Article
Chemistry, Physical
Eunsang Lee, Florian Mueller-Plathe
Summary: The Cassie-Baxter state of wetting can explain the behavior of water droplets on superhydrophobic rough surfaces, including the equilibrium contact angle and the slippery dynamics. This study provides a deeper understanding of the contact line dynamics on rough surfaces using the molecular kinetic theory. The findings demonstrate the importance of additional friction forces and shed light on the origin of contact angle hysteresis.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Engineering, Chemical
Dipak Rana, Takeshi Matsuura, Christopher Q. Lan
Summary: The re-entrant structure of the membrane surface has been a focus of recent research due to its ability to enhance the wetting resistance of the membrane. This study evaluated the energy barrier of a cone-shaped pore and found that it can be enhanced by increasing the angle of the apex of the cone, the pore length, and the contact angle. The effects of the angle and pore length were found to be stronger than the contact angle. The findings of this study provide guidance for the rational design of membranes to reduce pore wetting, particularly for applications such as oil/water separation and membrane distillation.
Article
Chemistry, Multidisciplinary
Ronghe Xu, Xiaoli Zhao, Liqin Wang, Chuanwei Zhang, Yuze Mao, Lei Shi, Dezhi Zheng
Summary: The study simulated the wetting modes of a droplet on a periodical grooved surface using the Cellular Potts Model (CPM) and proposed an optimization approach based on Synthesis Minimum Energy (SME). The results showed that an increase in the fluctuation parameter T led to a transition in the wetting mode of the droplet. Additionally, the wetting mode of the droplet was also influenced by the pillar height and interpillar distance.
Article
Chemistry, Physical
Sarah Marie Loesslein, Frank Mucklich, Philipp G. Gruetzmacher
Summary: The wetting characterization and production of engineered surfaces with distinct contact angles or spreading behavior have significant importance in various industrial and scientific applications. The wetting behavior and droplet spreading on anisotropic surface patterns are highly dependent on both surface topography and chemistry. The study demonstrated that the combination of surface chemistry and directional patterns can result in anisotropic wetting behavior.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Chemistry, Physical
Chongyang Mai, Chengcheng Lv, Li Yang, Lielun Zhao, Yawen Guo, Yan Jiang, Hongwen Zhang
Summary: In this article, a raspberry-like particle-assisted breath figures method was introduced to fabricate superhydrophobic surfaces. SiO2 particles were generated on the surface of microspheres and then separated according to their structures. The superhydrophobic surface was prepared using the breath figures method. The adhesion of the surface could be transformed by changing the amount of microspheres added. The contact mode and the height to width ratio of the pores were also found to be key factors affecting the surface adhesion.
SURFACES AND INTERFACES
(2023)
Article
Chemistry, Physical
Mohamadreza Beitollahpoor, Melika Farzam, Noshir S. Pesika
Summary: Dynamic friction measurements provide a more accurate characterization of the wetting properties of superhydrophobic surfaces compared to contact angle and sliding angle measurements. The force-based technique reduces standard deviations and provides higher accuracy in determining sliding angles and stability transitions.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Multidisciplinary Sciences
Jubair A. A. Shamim, Yukinari Takahashi, Anjan Goswami, Nadeem Shaukat, Wei-Lun Hsu, Junho Choi, Hirofumi Daiguji
Summary: This study investigated the evaporation and wetting transition behavior of fakir droplets on different microstructured surfaces. The substrate used was diamond-like carbon, and the effect of varying the micro pillar dimensions was analyzed. The results showed that the interfacial properties of the surfaces influenced the evaporation behavior and wetting transition. An important finding was the demonstration of a slippery superhydrophobic surface that suppresses the transition to a wetted state for small droplets, without the need for large pillar height or multiscale roughness. The study also assessed the accuracy of theoretical models and developed a numerical model to compute droplet penetration within the micropillars.
SCIENTIFIC REPORTS
(2023)
Article
Chemistry, Physical
Khaloud Moosa Al Balushi, Khellil Sefiane, Daniel Orejon
Summary: This study investigates the effects of liquid surface tension and solid structure on the wetting and non-wetting behavior of droplets on solid substrates. The results show that the wetting behavior and droplet asymmetry are influenced by the liquid composition and structure spacing. A wetting regime map for a wide range of surface tension fluids and solid fractions is proposed.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Yujie Wang, Boce Zhang, Hanna Dodiuk, Shmuel Kenig, Carol Barry, JoAnn Ratto, Joey Mead, Zhen Jia, Sevil Turkoglu, Jinde Zhang
Summary: This study found that protein solutions significantly weaken the stability of air plastron (AP) on superhydrophobic (SHP) materials, mainly due to the surface tension of protein solutions and protein adsorption on SHP substrates.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Physics, Multidisciplinary
Joel De Coninck, Francois Dunlop, Thierry Huillet
Summary: The analytical expressions of liquid-vapor equilibrium contact angles are studied for various simple geometries and arrangements of the substrate, showing the relevance of intermediate wetting states in competition with the Wenzel and Cassie-Baxter states.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2021)
Article
Chemistry, Multidisciplinary
William S. Y. Wong, Doris Vollmer
Summary: This study presents the concept of passive on-demand recovery of the plastron through a chemical reaction (effervescence), offering a new approach for intervention-free and immersion-durable superhydrophobic/superamphiphobic surfaces.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Engineering, Chemical
Donovan Chaffart, Luis A. Ricardez-Sandoval
Summary: This study develops a Moving Front kinetic Monte Carlo (MFkMC) algorithm to study the behaviour of droplets on pillared superhydrophobic surfaces (SHSs). The model captures the stochastic evolution of droplets on an SHS based on the balance of forces along the droplet interface length. The proposed SHS-MFkMC model incorporates novel features to accommodate for the geometry and physics of SHS-based droplet spreading.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
K. Maghsoudi, G. Momen, R. Jafari
Summary: We fabricated hierarchical superhydrophobic silicone rubber surfaces using a direct replication method. Surface roughness ratios and equilibrium contact angles were calculated, and the contribution of submicrostructures on wettability properties was considered. Comparison between theoretical predictions and experimental measurements showed good agreement, providing valuable insights for the design and fabrication of superhydrophobic surfaces.
APPLIED MATERIALS TODAY
(2023)
Article
Soil Science
Helen M. Balshaw, Peter Douglas, Stefan H. Doerr
Summary: This study presents a new interpretation of anomalously high contact angles measured on non-flat surfaces, proposing a geometric correction factor to address this anomaly. Experimental data showed that applying this correction factor can adjust the measured contact angle to a value closer to the flat-plane contact angle, providing a useful tool for interpreting goniometer contact angle measurements on irregular surfaces.
Article
Materials Science, Multidisciplinary
Gunwoo Kim, Kyuin Park, Sungho Jin
Summary: The study demonstrates the preparation of a superhydrophobic polystyrene surface through a convenient synthesis method, which exhibits multiple stabilization wetting points and achieves superhydrophobicity through hierarchical roughness.
ACS APPLIED POLYMER MATERIALS
(2021)
Correction
Engineering, Chemical
Shuyana A. Heredia Deba, Bas A. Wols, Doekle R. Yntema, Rob G. H. Lammertink
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Mechanics
Naoki Hori, Chong Shen Ng, Detlef Lohse, Roberto Verzicco
Summary: This study investigates the behavior of immiscible and incompressible liquid-liquid flows in a Taylor-Couette geometry using direct numerical simulations coupled with the volume-of-fluid method and a continuum surface force model. The interactions between the interface and the Taylor vortices are studied by varying the secondary-phase volume fraction and the system Weber number. The results reveal two different flow regimes depending on the Weber number, namely an advection-dominated regime and an interface-dominated regime.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Engineering, Chemical
Moritz A. Junker, Wiebe M. de Vos, Joris de Grooth, Rob G. H. Lammertink
Summary: A novel method of making nanofiltration membranes is to use the Layer-by-Layer method, which involves coating polyelectrolytes alternately on a porous ultrafiltration membrane to form a controllable nanometer-thin separation layer known as Polyelectrolyte Multilayer (PEM). Understanding the structural properties of PEMs and their relationship to coating conditions and membrane performance is crucial for membrane optimization. In this study, the separation performance of NF PEM membranes based on different polymer systems (PDADMAC/PSS and PAH/PAA) was investigated by analyzing the structure of the membrane, particularly the pore size distribution.
JOURNAL OF MEMBRANE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Burak Akdeniz, Jeffery A. Wood, Rob G. H. Lammertink
Summary: Chemically induced transport methods provide new opportunities for colloidal transport in dead-end channel geometries. Diffusiophoresis, which involves particle movement under an electrolyte concentration gradient, has been previously demonstrated in such channels. This study shows that concentration-dependent zeta potentials are necessary for accurately describing particle transport in dead-end channels when the zeta potential strongly depends on electrolyte concentration. Simulations incorporating concentration-dependent zeta potentials match experimental observations, while simulations using constant zeta potentials fail to capture particle dynamics. These findings contribute to a better understanding of diffusiophoresis and the diffusio-osmosis process.
Article
Electrochemistry
Korcan Percin, Jonas Hereijgers, Nicolas Mulandi, Tom Breugelmans, Matthias Wessling
Summary: Complex geometries for electrodes pose a challenge in electrochemical applications. Slurry electrodes utilize complex flow distributors to enhance charge transfer between the current collector and slurry particles. In this study, titanium-based flow distributors produced by indirect 3D-printing were used to further improve electron transfer in vanadium redox flow applications. The titanium static mixers were coated with graphite to enhance activity for vanadium redox reactions. Heat treatment of the electrodes significantly improved anodic and cathodic current peaks, and testing in a redox flow cell showed discharge polarization of 110 mA cm(-2).
Article
Mechanics
Vatsal Sanjay, Srinath Lakshman, Pierre Chantelot, Jacco H. H. Snoeijer, Detlef Lohse
Summary: When a liquid drop falls on a solid substrate, the air film between them delays the contact. For impacts on smooth substrates, the air film can prevent wetting and cause bouncing. This paper investigates bouncing phenomena on viscous liquid films that mimic atomically smooth substrates and explores their repellency. The study reveals the mechanisms associated with the bouncing and non-bouncing transition and predicts the characteristics of drop impact using experiments, simulations, and a minimal model.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Engineering, Chemical
Shuyana A. Heredia Deba, Bas A. Wols, Doekle R. Yntema, Rob G. H. Lammertink
Summary: Membranes with different TiO2 top layer thicknesses were fabricated and characterized. The optimal photocatalyst thickness was found to be 2.74 μm for single-layer membranes, while an increase in degradation was observed for membranes with multiple TiO2 layers. A mass transport and reaction model was developed to describe the coating thickness effect.
JOURNAL OF MEMBRANE SCIENCE
(2023)
Article
Chemistry, Physical
Shuyana A. Heredia Deba, Bas A. Wols, Doekle R. Yntema, Rob G. H. Lammertink
Summary: The impact of UV light intensity and distribution on the semiconductor surface during the degradation of organic compounds in water was studied using a mono and a multi-LED lamp. The electromagnetic radiation profile on the surface of the membrane was scanned and evaluated. Comparing two lamp configurations, a 20% higher degradation was achieved with the most homogeneous light distribution. The surface reaction constant increased linearly with the irradiation intensity for the most homogeneous illumination distribution.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
(2023)
Article
Physics, Multidisciplinary
Jochem G. Meijer, Pallav Kant, Duco van Buuren, Detlef Lohse
Summary: Freezing of dispersions is a common phenomenon in science and technology. While the freezing process on solid particles is understood, it is not the case for soft particles. This study uses an oil-in-water emulsion to show that when engulfed by a growing ice front, soft particles undergo severe deformation, which is strongly dependent on the engulfment velocity. The deformation is mediated by interfacial flows in nanometric thin liquid films and can be modeled using a lubrication approximation.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Jonas Baessler, Tamara Oliveira, Robert Keller, Matthias Wessling
Summary: In this study, the researchers replaced the energy-intensive oxygen evolution reaction with partial methanol oxidation, reducing the energy demand and producing high-value chemicals. They achieved high current efficiencies for formaldehyde and formic acid production through paired CO2 reduction with electrochemical methanol oxidation.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Tobias Harhues, Maria Padligur, Franziska Bertram, Daniel Matthias Roth, John Linkhorst, Andreas Jupke, Matthias Wessling, Robert Keller
Summary: The electrochemical conversion of hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is demonstrated in this work, along with the biphasic dehydration of fructose to HMF. The integrated approach eliminates the need for intermediate purification as the HMF-rich phase is directly fed into the electrochemical reactor. The results show a promising synthesis process for green platform chemicals and provide insights into biphasic solutions in electrochemical conversions.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Lea Steinbeck, Dominik L. Braunmiller, Hanna J. M. Wolff, Vincent Huettche, Julia Wang, Matthias Wessling, Jerome J. Crassous, John Linkhorst
Summary: Complex-shaped microgels with active and remote orientational control have great potential in the field of soft metamaterials. This work introduces a method for spatio-temporal flow control using magnetically actuable microgels of complex shape, and demonstrates the concept in microfluidic impellers. The fabrication of these microgels is achieved through stop-flow lithography, and their magnetic response is comprehensively quantified. These complex-shaped microgels are then integrated as actuable impellers in a microfluidic chip, showcasing the versatility of the fabrication methodology.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Green & Sustainable Science & Technology
Matthias Hesselmann, Hannah Minten, Tristan Geissler, Robert Gregor Keller, Andre Bardow, Matthias Wessling
Summary: Electrolyzing carbon dioxide into valuable chemicals is a promising alternative to fossil fuel-based processes. Extensive research has focused on catalysis and electrode design, but the choice of ion exchange membrane for CO2 electrolysis from an economic perspective remains an important question. Holistic process optimization reveals that CO2 electrolysis using an anion exchange membrane achieves competitive production costs for CO, outperforming cation exchange and bipolar membranes. Contrary to common belief, the CO2 pumping effect does not significantly impact the economics and instead offers an efficient means of regenerating dissociated CO2.
ADVANCED SUSTAINABLE SYSTEMS
(2023)
Article
Chemistry, Multidisciplinary
Sunghak Park, Luhao Liu, Cayan Demirkir, Onno van der Heijden, Detlef Lohse, Dominik Krug, Marc T. M. Koper
Summary: Understanding and manipulating gas bubble evolution during electrochemical water splitting is crucial for optimizing the electrode/electrolyte/gas bubble interface. The study investigates gas bubble dynamics during the hydrogen evolution reaction on a platinum microelectrode by varying the electrolyte composition. The results reveal that the efficiency of microbubble coalescence follows the Hofmeister series of anions in the electrolyte, leading to different types of H-2 gas bubble evolution in different electrolytes.
Article
Chemistry, Multidisciplinary
Binglin Zeng, Haichang Yang, Ben Bin Xu, Detlef Lohse, Xuehua Zhang
Summary: According to Archimedes' principle, a submerged object with a lower density is more buoyant than a smaller one. In this study, a remarkable phenomenon is reported where a dissolving drop on a surface rises in water only after it has diminished to a smaller size. This phenomenon is controlled by the stick-jump behavior during drop dissolution and the Archimedes number greater than 1, signifying that buoyancy overcomes the viscosity of the surrounding medium. The study suggests that this novel mechanism for programmable drop rise may have important applications in microfluidics, microrobotics, and device engineering.
