Liquid Surface Energy Research Articles

Wet adhesion on rough surfaces: A JKR model with thermodynamic considerations

Understanding wet adhesion is vital for advancing technologies such as underwater robotics, aquatic microsystems, and sweat-interfaced devices. It involves the formation of a liquid bridge with a meniscus between two solid surfaces. This phenomenon has a significant impact on surface adhesion, particularly in relation to roughness. Determining the profile of this liquid bridge is critical for accurately characterizing wet adhesion. In this paper, we propose a JKR mechanical model combined with a thermodynamic approach to investigate adhesive contact between a spherical indenter and an axisymmetric wavy surface in a wetting environment. The numerical solution for the pull-off force is obtained by considering parameters such as waviness, roughness, liquid volume, and liquid surface energy. The theoretical findings validated by experimental results provide insights into wet adhesion mechanisms on rough surfaces.

A volume of fluid method for three dimensional direct numerical simulations of immiscible droplet collisions

This paper presents an advanced Volume of Fluid (VOF) method that enables performant three dimensional Direct Numerical Simulations (DNS) of the interaction of two immiscible fluids in a gaseous environment with large topology changes, e.g., binary droplet collisions. One of the challenges associated with the introduction of a third immiscible phase into the VOF method is the reconstruction of the phase boundaries near the triple line in arbitrary arrangements. For this purpose, an efficient method based on a Piecewise Linear Interface Calculation (PLIC) is shown. Moreover, the surface force modeling with the robust Continuous Surface Stress (CSS) model was enhanced to treat such three-phase situations with large topology changes and thin films. A consistent scaling of the fluid properties at the interfaces ensures energy conservation.The implementation of these methods in the multi-phase flow solver Free Surface 3D (FS3D) allowed a successful validation. A qualitative comparison of the morphology in binary collisions of immiscible droplets as well as a quantitative comparison regarding the threshold velocities that distinguish different collision regimes shows excellent agreement with experimental results.These simulations enable the evaluation of experimentally inaccessible data like the contributions of kinetic, surface and dissipative energy of both immiscible liquids during the collision process. Furthermore, the comparison against binary collisions of the same liquids highlights similarities and differences between immiscible and equal droplet collisions. Both can support the modeling of the immiscible liquid interaction in the future.

Transforming Droplets into Liquid Films in Nanochannels under Rotating Electric Fields Studied by Molecular Dynamics.

It is first proposed to use a rotating electric field to stretch a droplet into a liquid film pinned to the insulated channel inner wall as a new type of active liquid valve. The molecular dynamics (MD) simulations are performed to prove that droplets in nanochannels can be stretched and expanded into closed liquid films under the action of rotating electric fields. The variations of the liquid cross-sectional area and droplet surface energy with time are calculated. The liquid film formation occurs mainly through two modes: gradual expansion and liquid column rotation. In most cases, increasing the electric field strength and angular frequency favors liquid film closing. At higher angular frequencies, decreasing the angular interval favors liquid film closing. The opposite is true at lower angular frequencies. The process of closing the hole-containing liquid film, which has formed a dynamic equilibrium, is a surface energy increase process, which requires greater electric field strength and angular frequency.

Additive Engineering Enables Ionic-Liquid Electrolyte-Based Supercapacitors To Deliver Simultaneously High Energy and Power Density

Ionic liquid (IL) electrolytes with a high potential window are promising candidates to high-energy-density supercapacitors; however, they commonly suffer from serious kinetic barriers that lead to poor power density. In this work, we propose an additive engineering method to promote rapid dynamics of IL-based supercapacitors. Additive engineering is based on adding cetyltrimethylammonium bromide-grafted Ti3C2 MXene (Ti3C2-CTAB) into 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4), a typical IL electrolyte for supercapacitors. Remarkably, IL electrolytes show a considerable increase by 38% in ionic conductivity and great reduction in solid–liquid surface energy from 18.03 to 12.37 mN m–1. We prove that electrostatic force and hydrogen bonds generated from the interaction between Ti3C2-CTAB and EMIMBF4 facilitate considerable dissociation of electrolyte ion pairs and ion-transfer capability. Consequently, additive engineering-designed IL-based supercapacitors deliver simultaneously a high energy density of 28.3 Wh kg–1 and power density of 18.3 kW kg–1. The increased high-power characteristics are supported by a faster ion diffusion coefficient (1.50 × 10–12 vs 4.04 × 10–13 cm2 s–1) and shorter relaxation time (3.83 vs 6.81 s). In addition, additive engineering guarantees a stable cycling life of 83.6% capacitance retention after 9000 cycles at the depth potential window from 0 to 3.0 V.

Modeling liquid penetration into porous materials based on substrate and liquid surface energies

HypothesisThe widely used Lucas-Washburn (LW) equation depends on the contact angle as the driving force for liquid penetration. However, the contact angle depends on both, the liquid and the substrate. It would be desirable to predict the penetration into porous materials, without the requirement to measure the solid–liquid interaction. Here, we propose a novel modeling approach for liquid penetration from mutually independent substrate- and liquid properties. For this purpose, the contact angle in the LW-equation is replaced by polar and dispersive surface energies, utilizing the theories of Owens-Wendt-Rabel-Kaelble (OWRK), Wu, or van Oss, Good, Chaudhury (vOGC). ExperimentsThe proposed modelling approach is validated exhaustively by measuring penetration speed for 96 substrate-liquid pairings and comparing the results to model predictions based on literature- and measured data. FindingsLiquid absorption is predicted very well (R2 = 0.8–0.9) with all three approaches, spanning a wide range of penetration speed, substrate- and liquid surface energy, viscosity, and pore size. The models for liquid penetration without measurement of solid–liquid interaction (contact angle) performed well. Modeling calculations are entirely relying on physical data of the solid and the liquid phase (surface energies, viscosity and pore size), which can be measured or retrieved from databases.

Molecular Visual Sensing, Boolean Logic Computing, and Data Security Using a Droplet-Based Superwetting Paradigm.

Inspired by information processing and logic operations of life, many artificial biochemical systems have been designed for applications in molecular information processing. However, encoding the binary synergism between matter, energy, and information in a superwetting system remains challenging. Herein, a superwetting paradigm was proposed for multifunctional applications including molecular visual sensing and data security on a superhydrophobic surface. A Triton X-100-encapsulated gelatin (TeG) hydrogel was prepared and selectively decomposed by trypsin, releasing the surfactant to decrease the surface tension of a droplet. Integrating the droplet with the superhydrophobic surface, the superwetting behavior was utilized for visual detection and information encoding. Interestingly, the proposed TeG hydrogel can function as an artificial gelneuron for molecular-level logic computing, where the combination of matters (superhydrophobic surface, trypsin, and leupeptin) acts as inputs to interact with energy (liquid surface tension and solid surface energy) and information (binary character), resulting in superwettability transitions (droplet surface tension, contact angle, rolling angle, and bounce) as outputs. Impressively, the TeG gelneuron can be further developed as molecular-level double cryptographic steganography to encode, encrypt, and hide specific information (including the maze escape route and content of the classical literature) due to its programmability, stimuli responsive ability, and droplet concealment. This study will encourage the development of advanced molecular paradigms and their applications, such as superwetting visual sensing, molecular computing, interaction, and data security.

The role of crosslinking density in surface stress and surface energy of soft solids.

Surface stress and surface energy are two fundamental parameters that determine the surface properties of any material. While it is commonly believed that the surface stress and surface energy of liquids are identical, the relationship between the two parameters in soft polymeric gels remains debatable. In this work, we measured the surface stress and surface energy of soft silicone gels with varying weight ratios of crosslinkers in soft wetting experiments. Above a critical density, k0, the surface stress was found to increase significantly with crosslinking density while the surface energy remained unchanged. In this regime, we can estimate a non-zero surface elastic modulus that also increases with the ratio of crosslinkers. By comparing the surface mechanics of the soft gels with their bulk rheology, the surface properties near the critical density k0 were found to be closely related to the underlying percolation transition of the polymer networks.

Numerical simulation of two-phase droplets on a curved surface using Surface Evolver

In this paper, we present a new approach for using the Surface Evolver (SE) finite element program to simulate the 3-D shape of a droplet on a curved surface. The approach proposed in this paper circumvents the need for carrying out complicated derivations to obtain analytical expressions for the total energy of the interfacial areas between air, liquid, and solid surfaces. More specifically, we use the solid–liquid surface energy in place of the contact angle when simulating a droplet using SE. This approach also makes it easier to use SE to model a two-phase droplet (e.g., a compound droplet) on a solid surface. To better illustrate our approach, the 3-D shape of single-phase and compound pendant droplets are simulated on a hydrophobic spherical surface in the presence of gravitational and magnetic fields. For validation purposes, our computational results are compared to dedicated experimental data obtained by compounding water droplets with oil-based ferrofluids of different surface tensions. • Droplet shape on a curved surface is simulated in a magnetic field using Surface Evolver. • The use of solid–liquid surface energy is proposed for Surface Evolver simulations. • Effective surface tension can be used in Surface Evolver to simulate a two-phase droplet. • Modeling of multiphase droplets is feasible using the proposed solid–liquid energy approach.

On the limitations of the applicability of Young’s equations temperature

The article uses the thermodynamics of interfacial phenomena to justify the fact that Young’s equations can correctly describe the three-phase equilibrium with any type of interatomic bonds. Wetting, adhesion, dissolution, surface adsorption, and other surface phenomena are important characteristics, whichlargely determine the quality and durability of materials, and the development of a number of production techniques, including welding, soldering, baking of metallic and non-metallic powders, etc. Therefore, it is important to study them.Using experimental data regarding surface energies of liquids (melts) and contact angles available in the literature, we calculated the surface energies of many solid metals, oxides, carbides, and other inorganic and organic materials without taking into account the amount of the interfacial energy at the solid-liquid (melt) interface. Some researchers assumed that in case of an acute contact angle the interfacial energy is low. Therefore, they neglected it and assumed it to be zero.Others knew that this value could not be measured, that is why they measured and calculated the difference between the surface energy of a solid and the interfacial energy of a solid and a liquid (melt), which is equal to the product of the surface energy of this liquid by the cosine of the contact angle. It is obvious that these methods of determining the surface energy based on such oversimplified assumptions result in poor accuracy.Through the use of examples this paper shows how the surface energies of solids were previously calculated and how the shortcomings of previous calculations can be corrected

Enhancing oil recovery using silica nanoparticles: Nanoscale wettability alteration effects and implications for shale oil recovery

Enhanced oil recovery (EOR) techniques have the potential to improve recovery in unconventional shale oil reservoirs which have prolific short-term success but elusive near-to-long term outlook. The use of silicon dioxide nanoparticles for enhancing shale oil recovery has recently gained significant attention in the oil industry. However, the technique remains novel partly due to inadequate fundamental understanding of oil release mechanisms. Herein, the oil recovery potential of untreated and treated silica nanoparticles is investigated using an atomic force microscope (AFM) by studying nanoscale interactions between different crude oil functional species and substrates of pure minerals found in a shale oil reservoir. Quartz and muscovite mica (clay substitute) were employed as substrates as these are the dominant rock minerals identified in the most productive zone of Tuscaloosa Marine Shale (TMS). Thiolates of undecane (CH3) and phenyl (C6H5) compounds were used to simulate alkane and aromatic fractions of TMS crude oil respectively, while undecanoic acid (COOH) thiol was used to represent carboxylic acid found in asphaltene and resin components. Following our in-house experimental protocol for liquid cell force spectroscopy, adhesion forces and surface energies between functionalized AFM probes and mineral substrates were characterized in untreated and amino-treated silica nanoparticle dispersions. Zeta potential of respective nanofluid solutions was measured and AFM adsorption data were supported with scanning electron microscope (SEM) micrographs of TMS rock samples. Results showed that aqueous dispersions of hydrophilic silicon dioxide nanoparticles promote wettability towards a less oil-wet state by significantly lowering the adhesion force and energy barrier to spontaneously detach oil molecules from clay and quartz mineral surfaces in shale reservoirs, shown at the nanoscale with AFM studies. However, the grafting of aminosilanes onto surfaces of silica nanoparticles generally increased adhesion forces and surface energies due to surface charge effect and hydrophobicity. Findings pertinent to nanoparticle silanization were consistent in molecular interactions on mica in nanofluids but not necessarily predictable with quartz surfaces, highlighting mineralogical effects. The irreversible adsorption of silica nanoparticles was also observed. Adhesion force and energy are resolved in various intermolecular forces such as electric double layer repulsion, non-electrostatic interaction and structural forces. The scientific significance and broad engineering implications of results were comprehensively discussed in the context of previously reported core-to-field scale observations of nanofluid EOR. This study pitches new light on the scientific understanding of silica-based nanofluid EOR by probing nanoscale wetting effects of silica nanoparticles with implications for shale oil recovery. The findings herein can help for better understanding of the design of nanofluid EOR reagents and the conditions that favor application of silica nanofluid EOR.

Effect of bionic hydrophobic structures on the corrosion performance of Fe-based amorphous metallic coatings

Fe-based amorphous metallic coatings (AMCs) were prepared by the activated combustion−high velocity air fuel (AC − HVAF) coating method. A micro/nanoscale hydrophobic surface based on the lotus effect was constructed on the AMCs by chemical etching and surface modification, and the controllable preparation of bionic hydrophobic structures was realized by optimizing the chemical etching time and etching concentration. The influence of surface treatment on the corrosion resistance of the coatings was analyzed by electrochemical testing, and the correlation between the hydrophobicity of the coating structure and its corrosion resistance was determined. Results showed that the surface of the hydrophobic AMCs is composed of micro/nanoscale hierarchical structures of synapses formed by unmelted particles and corrosion products. Several pores and pits were observed after chemical etching. As the chemical etching concentration and etching time increased, the solid−liquid contact fraction and surface energy of the hydrophobic AMCs first decreased and then increased. The water contact angle peaked at 142.52° when the coatings were chemically etched in 3 mol/L HCl solution for 60 min, thereby conforming to the Cassie−Baxter model. The passivation current density and pitting tendency of the hydrophobic AMCs in 3.5% NaCl solution were closely related to the chemical etching process. The prepared hydrophobic interface could form an effective air wall that isolates the coating surface from the corrosive medium and enhances its uniform corrosion resistance. However, chemical etching aggravated the pores and intensified the dissolution of inclusions, thereby increasing the pitting sensitivity of these concavities. The construction of robust and compact bionic hydrophobic interfaces is an effective approach to enhance the uniform corrosion resistance of AMCs.

Universal and Switchable Omni-Repellency of Liquid-Infused Surfaces for On-Demand Separation of Multiphase Liquid Mixtures.

Mixtures of immiscible liquids are commonly found in the scenarios of environmental protection and many industrial applications. Compared to widely explored water-oil mixtures, small differences in the surface energy of organic liquids, especially for those in multiphase mixtures, make their separation a formidable challenge. Here, a family of versatile coatings based on the reactions between plant polyphenols and 3-aminopropyl triethoxysilane is introduced to regulate the wetting behavior of substrates by forming stable liquid-infused interfaces. The key finding is that when a coated substrate is prewetted with a liquid forming a stable liquid-infused interface, it becomes repellent to any other immiscible liquids. This phenomenon is independent of the surface energy of the initial wetting liquid. This exclusive wetting behavior can lead to distinctive repellency toward almost any liquid by the infusion of an immiscible liquid, even if the difference of surface energy and dielectric constant of a liquid pair is as small as 2.0 mJ m-2 and 1.8, respectively, resulting in universal and switchable omni-repellency. Of particular importance is that the as-prepared coating makes possible the on-demand separation of multiphase liquid mixtures by both continuous membrane filtration and static absorption, presenting a green and cost-effective approach to addressing this major environmental and industrial challenge.

A Monte Carlo Model of Gas-Liquid-Hydrate Three-phase Coexistence Constrained by Pore Geometry in Marine Sediments

Gas hydrates form at relatively high pressures in near-surface, organic-rich marine sediments, with the base of the hydrate stability field and the onset of partial gas saturation determined by temperature increases with depth. Because of pore-scale curvature and wetting effects, the transition between gas hydrate and free gas occurrence need not take place at a distinct depth or temperature boundary, but instead can be characterized by a zone of finite thickness in which methane gas bubbles and hydrate crystals coexist with the same aqueous solution. Previous treatments have idealized pores as spheres or cylinders, but real pores between sediment grains have irregular, largely convex walls that enable the highly curved surfaces of gas bubbles and/or hydrate crystals within a given pore to change with varying conditions. In partially hydrate-saturated sediments, for example, the gas–liquid surface energy perturbs the onset of gas–liquid equilibrium by an amount proportional to bubble-surface curvature, causing a commensurate change to the equilibrium methane solubility in the liquid phase. This solubility is also constrained by the curvature of coexisting hydrate crystals and hence the volume occupied by the hydrate phase. As a result, the thickness of the three-phase zone depends not only on the pore space geometry, but also on the saturation levels of the hydrate and gaseous phases. We evaluate local geometrical constraints in a synthetic 3D packing of spherical particles resembling real granular sediments, relate the changes in the relative proportions of the phases to the three-phase equilibrium conditions, and demonstrate how the boundaries of the three-phase zone at the base of the hydrate stability field are displaced as a function of pore size, while varying with saturation level. The predicted thickness of the three-phase zone varies from tens to hundreds of meters, is inversely dependent on host sediment grain size, and increases dramatically when pores near complete saturation with hydrate and gas, requiring that interfacial curvatures become large.

Effect of crystal orientation on droplet wetting behavior on single-crystal Al2O3 substrates: An experimental study

The wetting property of liquids on a solid surface is of key relevance to many areas ranging from biological systems to industrial applications. The wetting behavior of water, glycerin, and castor oil (featuring varying viscosities and surface energies) on single-crystal α-Al2O3 substrates with various crystal orientations of (0001), (112¯0), (101¯0), and (011¯2) was studied using the improved sessile drop method at room temperature and a closed environment. The effects of substrate crystal orientation on the liquid wetting behavior and its dependence on the liquid type were investigated. The contact angle of all three liquids on the (0001)-orientated substrates was obviously smaller than those of the other substrate orientations. The effects of α-Al2O3 substrate crystal orientation on the liquid wetting behavior on the substrates can be attributed to the liquid and substrate surface energies, the liquid viscosity, and the substrate atomic arrangement. The wetting process of water on α-Al2O3 could be divided into two stages. The contact angle was basically unchanged in stage I, and evaporation of droplets causes stepwise decreases of the contact angle in stage II. The height and contact angle of glycerin and castor oil on the substrates change very slowly in 1800 s. The findings of this study help provide a better understanding of the wetting behavior of liquids on solids and its mechanism.

Solvation pressure in spherical mesopores: Macroscopic theory and molecular simulations

AbstractFluids adsorbing in nanoporous solids cause high solvation pressures that deform the solids and affect properties of the fluids themselves. We calculate solvation pressure of nitrogen adsorbed at 77.4 K in spherical silica mesopores using two methods: the macroscopic Derjaguin–Broekhoff–de Boer theory and molecular simulations. We show that both approaches give consistent results, and the observed pressures increase in smaller pores reaching the order of a hundred megapascals. The results are also typical for the solvation pressure in mesoporous materials, yet noticeably differ from the results for the cylindrical pore geometry. Furthermore, we show that the dependence of the solvation pressure at saturation on the reciprocal pore size is linear, and we use this relation for the calculation of the solid–liquid surface energy. The results can be employed for the prediction of the solvation pressure and the adsorption‐induced deformation in the material with the spherical pore geometry.

Interaction of 3D waves with thermocapillary structures in a heated liquid film

The evolution of three-dimensional waves into thermocapillary-wave structures at heating a vertically falling water film with Reynolds number of 50 was studied experimentally. A high-resolution, high-speed infrared camera and fluorescence thickness measurement method were used to study of interaction of hydrodynamic disturbances with thermocapillary instabilities. The thickness and temperature fields of the film surface were measured synchronously. The amplitudes and velocities of waves, amplitudes of rivulet deflection, temperature fluctuations on the liquid film surface, frequency spectra and pulsation energies were determined. The method of dynamic mode decomposition (DMD) was used to calculate characteristic frequencies (global frequencies) in the flow and reveal spatial distributions of thickness and temperature fluctuations (dynamic modes) evolving in the flow with a characteristic frequency. It is shown that the main deformation of wave fronts occurs because of their interaction with a thermocapillary structure, which formed in the residual layer near the leading edge of the heater. The high temperature gradients of up to 10–20 K/mm were observed in this region. In this case, the wave amplitudes increase in the initial region of heating under the action of thermocapillary forces directed against the film flow. Thermocapillary structures transform into another type in the lower part of the heater, where the small values of temperature gradients were observed.

A Numerical Study on Droplet-Particle Collision

This paper investigates the collision between a droplet and a spherical particle for non-reacting, isothermal flows based on the design of computer experiment and statistical learning methods, using the Volume of Fluid method along with a momentum conserving formulation on an adaptive octree grid. It has increasingly been a subject of numerical investigation due to the growing demand for full industrial plant control and processes optimization, for instance, fluid catalytic cracking and wet cleaning of dusty gases.Simulations are first validated against experimental data for droplet-to-particle diameter ratio $$D_r=1.75$$ , considering the geometrical parameters of the formed lamella, i.e., height, base diameter and remaining liquid thickness on the particle. Since the lamella area is an important factor on mass and heat transfer on common industrial processes, the effects of droplet Reynolds $$[10^3$$ – $$10^4]$$ and Weber $$[10^2$$ – $$10^3]$$ numbers on this output are investigated using the design of computer experiment, along with a mechanical energy analysis. At dimensionless post-impact time equal to one, the Reynolds and Weber numbers show a negative and a positive effect on the lamella area, respectively. This is in agreement with our mechanical energy analysis of interfacial flows, since we found that the Reynolds number expresses a potential of liquid and gas kinetic energies exchange, whereas the Weber number expresses a potential of liquid kinetic energy and surface energy exchange. Lastly, a correlation for the dimensionless lamella area as function of the dimensionless time, the Reynolds and Weber numbers is proposed based on statistical learning methods.

Phase transformation from rutile to anatase with oxygen ion dose in the TiO2 layer formed on a Ti substrate

The oxygen plasma immersion ion implantation (O-PIII) method was used to form a TiO2 layer on a Ti substrate. The content of the anatase polycrystalline phase increased from 5.1% to 22.3% of the total TiO2 amount with a higher O+ ion dose. The oxygen ion doses were 3.6 × 1016 ions, 8.1 × 1016 ions, 1.26 × 1017 ions, for 1, 2, and 3 h, respectively, with ion energies of E ≈ 0.8 keV. The polycrystalline phases and morphology of the obtained films were characterized by XRD, FESEM, AFM, and Raman spectroscopy. The chemical bond analysis and layer-by-layer measurements for TiO2 layer thickness evaluation were performed by XPS. The photocatalytic decomposition reaction constants of a methylene blue solution increased from 3.2 × 10−3 min−1 to 4.2 × 10−3 min−1 under UV-A irradiation and the liquid free surface energy increased from 39.0 mJ/m2 to 49.5 mJ/m2 with a higher O-PIII treatment doses. These results were explained by the partial phase transition of the TiO2 layer from rutile to anatase. Thus, the increase in the O+ ions implantation dose into the Ti substrate invoked the reduction of material density from Ti (ρ = 4.506 g/cm3) through TiO2 rutile (4.23 g/cm3) to TiO2 anatase (3.78 g/cm3) phase.

Ultrathin initiated chemical vapor deposition polymer interfacial energy control for directed self-assembly hole-shrink applications

Integrated circuit layouts consist of patterned lines and holes, where holes define the electrical contacts between adjacent layers. Block copolymer directed self-assembly (DSA) successfully shrinks the critical dimension (CD) of these contacts beyond the resolution of conventional lithography. DSA also radically improves the CD uniformity. One particularly difficult step of the DSA hole-shrink process involves establishing the correct interfacial energy throughout a lithographically templated hole to ensure good assembly. Initiated chemical vapor deposition (iCVD) is a uniform, ultrathin, ultraconformal, all-organic deposition technique that allows for precise control of the interfacial energy. In this work, the authors use iCVD of polydivinylbenzene at film thicknesses below 5 nm to blend the interfacial energy of the coated film with that of the silicon/spin-on carbon template. They fully characterize the iCVD surface by means of two liquid surface energy measurements. They further identify the interfacial energies presented by these functionalized templates through qualitative hole-island tests as well as quantitative harmonic mean estimations. In parallel, the authors run theoretically informed coarse grained simulations with the determined interaction parameters and DSA experiments and find good agreement across the range of chemistries created. Through careful control of iCVD conditions, especially filament temperature, they achieve a strong polystyrene-preferential sidewall with a nonpreferential bottom which they then demonstrate, both in the simulation and in the experiment, allows for a successful hole-shrink process across a wide range of template hole diameters.

Interaction of Surface Energy Components between Solid and Liquid on Wettability, and Its Application to Textile Anti-Wetting Finish.

With various options of anti-wetting finish methods, this study intends to provide basic information that can be applied in selecting a relevant anti-wetting chemical to grant protection from spreading of liquids with different surface energy profiles. With such an aim, the anti-wetting effectiveness of fluorinated coating and silane coating was investigated for liquids having different surface energy components, water (WA), methylene iodide (MI) and formamide (FA). The wetting thermodynamics was experimentally investigated by analyzing dispersive and polar component surface energies of solids and liquids. The role of surface roughness in wettability was examined for fibrous nonwoven substrates that have varied surface roughness. The presence of roughness enhanced the anti-wetting performance of the anti-wetting treated surfaces. While the effectiveness of different anti-wetting treatments was varied depending on the liquid polarities, the distinction of different treatments was less apparent for the roughened fibrous surfaces than the film surfaces. This study provides experimental validation of wetting thermodynamics and the practical interpretation of anti-wetting finishing.