Article
Chemistry, Physical
Jinming Zhang, Wei Ding, Uwe Hampel
Summary: This study deconstructs a complex surface defect into three primary surface defects and uses large-scale Molecular Dynamics simulations to investigate the mechanisms of droplet-solid static friction forces induced by these defects. Three element-wise static friction forces related to the primary surface defects are revealed, and it is found that the static friction force induced by chemical heterogeneity is contact line length dependent while the static friction force induced by atomic structure and topographical defect is contact area dependent. The latter causes energy dissipation and leads to a wiggle movement of the droplet during the static-kinetic friction transition.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2023)
Article
Nanoscience & Nanotechnology
Jack Dawson, Samual Coaster, Rui Han, Johannes Gausden, Hongzhong Liu, Glen McHale, Jinju Chen
Summary: This study investigates the dynamics of droplets impacting three hydrophobic slippery surfaces and finds that the impact regime strongly depends on the surface properties. The findings provide insights for selecting surface properties to achieve desirable droplet impact characteristics.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Chemical
Ziqi Li, Guina Yi, Ziqi Cai, Zhengming Gao
Summary: In this study, the behavior of two non-Newtonian droplets during their impingement and mixing on a solid surface was investigated using the Many Body Dissipative Particle Dynamics method. The relationship between droplet morphology and the Weber number of the impinging droplet was studied, and the mixing process was divided into two stages dominated by convection and molecular diffusion, respectively. The study also revealed a special phenomenon in the mixing process caused by the difference in particle diffusion coefficients.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Physics, Multidisciplinary
Katrina Smith-Mannschott, Qin Xu, Stefanie Heyden, Nicolas Bain, Jacco H. Snoeijer, Eric R. Dufresne, Robert W. Style
Summary: This study found that a stretched soft substrate can exhibit asymmetric wetting behavior, affecting the sliding and static shape of droplets. The stretch significantly influences droplet dynamics, and static droplets appear elongated, all due to droplet-induced deformations of the substrate.
PHYSICAL REVIEW LETTERS
(2021)
Article
Thermodynamics
Datta Prasad, Susmita Dash
Summary: In this study, a theoretical model is proposed to determine the total heat transfer to a Leidenfrost droplet on microtextured substrates, considering the curved shape of the liquid-vapor interface. The results show that the vapor gap and flow field beneath the Leidenfrost droplet on a microtextured substrate depend on the substrate morphology, and the shape of the liquid-vapor interface influences the evaporation rate on the substrate.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Chemistry, Physical
Yukihiro Yonemoto, Minori Yamashita, Kanta Tashiro, Tomoaki Kunugi
Summary: The splashing of droplets on solid surfaces is a complex behavior affected by liquid properties, impingement velocity, and solid surface properties. Understanding the behavior of the unstable liquid film during splashing is still challenging. This study proposes new models that consider the liquid film thickness and surface wettability and roughness, to characterize the number and size of ejected secondary droplets. Experimental data align well with the predictions of the proposed model, providing insights into the mechanism of rim or liquid film fragmentation.
COLLOID AND INTERFACE SCIENCE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Josua Grawitter, Holger Stark
Summary: The study shows that droplets exhibit stable oscillations on substrates with oscillating uniform wettability, with the amplitude decreasing as frequency increases. For slow oscillations, numerical results align well with the linearized spherical-cap model, while significant deviations are observed for fast oscillations.
Article
Thermodynamics
Pradeep Gurrala, Saravanan Balusamy, Sayak Banerjee, Kirti Chandra Sahu
Summary: This study investigates the evaporation of pure ethanol, water, and ethanol-water binary droplets on one-dimensional cylindrical substrates using shadowgraphy and infrared imaging techniques. The results reveal different wetting behaviors of droplets on curved and flat substrates, and the three-dimensional solid modeling provides insights into the morphological evolution during evaporation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Chemistry, Multidisciplinary
Anastasia Islamova, Pavel Tkachenko, Nikita Shlegel, Geniy Kuznetsov
Summary: The study investigated the effects of different liquid properties on the collision behavior between droplets and solid particles, identifying the collision regimes and characteristics of secondary liquid fragments. Guidelines were provided for the development of liquid droplet secondary atomization technologies in gas-vapor-droplet applications.
APPLIED SCIENCES-BASEL
(2022)
Article
Physics, Fluids & Plasmas
S. Amiri, C. A. Volkert, R. L. C. Vink
Summary: The study reveals that sliding friction is maximal at specific resonance velocities, and partially thermalized states may occur off-resonance, while anharmonicity and defects lead to higher friction. Thermalization begins with vibrations compatible with the lattice for sliders with periodic boundaries, and with vibrations corresponding to the slider radius for disk-shaped sliders.
Article
Chemistry, Multidisciplinary
Jingang Li, Pavana Siddhartha Kollipara, Ya Liu, Kan Yao, Yaoran Liu, Yuebing Zheng
Summary: Motors that can convert different forms of energy into mechanical work play a crucial role in the development of human societies. The miniaturization of motors to the nanoscale is challenging due to the strong Brownian motion in liquid environments. In this study, we develop light-driven optothermocapillary nanomotors that can operate on solid substrates, effectively suppressing the interference of Brownian motion. Our nanomotors demonstrate robust orbital rotation and have the capability to power functional devices at the nanoscale.
Article
Materials Science, Multidisciplinary
Arun K. Singh, Vinay A. Juvekar, Jayesh R. Bellare
Summary: This article presents a model for the dynamics of relaxation of friction stress at the interface between soft and hard surfaces during the hold phase of the SHS experiment. The model is validated using experimental data on sliding of gelatin hydrogels on glass substrate, and proposes scaling laws based on the dynamic shear modulus of the gelatin hydrogel.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Chemistry, Physical
Israr Ahmad, Manabendra Pathak, Mohd Kaleem Khan
Summary: This work presents numerical and experimental techniques for studying electrowetting-induced oscillating water droplets on surfaces with different hydrophobicity. The results show that the hydrophobicity of the surface affects the deformation, internal flow structures, amplitude, and frequency of the oscillating droplets. Additionally, a simplified analytical model is developed to establish the correlation between the maximum amplitude of the oscillating droplets and the static contact angle.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Chemistry, Physical
Josua Grawitter, Holger Stark
Summary: In this study, a boundary-element method was used to simulate the movement of droplets on substrates with spatio-temporal wettability patterns. It was found that droplets move towards higher wettability regions in step profile wettability patterns and a feedback loop can maintain a constant velocity for droplets surfing on wettability steps.
Article
Mechanics
Abbasali Bagheri, Mohammad Sadegh Aghareb Parast, Abdolvahed Kami, Mohammad Azadi, Vahid Asghari
Summary: This study utilized rotary friction welding to connect 3D printed parts with non-printed parts, and evaluated the fatigue strength of the weld joints through fatigue testing. The results showed that non-welded ABS, solid ABS/solid ABS, solid ABS/3D printed ABS, and solid ABS/3D printed PLA had the best fatigue performance.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2022)
Article
Chemistry, Physical
Mark Frenkel, Alexander A. Fedorets, Leonid A. Dombrovsky, Michael Nosonovsky, Irina Legchenkova, Edward Bormashenko
Summary: Symmetry and orderliness of two-dimensional levitating microdroplet clusters were quantified using Voronoi entropy and continuous symmetry measure. The correlation between the two measures was investigated, with the maximum correlation found for clusters enabling the formation of hexagons. However, in certain cases, the maxima of symmetry and orderliness measures may not be well correlated.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Pritam Kumar Roy, Irina Legchenkova, Shraga Shoval, Edward Bormashenko
Summary: The study shows that interfacial crystallization occurs in Janus saline marbles, which is in line with the theory of heterogeneous nucleation. The energetic barrier of heterogeneous nucleation is smaller for the saline/carbon black hemisphere, leading to crystal formation. In the case of half-coated marbles, crystallization starts from the equatorial contact line separating the coated and naked hemispheres.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Physics, Multidisciplinary
Edward Bormashenko
Summary: This study addresses minimal rotating thermodynamic systems and examines the conditions for recording and erasing information as well as the role of symmetry.
Article
Physics, Multidisciplinary
Edward Bormashenko
Summary: The study explores the temperature-dependent entropic force between a matrix of magnets and direct current, finding that the entropic force acts as repulsion at a large distance and scales with temperature.
Article
Chemistry, Multidisciplinary
Edward Bormashenko, Irina Legchenkova, Mark Frenkel, Nir Shvalb, Shraga Shoval
Summary: In this paper, informational (Shannon) measures of symmetry for patterns built of 1D and 2D shapes are introduced and analyzed. These measures characterize the uncertainty and appearance of symmetry elements in a pattern, are independent of pattern size and shape quantity, and are robust to long-range order. Additionally, the paper discusses the measures' applications in fractal patterns, mixed patterns, time evolution, and chemical reaction analysis.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Physical
Anfisa Ayalon, Alexander Rubowitz, Pritam Kumar Roy, Shraga Shoval, Irina Legchenkova, Edward Bormashenko
Summary: This paper focuses on the behavior, migration, and distribution of commonly injected ophthalmic drugs in eyes filled with medical-grade silicone oil. The results from in vitro and ex vivo models show that the drugs quickly sink in the silicone oil and spread over the retinal surface, suggesting their effective use in eyes with silicone oil tamponade.
SURFACE INNOVATIONS
(2022)
Review
Physics, Multidisciplinary
Irina Legchenkova, Mark Frenkel, Nir Shvalb, Shraga Shoval, Oleg V. Gendelman, Edward Bormashenko
Summary: This study reports the properties of Voronoi tessellations generated from random 2D distribution points. By applying an iterative procedure, order can be introduced into an initially disordered system. However, the Shannon entropy is not an accurate measure of the level of order in the patterns.
Article
Physics, Multidisciplinary
Edward Bormashenko, Irina Legchenkova, Mark Frenkel, Nir Shvalb, Shraga Shoval
Summary: We used a complete set of convex pentagons to achieve a plane filling without any overlaps or gaps using Voronoi tessellations. The Shannon entropy of the tessellations was calculated and it varied widely. We found that the most abundant Voronoi tessellations are made up of pentagons, hexagons, and heptagons, with pentagons and hexagons being the most common polygons.
Article
Chemistry, Physical
Anton Starostin, Vladimir Strelnikov, Leonid A. Dombrovsky, Shraga Shoval, Oleg Gendelman, Edward Bormashenko
Summary: The freezing of water droplets on bare and superhydrophobic surfaces of polymer wedges was investigated both experimentally and computationally. Numerical calculations revealed that the direction of heat flux from the droplet through the thermal contact region with the wedge differs significantly from the normal to the wedge surface. A new computational model was proposed to account for the variable area of the water freezing front in the droplet, which accurately predicted the faster freezing on bare surface. The experimental results showed that the direction of the freezing cone axis was noticeably different for bare and superhydrophobic wedge surfaces due to the influence of the local heat flux direction.
SURFACE INNOVATIONS
(2023)
Article
Multidisciplinary Sciences
Mark Frenkel, Irina Legchenkova, Nir Shvalb, Shraga Shoval, Edward Bormashenko
Summary: This study reports on Voronoi mosaics inspired by seed points placed on the Archimedes Spirals. Voronoi (Shannon) entropy was calculated for these patterns. Equidistant and non-equidistant patterns were examined. The Voronoi tessellations generated by the seeds located on the Archimedes spiral demonstrated a switch in their chirality with linearly growing radial distance. The study also discusses the aesthetic attraction of the Voronoi mosaics arising from seed points placed on the Archimedes Spirals.
Article
Mathematics
Nir Shvalb, Mark Frenkel, Shraga Shoval, Edward Bormashenko
Summary: In this paper, we use the Ramsey theory to study the geometrical characteristics of closed contours. By examining a set of six points arranged on a closed contour and connected as a complete graph, we find that the curve must contain at least one monochromatic triangle. This finding has practical applications in dynamical billiards. We also discuss Ramsey constructions arising from differential geometry and the applications of the Ramsey theory.
Article
Physics, Multidisciplinary
Mark Frenkel, Shraga Shoval, Edward Bormashenko
Summary: This paper introduces and calculates Shannon entropy for bi-colored Ramsey complete graphs, with up to six vertices. The graphs considered are complete graphs with two types of links, alpha-links and beta-links. The Shannon entropy is introduced to describe the uncertainty of monochromatic polygons in the given complete graph, and it is insensitive to the exact shape of the polygons but sensitive to their distribution. The suggested Shannon entropies, S alpha and S beta, are interpreted as the average uncertainty of finding specific colored polygons in the graph.
Article
Chemistry, Multidisciplinary
Abhishek Kaushal, Shraga Shoval, Bernard P. Binks, Edward Bormashenko
Summary: The impact of liquid marbles coated with different hydrophobic powders on various solid substrates was investigated. The contact time of the bouncing marbles was studied and a scaling behavior of the contact time as a function of Weber number was established. The spreading time and retraction time of the marbles were found to be weakly dependent on the Weber number. The scaling law changed at a threshold Weber number, which was attributed to the breaking of the Leidenfrost regime.
Article
Chemistry, Physical
Pritam Kumar Roy, Shraga Shoval, Nir Shvalb, Leonid A. Dombrovsky, Oleg Gendelman, Edward Bormashenko
Summary: In this paper, the deformation of a paraffin wax droplet during solidification is studied through experiments and numerical simulations. It is found that the droplet's upper surface becomes nearly flat and a dimple is formed in the center, resembling the shape of a fruit. The formation of the dimple is attributed to the presence of the mushy zone between the liquidus and solidus of the paraffin wax. These findings contribute to a better understanding of the deformation mechanism of paraffin wax droplets.
Article
Physics, Fluids & Plasmas
Mark Frenkel, Alexander A. Fedorets, Dmitry V. Shcherbakov, Leonid A. Dombrovsky, Michael Nosonovsky, Edward Bormashenko
Summary: In this study, scaling laws for polymer chains in two-dimensional levitating microdroplet clusters were examined. The results confirmed the predicted power exponent for 2D polymer chains and demonstrated the applicability of the Kramers theorem for branched droplet chains.
