The Experts below are selected from a list of 39912 Experts worldwide ranked by ideXlab platform
Frieder Mugele - One of the best experts on this subject based on the ideXlab platform.
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contact angle hysteresis and Oil film lubrication in electrowetting with two immiscible liquids
Applied Physics Letters, 2018Co-Authors: Niels Mendel, Davood Baratian, Frieder MugeleAbstract:Electrowetting (EW) of water drops in ambient Oil has found a wide range of applications including lab-on-a-chip devices, display screens, and variable focus lenses. The efficacy of all these applications is dependent on the contact angle hysteresis (CAH), which is generally reduced in the presence of ambient Oil due to thin lubrication Layers. While it is well-known that AC voltage reduces the effective contact angle hysteresis (CAH) for EW in ambient air, we demonstrate here that CAH for EW in ambient Oil increases with increasing AC and DC voltage. Taking into account the disjoining pressure of the fluoropolymer-Oil-water system, short range chemical interactions, viscous Oil entrainment, and electrostatic stresses, we find that this observation can be explained by progressive thinning of the Oil Layer underneath the drop with increasing voltage. This exposes the droplet to the roughness of the underlying solid and thereby increases hysteresis.
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contact angle hysteresis and Oil film lubrication in electrowetting with two immiscible liquids
arXiv: Fluid Dynamics, 2018Co-Authors: Niels Mendel, Davood Baratian, Frieder MugeleAbstract:Electrowetting (EW) of water drops in ambient Oil has found a wide range of applications including lab-on-a-chip devices, display screens, and variable focus lenses. The efficacy of all these applications is dependent on the contact angle hysteresis (CAH), which is generally reduced in the presence of ambient Oil due to thin lubrication Layers. While it is well-known that AC voltage reduces the effective contact angle hysteresis (CAH) for EW in ambient air, we demonstrate here that CAH for EW in ambient Oil increases with increasing AC and DC voltage. Taking into account the disjoining pressure of the fluoropolymer-Oil-water system, viscous Oil entrainment and electrostatic stresses, we find that this observation can be explained by progressive thinning with increasing voltage of the Oil Layer underneath the drop. This exposes the droplet to the roughness of the underlying solid and thereby increases hysteresis.
Baoliang Peng - One of the best experts on this subject based on the ideXlab platform.
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Molecular Dynamics Simulations of the Oil-Detachment from the Hydroxylated Silica Surface: Effects of Surfactants, Electrostatic Interactions, and Water Flows on the Water Molecular Channel Formation
Journal of Physical Chemistry B, 2018Co-Authors: Jian Tang, Zhou Qu, Lanyan He, Xianqiong Tang, Pingmei Wang, Ping Zhang, Bin Ding, Baoliang PengAbstract:The detachment process of an Oil molecular Layer situated above a horizontal substrate was often described by a three-stage process. In this mechanism, the penetration and diffusion of water molecules between the Oil phase and the substrate was proposed to be a crucial step to aid in removal of Oil Layer/drops from substrate. In this work, the detachment process of a two-dimensional alkane molecule Layer from a silica surface in aqueous surfactant solutions is studied by means of molecular dynamics (MD) simulations. By tuning the polarity of model silica surfaces, as well as considering the different types of surfactant molecules and the water flow effects, more details about the formation of water molecular channel and the expansion processes are elucidated. It is found that for both ionic and nonionic type surfactant solutions, the perturbation of surfactant molecules on the two-dimensional Oil molecule Layer facilitates the injection and diffusion of water molecules between the Oil Layer and silica sub...
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Molecular Dynamics Simulations of the Oil-Detachment from the Hydroxylated Silica Surface: Effects of Surfactants, Electrostatic Interactions, and Water Flows on the Water Molecular Channel Formation
2018Co-Authors: Jian Tang, Xianqiong Tang, Pingmei Wang, Ping Zhang, Bin Ding, Jianhui Luo, Yong Pei, Baoliang PengAbstract:The detachment process of an Oil molecular Layer situated above a horizontal substrate was often described by a three-stage process. In this mechanism, the penetration and diffusion of water molecules between the Oil phase and the substrate was proposed to be a crucial step to aid in removal of Oil Layer/drops from substrate. In this work, the detachment process of a two-dimensional alkane molecule Layer from a silica surface in aqueous surfactant solutions is studied by means of molecular dynamics (MD) simulations. By tuning the polarity of model silica surfaces, as well as considering the different types of surfactant molecules and the water flow effects, more details about the formation of water molecular channel and the expansion processes are elucidated. It is found that for both ionic and nonionic type surfactant solutions, the perturbation of surfactant molecules on the two-dimensional Oil molecule Layer facilitates the injection and diffusion of water molecules between the Oil Layer and silica substrate. However, the water channel formation and expansion speed is strongly affected by the substrate polarity and properties of surfactant molecules. First, only for the silica surface with relative stronger polarity, the formation of water molecular channel is observed. Second, the expansion speed of the water molecular channel upon the ionic surfactant (dodecyl trimethylammonium bromide, DTAB and sodium dodecyl benzenesulfonate, SDBS) flooding is more rapidly than the nonionic surfactant system (octylphenol polyoxyethylene(10) ether, OP-10). Third, the water flow speed may also affect the injection and diffusion of water molecules. These simulation results indicate that the water molecular channel formation process is affected by multiple factors. The synergistic effects of perturbation of surfactant molecules and the electrostatic interactions between silica substrate and water molecules are two key factors aiding in the injection and diffusion of water molecules and helpful for the Oil detachment from silica substrate
Utai Klinkesorn - One of the best experts on this subject based on the ideXlab platform.
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Influence of rice bran stearin on stability, properties and encapsulation efficiency of polyglycerol polyricinoleate (PGPR)-stabilized water-in-rice bran Oil emulsions
Food Research International, 2017Co-Authors: Nattapong Prichapan, David Julian Mcclements, Utai KlinkesornAbstract:Abstract In the present study, rice bran stearin was used to improve the physical stability and encapsulation efficiency of water-in-Oil (W/O) emulsions fabricated from rice bran Oil and polyglycerol polyricinoleate ester (PGPR). In the absence of rice bran stearin, the emulsions were highly unstable to phase separation with an Oil Layer forming on their surfaces. Phase separation was delayed by increasing the PGPR concentration because this reduced the water droplet size. Phase separation could be completely inhibited by replacement of 30 to 45 wt% of rice bran Oil with rice bran stearin due to the formation of a semi-solid fat crystal network that prevented droplet movement. Moreover, addition of rice bran stearin delayed the release of ferrous sulfate from the W/O emulsions. These results demonstrate that rice bran stearin can be used to improve the stability and encapsulation efficiency of W/O emulsions and reduce the level of PGPR required to stabilize them.
Alban Sauret - One of the best experts on this subject based on the ideXlab platform.
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Drop impact dynamics on slippery liquid-infused porous surfaces: influence of Oil thickness
Soft Matter, 2018Co-Authors: Mégane Muschi, Barbara Brudieu, Jérémie Teisseire, Alban SauretAbstract:Slippery liquid-infused porous surfaces (SLIPS) are porous nanostructures impregnated with a low surface tension lubricant. They have recently shown great promise in various applications that require non-wettable superhydrophobic surfaces. In this paper, we investigate experimentally the influence of the Oil thickness on the wetting properties and drop impact dynamics of new SLIPS. By tuning the thickness of the Oil Layer deposited through spin-coating, we show that a sufficiently thick Layer of Oil is necessary to avoid dewetting spots on the porous nanostructure and thus increasing the homogeneity of the liquid distribution. Drop impact on these surfaces is investigated with a particular emphasis on the spreading and rebound dynamics when varying the Oil thickness and the Weber number.
Sannakaisa Virtanen - One of the best experts on this subject based on the ideXlab platform.
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corrosion behavior of a slippery liquid infused porous surface on anodized stainless steel
Materials Letters, 2021Co-Authors: Lucia Helena Prado, Evangelia Anastasiou, Sannakaisa VirtanenAbstract:Abstract In this work we present fabrication of slippery liquid infused porous surface (SLIPS) for anodized stainless steel AISI 316L. First, a porous sponge-like oxide Layer was grown that subsequently was functionalized with perfluorinated molecules and finally infused with fluorinated Krytox Oil. Morphology, composition analysis and wettability (also after corrosion testing) were characterized. Furthermore, corrosion behavior was studied with potentiodynamic polarization curves in 0.1 M H2SO4 and 0.1 M NaCl electrolytes. Our results demonstrate that the SLIPS coating protects the underlying material from corrosion, and the self-healing properties of the Oil Layer allow to recover localized damage during corrosion experiments.
