Angel Fernandez-Rodriguez; Bernard P. Binks; Miguel Angel Rodriguez-Valverde; Miguel Angel Cabrerizo-Vilchez; Roque Hidalgo-Alvarez. Particles adsorbed at various non-aqueous liquid-liquid interfaces. Advances in Colloid and Interface Science 2017, 247, 208 -222.
AMA StyleMiguel Angel Fernandez-Rodriguez, Bernard P. Binks, Miguel Angel Rodriguez-Valverde, Miguel Angel Cabrerizo-Vilchez, Roque Hidalgo-Alvarez. Particles adsorbed at various non-aqueous liquid-liquid interfaces. Advances in Colloid and Interface Science. 2017; 247 ():208-222.
Chicago/Turabian StyleMiguel Angel Fernandez-Rodriguez; Bernard P. Binks; Miguel Angel Rodriguez-Valverde; Miguel Angel Cabrerizo-Vilchez; Roque Hidalgo-Alvarez. 2017. "Particles adsorbed at various non-aqueous liquid-liquid interfaces." Advances in Colloid and Interface Science 247, no. : 208-222.
F. Javier Montes Ruiz-Cabello; J.C. Rodríguez-Criado; M. Cabrerizo-Vílchez; M.A. Rodríguez-Valverde; G. Guerrero-Vacas. Towards super-nonstick aluminized steel surfaces. Progress in Organic Coatings 2017, 109, 135 -143.
AMA StyleF. Javier Montes Ruiz-Cabello, J.C. Rodríguez-Criado, M. Cabrerizo-Vílchez, M.A. Rodríguez-Valverde, G. Guerrero-Vacas. Towards super-nonstick aluminized steel surfaces. Progress in Organic Coatings. 2017; 109 ():135-143.
Chicago/Turabian StyleF. Javier Montes Ruiz-Cabello; J.C. Rodríguez-Criado; M. Cabrerizo-Vílchez; M.A. Rodríguez-Valverde; G. Guerrero-Vacas. 2017. "Towards super-nonstick aluminized steel surfaces." Progress in Organic Coatings 109, no. : 135-143.
Katarzyna Rudzka; Alda Y. Sanchez Treviño; Miguel Angel Rodriguez-Valverde; Miguel A. Cabrerizo-Vílchez. Formation of mixed and patterned self-assembled films of alkylphosphonates on commercially pure titanium surfaces. Applied Surface Science 2016, 389, 270 -277.
AMA StyleKatarzyna Rudzka, Alda Y. Sanchez Treviño, Miguel Angel Rodriguez-Valverde, Miguel A. Cabrerizo-Vílchez. Formation of mixed and patterned self-assembled films of alkylphosphonates on commercially pure titanium surfaces. Applied Surface Science. 2016; 389 ():270-277.
Chicago/Turabian StyleKatarzyna Rudzka; Alda Y. Sanchez Treviño; Miguel Angel Rodriguez-Valverde; Miguel A. Cabrerizo-Vílchez. 2016. "Formation of mixed and patterned self-assembled films of alkylphosphonates on commercially pure titanium surfaces." Applied Surface Science 389, no. : 270-277.
Titanium implant surface etching has proven an effective method to enhance cell attachment. Despite the frequent use of hydrofluoric (HF) acid, many questions remain unresolved, including the optimal etching time and its effect on surface and biological properties. The objective of this study was to investigate the effect of HF acid etching time on Ti topography, surface chemistry, wettability, and cell adhesion. These data are useful to design improved acid treatment and obtain an improved cell response. The surface topography, chemistry, dynamic wetting, and cell adhesiveness of polished Ti surfaces were evaluated after treatment with HF acid solution for 0, 2; 3, 5, 7, or 10 min, revealing a time-dependent effect of HF acid on their topography, chemistry, and wetting. Roughness and wetting increased with longer etching time except at 10 min, when roughness increased but wetness decreased. Skewness became negative after etching and kurtosis tended to 3 with longer etching time. Highest cell adhesion was achieved after 5–7 min of etching time. Wetting and cell adhesion were reduced on the highly rough surfaces obtained after 10-min etching time.
R. Zahran; J. I. Rosales Leal; Miguel Angel Rodriguez-Valverde; M. A. Cabrerizo Vílchez. Effect of Hydrofluoric Acid Etching Time on Titanium Topography, Chemistry, Wettability, and Cell Adhesion. PLOS ONE 2016, 11, e0165296 .
AMA StyleR. Zahran, J. I. Rosales Leal, Miguel Angel Rodriguez-Valverde, M. A. Cabrerizo Vílchez. Effect of Hydrofluoric Acid Etching Time on Titanium Topography, Chemistry, Wettability, and Cell Adhesion. PLOS ONE. 2016; 11 (11):e0165296.
Chicago/Turabian StyleR. Zahran; J. I. Rosales Leal; Miguel Angel Rodriguez-Valverde; M. A. Cabrerizo Vílchez. 2016. "Effect of Hydrofluoric Acid Etching Time on Titanium Topography, Chemistry, Wettability, and Cell Adhesion." PLOS ONE 11, no. 11: e0165296.
Colloidal interactions have been extensively studied due to the wide number of applications where colloids are present. In general, the electric double layer force and the van der Waals interaction dominate the net force acting between two colloids at large separation distances. However, it is well accepted that some other phenomena, especially those acting at short separation distances, might be relevant and induce substantial changes in the force profiles. Within these phenomena, those related to the surface contact angle, the hydration degree of the ions, or the pH, may dominate the force profiles features, not only at short distances. In this paper, we analyzed the effect of the pH and counterion type on the long-range as well as short-range forces between polystyrene colloidal particles by using the colloidal probe technique based on AFM. Our results confirm that the features of the force profiles between polystyrene surfaces are strongly affected by the pH and hydration degree of the counterions in solution. Additionally, we performed a study of the role of the pH on the wettability properties of hydrated and nonhydrated polystyrene sheets to scan the wettability properties of this material with pH. Contact angle measurements confirmed that the polystyrene surface is hydrophobic in aqueous solutions over the entire range of pHs investigated. These results are in good agreement with the features observed in the force profiles at low pH. At high pH, a short-range repulsion similar to the one observed for hydrophilic materials is observed. This repulsion scales with the pH, and it also depends on the hydration degree of the ions in solution. This way, the short-range forces between polystyrene surfaces may be tunable with the pH, and its origin does not seem to be related to the hydrophobicity of the material.
F. Javier Montes Ruiz-Cabello; T. Oncsik; Miguel Angel Rodriguez-Valverde; P. Maroni; M. Cabrerizo-Vilchez. Specific Ion Effects and pH Dependence on the Interaction Forces between Polystyrene Particles. Langmuir 2016, 32, 11918 -11927.
AMA StyleF. Javier Montes Ruiz-Cabello, T. Oncsik, Miguel Angel Rodriguez-Valverde, P. Maroni, M. Cabrerizo-Vilchez. Specific Ion Effects and pH Dependence on the Interaction Forces between Polystyrene Particles. Langmuir. 2016; 32 (45):11918-11927.
Chicago/Turabian StyleF. Javier Montes Ruiz-Cabello; T. Oncsik; Miguel Angel Rodriguez-Valverde; P. Maroni; M. Cabrerizo-Vilchez. 2016. "Specific Ion Effects and pH Dependence on the Interaction Forces between Polystyrene Particles." Langmuir 32, no. 45: 11918-11927.
Gold patchy nanoparticles (PPs) were prepared under surfactant-free conditions by functionalization with a binary ligand mixture of polystyrene and poly(ethylene glycol) (PEG) as hydrophobic and hydrophilic ligands, respectively. The interfacial activity of PPs was compared to that of homogeneous hydrophilic nanoparticles (HPs), fully functionalized with PEG, by means of pendant drop tensiometry at water/air and water/decane interfaces. We compared interfacial activities in three different spreading agents: water, water/chloroform, and pure chloroform. We found that the interfacial activity of PPs was close to zero (∼2 mN/m) when the spreading agent was water and increased to ∼14 mN/m when the spreading agent was water/chloroform. When the nanoparticles were deposited with pure chloroform, the interfacial activity reached up to 60 mN/m by compression. In all cases, PPs exhibited higher interfacial activity than HPs, which were not interfacially active, regardless of the spreading agent. The interfacial activity at the water/decane interface was found to be significantly lower than that at the water/air interface because PPs aggregate in decane. Interfacial dilatational rheology showed that PPs form a stronger elastic shell at the pendant drop interface, compared to HPs. The significantly high interfacial activity obtained with PPs in this study highlights the importance of the polymeric patchy shell and the spreading agent.
Miguel A. Fernández-Rodríguez; Ana M. Percebom; Juan J. Giner-Casares; Miguel A. Rodríguez-Valverde; Miguel A. Cabrerizo-Vílchez; Luis M. Liz-Marzán; Roque Hidalgo-Álvarez. Interfacial Activity of Gold Nanoparticles Coated with a Polymeric Patchy Shell and the Role of Spreading Agents. ACS Omega 2016, 1, 311 -317.
AMA StyleMiguel A. Fernández-Rodríguez, Ana M. Percebom, Juan J. Giner-Casares, Miguel A. Rodríguez-Valverde, Miguel A. Cabrerizo-Vílchez, Luis M. Liz-Marzán, Roque Hidalgo-Álvarez. Interfacial Activity of Gold Nanoparticles Coated with a Polymeric Patchy Shell and the Role of Spreading Agents. ACS Omega. 2016; 1 (2):311-317.
Chicago/Turabian StyleMiguel A. Fernández-Rodríguez; Ana M. Percebom; Juan J. Giner-Casares; Miguel A. Rodríguez-Valverde; Miguel A. Cabrerizo-Vílchez; Luis M. Liz-Marzán; Roque Hidalgo-Álvarez. 2016. "Interfacial Activity of Gold Nanoparticles Coated with a Polymeric Patchy Shell and the Role of Spreading Agents." ACS Omega 1, no. 2: 311-317.
The fabricated superhydrophobic galvanized steel surfaces possess a hierarchic micro/nano texture. Micro-texture is incorporated by sandblasting, while the nano-texture by “soft” acid etching. The design of durable superhydrophobic coatings for metal surfaces is a subject of interest and research. Galvanized steel is one of the most used metallic materials for components of automobiles, building structures and roofing. In spite of its wide number of applications, galvanized steel has been scarcely modified to reach superhydrophobicity. The main reason for this is that galvanized steel is essentially a zinc-coated steel surface and most of the strategies to prepare superhydrophobic coatings on metal substrates require partial removal of the surface material. For this reason, providing a non-aggressive strategy to create superhydrophobic galvanized steel (or other metal coated materials) is an important challenge. With this aim, we propose in this paper a methodology based on a two-step texturing process (sandblasting and “soft” acid-etching) followed by a fluoropolymer deposition as a non-invasive strategy to produce water repellent surfaces on this material. The roughness of the samples was analyzed by confocal microscopy and FE-SEM imaging, the surface chemical composition by EDX and the wettability properties by contact angle measurements. Our results show that both texturing methods are necessary to create hierarchically micro/nano-structured surfaces on galvanized steel. This structure induces superhydrophobic properties once the metal is subsequently Teflon-coated. Sandblasting introduces a micro-scale texture, while soft acid-etching incorporates nano-asperities.
Francisco Javier Montes Ruiz-Cabello; A. Amirfazli; M. Cabrerizo-Vílchez; Miguel Angel Rodriguez-Valverde. Fabrication of water-repellent surfaces on galvanized steel. RSC Advances 2016, 6, 71970 -71976.
AMA StyleFrancisco Javier Montes Ruiz-Cabello, A. Amirfazli, M. Cabrerizo-Vílchez, Miguel Angel Rodriguez-Valverde. Fabrication of water-repellent surfaces on galvanized steel. RSC Advances. 2016; 6 (76):71970-71976.
Chicago/Turabian StyleFrancisco Javier Montes Ruiz-Cabello; A. Amirfazli; M. Cabrerizo-Vílchez; Miguel Angel Rodriguez-Valverde. 2016. "Fabrication of water-repellent surfaces on galvanized steel." RSC Advances 6, no. 76: 71970-71976.
Since de Gennes coined in 1992 the term Janus particle (JP), there has been a continued effort to develop this field. The purpose of this review is to present the most relevant theoretical and experimental results obtained so far on the surface activity of amphiphilic JPs at fluid interfaces. The surface activity of JPs at fluid–fluid interfaces can be experimentally determined using two different methods: the classical Langmuir balance or the pendant drop tensiometry. The second method requires much less amount of sample than the first one, but it has also some experimental limitations. In all cases collected here the JPs exhibited a higher surface or interfacial activity than the corresponding homogeneous particles. This reveals the significant advantage of JPs for the stabilization of emulsions and foams.
Miguel Angel Fernandez Rodriguez; Miguel Angel Rodriguez-Valverde; Miguel Angel Cabrerizo-Vilchez; Roque Hidalgo-Alvarez. Surface activity of Janus particles adsorbed at fluid–fluid interfaces: Theoretical and experimental aspects. Advances in Colloid and Interface Science 2016, 233, 240 -254.
AMA StyleMiguel Angel Fernandez Rodriguez, Miguel Angel Rodriguez-Valverde, Miguel Angel Cabrerizo-Vilchez, Roque Hidalgo-Alvarez. Surface activity of Janus particles adsorbed at fluid–fluid interfaces: Theoretical and experimental aspects. Advances in Colloid and Interface Science. 2016; 233 ():240-254.
Chicago/Turabian StyleMiguel Angel Fernandez Rodriguez; Miguel Angel Rodriguez-Valverde; Miguel Angel Cabrerizo-Vilchez; Roque Hidalgo-Alvarez. 2016. "Surface activity of Janus particles adsorbed at fluid–fluid interfaces: Theoretical and experimental aspects." Advances in Colloid and Interface Science 233, no. : 240-254.