Polyelectrolyte electrical properties

The ion mobility in decoupled hybrid polyelectrolytes electrical properties... 

A simple thin film technique has been developed to measure the electrical properties of polyelectrolyte solutions under sinusoidal electric fields of 100-500 v/cm at frequencies of. 10-10 KHz. Ohmic heating is largely avoided by the rapid transfer of heat to the electrodes and by the high surface to volume ratios. The resulting temperature is not sufficient to damage the medium. Current and voltage wave forms are monitored directly so that dispersion and nonlinear phenomena of the medium can be viewed directly as functions of frequency, voltage, and concentration of the solution. Possible mechanisms for the observed phenomena are discussed. 

The electrical properties of polyelectrolyte complexes are more closely related to those of biologically produced solids. The extremely high relative dielectric constants at low frequencies and the dispersion properties of salt-containing polyelectrolyte complexes have not been reported for other synthetic polymers. Neutral polyelectrolyte complexes immersed in dilute salt solution undergo marked changes in alternating current capacitance and resistance upon small variations in the electrolyte concentration. In addition, their frequency-dependence is governed by the nature of the microions. As shown in... 

Although in our simulations, solvent convection is suppressed [35,39], characteristic features of the electric properties of polyelectrolytes in salt-free aqueous solutions are reproduced. The anisotropy of the electrical polarizability Aa of DNAs in salt-free aqueous solution increases on dilution of the polymer concentration and is proportional to the second power of the molecular weight. 

We have not taken into consideration electrophoretic motion of polyions [35,39], However, we have already obtained characteristic features of the electric properties of polyelectrolytes in aqueous solution. Electric polarizability components originating from the fluctuations of condensed counterions show smaller concentration and salt dependence, while those due to a diffuse ion atmosphere, by contrast, a larger dependence. Anisotropy of the electrical polarizability Aa is positive without invoking an enhancement of the longitudinal component by the solvent flow. Simulation on the frequency dependence of the electrical polarizability is in progress to study how the... 

The results collected in this review are focused to demonstrate the advantages of electro-optics for investigation of the electrical properties of anisometric particles in dilute suspensions containing polyelectrolytes. Results on the structure of the adsorbed macromolecules and the stability of suspensions containing polyelectrolytes will also be discussed. 

IV. ELECTRICAL PROPERTIES OF ADSORBED POLYELECTROLYTES IN STABILIZED SUSPENSION... 

Radeva Ts, Petkanchin I. Electric properties of adsorbed polystyrenesulfonate I dependence on the polyelectrolyte molecular weight. J Colloid Interface Sci 1999 220 112-117. 

The essential point is that such an adsorption process markedly influences the hydrodynamic and electrical properties of the interface. Figure 3.16 is a schematic representation of the structure formed polymer chains with fixed charges extend out of the solid surface to an average distance d = b — a in this region, the fluid can move, although with an increased viscosity because of the hydrodynamic resistance of the polyelectrolyte layer (also called hydrogel layer). To take this into account, a friction term — yv is included in the Navier-Stokes equation. 

Polyelectrolyte gels exhibit various anomalous phenomena, including volumetric phase transitional electrical shrinkage, and nonfrozen water [29-32]. Of these, the electrical properties of ionic gels (e.g., electrical shrinkage) have been extensively studied because of their important role in response and control by electricity. They can also be involved in the information transfer of biomaterials. The sol-gel transition using direct... 

The electrical conductivity of polyelectrolyte solutions has been extensively studied but it is a new area with a very short history. Only recently has it been possible to achieve electrical conductivity that is both accurate and reproducible because the electrical properties of a gel remain dependent upon the preparation methods. It is also due to the experimental difficulties encountered in electrolysis and the electrode polarization effect. 

O Konski, C.T. 1960. Electric properties of macromolecules. V. Theory of ionic polarization in polyelectrolytes. J. Phys. Chem. 64 605-619. 

Milkova, V. and T. Radeva. 2013. Effect of ionic strength and molecular weight on electrical properties and thickness of polyelectrolyte bi-layers. Colloids Surf. A Physicochem. Eng. Asp. 424 52-58. 

Polyelectrolytes such as the ion exchange plastics form an interesting group of materials because of their ability to interact with water solutions. They have been used in medical applications involving the removal of heavy metal ions from the human body. They can be used to interact with external electric fields and change their physical properties drastically as is illustrated by the fact that some electrically active liquid crystals are polyelectrolytes of low molecular weight. 

Electric field-induced deformation of polyelectrolyte gels has attracted much attention because of the property of smartness. If the size and shape of gels can be controlled as we hope, this may open a new door for gel technology. In this Section, studies on electric field-induced deformation of gels will first be surveyed. 

Many of these systems employ charged polymers or polyelectrolytes that confer on them particular properties due to the existence of electrical charges in the polymer structure. Oyama and Anson [14,15] introduced polyelectrolytes at electrode surfaces by using poly(vinylpiridine), PVP, and poly-(acrylonitrile) to coordinate metal complexes via the pyridines or nitrile groups pending from the polymer backbone. Thomas Meyer s group at North Carolina [16, 17[ also employed poly(vinylpyridine) to coordinate Ru, Os, Re and other transition-metal complexes by generating an open coordination site on the precursor-metal complex. 

In this context numerous changes were made. The chapter Properties of Polymers was revised and a new section Correlations of Structure and Morphology with the Properties of Polymers was added. The chapter Characterization of Macromolecules was revised and enlarged. 15 examples have been deleted as they did no longer represent the state of the art and/or were of minor educational value. Several new experiments (plus background text) were added, as, for example controlled radical polymerization - enzymatic polymerization - microemulsions - polyelectrolytes as superabsorbants - hyperbranched polymers - new blockcopolymers - high impact polystyrene - electrical conducting polymers. 

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