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Microgels are soft colloidal particles constituted by cross-linked polymer networks with a high potential for applications. In particular, after adsorption at a fluid interface, interfacial tension provides two-dimensional (2D) confinement for microgel monolayers and drives the reconfiguration of the particles, enabling their deployment in foam and emulsion stabilization and in surface patterning for lithography, sensing and optical materials. However, most studies focus on systems of fluids with a high interfacial tension, e.g. alkanes/ or air/water interfaces, which imparts similar properties to the assembled monolayers. Here, instead, we compare two organic fluid phases, hexane and methyl tert-butyl ether, which have markedly different interfacial tension () values with water and thus tune the deformation of adsorbed microgels. We rationalize how controls the single-particle morphology, which consequently modulates the structural and mechanical response of the monolayers at varying interfacial compression. Specifically, when is low, the microgels are less deformed within the interface plane and their polymer networks can rearrange more easily upon lateral compression, leading to softer monolayers. Selecting interfaces with different surface energy offers an additional control to customize the 2D assembly of soft particles, from the fine-tuning of particle size and interparticle spacing to the tailoring of mechanical properties., Journal of Colloid and Interface Science, 608 (3), ISSN:0021-9797, ISSN:1095-7103

Purpose Deep anterior lamellar keratoplasty (DALK) has become a safe and standardized technique for the treatment of corneal diseases. The use of femtosecond lasers for corneal trephination in DALK allows for a precise and controlled corneal trephination very close to Descemet’s membrane (DM) which is important for a successful pneumatic dissection and results in separation of Pre-Descemet’s layer (Dua’s layer, PDL) and/or DM from the stroma. However, even with newer curved contact interfaces the cornea becomes massively warped during trephination causing irregular trephination patterns which results in high postoperative astigmatism. Here we present a novel technique of Femto-DALK using a non-contact liquid interface where the cornea keeps its natural curvature during the complete laser process. Methods Case series of two patients, which underwent femtosecondlaser-assistant deep anterior lamellar keratoplasty by using a non-contact liquid interface. The laser device (Ziemer LDV Z8, Ziemer Ophthalmic Systems AG, Port, Switzerland) was used for trephination of the donor and recipient cornea. In one patient Femto-DALK was combined with femtolaser-assisted cataract surgery (Femto-Phaco). Read-out parameters were the feasibility of the technique and postoperative outcome. Results Trephination was successful in both cases leading to a circular trephination very close to the recipients’ Descemet’s membrane. In both patients a big bubble type 1 was induced successfully. Conclusions Femtosecondlaser-assisted DALK using a liquid interface is a novel procedure representing an alternative to manual DALK or Femto-DALK with a contact interface. Future studies need to evaluate outcomes and complication rates in comparison to manual DALK and microscope-integrated Optical Coherence Tomography-aided DALK.

Hypothesis Monitoring progression of biochemical processes is required for medical and industrial applications. Spatiotemporal changes in fluid properties can be measured to determine progress of biochemical processes like blood coagulation. Localised electrowetting-on-dielectric (EWOD) actuates a part of droplet contact line, allowing local measurement of fluid properties without inducing bulk fluid motion, which is unlike full droplet oscillation-based techniques. Experiments In this work, narrow electrodes (50–450 μm) were used to actuate a portion of drop interface. Dynamics of interface actuation and relaxation was used to estimate the local visco-elastic properties of the droplet. Findings For local interface motion, theory predicts a generic dispersion relation ω = c q n . In agreement with theory, decay time was found to be proportional to viscosity and inversely proportional to surface tension. Interface displacement remained almost constant for different viscosities, but it decreased with increase in surface tension. Capability to measure spatiotemporal dynamics of chemical process was demonstrated for sugar dissolution in a droplet of water. For full droplet oscillation-based techniques, the induced bulk flows adversely affect the monitored process. Localised EWOD reduces bulk flows in the sample. So, this technique was applied to study blood coagulation dynamics, enlightening the future prospect of developing biomedical sensors.

Carbonic anhydrases (CAs) are enzymes that can function at physiologic interfaces and catalyze the interfacial conversion of carbon dioxide (CO2) into bicarbonate (HCO3−) with an extraordinarily high catalytic efficiency. Even though CAs have potential to be used for CO2 sequestration, significant mass transfer resistance and poor enzyme stability at gas-liquid interface often limit the effectiveness of the enzyme. Here, we report a density-adjustable 3D-printed platform, which can accommodate electrospun polymer fibers with immobilized CA and enable the positioning of immobilized CA in an air-water biphasic system. By using 3D printing, we fabricate interfacial devices consisting of two floating units and different number of biocatalytic units. Two mesh structures of each biocatalytic unit are used to sandwich immobilized CA while two floating units, connected on either side of the biocatalytic units, have an internal hollow volume that enables controlling the position of the enzyme-loaded interfacial device at or near the air-water interface. The positioning of interfacial device directly at the biphasic interface accelerated CO2 conversion by 1.8- and 3.4-fold when compared to reactions performed with immobilized CA within the aqueous solution and a control interfacial device without immobilized CA, respectively. The CA-loaded interfacial device retained 99.3 % and 88.2 % of its initial CO2 conversion rate after ten recycles and after subsequent storage in an aqueous buffer at 4 °C for 459 days, respectively. Facile combination of interfacial devices and immobilized enzymes on polymer fibers has paved the way to practical uses of biocatalysts for interfacial CO2 sequestration.

We investigate a novel textured window design for the continuous stereolithography process. The proposed textured window allows the formation of a liquid interface, enabling a reliable continuous projection stereolithography process. Both solid and hollow structures have been studied as test cases and were continuously printed using textured window-based projection stereolithography systems. The surface roughness of printed parts is characterized, and the effect of the continuous printing speed on the surface quality is investigated. Experimental results verified the effectiveness of the proposed textured window for enabling continuous printing, preventing the overlarge separation force, and achieving a high surface finish.

Experimental investigations on microsegregation during directional solidification of two Al–Cu alloys with and without a steady magnetic field (SMF) were carried out. The solidification morphologies and microsegregation behaviors were examined. The amount of non-equilibrium eutectics and the concentration versus solid fraction profiles were obtained. The results indicated that the amount of microsegregation was increased under an SMF when the solid/liquid interface was planar. For cellular and dendritic growth, however, the SMF alleviated the microsegregation level. The change of the factors affecting microsegregation under the SMF was analyzed. The reduction in solid diffusion coefficient in an SMF aggravated the microsegregation level, while the thermoelectric magnetic convection (TEMC) was found to have a positive effect. It was concluded that the change in microsegregation in different conditions might be attributed to the combined action of solid diffusion suppression and TEMC in mushy zone under an SMF. Based on Brody model, the microsegregation behavior in an SMF was predicted. The calculated results were in agreement with experiment observations.

Separation and recycling of rare-earths using ionic liquids as extractant are becoming a promising approach to replace traditional volatile organic solvents in recent years. Generally, the addition of some special salts could improve the extraction efficiency of rare-earths by numerous non-functional ionic liquids. However, knowledge behind the nature of the salt effect is limited. Here, we found that the enhancement in the extraction of rare-earth ions, Pr3+ ions, using non-functional ionic liquid, [A336][NO3] (Tricaprylmethylammonium nitrate) was driven by the synergism of Hofmeister bias and complexation behaviors of salt anions with Pr3+ ions. Molecular dynamic simulations offered a new insight into the interaction mechanism of the ionic liquid with Pr3+ ions at liquid/liquid interface. It was revealed that salt anions could perform as a bridge to connect Pr3+ ions and the ionic liquid, so that promoted the extraction of Pr3+ ions. Therefore, the strong complexation ability of salt anions with Pr3+ ions and poor hydration of salt anions faciliated the transport of Pr3+ ions across liquid/liquid interface.

Biomimetic lubricant-infused surfaces are developed as an effective approach to solve the problem of biofouling. Herein, lubricant-infused surfaces were fabricated on various structured surfaces with polished, nanostructured, microstructured, and micro/nanostructured features. The influences of surface topographies on their infused configurations, stability and antifouling performance were studied in detail. The results indicated that the structures played a decisive role in the formation of lubricant-infused surfaces. Infused configurations of lubricant were various responded to the different structures, including floated on polished surfaces, encapsulated on nanostructured surfaces, impregnated with emergent features on microstructured surfaces and impregnated/encapsulated on micro/nanostructured surfaces. Stability and antifouling performance were decided by the infused configurations. The encapsulated lubricant entrapped by a capillary force in nanostructures can form a continuous liquid interface to retain stability and provide antifouling performance. The results would show great potential for the construction of antifouling coatings by lubricant-infused techniques.

We developed a new method for removing gaseous substances by using high frequency (200 kHz) ultrasonic irradiation of water, and the effects of ultrasonic irradiation on gas-phase toluene were evaluated quantitatively for the first time. The removal ratio of gaseous toluene increased with increasing ultrasonic power, but the reaction was inhibited by the addition of radical scavengers, indicating that ultrasonic irradiation not only accelerated the dissolution of gaseous toluene but also induced toluene decomposition. The contribution made by OH radicals to the decomposition of gaseous toluene at the gas–liquid interface was confirmed by the difference in removal ratios between addition of KI and addition of tert-butyl alcohol. The toluene removal mechanism was investigated by studying the logarithmic plots for toluene concentration at specified times. The results of this study clearly showed the promotion of gaseous toluene dissolution and the reaction via OH radicals at the gas–liquid interface by sonophysical and sonochemical effects with both effects contributing to the removal of gaseous toluene. Furthermore, the total organic carbon concentration in the aqueous phase increased with increasing reaction time, indicating that the toluene degradation products were trapped and decomposed into low-molecular-weight organic compounds in the aqueous phase.

This study investigated the influence of the solid cohesion, fsc, on the viscous properties (m-value and k-value in the Norton law) for aluminum alloys during partial solidification. In the previous study of Haaften (Mater. Sci. Eng. A, 336 (2002), 1–6), a constitutive model taking into account fsc was proposed as e ˙ = k (T) (σ/fsc (θ,T)) n (=1/m), where θ referred to the dihedral angle at the solid/liquid interface. However, even though it is well known that the m-value decreases with the decreasing temperature in the semi-solid state, the model defined the m-value as a constant to the temperature. Therefore, m = f(fsc) and k = g(fsc) during solidification were clarified in this study. The viscous properties were obtained by tensile tests during partial solidification for Al-5mass%Mg and Al-2mass%Cu alloys. As a result, it was found that the change in the m-value of 0 ≤ fsc

Cooling rate is a critical factor controlling the grain size of cast metals. Generally, it is accepted that higher cooling rate leads to smaller grains due to the high undercooling achieved. However, the present work observed grain coarsening after solidification with higher cooling rate in some specific aluminium alloys. Using a V-shape cooper mould, different solidification cooling rates were achieved on the aluminium alloy ingots. It was found that the grains at the tips of the ingots, where corresponded to the highest cooling rate, were significantly coarser than the other parts of the ingots with lower cooling rate for Al-3.0 wt%Si and Al-0.1 wt%Ti alloys. However, such phenomenon was not observed in other aluminium alloys. It was believed that such grain coarsening phenomenon at fast cooling was related to both the constitutional undercooling zone ahead of the solid/liquid interface and the growth restriction factor of the solutes. The results can be well explained in terms of the interdependency theory for grain refinement of cast metals.

An improved general understanding of electrocatalytic gas evolution reactions may - besides contributing to fundamental knowledge - play a crucial role in efforts directed to energy savings during large-scale industrial electrocatalytic processes. Aside from the search for new electrocatalytically active materials, in-depth understanding of electrode surface properties may contribute to more efficient utilization of known electrocatalysts. SECM is applied in the sample generation/tip collection mode to determine the spatial distribution of electrocatalytic activity during Cl2 evolution at the solid/liquid interface of dimensionally stable anodes. Statistical interpretation of the local microscopic distribution of the electrocatalytic activity of dimensionally stable anodes was used as a basis for improved understanding of their overall electrocatalytic performance.

Expressions for the roughening transition of solid/liquid interface in multicomponent alloys are developed and a related thermodynamic model of roughening transition is proposed. The alloying and configurational entropy effects on the interface structure are discussed based on the Gibbs free energy of roughening transition. The surface roughness in alloys depends on the Gibbs free energy of phase transition and the partition coefficient.

Microneedle patches, arrays of micron-scale projections that penetrate skin in a minimally invasive manner, are a promising tool for transdermally delivering therapeutic proteins. However, current microneedle fabrication techniques are limited in their ability to fabricate microneedles rapidly and with a high degree of control over microneedle design parameters. We have previously demonstrated the ability to fabricate microneedle patches with a range of compositions and geometries using the novel additive manufacturing technique Continuous Liquid Interface Production (CLIP). Here, we establish a method for dip coating CLIP microneedles with protein cargo in a spatially controlled manner. Microneedle coating mask devices were fabricated with CLIP and utilized to coat polyethylene glycol-based CLIP microneedles with model proteins bovine serum albumin, ovalbumin, and lysozyme. The design of the coating mask device was used to control spatial deposition and loading of coated protein cargo on the microneedles. CLIP microneedles rapidly released coated protein cargo both in solution and upon insertion into porcine skin. The model enzyme lysozyme was shown to retain its activity throughout the CLIP microneedle coating process, and permeation of bovine serum albumin across full thickness porcine skin was observed after application with coated CLIP microneedles. Protein-coated CLIP microneedles were applied to live mice and showed sustained retention of protein cargo in the skin over 72 h. These results demonstrate the utility of a versatile coating platform for preparation of precisely coated microneedles for transdermal therapeutic delivery.

The paper highlights and discusses the role of interfacial phenomena in the interactions between inhaled solid particles with different properties (size, structure, surface characteristics) and air/liquid interface of the alveolar region of the lungs. The greatest attention is paid to man-made nanosized and nanostructured particles which often belong to the class of “engineered particles”. Their applications in several novel technologies may be associated with accidental particle release to the air and formation of potentially harmful aerosol. Extraordinary, dynamic surface-active properties of the lung surfactant, which are responsible for several physiological functions - including the pulmonary mass transfer - may be altered by such inhaled particles in a material- and dose-dependent manner. Certain effects can be assessed by specialized experimental in vitro methods allowing predictions of possible in vivo interactions. On the other hand, interactions with the lung surfactant can modify the original properties of inhaled particles which in turn will influence their bioavailability or toxicity. All mentioned effects are dependent on particles properties as proven by numerous studies, however such results should be carefully judged due to essential differences in experimental methodology used. The paper also discusses some ideas related to the practical meaning of discussed effects for novel concepts of pulmonary drug delivery by inhalation.

The Sn-36 at.%Ni peritectic alloy in which both the primary and peritectic phases are intermetallic compounds was directionally solidified attending different deceleration growth conditions. The cellular-dendrite growth of the primary Ni 3 Sn 2 phase was studied in this analysis, and the influence of the deceleration rate on the microstructure length scales including primary/higher order dendrite arm spacing ( λ 1 , λ 2 , λ 3 ) and dendrite tip radius ( R ) were analyzed. Experimental results showed that although these length scales all decreased with the increasing deceleration rate, the responses of the secondary dendrite arm spacing λ 2 and the tip radius of primary dendrite R are faster than that of λ 1 . This difference in response leads to a larger variation in the λ 1 / λ 2 ratio with the increasing deceleration rates, as compared with the λ 2 / R ratio. Furthermore, the ratio of the thickness of primary dendrite stem d to the primary dendrite arm spacing λ 1 , d / λ 1 was used to predict the melt concentration at the solid/liquid interface C l . These length scales were related to the melt concentration C l which is obtained through the d / λ 1 ratio.

The reasons for nonionic surfactants mitigated the cellulase deactivation were investigated from the points of lignocellulose-cellulase interaction and gas-liquid interface-cellulase interaction. Surfactants strengthened the interaction between substrate and cellulase, increasing the adsorption capacity by 19.0 %–45.8 % and glucose yield by 15.4 %–17.0 % respectively. Gas-liquid interface had a negative effect on the enzymatic hydrolysis with low enzyme loading at high shaking speed or large interfacial size. The enhancement in glucose yield by surfactants at 250 rpm or large interfacial size was greater than that at 0−150 rpm or small interfacial size. When cellulase solution was incubated at 250 rpm and large interface, the addition of Tween 80 increased the endoglucanase and cellobiohydrolase activities from 76.7 % and 63.0 % to 103.1 % and 123.2 %, respectively. Surfactants protected the endoglucanase and cellobiohydrolase from gas-liquid interface to enhance the enzymatic hydrolysis of hydrogen peroxide/acetic acid-pretreated poplar.

Stereolithographic 3D printing has been increasingly applied in the rapid fabrication of gels with specially-designed 3D structures. Herein, MXene (Ti3C2Tx) is reported for the first time as a versatile photo blocker for a photo-curable aqueous ink for a newly developed stereolithography technology (Continuous Liquid Interface Production, CLIP) to fabricate hydrogels with delicate geometries. As an effective photo blocker, the MXene nanosheets can significantly suppress the light scatting in the hydrogel precursor ink during CLIP printing, giving rise to printing quality. Subsequent solvent exchange with glycerin produces an organogel, which shows excellent adhesive properties towards various surfaces, making it a promising adhesive sensor to detect different body movements. Meanwhile, the CLIP-printed organogel demonstrates promise in atmospheric water harvesting taking advantage of the natural hygroscopicity of organogel and excellent light-to-heat conversion performance with MXene nanosheets. Furthermore, the CLIP-printed hollow organogel shows higher efficiency benefiting from larger surface area of hollow organogel. The results of this work strongly suggest that MXene can serve as an effective multifunctional additive for CLIP inks, which may open up new opportunities for the 3D printing of various advanced devices.

In this study, partially submerged iron scraps were allowed to react to the contaminants at the headspace air and liquid interface for pollutants removal in the serum bottle reactors. The experiments were conducted using Box–Behnken design of Response Surface Methodology in anaerobic batch reactors (120 ml) at different concentrations of sulfate (0.5, 1.75, 3 g/L), nitrate (0.25, 0.375, 0.5 g/L) and iron scraps (0, 0.125, 0.250 g/50 ml). The sulfate reducer enriched mixed culture was used for simultaneous removal of SO 4 2 − and NO 3 − . The highest sulfate removal of 49.37 % was achieved at 0 g/50 ml ISs, 3 g/L SO 4 − 2 , and 0.375 g/L NO 3 − . Even at a higher concentration of both SO 4 2 − (3 g/L) and NO 3 − (0.5 g/L), a significant SO 4 2 − removal of 44.65% was achieved at an iron concentration of 125mg/50ml accompanied with NO 3 − conversion. Both the lower and higher concentrations of iron scraps were showing effective interaction at higher SO 4 2 − and NO 3 − levels. The results of the confirmatory experiments with iron scraps of 0.039 g/50 ml with the desirability of 0.92 showed a maximum SO 4 2 − removal of 50.62 % with complete conversion of nitrate.

Continuous liquid interface production (CLIP) strategy is a promising fast shaping additive manufacturing method due to its continuous UV-polymerization process. However, the large-scale extension of CLIP technology, especially for the printing of ceramics, is far from maturity. Herein, a highly cost-effective desktop top-down CLIP strategy was employed for the shaping of polymer-derived ceramics at a fast speed (100 mm/h in height). The deliberate shaping direction of the top-down CLIP strategy not only improved the printing speed, but also enabled full utilization of the natural oxygen in the air to generate the liquid interface on the top of the photocurable resin, ensuring that the printing process can be carried out continuously. These printed 3D-polysiloxane components can be further converted into dense and crack-free 3D-SiOC ceramics with a smooth surface upon a heat treatment. The strategy of top-down CLIP printing SiOC ceramics can be applied to the fast fabrications of other polymer-derived ceramics.

We studied the behaviour of three lipid tear products, commercialised by the same brand, as Langmuir films at the air/liquid interface to simulate the ocular environment. No significant differences were observed in the surface behaviour of two of them disclosing the same composition, but commercialised for different applications. The interaction of several subphases, namely sodium chloride, glucose, albumin and lysozyme present in the natural tear, with the lipid films was assessed at room temperature and the temperature of human tear using surface pressure-area isotherms and elastic modulus plots. There is a notable influence of sodium chloride and the proteins albumin and lysozyme on the surface pressure-area isotherm of the lipid Langmuir films. Albumin shifted this isotherm to lower areas while an opposite shift was caused by lysozyme. These studies could be useful for the formulation of new lipid-containing artificial tears, and for increasing the confidence of the customers in commercial eye care formulations

The main objective of this research work is to examine experimentally the tribological performance of polymeric viscosity index improver (VII) in boundary/mixed and hydrodynamic lubricated concentrated contact by simulating non-conformal and conformal geometry in the versatile multispecimen tribotester. Three different experimental approaches (Four ball tester, pin on roller tester and journal bearing test rig) were used to study Polyisobutylene (PIB) as VII. The ability of Polyisobutylene (PIB) blends to reduce friction and wear on the solid/liquid interface has been observed to depend strongly on the polymer concentrations. This study is useful for reducing wear and friction significantly for 15% concentration by weight of PIB blend in paraffinic low viscosity base oil N150. For higher concentration studied, the friction was observed eventually increase giving antagonistic behaviour with base oil.

We report experimental interfacial tension, coexisting densities and relative Gibbs adsorption measurements for carbon dioxide + tetrahydrofuran mixture in the vapor-liquid equilibrium at 298.15 K and 353.15 K and pressure up to 12.0 MPa. Measurements are based on the use of a high-pressure pendant drop tensiometer coupled to a high-pressure densimeter. The results were compared to literature values where possible. In order to complement experimental measurements, theoretical modeling on the interfacial behavior was carried out using the Square Gradient Theory based on a Peng-Robinson equation of state. Investigating the applicability of the model to describe interfacial behavior in the mixture revealed very good agreement between calculated and experimental data, where the interfacial tension decreases as the pressure increases. In order to examine accumulation of compounds at the interface the model was applied. Thereby, peculiar adsorption effects of carbon dioxide in the liquid interface of tetrahydrofuran were observed.

Peritectic alloys form a variety of solidification morphologies of which peritectic coupled growth (PCG) is the most peculiar. Because the conditions that lead to PCG are still under discussion, in-situ investigations of the evolution from lateral bands to PCG were carried out by using binary organic TRIS-NPG model alloys at concentrations in the peritectic region. The experiments were done vertically with relatively large rectangle glass tubings. For a hyper-peritectic alloy at growth rates below the morphological stability limits of both solid phases, we found that first the properitectic phase grew while lateral bands of the peritectic phase formed between the glass walls and the properitectic phase. Then, the peritectic phase dominated the growth until lateral bands of the now properitectic phase occurred, again close to the glass walls. Now both phases grew side-by-side as two layers at different depths in the sample. However, the properitectic phase spread locally onto the peritectic/liquid interface, so that patches of peritectic phase surrounded by a properitectic matrix developed. This resulted in creating an unstable PCG mode with cycles of increasing and decreasing phase amounts, which from a side-on view resemble tulip- and onion-like structures respectively.

The recent development of Continuous Liquid Interface Production, also known as CLIP, has successfully alleviated the main obstacles surrounding 3D printing technologies: production speed and part quality. Based on this technology, we developed the μCLIP process to allow for 3D printing of biomedical devices with micron-scale precision. In this study, we report the process development in manufacturing high-resolution bioresorbable scaffolds using our own μCLIP system and a bioresorbable photopolymerizable biomaterial (B-Ink). Through optimization of our μCLIP process and concentration of B-Ink components, we have reduced the fabrication time of a customizable BVSs from several hours to 11.25 minutes. Optimized ink was shown to possess mechanical stiffness comparable to a nitinol control stent.

The emerging trend towards miniaturization of robotic grippers is motivated by the needs for precise manipulation of smaller objects within confined spaces. However, it faces a multitude of challenges in micro-fabricating, assembling, and actuating the grippers with increasingly smaller dimensions. To overcome these challenges, we report here a method to 3D print a magnetically-driven triple-finger micro-gripper for robust micro-manipulation in air and water. Magnetic actuation was chosen for its advantage of untethered operation in complex surroundings. Mitigating the trade-off between mechanical compliance and magnetic actuation forces, the monolithic micro-gripper design comprising compliant mechanical flexures and magnetic force actuation units was rapidly fabricated using micro-continuous liquid interface production (μCLIP) process. Finally, we attached the 3D printed gripper to a robotic arm and demonstrated its ability to manipulate micro objects both air and water. This work may enable potential biological and biomedical applications such as operation of live cells and soft tissues.

Sulfolane (SL) has attracted a great deal of interest as an electrolyte solvent in Li-metal batteries owing to its suitable properties. In this study, we performed a first-principles molecular dynamics simulation involving an Li metal | LiB F 4 -SL liquid interface. It was found that two S − O bonds of SL preferentially dissociate on the Li surface, while decomposition of B F 4 was not observed. Since the dissociated O atoms dissolved into the Li surface, our results indicate that an Li-oxide layer formed on the Li surface, which suggests that a preferable performance of the Li-metal negative electrode can be expected for this system.

Understanding the adsorption behavior of fluorinated surfactants at air/liquid interfaces are important in many academic and industrial applications. Most surfactants contain spacers, which are employed to separate and link the hydrophobic/hydrophilic groups. In this work, molecular dynamics (MD) simulations were employed to investigate the microscopic structure of perfluorooctane sulfonate (PFOS) with different spacer at the air/liquid interface. The influence of different spacer on the interfacial structure and hydrophilicity of the head group were investigated as well. The relationship between the component of the spacer and the surface activity of surfactants is revealed. It is found that the orientation and conformation of hydrophobic chains in surfactants would not be influenced much when some functional groups are employed as spacers. While the hydrophilicity of the head group would be improved by introducing hydrophilic groups as spacers. The amide(CONH) group performs better than other functional groups.

The diffusion-limited growth of an initially spherical particle of dilute ternary alloy in contact with its melt has been studied from a theoretical point of view and the effects of interface kinetics and multicomponent diffusion have been characterized on the development of a shape perturbation of the sphere. When both concentrations of the diffusing species are imposed in the far-field, the different radii related to the absolute and relative stability of the particle with respect to the development of spherical harmonics have been determined when a linear kinetics law is considered for the solid/liquid interface. The development of the shape fluctuations of the sphere has been also characterized when the flux of both species are set in the far-field.

Improving foam stability is an important issue in foam fractionation of proteins from their aqueous solutions with low foam properties. In this work, enhancing protein self-association at the gas–liquid interface by sodium citrate (Na-citrate), instead of adding surfactants, was used to improve the stability of protein foams. Using bovine serum albumin (BSA) as a model protein, the role of Na-citrate in enhancing self-association of BSA at the gas–liquid interface was studied at the molecular level. Then, the role of the enhanced protein self-association in intensifying foam fractionation of BSA was studied. The results show that by weakening electrostatic repulsion between the BSA molecules and unfolding their structures, Na-citrate induced the formation of 12 and 18 BSA aggregates at the gas–liquid interface. The enhanced protein self-association effectively increased the interfacial adsorption of BSA and improved the foam stability. At BSA concentration 50 mg/L, the recovery percentage of BSA with 30 mmol/L Na-citrate increased by 4 folds while its enrichment ratio just decreased by 11.5%, compared to those without Na-citrate. The results give a clear understanding of the role of protein self-association in foam fractionation of proteins.

To improve the mass transfer efficiency in many industrial applications better understanding of the mass transfer rate is required. High speed images of single CO2 bubbles rising in tap water were analysed to investigate the relationship between the mass transfer and properties of single bubbles. Transition to a lower mass transfer rate was shown to correspond with the transition from a mobile to an immobile bubble surface. This was indicated by the change in bubble rise velocity, bubble rise path and bubble shape. The presence of surfactants in untreated tap water appear to effect the transition point, particularly for bubbles with a smaller initial diameter and lower rise velocity.

Techniques for the determination of protein concentrations in the bulk of ionic fluids have been developed using tritiumlabeled proteins and adsorption at the water–ionic liquid interface with the aid of a sessile drop method.

The three-dimensional (3-D) simulation of powder particle entering melt pool during laser solid forming (LSF) was carried out in our quest to establish a general representative model of this phenomenon. The effect of the gas-liquid interface on the motion state of the powder was analyzed, and the accuracy and universality of the model were verified using a high-speed photographic experimental approach. Further, the simulation process of the Ti-6Al-4V powder particle entering the high-temperature Ti-6Al-4V melt pool was carried out. The effects of the gas-liquid interface of the melt pool on the motion state of the powder particle and the disturbing of the powder particle on the melt pool were studied. It was found that the running speed of the particle experienced a rapid decrease and then a slower decrease in the process of entering the pool. Also, the particle serves as a transport medium of gases and carries the gases into the pool, which could form pores in the deposited layer. When the particles enter the melt pool at varied speeds, the ratio of the instantaneous speed of the particle entering the pool to the initial incident speed differs, which increases with increasing initial speed.

We apply continuum models to analyze phase change, heat transfer, fluid flow, solute transport, and segregation in order to understand prior neutron imaging observations of the vertical gradient freeze growth of Eu-doped BaBrCl. The models provide a rigorous framework in which to understand the mechanisms that are responsible for the complicated evolution of interface shape and dopant distribution in the growth experiment. We explain how a transition in the solid/liquid interface shape from concave to convex is driven by changes in radial heat transfer caused by furnace design. We also provide a mechanistic explanation of how dynamic growth conditions and changes of the flow structure in the melt result in complicated segregation patterns in this system. A growth pause caused by controller lock-up is shown to result in a band of solute depletion in accordance with classical theory. However, changing flow patterns during growth result in a non-monotonic axial distribution of solute that cannot be explained by simple application of classical segregation models. We assert that the approach presented here, namely the use of rigorous models in conjunction advanced diagnostics, such as neutron imaging, provides an exciting path forward for process optimization and control, accelerating the incremental advances that have, in the past, typically relied on empiricism, experience, and intuition.

Nowadays, superhydrophobic surfaces have attracted a lot of interest because of the wide range of applications in industries. These surfaces can significantly reduce the drag force due to the formation of air gaps between the substrate and liquid interface. The present review mainly focuses on the very recent progresses in the drag reduction studies using superhydrophobic surfaces. Also, a brief discussion about the mathematical modeling and the theories of superhydrophobic surfaces, natural water repellent surfaces, various fabrication techniques with advantages and disadvantages of each method and different properties of the fabricated surfaces in industrial applications is presented. Finally, the limitations of using such surfaces in industrial applications, which deals with harsh and destructive environment conditions, are addressed and further research topics and future outlooks to improve the durability of the superhydrophobic surfaces are discussed.

Two novel imidazoline derivatives, 2-(2-trifluoromethyl-4,5-dihydro-imidazol-1-yl)-ethylamine (1-IM) and 2-(2-trichloromethyl-4,5-dihydro-imidazol-1-yl)-ethylamine (2-IM), have been investigated as corrosion inhibitors for mild steel in 0.5 M HCl solution by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. The surface morphology of sample was presented through scanning electron microscope (SEM) and the inhibition mechanism was elucidated by measuring the potential of zero charge (Epzc) at the solid/liquid interface. Results of theoretical calculation confirm that the chloride-substituted compound shows better inhibitive performance than the fluoride-substituted one.

The transition of classical spray atomization processes to single-phase continuous dense-fluid mixing dynamics with diminished surface tension forces is poorly understood. Recently, a theory has been presented that established, based on a Knudsen-number criterion, that the development of such mixing layers is initiated because the multicomponent two-phase interface becomes much wider than the mean free molecular path. This shows that the transition to mixing layers occurs due to interfacial dynamics and not, as conventional wisdom had suggested, because the liquid phase has heated up to supercritical temperatures where surface tension forces diminish. In this paper we focus on the dynamics of this transition process, which still poses many fundamental questions. We show that such dynamics are dictated by substantial statistical fluctuations about the average interface molecule number and the presence of significant interfacial free energy forces. The comprehensive analysis is performed based on a combination of non-equilibrium mean-field thermodynamics and a detailed modified 32-term Benedict–Webb–Rubin mixture state equation. Statistical fluctuations are quantified using the generally accepted model of Poisson-distributions for variances in systems with a small number of molecules. Such fluctuations quantify the range of pressure and temperature conditions under which the gradual transition to dense-fluid mixing dynamics occurs. The interface begins to deteriorate as it broadens substantially. The related interfacial free energy forces do not instantly diminish only because vapor–liquid equilibrium conditions do not apply anymore. Instead, such forces along with the present interfacial statistical fluctuations are shown to gradually decrease as the interface transitions through the molecular chaos regime and to diminish once the interface enters the continuum regime. Then, the interfacial region becomes a continuous gas–liquid mixing layer with diminished free energy forces that is significantly affected by single-phase real-fluid thermodynamics and transport properties.

A phase-separated CsI–NaCl scintillator with light-guiding properties was grown by the Czochralski method. The CsI–NaCl eutectic phase usually consists of NaCl cylinders in a CsI matrix and contains grain boundaries. However, we have grown composites without grain boundaries by creating a convex solid/liquid interface, selecting a single grain by Dash’s neck method, and increasing the diameter of the composite moderately. The good continuous convection flow required for these conditions was achieved by suppressing the drop in the aspect ratio of the melt height to the crucible radius with a double crucible setup. We successfully obtained a CsI–NaCl:Tl composite that was uniform with no grain boundaries greater than 30 mm in diameter.

Metal-complex film with super-hydrophobic property is fabricated on copper (Cu) surface with one-step electrochemical method in laurylamine/ethanol solution. "Dissolution-coordination-precipitation" model is proposed to illuminate formation mechanism of Cu(II)-laurylamine complex film. The super-hydrophobic film can act as a barrier to corrosion of underlying copper with inhibition efficiency close to 100%, and it maintains stability within a wide potential range. The origin of such corrosion protection property is explained from view point that hierarchical micro-structure of the super-hydrophobic film can maintain a stable air/liquid interface which inhibits erosion of corrosive medium. (c) 2014 Elsevier Ltd. All rights reserved.

The adsorption process of sodium dodecyl sulfate (SDS) at a hydrophobic layer was investigated by dual polarization interferometry (DPI), which provided the real-time information at solid/liquid interface. In dilute solution, the molecules adsorb at the surface as isotropic layer. With the increase in concentration, the molecules aggregate to form hemimicelles and the critical hemimicelles concentration (HMC) is 1 mM. The adsorption of SDS at C18 surface obeys two-step process. The competitive formations of micelles in solution and hemimicelles on C18 surface lead to particular adsorption behavior in higher concentration. We also proposed a four-stage adsorption model of SDS at C18 surface according to bulk concentration.

The texture properties and the stability of foam are highly dependent on foam structure after processing. The Weber Number, widely used to predict mean bubble size, takes in account the shearing rate during process, the bulk viscosity, and the surface tension at equilibrium. The objective of this study was to illustrate the importance of surface tension kinetics on structure of food foam. Since surfactant adsorption is a complex process, it is essential to decide whether equilibrium or surface tensions at short times have to be considered for the size prediction of bubbles generated at pilot scale. To do so, we formulated model systems with controlled bulk viscosity and interfacial properties: Newtonian fluids at different viscosity levels and various surface tension kinetics. Characteristic parameters were obtained by adjusting the dynamic surface tension measurements to kinetic models found in the literature. Structure of processed foam was accessed by Sauter Diameter and bubble size distribution. Whipping conditions were the same for all solutions. The experimental design showed a clear effect of viscosity and surfactant concentration on adsorption kinetics. These had in turn an impact on foam structure: slow adsorption kinetic led to bigger bubbles with larger size distribution whereas fast adsorbing conditions produced smaller and more homogeneous bubbles.

In a recent issue of Nature Materials, Yiyang Li, Saiful Islam, Martin Bazant, William Chueh, and colleagues identify the major role of solvent-assisted lithium migration in LiFePO4 particles along the solid/liquid interface using a combination of X-ray diffraction, microscopy experiments, and ab initio molecular dynamics simulations. This finding suggests that at the particle scale LiFePO4 effectively becomes a three-dimensional Li conductor, and follow-up phase-field simulations suggest that lowering surface diffusivity is a predominant factor in determining the bulk phase transformation behavior during cycling.

A sharp interface model and a diffuse interface model describing rapid solidification are compared. Both models are based on the assumption of two independent processes at the solid/liquid interface that together consume the available driving force. These two processes are (1) the interface motion and (2) the redistribution of atoms between the two phases. The sharp interface model is based on an interface thermodynamics model (Hillert and Rettenmayr, [3,4]) and derives its driving force for the phase transformation directly from Gibbs free energy formulations of the liquid and solid phases. In contrast, the Finite Interface Disspiation model (Steinbach et al., [10]), a diffuse interface model, is based on a grand potential formulation. The models are benchmarked against experimental data on solute trapping in the Al–Sn system (Smith and Aziz, [23]). The sharp interface model reproduces the experimental data with a single set of kinetic parameters, the diffuse interface model requires a velocity dependent interface permeability. It is concluded that due to the investigated high Peclet number regime the permeability in the diffuse interface model does not only describe the transport processes through the interface, but also the diffusion processes in the layer directly in front of it.

The Jackson’s factors of three low Miller-index crystal planes of Mg2Si were calculated with a rough interface model by using a growth unit of coordination polyhedron instead of atom. The Jackson’s factors of the {1 0 0}, {1 1 0} and {1 1 1} planes were obtained to be 2.53, 1.27 and 3.80, respectively. The physical meaning of using coordination polyhedron to calculate the Jackson’s factor was interpreted reasonably. The thermodynamic possibility of growing units onto a solid/liquid interface was linked to the microscopic appearance of crystal planes and to the macroscopic shape of Mg2Si crystals formed.

Mixed protein–surfactant adsorption layers at liquid interfaces are described including the thermodynamic basis, the adsorption kinetics and the shear and dilational interfacial rheology. It is shown that due to the protrusion of hydrophobic protein parts into the oil phase the adsorption layers at the water–hexane interface are stronger anchored as compared to the water-air surface. Based on the different adsorption protocols, a sequential and a simultaneous scheme, the peculiarities of complexes between proteins and added surfactants are shown when formed in the solution bulk or at a liquid interface. The picture drawn from adsorption studies is supported by the findings of interfacial rheology.

Interfacial electron transfer at semiconductor nanoparticles is a fundamental process that is relevant to many applications in photocatalysis such as wastewater cleaning, air cleaning and energy production. Fundamental understanding of the dynamic of the electron transfer is of crucial importance for the understanding of the fundamental concepts of photocatalytic processes and hence results in understanding and industrialization of photocatalytic reactions as well as a rational design of the photocatalytic systems. This review summarizes the progress in understanding electron transfer dynamics from semiconductor nanoparticles to the electron acceptor molecules. The approaches to improve the electron transfer efficiency will be also reviewed. Of particular focus will be the advancement of methodology as well as overview of some new highlights in electron transfer reactions at TiO2/liquid interface.

Scattering of jet-cooled molecules by non-metallic liquids, and molecular dynamics simulations of scattering by self-assembled-monolayers (SAMs) lead to remarkably similar values of the rotational and translational temperatures of the scattered molecules. We explore whether this might reflect a transient equilibration of the molecules with microscopic ‘hot-spots’ created by the collision. Calculations of surface temperature for non-metallic liquids and SAMs as a function of time and distance from the impact suggest that collisions with the randomly bumpy surface should result in similar rotational and translational temperatures of the scattered molecules, but the high thermal conductivity of liquid metals makes such ‘hot spots’ too short-lived to be relevant.