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This dissertation explored the innovative avenues for the confinement growth of materials, leveraging both space-confined and area-selective synthesis strategies through a variety of interface engineering approaches. It highlighted the multifaceted roles of the interface during the synthesis process, acting not only as a nanoreactor and/or a physical scaffold to constrain the geometry of the resulting materials, but also setting a specific chemical microenvironment. This environment is instrumental in facilitating the confined nucleation, growth, and stabilization of intermediates or final products, a process pivotal to area-selective synthesis. Towards it, we first focused on the intercalation of large molecules, such as P2O5, through the basal plane of graphene. This process yielded a confined P2O5 and/or metal phosphate structure within the graphene/Ge (110) heterointerface, following a two-step mechanism. This mechanism involved the dissociation of P2O5 and the subsequent intercalation of its fragments, as corroborated with density functional theory (DFT). The focus was then turned to area-selective synthesis of materials by engineering the surface energy profile at the vacuum-liquid and/or graphene/diamond like carbon (DLC) interface. In one study, a complex surface energy profile was achieved at liquid metal-vacuum interface using Laguerre-gaussian (????) lasers as the heat source, which induced novel Marangoni flow pattern. Marangoni surface flow, and convective flow in bulk liquid metal directed the movement of microparticles within the liquid, demonstrating that careful tuning over the parameters of the ???? laser (i.e., laser mode, spot size, and intensity of the electric field) allowed for precise control over the structure of the ring-shaped particle assemblies at solid-liquid interface. Finally, this dissertation presented a novel method for tuning the work function of monolayer graphene across a broad temperature range. This was achieved through engineering the graphene-Ga implanted DLC heterointerface, allowing for bipolar tuning (either increase or decrease) of the local work function landscape of graphene up to 500°C. This comprehensive study established a clear link between interface engineering and the confinement growth capabilities of materials, offering new strategies and advanced understanding for confinement materials synthesis.

Nanoceramics have unique properties compared to bulk materials, primarily because of their large interfacial areas. This gives rise to considerable surface and grain boundary energies that play an important role in thermodynamic stability and the sintering process. During sintering, densification of the nanoceramic occurs by the mass transport phenomena, and the reduction of interfacial energy is the driving force for this process. Experimental thermodynamic data on surface energies, and in particular on free surface energies, is lacking, though. Yttrium oxide is selected as a model material because of its wide range of applications and abundant sintering studies in the literature. Faceted nanocrystalline yttrium oxide was synthesized by hydrothermal synthesis, and the morphology of these nanoceramics was studied using electron microscopy. Surface energies of specific planes were determined experimentally by water adsorption calorimetry using an experimental setup that includes a water micro-dosimeter combined with a micro-calorimeter. This characterization technique is based on the thermodynamics of water adsorption on the anhydrous surface of the ceramics. Molecular dynamic simulations were also performed to estimate the free surface energies as a function of the surface normal, and corroborate the experimental results.

As materials approach the nanoscale, they begin to exhibit size dependent properties. In particular, a larger fraction of atoms that make up the whole of the material are located on the material’s surface. Colloidal nanocrystals are commonly synthesized where their surfaces are terminated by organic molecules, often referred to as ligands. Calorimetric techniques such as isothermal titration calorimetry have been applied to colloidal nanocrystals to study reactions at their surfaces over the past several years, but modeling these reactions has proven challenging. In this work, isothermal titration calorimetry was used to understand reaction mechanisms that increase the luminescence in semiconductor nanocrystals, or quantum dots. Furthermore, the collective effects of the aliphatic carbon chains that make up much of the organic component of colloidal nanocrystals were examined and insights from simulations using a local environment dependent model, the Ising model, will be discussed. With these insights, the structure of the organic ligand shell surrounding the nanocrystal was further probed using traditional X-ray diffraction techniques, which showed ordering of ligands in the organic ligand shell, both as dried powders and in a liquid environment. Finally, dissolution calorimetry experiments measuring negative surface energies of colloidal nanocrystals will be discussed as well as their implications for understanding the thermodynamics of colloidal nanocrystals.Chapters 1 and 2 will lay the ground work for understanding the structure of colloidal nanocrystals and the main techniques used to study reactions at nanocrystal's surface. Chapter 3 will discuss measurements of reactions at the nanocrystal surface that impact their luminescence, while Chapter 4 will delve into parameters that influence the strength of collective effects between organic ligands bound to nanocrystal surfaces. Chapter 5 will focus on X-ray diffraction measurements of the structure of the organic ligand shell, while Chapter 6 will be devoted to studying negative surface and interface energies of colloidal nanocrystals. Chapter 7 will discuss the future of thermodynamic studies on the surfaces of colloidal nanocrystals.

Formation of super-hydrophobic and corrosion-resistant coatings can provide significant corrosion protection to magnesium alloys. However, it remains a grand challenge to produce such coatings for magnesium-lithium alloys due to their high chemical reactivity. Herein, a one-step hydrothermal processing was developed using a stearic-acid-based precursor medium, which enables the hydrothermal conversion and the formation of low surface energy materials concurrently to produce the super-hydrophobic and corrosion-resistant coating. The multiscale microstructures with nanoscale stacks and microscale spheres on the surface, as well as the through-thickness stearates, lead to the super-hydrophobicity and excellent corrosion resistance of the obtained coating.

This work probed the two types of solid degradation in aqueous environment: steel corrosion, and acoustically stimulated mineral dissolution.First, the steel corrosions in gas/oil wells and nuclear power plant environment were studied. The inhibition of corrosion of API-P110 steel by Ca(NO3)2 was first studied using vertical scanning interferometry (VSI) in halide-enriched solutions. The results indicate that, at low concentrations, Ca(NO3)2 successfully inhibited steel corrosion in the presence of both CaCl2 and CaBr2. Statistical analysis of surface topography data reveals that such inhibition results from suppression of corrosion at fast corroding pitting sites. Built on the methodology established from above, the effect of grain orientation on the corrosion rates of austenitic AISI 316L stainless steel was studied. The oxidation rates follow a scaling that is given by: {001} < {101} < {111} for grains undergoing both active and transpassive oxidation. The corrosion tendencies of {001} and {101} grains indicate that the activation energy of dissolution follows a scaling similar to that of the surface energy. However, the high corrosion rates of {111} grains, which featured a surface energy lower than those of the {001} and {101} grains, is attributed to their lower tendency to adsorb passivating species, from solution, that leads to a net reduction in the activation energy of oxidation.Second, this work further investigated the low-temperature pathway of aqueous activation of minerals and industrial alkaline wastes using acoustic stimulation, as an alternative to calcination process in cement production. It is revealed that the acoustic fields enhance mineral dissolution rates (reactivity) by inducing atomic dislocations and/or atomic-bond rupture. The relative contributions of these mechanisms depend on the mineral’s underlying mechanical properties. Based on this new understanding, a unifying model was created that comprehensively describes how cavitation and acoustic stimulation processes affect mineral dissolution rates. On the basis of the mechanisms described above, the effectiveness and efficiency of applying acoustic stimulation in dissolving industrial alkaline wastes were further analyzed. Ultrasonication promoted dissolution of air-cooled blast furnace slag (ACBFS) in a significant and more energy-efficient manner, compared to traditional methods, such as grinding the solute, heating, and/or convectively mixing the solvent. The advantages of acoustic stimulation for dissolution enhancement and for energy savings are also observed for Si release from stainless steel slag (SSS), Class C fly ash, and Class F fly ash. The results demonstrate the wide applicability of acoustic processing, and the outcomes offer new insights into additive-free pathways that enable waste utilization, circularity, and efficient resource extraction from industrial wastes that are produced in abundance globally.The results yielded from this work provide enhanced understanding of corrosion inhibition and suggest processing pathways for improving the oxidation resistance of steels in different industry scenarios. In addition, the results provide insights of additive-free pathway by using acoustic stimulation to enable fast elemental extraction from mineral species into aqueous solution.

Journal of magnesium and alloys 10(11), 3281-3287 (2022). doi:10.1016/j.jma.2021.08.008, Published by Elsevier, Amsterdam [u.a.]

Molecular dynamics simulations have been performed to explore the underlying synergistic mechanism of pillared graphene or non-covalent connected graphene and carbon nanotubes (CNTs) on the mechanical properties of polyethylene (PE) nanocomposites. By constructing the pillared graphene model and CNTs/graphene model, the effect of the structure, arrangement and dispersion of hybrid fillers on the tensile mechanical properties of PE nanocomposites was studied. The results show that the pillared graphene/PE nanocomposites exhibit higher Young’s modulus, tensile strength and elongation at break than non-covalent connected CNTs/graphene/PE nanocomposites. The pull-out simulations show that pillared graphene by CNTs has both large interfacial load and long displacement due to the mixed modes of shear separation and normal separation. Additionally, pillared graphene can not only inhibit agglomeration but also form a compact effective thickness (stiff layer), consistent with the adsorption behavior and improved interfacial energy between pillared graphene and PE matrix.

Ceria-zirconia mixed oxides (CZMO) is widely used in many important catalysis fields. However, pure CZMO is known to have poor thermal stability. In this paper, a strategy was proposed to design high thermal stability Ce0.475Zr0.475M0.05O2 (M=La, Y, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Er, Lu, and, Yb) oxide surface by using first-principles molecular dynamics (FPMD) simulation and experiment method. Through the structure stability analysis at different temperatures, the surface energy γ as a function of Rion/Dave is identified as a quantitative structure descriptor for analyzing the doping effect of rare earth (RE) elements on the thermal stability of Ce0.475Zr0.475M0.05O2. By doping the suitable RE, the γ can be adjusted to the optimal range to enhance the thermal stability of Ce0.475Zr0.475M0.05O2. With this strategy, it can be predicted that the sequence of thermal stability improvement is Y > La > Gd > Nd > Pr > Pm > Sm > Eu > Tb > Er > Yb > Lu, which was further verified by our experiment results. After thermal treatment at 1100 °C for 10 h, the specific surface area (SSA) of aged Y-CZ and La-CZ samples can reach 21.34 m2/g and 19.51 m2/g, which is 63.02% and 49.04% higher than the CZMO sample without doping because the surface doping of Y and La is in favor of inhibiting the surface atoms thermal displacement. In a word, the strategy proposed in this work can be expected to provide a viable way for designing the highly efficient CZMO materials in extensive applications and promoting the usages of the high-abundance rare-earth elements Y and La.

Surface engineering of active materials to generate desired energy state is critical to fabricate high-performance heterogeneous catalysts. However, its realization in a controllable level remains challenging. Using oxygen evolution reaction (OER) as a model reaction, we report a surface-mediated Fe deposition strategy to electronically tailor surface energy states of porous Co3O4 (Fe-pCo3O4) for enhanced activity towards OER. The Fe-pCo3O4 exhibits a low overpotential of 280 mV to reach an OER current density of 100 mA cm−2, and a fast-kinetic behavior with a low Tafel slop of 58.2 mV dec−1, outperforming Co3O4-based OER catalysts recently reported and also the noble IrO2. The engineered material retains 100% of its original activity after operating at an overpotential of 350 mV for 100 h. A combination of theoretical calculations and experimental results finds out that the surface doped Fe promotes a high energy state and desired coordination environment in the near surface region, which enables optimized OER intermediates binding and favorably changes the rate-determining step.

Statement of problem Polyphenylene sulfone (PPSU) is a thermoplastic that can be processed using 3-dimensional printing. PPSU is new to dentistry, and scientific data on its properties are lacking. Purpose The purpose of this in vitro study was to test the surface properties and the tensile bond strength (TBS) between PPSU and a veneering composite resin in comparison with a polyetheretherketone (PEEK). Material and methods Gehr PPSU (PPSU-B1), Radel R-5000 NT (PPSU-B2), and Juvora Dental Disc (PEEK-CG) substrates were cut from bulk material, while FIL-A-GEHR PPSU (PPSU-3D) was 3-dimensionally printed (N=504, n=126/material). TBS to veneering composite resin (CeramageUp) was tested initially and after 5000 and 10 000 thermocycles, and fracture types were analyzed. Surface free energy (SFE) and surface roughness (Ra) were determined after pretreatment with aluminum oxide (Al2O3) of different grain sizes (50 and 110 μm) applied with different pressures (0.1, 0.2, 0.4 MPa), silicon dioxide (SiO2)-coated Al2O3 (0.28 MPa), sulfuric acid, or polished. Qualitative surface characterization was performed by using a scanning electron microscope (SEM). One-way ANOVA, the Kruskal-Wallis, Mann-Whitney U, and the Spearman correlation tests were computed (α=.05). Results PPSU-3D and PEEK-CG presented higher TBS results than PPSU-B1 and PPSU-B2. Initial TBS values were higher than after 10 000 thermocycles. Adhesive fractures between substrate and veneering composite resin occurred most frequently. With a few exceptions, PEEK-CG presented higher SFE values than all other materials within a pretreatment group, while PPSU-3D and PEEK-CG showed consistently high Ra values. An increase in pressure and particle size increased SFE and Ra. Conclusions FFF-printed PPSU-3D showed similar TBS values with the veneering composite resin to the more established PEEK. Pretreatment methods devised for PEEK represent valid strategies for increasing both the SFE and Ra of the high-performance polymer PPSU.

The continuous and isothermal crystallization diagrams of the Pt 42.5 Cu 27 Ni 9.5 P 21 and the Pt 60 Cu 16 Co 2 P 22 bulk glass forming compositions are determined using calorimetric experiments. In the case of the Pt 42.5 Cu 27 Ni 9.5 P 21 bulk metallic glass, the formation of the primary crystalline phase can be prevented by rapid cooling in a conventional DSC. In contrast, for similar cooling conditions, the formation of the primary precipitating compound in Pt 60 Cu 16 Co 2 P 22 cannot be prevented in a conventional DSC as also observed in in-situ synchrotron X-ray scattering experiments. This is attributed to a critical overheating, above which remaining structures dissolve, resulting in a drastic increase of the degree of undercooling, similar to what is observed in Zr-based BMGs. Using the classical nucleation theory, the combined thermodynamic and kinetic data are used to model the isothermal crystallization data for Pt 42.5 Cu 27 Ni 9.5 P 21 , yielding an interfacial energy value of 0.11 J/m 2 between the primary nucleating crystal and the liquid. This value is three times higher than the value for good Zr-based glass-formers, suggesting that the interfacial energy plays a pivotal role in the exceptionally high glass-forming ability of Pt-P-based systems and compensates for the fragile liquid behavior and the large driving force for crystallization.

Materials design is a cornerstone of every device. Historically, the materials selection process was characterized by a time consuming, expensive, Edisonian approach. In recent years however, rapid advancements in computational power and materials simulation software has spawned the field of computational materials science. Computational materials science opens a new avenue to materials discovery called high-throughput materials design. This approach allows for rapid prototyping of materials in a large, complex chemical space. In this work, the scope of highthroughput materials design approach is used in the analysis of several topics: magnetic full-heuslers, hybrid perovskites, and grain boundary structures. Using high-throughput density functional theory (DFT), we study the surface energy of 68 magnetic full heuslers to guide the synthesis of magnetic tunnel junctions for applications in memory storage devices. We employ a high-throughput machine learning approach to explore the chemical space of single and double perovskite materials for applications in stable, high-performance solar cells. We also look deeper into hybrid perovskite materials in a literature review of two-dimensional hybrid perovskites, which demonstrate greater stability and tunable band gaps with simple fabrication routes. In addition, their strong binding energies lead to strong light emitting properties, with potential applications in light emitting diode devices. We also examine the configurational entropy of yttria-stabilized zirconia grain boundaries and provide example usage and applications of AIMSGB, an open-source python library for grain boundary structure generation.

Statement of problem A vinegar-hydrogen peroxide mixture has been reported to be effective in eliminating Candida albicans and Staphylococcus aureus from acrylic resin, and its action has been reported to be comparable with that of sodium hypochlorite or peracetic acid. However, the effects of this mixture on cobalt-chromium alloys remain unknown. Purpose The purpose of this in vitro study was to evaluate the surface roughness, Knoop microhardness, surface free energy, and wettability of a cobalt-chromium alloy when exposed to a vinegar-hydrogen peroxide mixture. Material and methods Fifty specimens of cobalt-chromium alloy were fabricated and immersed for 900 minutes, simulating 3 months of a daily 10-minute immersion in the following chemical agents (n=10): distilled water (W); 0.5% sodium hypochlorite (H); 3% hydrogen peroxide and water dilution in 1:1 ratio (HP); white-wine vinegar and water dilution in 1:1 ratio (V); and vinegar and hydrogen peroxide mixture in 1:1 ratio (VHP). Surface roughness, Knoop microhardness, surface free energy, and wettability were measured with single blinding before and after immersions. Data were statistically analyzed by using 2-way repeated measures ANOVA (α=.05). Results The vinegar-hydrogen peroxide mixture did not affect the surface roughness or Knoop microhardness. However, 0.5% sodium hypochlorite significantly increased the roughness and decreased microhardness. Surface free energy and wettability increased after immersions, regardless of the types of solution. Conclusions Immersion in a vinegar-hydrogen peroxide mixture did not affect the surface characteristics of a cobalt-chromium alloy.

Introduction Nano-SiC has attracted great attention as ceramic reinforcement in metal matrix composites, but the weak interface bonding between them remains a bottleneck for efficient strengthening. Objective In this study, pre-oxidation treatments and selective laser melting (SLM) were employed to prepare Zn/nano-SiC biocomposites with strengthened interface bonding via in situ reaction. Methods Nano-SiC and Zn powders were pre-oxidized respectively, and then used to prepare Zn/nano-SiC biocomposites via SLM. The powder microstructure, and the interface characteristics and mechanical properties of the biocomposites were investigated. The degradation properties and cell response were analyzed to evaluate their feasibility for orthopedic applications. Results The results indicated that the pre-oxidation treatments generated a uniform oxide layer on the surface of both nano-SiC and Zn particles and the thickness of the oxide layer increased with pre-oxidation temperature. During the SLM process, the oxide layers not only improved the metal-ceramic wettability by reducing interface energy, but also induced in situ reaction to form chemical bonding between the Zn matrix and nano-SiC, thereby improving the interface bonding. Consequently, the Zn biocomposite reinforced by nano-SiC with a pre-oxidation temperature of 1000 °C (ZS1000 biocomposite) exhibited more transgranular fracture and significantly enhanced compressive yield strength of 171.5 MPa, which was 31.6% higher than that of the Zn biocomposite reinforced by nano-SiC without pre-oxidation. Moreover, the ZS1000 biocomposite presented slightly accelerated degradation which might be ascribed to the facilitated electron transfer by the interface product (Zn2SiO4). In addition, the ZS1000 biocomposite also showed appropriate biocompatibility for MG-63 cell adhesion, growth, and proliferation. Conclusion This study shows the potential practical applicability for the preparation of Zn-based biocomposites with strong interface bonding and mechanical properties for orthopedic applications.

Cerium oxide possesses intrinsic hydrophobic properties ascribed to the unique electronic structure. However, the relationship between the crystal structure and hydrophobicity of cerium oxide has not been systematically studied. Herein, it is experimentally and theoretically demonstrated that the water contact angle (105.9°) of the (111) surface is higher than that (91.7°) of the (220) surface, associated with the lower surface free energy (28.44 mN/m) of (111) surface than that (38.48 mN/m) of (220) surface. Furthermore, cerium oxide films with (111)-terminated surface are annealed at 300 °C and 600 °C for 1 h, respectively. The lattice constant increases (5.4594 A 300 °C > the as-deposited), leading to the increased water contact angle (96.7°

Excellent comprehensive mechanical properties and corrosion resistance of TiZrNb equiatomic ratio medium-entropy alloy were obtained through recrystallization and spinodal decomposition. In addition to solid solution strengthening and recrystallization, the excellent mechanical properties can also be attributed to the hindering effect of nanoprecipitation formed via spinodal decomposition on the movement of dislocations. The high atomic arrangement density due to spinodal decomposition reduces the surface energy of the alloy passivation film, thereby increasing the activation energy of dissolution and the bonding energy between atoms, which improve the corrosion resistance and stability of the alloy passivation film. This work provides a new strategy to control the mechanical properties and corrosion resistance by combining recrystallization and spinodal decomposition.

To investigate the influence of an anti-aging agent on the properties of asphalt mixtures modified with styrene–butadiene–styrene, the surface energy parameters of a modified asphalt binder with two types of anti-aging agents and aggregates were measured using the Wilhelmy plate method and the static adsorption method. Based on the surface free energy theory, the bonding energies of the modified asphalt and aggregates were quantitatively analysed. A performance test of a modified asphalt mixture with a different anti-aging agent was then conducted. The results showed that an anti-aging agent could effectively improve the cohesive strength of an asphalt modified with styrene–butadiene–styrene, as well as the adhesive strength between the asphalt and aggregates. Additionally, an anti-humidity aging agent had a better effect on the polar component of a modified asphalt–aggregate interface, whereas an anti-ultraviolet aging agent had a better effect on the non-polar component. In addition, an anti-aging agent could significantly improve the high-temperature stability and water stability of a modified asphalt mixture. However, there was a certain degree of decrease in the low-temperature crack resistance.

Nickel oxide (NiOx) has significant cost and stability advantages over poly[bis (4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) for inverted p-i-n perovskite solar cells (PSCs), but the poor NiOx/perovskite contact stemming from some reactive species at the interface led to suboptimal device performance. To solve this problem, we take a multiple donor molecule approach, using 3,3'-(4,8-bis(hexylthio)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl)bis(10-(6-bromohexyl)-10H-phenoxazine) (BDT-POZ) as an example, to modify the NiOx/perovskite interface. The primary goal was to reduce the under-coordinated Ni≥3+ cations via electron transfer from the donor molecules to NiOx, thus mitigating the detrimental reactions between perovskite and NiOx. Equally importantly, the hole extraction at the interface was greatly enhanced after the organic donor modification, since the hydrophobic species atop NiOx not only enabled pinhole-free crystallization of the perovskite but also properly tuned the interfacial energy level alignment. Consequently, the PSCs with NiOx/BDT-POZ HTL achieved a high power conversion efficiency (PCE) up to 20.16%, which compared excellently with that of the non-modified devices (17.83%). This work provides a new strategy to tackle the exacting issues that have so far impeded the development of NiOx based PSCs.

Polycarbonate (PC) is a durable and transparent optical plastic material commonly used as shatter-resistant alternative to traditional optical glass. Broadband antireflective (AR) coatings with excellent mechanical strength and environmental stability are essential for PC to achieve high light transmission and visual quality. In this work, chloroform vapor treatment was employed to partially embed the silica coating into the PC substrate for adhesion enhancement, which also divided the silica coating layer into bottom and middle layers with different refractive indices. The contact between the silica nanoparticles and the substrate was transformed from “point-contact” to “area-contact”, which enhanced the adhesion between coating and PC substrate. After the deposition of a top layer coating consisted of silica nanoparticles with smaller diameter, a triple-layer refractive index graded AR structure was constructed. Hexamethyldisilazane vapor surface modification was performed to decrease the surface free energy of top coating layer. The triple-layer coating coated PC exhibits superior antireflection property with an average reflectance of only 0.43% over a wide wavelength range of 400–1000 nm. After 100 times of friction or 5 months of exposure to a contaminated environment, the reflectance of coated PC shows barely noticeable difference, indicating its excellent mechanical strength and environmental stability.

The impact of the addition of TiO2 nanoparticles and nanowires on the morphology, phase characteristics, contact angle, and electrochemical performance of chemically bonded phosphate ceramic coatings (CBPCs) was investigated. The chemical composition and surface morphology of the TiO2 nanoparticle and nanowire modified with and without (heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane were characterized. Results indicated that the hydrophobic –CF2– and –CF3 groups were successfully introduced into the TiO2 nanoparticles and nanowires after modification. Corrosion resistance of CBPCs with TiO2 was evidently improved compared with that without TiO2. Such improvement was mainly due to the combined effects of low surface energy materials and micro/nano structures. In addition, CBPCs with TiO2 nanowires exhibited higher hydrophobicity and corrosion resistance than those with TiO2 nanoparticles because of the special columnar structure of the nanowires.

Constructing interpenetrating heterointerface with reasonable interface energy barriers to improve electron/ion transport and accelerate the deposition/decomposition of lithium sulfide (Li2S) is an effective method to improve the electrochemical performance of lithium-sulfur (Li-S) batteries. Herein, NiCoO2/NiCoP heterostructures with hollow nanocage morphology are prepared for efficient multifunctional Li-S batteries. The hollow nanocage structure exposes abundant active sites, traps lithium polysulfides and inhibits the shuttle effect. The NiCoO2/NiCoP heterostructure, combing strong adsorption capacity of NiCoO2 and excellent catalytic ability of NiCoP, facilitates the process of anchoring-diffusion-transformation of polysulfides. The successful construction of heterostructures reduces the reaction barrier, accelerating the lithium ion (Li+) diffusion rate and thus effectively enhancing the redox reaction kinetics. More importantly, NiCoO2/NiCoP heterostructure plays a role in self-cleaning that minimizes solid sulfur species accumulation to maintain surface clean during long cycling for a continuously catalysis of the polysulfides conversion reactions. With the merit of these features, the NiCoO2/NiCoP modified separator exhibits excellent cycling stability with a low capacity decay of 0.043% per cycle up to 1000 cycles at 2 C. The design of NiCoO2/NiCoP hollow nanocage heterostructures offers a new option for high-performance electrochemical energy storage devices.

Reactive air brazing of Si3N4 ceramic was successfully achieved by using Ag-CuO filler metal. The effects of CuO content on the wettability of Ag-CuO/Si3N4 system and the shear strength of Si3N4/Si3N4 joint were investigated, and meanwhile the interfacial behavior was analyzed and discussed. Moreover, the work of adhesion, interfacial energy, and electronic properties of Ag/Si3N4, Ag/CuO and Ag/SiO2 interfaces were evaluated by first-principles calculations. The Ag-CuO/Si3N4 system transforms from no-wetting into wetting due to the oxidation of Si3N4 substrate and the formation of SiO2 layer on the substrate surface. The maximum average joint shear strength of over 50 MPa is obtained as the CuO content is 8 at.%. Compared with the Ag(111)/Si3N4(0001) interface, the Ag(110)/CuO(001) and Ag(110)/SiO2(001) interfaces show stronger interfacial bonding due to the formation of Ag-O ionic bond, indicating that the addition of CuO and the formation of SiO2 contribute to the enhancement of interfacial bonding.

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

Colloid-sized particles (10 nm–10 μm in characteristic size) adsorb onto fluid interfaces, where they minimize their interfacial energy by straddling the surface, immersing themselves partly in each phase bounding the interface. The energy minimum achieved by relocation to the surface can be orders of magnitude greater than the thermal energy, effectively trapping the particles into monolayers, allowing them freedom only to translate and rotate along the surface. Particles adsorbed at interfaces are models for the understanding of the dynamics and assembly of particles in two dimensions and have broad technological applications, importantly in foam and emulsion science and in the bottom-up fabrication of new materials based on their monolayer assemblies. In this review, the hydrodynamics of the colloid motion along the surface is examined from both continuum and molecular dynamics frameworks. The interfacial energies of adsorbed particles is discussed first, followed by the hydrodynamics, starting with isolated particles followed by pairwise and multiple particle interactions. The effect of particle shape is emphasized, and the role played by the immersion depth and the surface rheology is discussed; experiments illustrating the applicability of the hydrodynamic studies are also examined.

Although the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has improved greatly in recent years, the challenges of efficiency and stability still need to be overcome before these solar cells can be used in commercial applications. Here, a weak acid buffer, hydroxyethyl piperazine ethane sulfonic acid (HEPES), is used to passivate the interface of an SnO2 electron transport layer (ETL) and a photoactive layer in n-i-p solar cells. The device efficiency based on a SnO2/HEPES ETL reaches 20.22%, which is 9.7% higher than that of the control (18.43%), and the device stability is also significantly improved. The improvement in the device performance is mainly due to the introduction of the HEPES interface layer to adjust the interface energy level, which also improves the crystallinity of the perovskite film and reduces the interface defects. Electrochemical impedance spectroscopy and transient photovoltage/photocurrent results show that the HEPES-modified PSCs have lower charge transfer resistance, weaker leakage current intensity and improved interfacial charge separation and transport.

Wettability has a major effect on the performance of the corrosion of ceramic refractory under normal operating conditions. Contact angle measurement is available to characterize the wettability of liquid metals and oxide ceramics. Therefore, it is necessary to develop a contact angle prediction model with generalizability. This work emphasizes on developing a model for predicting the contact angle of a liquid metal with a solid oxide and analyzes the influence of factors affecting the contact angle when contact angle is predicted. In this paper, six contact angle prediction models are developed based on machine learning methods and contact angle data from the previous literature. The comparison between six contact angle prediction models evidences that the gaussian process regression (GPR) model has the best prediction accuracy and reaching 96%. Furthermore, the comparative results indicate that when surface energy of metal, surface energy of oxide, formation free energy of oxide, and bandgap energy of oxide are ignored respectively, the prediction accuracy of the model decreases by 4%, 3%, 1% and 1% respectively.

Crystallization growth plays a crucial role in influencing the film quality and final photoelectric conversion performance of a Kesterite Cu2ZnSn(S, Se)4 (CZTSSe) solar cell. Herein, an exploration of a two-step selenization strategy to control the growth kinetics of the aqueous solution derived CZTSSe film for high solar cell efficiency is reported. By synergistically exploiting the benefits of high and low temperature selenization in facilitating the CZTSSe phase formation, introducing beneficial point defect states, configuring the interfacial energy band structure, and sustaining excellent surface microstructure, a total-area cell efficiency of 12.5% has been achieved. These results demonstrate the significance of controlling the crystallization growth of CZTSSe to improve the device performance. The high cell performance achieved here is comparable to that of the hydrazine or dimethyl sulfoxide solution-based cells and thus would help facilitate the development of CZTSSe solar cells toward more diversified film fabrication technologies.

Particle sizing is the most commonly employed and critical unit operation across powder processing industries. In this work, we show the surface energy changes prompted by the sizing operations like milling and sieving in α-lactose monohydrate powders using Finite Dilution Inverse gas chromatography (FD-IGC) analysis. Three separate sieved fractions of α-lactose monohydrate powder were divided into a top, middle and bottom fraction from the same starting material. Similarly, a custom grade α-lactose monohydrate was milled for a different duration to produce two milled samples with different median particle sizes. Sieved sample results showed that the bottom fraction exhibited higher heterogeneity with higher dispersive (γd) surface energy values ranging from 42.5 mJ/m2 to 45.9 mJ/m2 compared to the top and middle fractions. The finest fraction contains more cleaved surfaces that are exposed during the preparation process, i.e. milling, of the material resulting in different surface properties. Furthermore, the surface energy analysis of the milled samples revealed slight but vital differences in the γd heterogeneity profiles. The site-specific distribution of energies was obtained using the Boltzmann probability distribution model and revealed two distinct regions for crystalline α-lactose monohydrate. Thus, our work confirmed that sizing operations like milling and sieving affect the surface energy of the particulate solids due to the changes in properties like size, shape, exposure of internal cleavage planes, etc. and that the surface energy heterogeneity determination using FD-IGC helped in characterising these changes.

Oil palm trunk (OPT) panel has high potential of being the substitution of wood due to the abundant of its availability in Malaysia and correspondingly resulted an increase in the export of palm oil in recent years. The properties of OPT has widely been studied including improvement on their strength and stability properties. In the present work, a hydrophobic coating was applied on compressed OPT panel prior to improve its surface quality. The hydrophobic properties were determined by water contact angle (WCA) and water sliding angle (WSA). The addition of SiO2 and chlorotrymethylsilane (CTMS) as a hydrophobic agent plays a critical role in enhancing the panel surface by generate roughness at nanoscales and lower its surface free energy which turn to higher WCA and smaller WSA values. Based on mechanical stability of hydrophobic compressed OPT, it shows that the WCAs of the surface panel remained almost constant and the coated surface remain non-wettable with the nanoscales features remain intact after performing scratch test.

Hypothesis Droplet wetting on a solid substrate is affected by the surface heterogeneity. Introducing patterned wettability on the solid substrate is expected to engender anisotropic wetting morphologies, thereby manipulating droplet wetting behaviors. However, when the droplet size is comparable with that of the surface heterogeneity, the wetting morphologies cannot be depicted by the quintessential Cassie’s theory but should be possible to be predicted from the perspective of thermodynamics via surface energy minimization. Methods Here, we investigate the equilibrium droplet shapes on chemically patterned substrates by using an analytical model, phase-field simulations, and experiments. The former two methods are sharp and diffuse interface treatments, respectively, which both are based on minimizing the free energy of the system. The experimental results are obtained by depositing droplets on chemically patterned glass substrates. Findings Various anisotropic wetting shapes are found from the three methods. Excellent agreement is observed between different methods, showing the possibility to quantify the anisotropic wetting droplet morphologies on patterned substrates by present methods. We also address a series of non-rotationally symmetric droplet shapes, which is the first resport about these special wetting morphologies. Furthermore, we reveal the anisotropic wetting shapes in a quasi-equilibrium evaporation process.