Effect Of Interfacial Characteristics Research Articles

Impact of interfacial layer number and Schiff base cross-linking on the microstructure, rheological properties and digestive lipolysis of plant-derived oil bodies-based oleogels

This study aims at development of plant-derived oil bodies (OBs) based oleogels via electrostatic layer-by-layer deposition technique that contained OB droplets coated by κ-carrageenan and chitosan, and then Schiff base cross-linked by vanillin. The effects of interfacial characteristics and Schiff bases on the formation and properties of OBs-based oleogels were investigated by analyzing microstructure, thermal stability, rheology, texture, protein degradation and lipid digestibility. Flowable to self-standing oleogels were obtained by alternating deposition of biopolymer coatings on OB droplets confirmed from macro-micro structure properties. The results from CLSM and cryo-SEM micrographs showed that OB droplets coated by the compact biopolymer layers were able to retain their structural integrity with uniform morphology and superior oil holding capacity (>99.7%), while vanillin addition fabricated micro-network structures that tightly packed the droplets. The creep-recovery rheology indicated that with an increase in vanillin concentration, oleogels changed from a viscoelastic bilayer interface to strong elastic oleogels due to Schiff bases formation. The resulting oleogels were thermally stable with high G′ (>3.5 × 104 Pa), yield stress (>1000 Pa), hardness (15.03 N), cohesiveness (0.60), and springiness (0.81) values, indicating that compact coating layers and vanillin-induced networks synergistically developed the solid oleogel structures. Furthermore, interfacial characteristics interfered with lipolysis as the FFA release rates of oleogels were considerably reduced with an increasing number of layers around OB droplets. Also, CLSM and SDS-PAGE results suggested that bilayer interface along with vanillin-induced interconnected structures exerted a strong protective effect during gastric process, being able to retain a part of undigested oleogels.

Surface modification of FO membrane by plasma-grafting polymerization to minimize protein fouling

The aim of this study was to compared the effect of two plasma gases, Argon (Ar) and carbon dioxide (CO2), in the acrylic acid (AAc) grafting modification of a commercial cellulose triacetate (CTA) membrane to improve water flux and anti-protein fouling properties in forward osmosis (FO) for protein recovery application. The successful grafting polymerization was evaluated by measuring the grafting yield and water contact angle, X-ray photoelectron spectroscopy (XPS) analysis, Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR) analysis. The contact angle of the CTA membrane was decreased from 64.0° to 37.1° and 36.4° by CO2 and Ar plasma gas treatment, respectively, which indicated an increase in hydrophilicity. The FO experiments were carried out in a lab-scale filtration apparatus. The effects of interfacial characteristics between membrane surfaces and model protein and polysaccharide foulants on flux decline and reversibility of foulants were compared. Ar gas was able to provide more free radicals and plasma electrons on the membrane surfaces, thus it was more effective than CO2 in increasing water flux and also decreased reverse salt flux and fouling tendency. The modified membranes had excellent anti-protein fouling properties, which makes them suitable for protein recovery applications. Using the Ar plasma modified membranes, tuna protein was concentrated from 4.5 % to 10.7 %, and excellent maintenance of water flux was achieved.

Effect of interfacial characteristics on magnesium to steel joint obtained using FAST

Friction-stir Assisted Scribe Technique (FAST) was used to join AZ31 magnesium alloy to Zn-coated steels including hot-dipped galvanized 590 and electroplated 270 steel with and without coating. The mechanical properties and performance of a FAST joint are governed by its underlying interfacial and microstructural characteristics, which in turn are determined by the FAST tool and process parameters. The FAST tool was utilized to create a different scribe engagement depth that can vary the extent of chemical intermixing and size of mechanical hooks. Microstructure and chemistry investigations on the weld interface were assessed using scanning electron microscopy and electron dispersive spectroscopy. Mechanical properties including lap shear tensile strength and micro and nano hardness at different interfacial regions were correlated to the local microstructures. A finite element-based modeling approach was developed to identify optimal interfacial characteristics that lead to a desired mechanical performance. The results of the computational model were compared to the experimental observations. A sensitivity analysis was conducted to study the variation in the mechanical response and failure modes of the joint with respect to the interfacial characteristics. Results indicate that interfacial characteristics including hook shape can have a significant impact on the joint strength and failure modes.

Effect of interfacial characteristics on toughness of nanocrystalline cemented carbides

Dense nanocrystalline cemented carbide bulks were prepared using a unique in situ synthesized WC–Co composite powder with a super-ultrafine nanostructure. Remarkable enhancement in the fracture toughness (with high hardness being maintained) was obtained in the nanocrystalline cemented carbides. Based on detailed studies on the combination of WC and Co phases, the WC/Co orientation relationship and the atomic correspondence at interfaces, the mechanisms for high toughness in the present nanocrystalline cemented carbides were demonstrated. The study proposed that interfacial characteristics play a significant role in the toughness of the nanocrystalline cemented carbides, and provided an effective approach to achieve superior combination properties of hardness and toughness in cermet materials.

Interface engineering in organic transistors

Recent technological advances in organic field-effect transistors (OFETs) have triggered intensive research into the molecular and mesoscale structures of organic semiconductor films that determine their charge-transport characteristics. Since the molecular structure and morphology of an organic semiconductor are largely determined by the properties of the interface between the organic film and the insulator, a great deal of research has focused on interface engineering. We review recent progress in interface engineering for the fabrication of high-performance OFETs and, in particular, engineering of the interfaces between semiconductors and insulators. The effects of interfacial characteristics on the molecular and mesoscale structures of π-conjugated molecules and the performance of OFET devices are discussed.

The effect of interface characteristics on the static and dynamic mechanical properties of three‐component polymer alloys

AbstractThe effect of interfacial characteristics on the structure‐property relationships of ternary polymer alloys and blends comprising polypropylene (PP), ethylene‐vinyl alcohol copolymer (EVOH) and glass beads (GB) or fibers (GF) was investigated. The systems studied were based on a binary PP/EVOH immiscible blend, representing a blend of a semi‐crystalline apolar polymer with a semi‐crystalline highly polar copolymer. The ternary systems studied consisted of filler particles encapsulated by EVOH, with some of the minor EVOH component separately dispersed within the PP matrix. Modification of the interfacial properties was done using silane coupling agents for the EVOH/glass interface and compatibilization using a maleic anhydride grafted PP (MA‐g‐PP) for the PP/EVOH interface.Both glass fillers increased the dynamic modulus and decreased the damping of the neat polymers and of their binary blends, especially in the rubbery region. GF has a more profound effect on both the modulus and the damping. Glass surface treatments and compatibilization have only a marginal effect on the dynamic mechanical behavior of the ternary blends. Yet, compatibilization shifted the polymers' TgS to higher temperatures.Both glass fillers increased the elastic modulus of the binary blends, where GF performed better than GB as a reinforcing agent. GF slightly increased the strength of the binary blends while, GB reduced it. Both fillers reduced the ductility of the binary blends. The blends' mechanical properties were related to the morphology and their components' crystallinity. The compatibilizer increases both stiffness and strength and reduces deformability.

The effect of interface characteristics on the morphology, rheology and thermal behavior of three‐component polymer alloys

AbstractImmiscible polymer blends are interesting multiphase host systems for fillers. Such systems exhibit, within a certain composition limits, either a separate dispersion of the two minor phases or a dispersion of encapsulated filler particles within the minor polymer phase. Both thermodynamic (e.g. interfacial tension) and kinetic (e.g. relative viscosity) considerations determine the morphology developed during the blending process.The effect of interfacial characteristics on the structure‐property relationships of ternary polymer alloys and blends comprising polypropylene (PP), ethylene‐vinyl alcohol copolymer (EVOH) and glass beads (GB), or fibers (GF), was investigated. The system studied was based on a binary PP/EVOH immiscible blend, representing a blend of a semi‐crystalline apolar polymer with a semicrystalline highly polar copolymer. Modification of the interfacial properties was obtained through using silane coupling agents for the EVOH/glass interface and compatibilization using a maleic anhydride grafted PP (MA‐g‐PP) for the PP/EVOH interface. The compatibilizer was added in a procedure aimed to preserves the encapsulated EVOH/glass structure. Blends were prepared by melt extrusion compounding and specimens by injection molding. The morphology was characterized using scanning electron microscopy (SEM) and high resolution SEM (HRSEM), the shear viscosity by capillary rheometry and the thermal behavior using differential scanning calorimetry (DSC).The system studied consisted of filler particles encapsulated by EVOH, with some of the minor EVOH component separately dispersed within the PP matrix. Modification of the interfaces resulted in unique morphologies. The aminosilane glass surface treatment enhanced the encapsulation in the ternary [PP/EVOH]GB blends, resulting in an encapsulated morphology with no separtely dispersed EVOH particles. The addition of a MA‐g‐PP compatibilizer preserves the encapsulated morphology in the ternary blends with some finely dispersed EVOH particles and enhanced PP/EVOH interphase interactions.The viscosity of the binary and ternary blends was closely related to the blend's morphology and the level of shear rate. The treated glass surfaces showed increased viscosity compared to the cleaned glass surfaces in both GB and GF containing ternary blends.Both EVOH and glass serve as nucleating agents for the PP matrix, affecting its crystallization process but not its crystalline structure. The aminosilane glass surface treatment completely inhibited the EVOH crystallization process in the ternary blend.In summary, the structure of the multicomponent blends studied has a significant effect on their behavior as depicted by the rheological and thermal behavior. The structure‐performance relationships in the three‐component blends can be controlled and varied.

Effect of interfacial characteristics on the failure-mechanism mode of a SiC reinforced A1 based metal-matrix composite

The present study addresses the interfacial behavior in a SiC reinforced 6061 A1 alloy synthesized using the conventional casting route. Microstructural characterization studies carried out on samples subjected to three different controlled heat-treatment cycles revealed the presence of Mg-rich intermetallics and SiC particulates as the two predominant secondary phases distributed in the metallic matrix. The results of scanning electron microscopy revealed the presence of solute-rich zones in the near vicinity of the interface formed between the metallic matrix and the SiC particulates. The dimensions of these solute-rich zones were found to decrease with the decrease in the cooling rate of the samples from the solutionizing temperature. Furthermore, the results of fractographic studies carried out on tensile fractured samples indicated a change in the failure mode from: SiC/Al matrix debonding and cracking of SiC particulates (exhibited by peak-aged samples); to interfacial matrix failure and limited SiC/Al matrix debonding (exhibited by composite samples cooled at 3°C min −1); to a predominant interfacial matrix failure (exhibited by composite samples cooled at 0.5°C min −1). This change in the failure mechanism mode is rationalized in terms of the constitutional variation of the interfacial region brought about by the various heat-treatment cycles employed in the present study.

The Effect of Interfacial Characteristics on the Mechanical Performance of Particulate, Fibrous and Layered Metal Matrix Composites - A Review of some Recent Work

The Effect of Interfacial Characteristics on the Mechanical Performance of Particulate, Fibrous and Layered Metal Matrix Composites - A Review of some Recent Work

Effect of interfacial characteristics on effective conductivities of composites containing randomly distributed aligned long fibers

The effect of interfacial characteristics on the effective thermal conductivity, k eff, of composites containing randomly distributed aligned long fibers is studied. An expression for the reduced effective thermal conductivity, k eff k 1 , is derived with pair interactions rigorously taken into account. Two types of interfaces are treated: one with finite thickness and one with no thickness but possessive of certain thermal barriers. The expressions of k eff k 1 for these two types of interfaces are found to be identical but with different definitions for involved multipole polarizabilities, θ n . The effect of interfacial characteristics, quantified as the relative interfacial thickness, δ a , reduced interfacial thermal conductivity, σ 3, and Biot number, Bi, on k eff k 1 is thoroughly investigated. It is further found that interfacial characteristics may be well represented by the dipole polarizability, θ 1, although higher orders of multipole polarizabilities appear in the expression of k eff k 1 . Comparison of the present results with those obtained from three less rigorous models, the equivalent inclusion model, modified effective medium theory, and modified Hashin and Shtrikman's bounds, is also presented. The present results stay well within the bounds for the combined area fraction of interface and inclusion, f, up to 0.5. Finally, the effect of microstructure on k eff k 1 is examined by a comparison of present results with those for square and hexagonal arrays. The randomness in configuration tends to intensify the thermal interactions between the effective inclusion and the matrix such that, under the same condition, k eff k 1 values of the random array deviate farther from unity than those of the regular arrays.

Effect of interfacial characteristics on effective conductivities of isotropic two-dimensional periodic composites

The effect of interfacial characteristics on the effective thermal conductivity, k eff, of isotropic two-dimensional periodic composites of infinitely long circular cylinders is studied with a boundary collocation scheme. Three types of problems are investigated: coated inclusion, debonded inclusion and contact resistance problems. It is shown that a critical relative interfacial layer thickness, (δ a) c , exists for the first two problems, at which the insulating or conducting effect of the inclusion is exactly balanced out by that of the interfacial layer such that no effect of inclusion addition can be realized. The expression for the critical relative interfacial layer thickness is derived and studied. For the third problem, the contact resistance is characterized by the Biot number, and a critical Biot number is found to exist and its expression is also derived. The second problem is further shown to reduce to the third problem for composites with thin debonding layer. A thorough parametric study is then conducted for the effective thermal conductivity subject to various system parameters including the reduced thermal conductivities of the inclusion ( σ 2) and interfacial layer ( σ 3), the relative interfacial layer thickness ( δ a ), the Biot number ( Bi), the total inclusion volume fraction (f), and the microstructure (square or hexagonal arrays). The parameter domains investigated are either complete or widely ranged to cover most practically realizable systems. Two new independent parameters, ( δ a ) σ 3 and ( Bi) σ 2, are identified for the coated inclusion and contact resistance problems, respectively, when the composites are not heavily loaded. Their physical implications are discussed and their effects on k eff are studied. It is found that composites with contact resistance characterized by Bi can be viewed as composites of no contact resistance but with σ 2 replaced by ( Bi) σ 2 for the calculation of k eff when σ 2 > 10 and Bi < 0.1. The effect of various parameters on the effect of interfacial characteristics is also investigated. The interfacial effect becomes more pronounced with increasing total inclusion volume fractions, and is more revealing for square arrays.