Interfacial layer and phase inversion behavior in the blend of polyethersulfone and polycarbonate

A blend of polyethersulfone (PES) and polycarbonate (PC) with a ratio of 40/60 was studied by scanning electron microscopy (SEM), dynamic mechanical analysis, and transmission electron microscopy (TEM). It was found that the PES-PC blend is a partially miscible, two-phase system, and an interfacial layer exists between the phases of PES and PC. Specific interaction resulting from the n-complex between PES and PC provides the driving force for formation of the interfacial layer. In addition, phase inversion behavior was also observed for the 40/60 composition.

The kinetics study in liquid-liquid systems with constant interfacial area cell with Laminar flow

A novel constant interfacial cell with laminar flow is proposed as an approach to obtain extraction kinetics data in liquid-liquid systems. Applications and theoretical fundamentals of the apparatus have been elaborated.. The equation which can express the mass transfer of liquid-liquid system run in the constant interfacial cell with laminar flow is deduced. Simulations from the equations indicate that diffusivity is a suitable factor to represent the characteristics of extraction kinetics rather than the extraction rate in the diffusion controlling step. The dependence of the aqueous phase concentration on time is recommended to determine the extraction regime. The diffusivities of the EuCl3-HDEHP extraction system obtained by different methods are compared to certify the hydrodynamic theory of the cell. The diffusivities of the ErCl3-HEH/EHP extraction system are determined, which show that this technique is a convenient method to obtain the diffusivities in the liquid-liquid system and to determine the extraction regime. (C) 1998 Elsevier Science Ltd. All rights reserved.

Interfacial characteristics of the self-assembly system of poly-L-lysine 3-mercaptopropionic acid gold electrode

The interfacial characteristics of poly-L-lysine (PL) attached on self-assembled monolayers (SAMs) of 3-mercaptopropionic acid (MPA) were studied by an electrochemical method. The results indicated that PL\MPA layer inhibited partly the diffusion process of redox species in solution, and the electrode surface behaved like a microelectrode array. Its permeation effect was also strongly affected by Mg2+. The more Mg2+ ions were added into the electrolyte solution, the greater the difficulty with which the electron transfer of potassium ferricyanide took place. The three different conformations of PL on the electrode surface had different influences on the electron transfer processes of ferricyanide. PL in random coil state hindered most strongly the electron transfer behavior of ferricyanide,while the alpha-helical PL had nearly no effect and the effect of the beta-sheet state PL was intermediate of these. (C) 1997 Elsevier Science S.A.

Morphology, mechanical properties and interfacial behaviour of PA1010/PP/PP-g-GMA ternary blends

Morphology, mechanical properties, and interfacial interaction of polyamide 1010/polypropylene (PA1010/ PP) blends compatibilized with polypropylene grafted with glycidyl methacrylate (PP-g-GMA) were studied. It was found that the size of the PP domains, tensile and impact strength of ternary blends, and adhesion fracture energy between two layers of PA1010 and PP were all significantly dependent on the PP-g-GMA contents in the PP layer. Correlations between morphology and related properties were sought. The improvements in properties have been attributed to chemical and physical interaction occurring between PA1010 and PP-g-GMA. (C) 1997 Elsevier Science Ltd.

Electrochemical study of the interfacial characteristics of redox-active viologen thiol self-assembled monolayers

The electrochemical behavior of the electroactive self-assembled monolayers (SAMs) of thiol-functionalized viologen, CH3(CH2)(9)V2+(CH2)(8)SH, where V2+ is a viologen group, on the gold electrodes is examined by cyclic voltammetry and electrochemical a.c. impedance. A monolayer of viologen is immobilized on the gold electrode surface via the Au-S bond and the normal potentials corresponding to the two successive one-electron transfer processes of the viologen active centers are -310 mV and -652 mV (vs. Ag/AgCl) in 0.1 mol l(-1) phosphate buffer solution (pH 6.96) respectively. These results suggest that the viologen SAMs are stable and well-behaved monolayers. The experimental impedance data corresponding to different forms of viologen group have been fitted to equivalent electrical circuits, and the surface capacitances and resistances have been given. The heterogenous electron transfer rates of the first and the second redox processes are 7.57 s(-1) and 1.49 s(-1) respectively through a.c. impedance.

Impedance spectrum measurement in liquid liquid interface electrochemistry .1. Analysis of various kinds of interfacial impedance in the four-electrode system

Applying impedance spectrum technique to liquid/liquid interfacial electrochemistry, we present the theoretical expression of the liquid/liquid interfacial impedance in the four - electrode electrolytic cell measured by alternating current impedance method. The influence of the electrolytic cell parameters and input passage parameters of the impedance apparatus on impedance spectrum curves are theoretically studied.

MOLECULAR-STATE OF GRAFT-COPOLYMERS IN THE INTERFACIAL AREA OF POLYOLEFIN AND POLAR POLYMER

In order to characterize the interface in polymer blends, a new method is suggested, in which the interface is exposed by selectively dissolving in solvent. By means of X-ray photoelectron spectrometry, we studied the molecular state in the interfacial ar

INTERFACIAL BEHAVIOR OF COMPATIBILIZERS IN POLYMER BLENDS

From an analysis of the literature and our experimental results, we have established that interfacial tension is a function of the concentration of a compatibilizer, and put forward a 'three-stage' physical model to account for the compatibilizing behavio

STUDIES ON INTERFACIAL PHENOMENA OF POLYCRYSTALLINE HG1-XCDXTE THIN-FILM ELECTRODE POLYSULFIDE REDOX SOLUTION

Electrode capacitance and photocurrent spectra of electrodeposited polycrystalline Hg1-xCdxTe thin films of varying (1-x) were measured in polysulfide redox solution, hence the flatband potentional PHI(fb) and the bandgap E(g) of Hg1-xCdxTe thin films obtained. It was of interest to find out that only the location of conduction band E(c) shifts negatively with increasing (1-x) while the valence band E(v), is almost constant. The experimental open circuit photovoltage V0 is smaller than theoretical value V(max) calculated through flatband potential PHI(fb), therefore there is a possibility of promoting the experimental open circuit photovoltage.

Third-order Stokes wave solutions for interfacial internal waves in a three-layer density-stratified fluid

Interfacial internal waves in a three-layer density-stratified fluid are investigated using a singular method, and third-order asymptotic solutions of the velocity potentials and third-order Stokes wave solutions of the associated elevations of the interfacial waves are presented based on the small amplitude wave theory. as expected, the third-order solutions describe the third-order nonlinear modification and the third-order nonlinear interactions between the interfacial waves. The wave velocity depends on not only the wave number and the depth of each layer but also on the wave amplitude.

Influence of the earth rotation on the interfacial wave solutions and wave-induced tangential stress in a two-layer fluid system

Interfacial waves and wave-induced tangential stress are studied for geostrophic small amplitude waves of two-layer fluid with a top free surface and a flat bottom. The solutions were deduced from the general form of linear fluid dynamic equations of two-layer fluid under the f-plane approximation, and wave-induced tangential stress were estimated based on the solutions obtained. As expected; the solutions derived from the present work include as special cases those obtained by Sun et al. (2004. Science in China, Set. D, 47(12): 1147-1154) for geostrophic small amplitude surface wave solutions and wave-induced tangential stress if tire density of the upper layer is much smaller than that of the lower layer. The results show that the interface and the surface will oscillate synchronously, and the influence of the earth's rotation both on the surface wave solutions and the interfacial wave solutions should be considered.

Higher-order Boussinesq-type equations for interfacial waves in a two-fluid system

Interfacial waves propagating along the interface between a three-dimensional two-fluid system with a rigid upper boundary and an uneven bottom are considered. There is a light fluid layer overlying a heavier one in the system, and a small density difference exists between the two layers. A set of higher-order Boussinesq-type equations in terms of the depth-averaged velocities accounting for stronger nonlinearity are derived. When the small parameter measuring frequency dispersion keeping up to lower-order and full nonlinearity are considered, the equations include the Choi and Camassa's results (1999). The enhanced equations in terms of the depth-averaged velocities are obtained by applying the enhancement technique introduced by Madsen et al. (1991) and Schaffer and Madsen (1995a). It is noted that the equations derived from the present study include, as special cases, those obtained by Madsen and Schaffer (1998). By comparison with the dispersion relation of the linear Stokes waves, we found that the dispersion relation is more improved than Choi and Camassa's (1999) results, and the applicable scope of water depth is deeper.

Strongly nonlinear long interfacial waves in uniform basic flows and their dispersion relationship

In this paper, long interfacial waves of finite amplitude in uniform basic flows are considered with the assumption that the aspect ratio between wavelength and water depth is small. A new model is derived using the velocities at arbitrary distances from the still water level as the velocity variables instead of the commonly used depth-averaged velocities. This significantly improves the dispersion properties and makes them applicable to a wider range of water depths. Since its derivation requires no assumption on wave amplitude, the model thus can be used to describe waves with arbitrary amplitude.

Second-order solutions for random interfacial waves under steady uniform currents

In the present research, the study of Song (2004) for random interfacial waves in two-layer fluid is extended to the case of fluids moving at different steady uniform speeds. The equations describing the random displacements of the density interface and the associated velocity potentials in two-layer fluid are solved to the second order, and the wave-wave interactions of the wave components and the interactions between the waves and currents are described. As expected, the extended solutions include those obtained by Song (2004) as one special case where the steady uniform currents of the two fluids are taken as zero, and the solutions reduce to those derived by Sharma and Dean (1979) for random surface waves if the density of the upper fluid and the current of the lower fluid are both taken as zero.