Influence Of Interfacial Interactions Research Articles

Numerical Modeling of the Interaction of a Monodisperse Gas Suspension with a Shock Wave Moving at an Angle to the Separation Boundary of a Homogeneous Gas and a Gas Suspension

The work is devoted to the study of the influence of the dispersed phase on the dynamics of gas suspensions during numerical modeling of the dynamics of gas suspensions. In this study, based on the continuum technique of dynamics of inhomogeneous media, the interaction of a shock wave propagating from a homogeneous gas with a gas suspension was numerically simulated. For each of the components of the mixture, a complete hydrodynamic system of equations of motion was solved, which included the equations of conservation of density, the equations of conservation of the spatial components of the momentum of the mixture components, and the equations of conservation of energy of the components. The carrier medium was described as a viscous, compressible heat-conducting gas. The mathematical model took into account interfacial heat transfer. The mathematical model also took into account the interphase exchange of momentum, which included the force of aerodynamic drag, the dynamic force of Archimedes and the force of added masses. The system of equations of the mathematical model was integrated using the finite difference method. To suppress numerical oscillations, a nonlinear correction scheme was used. Large volumetric contents of the dispersed phase were considered. The influence of interfacial interaction on the process of shock wave propagation has been studied.

Influence of Interfacial Interaction and Composition on Fracture Toughness and Impact Properties of Carbon Fiber-Reinforced Polyethersulfone.

In this study, the interlaminar fracture toughness and impact strength of polyethersulfone reinforced with continuous carbon fibers were studied. Interlaminar fracture toughness tests were performed using the double cantilever beam method. It was shown that surface modification using the thermal oxidation method of the carbon fibers can strongly increase the interlaminar fracture toughness of the obtained composites. Thus, the maximum value reached 1.72 kJ/m2, which was 40% higher than the fracture toughness of the composites reinforced with initial carbon fibers. Moreover, fractographic analysis using a scanning electron microscope allowed us to highlight the main reasons for the dependence of fracture toughness on fiber content and surface modification conditions of the carbon fibers. It was shown that the main factor that allowed for an increase in fracture toughness was the enhanced interfacial interaction between the fibers and polymer matrix. Additionally, it was found that expectedly, there was a good correlation between interlaminar fracture toughness and interlaminar shear strength results. However, a negative influence of surface modification on the impact properties of composites was found. Such behavior occurred because of higher structural stability and lower exposure to delamination in multiple layers of the composites reinforced with the modified carbon fibers. It was found that impact energy reached ~150 kJ/m2 for the polyethersulfone-based composites reinforced with initial fibers, while the composites reinforced with modified carbon fibers showed impact energy values of only ~80 kJ/m2. Nevertheless, surface modification of carbon fibers using the thermal oxidation method can be an effective method for improving the performance properties of polyethersulfone-based composite materials.

Environmental Stability and Transmissibility of Enveloped Viruses at Varied Animate and Inanimate Interfaces.

Enveloped viruses have been the leading causative agents of viral epidemics in the past decade, including the ongoing coronavirus disease 2019 outbreak. In epidemics caused by enveloped viruses, direct contact is a common route of infection, while indirect transmissions through the environment also contribute to the spread of the disease, although their significance remains controversial. Bridging the knowledge gap regarding the influence of interfacial interactions on the persistence of enveloped viruses in the environment reveals the transmission mechanisms when the virus undergoes mutations and prevents excessive disinfection during viral epidemics. Herein, from the perspective of the driving force, partition efficiency, and viral survivability at interfaces, we summarize the viral and environmental characteristics that affect the environmental transmission of viruses. We expect to provide insights for virus detection, environmental surveillance, and disinfection to limit the spread of severe acute respiratory syndrome coronavirus 2.

Enhanced hydrogen evolution reaction via regulating the adsorbability between 2D CoO nanosheets and CC substrate.

In recent years, bifunctional electrocatalysts, nanomaterials directly grown on the substrate for application towards the hydrogen evolution reaction (HER), have become of interest for sustainable and clean energy technologies. However, the influence of interfacial interactions between the electrode materials and substrate on device performance remains unclear and is rarely investigated. Herein, we report two-dimensional (2D) CoO nanosheets grown on carbon cloth (CC) (2D CoO/CC) to construct a hybrid electrocatalyst with a seamlessly conductive network. By a series of structure analyses, we recommend that the CoO nanosheets and CC are connected via adsorption. The 2D CoO/CC nanosheets show superior HER performance to the commercial Pt/C and CoO(aq.)/CC nanosheets, including onset potentials of 2 mV, low overpotential of 22 mV at 10 mA cm-2 and Tafel slope of 37 mV dec-1. The results of density functional theory (DFT) calculations reveal that the adsorbability plays an important role in determining the performance of the electrocatalysts for the HER. This work provides a new insight into the interfacial interactions between the electrode material and the substrate in electrochemical devices, and paves the way for the rational design and construction of high-performance electrochemical devices for practical energy applications.

The influence of hydrogen bond and electrostatic interaction on the mechanical properties of the WPU/modified SiO2 nanocomposites

A variety of nano SiO2 microspheres with negative charge or positive charge were prepared by hydrochloric acid treatment or/and γ-mercaptopropyltrimethoxysilane modification respectively. The obtained modified SiO2 with different content of -OH or -SH and different charges were physically introduced into water-borne polyurethane (WPU) dispersion to fabricate the WPU/modified SiO2 nanocomposites with interfacial interaction of hydrogen bond and electrostatic interaction. The influence of interfacial interaction (hydrogen bond and electrostatic interaction) between WPU and modified SiO2 on the interface structure and mechanical properties of the WPU/modified SiO2 nanocomposites were investigated. The results showed that when both hydrogen bond and electrostatic interaction were present between WPU and modified SiO2, the microstructure and the tensile strength of the WPU/modified SiO2 nanocomposite were mainly affected by the electrostatic interaction, while the elongation at break was mainly affected by the hydrogen bond interaction. Overall, a methodology of the combination of molecular dynamics simulation and experiment study was established to reveal the influence of surface characteristic of SiO2 on the interface interaction and mechanical properties of the WPU/modified SiO2 nanocomposites.

Reduced Fracture Strength of 2D Materials Induced by Interlayer Friction.

The potential applications of 2D layered materials (2DLMs) as the functional membranes in flexible electronics and nano-electromechanical systems emphasize the role of the mechanical properties of these materials. Interlayer interactions play critical roles in affecting the mechanical properties of 2DLMs, and nevertheless the understanding of their relationship remains incomplete. In the present work, it is reported that the fracture strength of few-layer (FL) WS2 can be weakened by the interlayer friction among individual layers with the assistance of finite element simulations and density functional theory (DFT) calculations. The reduced fracture strength can be also observed in FL WSe2 but with a lesser extent, which is attributed to the difference in the interlayer sliding energies of WS2 and WSe2 as confirmed by DFT calculations. Moreover, the tip-membrane friction can give rise to the underestimation of the Young's modulus except for the membrane nonlinearity. These results give deep insights into the influence of interfacial interactions on the mechanical properties of 2DLMs, and suggest that importance should be also attached to the interlayer interactions during the design of nanodevices with 2DLMs as the functional materials.

Use of Dynamic Mechanical Analysis (DMA) for Characterizing Interfacial Interactions in Filled Polymers

Dynamic mechanical analysis (DMA) provides reliable information about the viscoelastic behavior of neat and filled polymers. The properties of filled polymers are relevant to different industries as protective organic coatings, composites etc. Interfacial interactions in filled polymers play an important role in determining their bulk properties and performance during service life. In this brief review article, studies that used DMA to characterize the interfacial interactions in filled polymers have been reviewed. The available open literature provides a mixed opinion about the influence of interfacial interactions on the glass transition temperature of filled polymers. Nevertheless, it appears that in the case of strong interfacial interactions between the filler particles and the polymeric matrix, the peak value of tan δ is reduced in comparison to that of a filled polymer where these interactions are weak.

Nature-inspired hierarchical materials for sensing and energy storage applications.

Nature-inspired hierarchical architectures have recently drawn enormous interest in the materials science community, being considered as promising materials for the development of high-performance wearable electronic devices. Their highly dynamic interfacial interactions have opened new horizons towards the fabrication of sustainable sensing and energy storage materials with multifunctional properties. Nature-inspired assemblies can exhibit impressive properties including ultrahigh sensitivity, excellent energy density and coulombic efficiency behaviors as well as ultralong cycling stability and durability, which can be finely tuned and enhanced by controlling synergistic interfacial interactions between their individual components. This tutorial review article aims to address recent breakthroughs in the development of advanced Nature-inspired sensing and energy storage materials, with special emphasis on the influence of interfacial interactions over their improved properties.

Structure and dynamics of water in TiO2 nano slits: The influence of interfacial interactions and pore sizes

Abstract The interaction of water with TiO2 surfaces is of enduring interest because of wide applications of the TiO2 materials in aqueous environments. The structure and dynamic properties of water molecules in TiO2 nanopores are crucial as increasingly TiO2 materials are synthesized into nanoporous structures. In this work, the structural and dynamic properties of water molecules in nanoscale slit pores of TiO2 are investigated, by using three sets of force field models for the water- TiO2 interaction, as well as four TiO2 slit pore widths. It is concluded that the water- TiO2 interaction dominates the interfacial structure of water molecules, while the dynamic properties of water molecules are primarily influenced by the slit width in both interfacial and central regions. These findings indicate that both of the fluid properties and the interactions of fluids with pore wall will determine the transport properties of fluid in nanopores. If the pore size is large enough, e.g. 1.0 nm or larger in this work, the transport properties will be determined most by the fluids themselves. For the cases of pores whose sizes are in the range of interfacial region, the influences of pore size and interfacial interaction will interfere each other.

Influence of interfacial interactions on the mechanical behavior of hybrid composites of polypropylene / short glass fibers / hollow glass beads

Ternary composites of Polypropylene (PP)/Short Glass fibers (GF)/Hollow Glass Beads (HGB), with varying total and relative GF/HGB contents and using untreated and aminosilane-treated HGB compatibilized with maleated-PP, were prepared by direct injection molding of pre-extrusion compounded GF and HGB concentrates. The mechanical strength properties (tensile, flexural and Izod impact) were correlated with theoretical model predictions for hybrid composites, which identified synergistic gains over the rule of hybrid mixtures, depending upon the degree of interfacial interactions between the components of the hybrid composite. SEM analysis of cryofractured composites surfaces revealed that the presence of untreated HGB particles induces fiber-polymer interfacial decoupling under mechanical loading of the hybrid composites at much lower stress levels than in the presence of treated HGB particles. Higher storage modulus (E′) and lower mechanical damping (tan δ) from DMTA established the importance of strong polymer-hybrid reinforcement interfacial interactions in the development of lightweight/high strength PP syntactic foams.

The influence of interfacial interactions on the conductivity and phase behaviour of organic ionic plastic crystal/polymer nanoparticle composite electrolytes

The interactions between OIPCs and polymer nanoparticles create interfacial layers that control the ion mobility of the resulting composite.

Influence of interfacial interaction on the mechanical properties of amorphous PE/MMT nanocomposites

We carried out molecular dynamics simulations to examine the structural, interfacial, and mechanical properties of amorphous polyethylene/montmorillonite (PE/MMT) nanocomposites loaded with 0 wt. %, 3.3 wt. %, 4.0 wt. %, and 5.1 wt. % of modified organic MMT (O-MMT). The MMT nanoparticles were simulated in two stages: first treated with octadecyl trimethyl ammonium chloride and then doped in amorphous PE. The effects of the O-MMT content on the microstructure parameters (interaction energy, free volume, and interfacial thickness) and macroscopic mechanical properties (Young’s modulus, bulk modulus, and shear modulus) were analyzed. A strong correlation between mechanical properties and interfacial thickness was observed by analyzing the obtained data from simulation, and we verified them through experiments.

On the Issue of the Influence of Interfacial Interactions on the Filtration Processes in Coal

The features of gas-liquid fluid filtration processes in a coal mass are discussed and general patterns of mass transfer, extending previously known concepts, are established in the article. It indicates the degree of the influence of wettability, contact angle of wetting on filtration processes. It is assumed the coal-liquid-gas interfacial interactions when infusing the coal mass lead to the deformation of capillary pore space of coal, splitting, swelling and clogging of filter pores and capillaries. A comparison is made between the thermal effect and the effect of surfactants on the deformation processes of the capillary-porous structure of coal. Filtration processes are described by the gas-liquid fluid mass transfer equations. Coal-liquid-gas interfacial processes lead to a change in the state of the interacting phases, which leads to a change in both the filtration properties of the liquid and the filtration properties of a capillary pore space, which is especially characteristic of coal in relation to other rocks. Investigating the interfacial interactions when filtering in the laboratory, it is possible to determine the functions of the variation of the key coefficients in the mass transfer equations. On the basis of such studies, it is possible to predict the results of mass transfer in a coal mass being infused or degassed, as well as the change in the coal mass stress state.

Multiwalled carbon nanotubes-based polypropylene composites: Influence of interfacial interaction on the crystallization behavior of polypropylene

Composites of polypropylene (PP) and multi-walled carbon nanotubes (MWCNTs) were prepared via melt-mixing utilizing Li-salt of 6-amino heaxanoic acid (Li-AHA) modified MWCNTs in the presence of a compatibilizer (polypropylene-g-maleic anhydride; PP-g-MA). Improved interaction between the anhydride group of PP-g-MA and the amine functionality of Li-AHA was confirmed via FTIR and Raman spectroscopic analysis. A higher glass transition temperature (Tg) of the PP phase has been observed in these composites as compared to pristine MWCNTs based composites. The crystallization temperature (Tc) of the PP phase was increased as a function of pristine MWCNTs concentration in PP/MWCNTs composites indicating hetero-nucleating action of MWCNTs. However, Tc value was decreased in the presence of Li-AHA modified MWCNTs indicating the adsorbed Li-AHA on the MWCNTs surface. Moreover, Tc value was higher in the presence of Li-AHA modified MWCNTs with PP-g-MA as compared to that of without PP-g-MA, suggesting the desorbed Li-AHA from the MWCNTs surface due to melt-interfacial reaction. Further, MWCNTs were extracted by hot vacuum filtration technique from PP/MWCNTs composites containing Li-AHA and PP-g-MA. The isothermal crystallization kinetics showed a variation in crystallization behavior of the PP phase in the corresponding composites as compared to the “extracted MWCNTs.” POLYM. ENG. SCI., 2016. © 2016 Society of Plastics Engineers

Influence of interfacial interactions on deformation mechanism and interface viscosity in α-chitin–calcite interfaces

The interfaces between organic and inorganic phases in natural materials have a significant effect on their mechanical properties. This work presents a quantification of the interface stress as a function of interface chemical changes (water, organic molecules) in chitin–calcite (CHI–CAL) interfaces using classical non-equilibrium molecular dynamics (NEMD) simulations and steered molecular dynamics (SMD) simulations. NEMD is used to investigate interface stress as a function of applied strain based on the virial stress formulation. SMD is used to understand interface separation mechanism and to calculate interfacial shear stress based on a viscoplastic interfacial sliding model. Analyses indicate that interfacial shear stress combined with shear viscosity can result in variations to the mechanical properties of the examined interfacial material systems. It is further verified with Kelvin–Voigt and Maxwell viscoelastic analytical models representing viscous interfaces and outer matrix. Further analyses show that overall mechanical deformation depends on maximization of interface shear strength in such materials. This work establishes lower and upper bounds of interface strength in the interfaces examined.

Insights into the relation between adhesion force and chalcopyrite-bioleaching by Acidithiobacillus ferrooxidans

This paper presents a study on the relation between bacterial adhesion force and bioleaching rate of chalcopyrite, which sheds light on the influence of interfacial interaction on bioleaching behavior. In our research, Acidithiobacillus ferrooxidans (A. ferrooxidans) were adapted to grow with FeSO4·7H2O, element sulfur or chalcopyrite. Then, surface properties of Acidithiobacillus ferrooxidans and chalcopyrite were analyzed by contact angle, zeta potential and Fourier transform infrared spectroscopy (FTIR). Adhesion force between bacteria and chalcopyrite was measured by atomic force microscopy (AFM). Attachment and bioleaching behaviors were also monitored. The results showed that A. ferrooxidans adapted with chalcopyrite exhibited the strongest adhesion force to chalcopyrite and the highest bioleaching rate. Culture adapted with sulfur bacteria took second place and FeSO4·7H2O-adapted bacteria were the lowest. Bioleaching rate and bacterial attachment capacity were positively related to bacterial adhesion force, which is affected by the nature of energy source. According to this work, the attachment of bacteria to chalcopyrite surface is one of the most important aspects that influence the bioleaching process of chalcopyrite.

Effect of transition metal salt additive on the structural packing and thermal stability of the non-aqueous lyotropic mesophases

The present study demonstrates the interfacial interplay between transition metal salt (TMS) additive and range of non-aqueous lyotropic mesophases. Structural aspect reveals the substantial influence of the additive addition on the self-assembly and packing of micelles as intense growth of hexagonal planes was seen in the vicinity of the pre-existed lamellar mesophase (as the surfactant concentration loomed to the higher value in the parent binary mixture). Such structural modulations certainly resulted from reduction in optimal surface area of head group and packing parameter under the influence of interfacial interactions amid charged counter ions and metal salt additive. The origin and thermal stability of hexagonal ordering have been addressed and discussed.

Interfacial and Annealing Effects on Primary α-Relaxation of Ultrathin Polymer Films Investigated at Nanoscale

The influence of interfacial interactions and annealing time on dynamics of the α-relaxation in ultrathin poly(vinyl acetate) films deposited on different substrates has been studied using local dielectric spectroscopy at ambient pressure and controlled humidity. After annealing at 323 K for about 3 days, for polymer films supported on gold and aluminum substrates, an increase of the relaxation rate with decreasing film thickness below 30–35 nm was observed, whereas for films deposited on silicon substrates a thickness-independent dynamics was found for films as thin as 12 nm. The difference in size effect on dynamics of the films could reasonably be related to the difference in interfacial energy between polymer films and substrates, even though a criterion simply based on interfacial energy cannot be used to explain all the results. In fact, further annealing at a higher temperature evidenced an annealing-dependent dynamics in films prepared on aluminum substrates consistent with the presence of long-living metastable states at the polymer/substrate interface. The lifetime of such metastable states seems related to the nature of the substrate as well as to the molecular weight of the polymer.

Copper Phthalocyanine on Hydrogenated and Bare Diamond (001)-2 × 1: Influence of Interfacial Interactions on Molecular Orientations

The molecular orientations of copper phthalocyanine (CuPc) organic semiconductor molecules on hydrogenated and bare diamond (001)-2 x 1 surfaces are studied using synchrotron-based photoemission spectroscopy (PES) and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Angular-dependent NEXAFS reveals that the CuPc molecular assemblies are orientationally ordered and lying down on hydrogenated diamond, whereas they undergo a molecular reorientation on bare diamond from lying down at submonolayer coverage to standing up in multilayers. The molecular film on bare diamond also exhibits an order-disorder-order transition in the molecular orientations. The distinct molecular orientation within the CuPc films on both diamond (001) surfaces is explained in terms of the interplay between intermolecular interactions and molecule-substrate interactions.

Rheological Properties of UV-curable Flexographic Ink (II) Influence of Interfacial Interactions in Relation to Rheological Variables of Ink and its Printability

The rheological properties of UV flexographic (flexo) inks were investigated. UV flexo suspensions of carbon black in liquid medium containing various binding materials, such as acylate pre-polymers, di-/multi-functional monomers, and diluents, were used as sample inks. The inks were characterized on a rheometer in terms of steady and dynamic behaviors. The rheological properties of polymer-pigment systems are a function of some interfacial parameters that characterize the degree of affinity of pigment surfaces to the polymer medium. The addition of pigments into liquid medium introduces polymer-pigment junctions besides the polymer-polymer junctions due to entanglement. These newly created junctions arise from the sorption of pigments to the polymer chains. In this study, we found that the frequency dependence of storage modulus G' at a certain strain amplitude is proportional to the number of acryloyl groups in the multi-functional monomer (TMPTA<PETTA<<DPHA). The chemical difference due to chain length (TMPTA<GPTA) is another factor affecting the rheological properties of UV flexo ink. In addition, we surmise that a transient network structure is formed by mechanical interactions that are induced by the addition of high concentrations of small solid particles such as carbon black to a polymer or a multi-phase solution. In such a system, the particle chains form the network structure, although the formation of polymer bridges by adsorbing to adjacent particles is another possibility.