Polyelectrolyte conductance

The plot of the equivalent conductivity vs. the polyelectrolyte concentration, however, is more suitable to demonstrate the concentration dependent changes of the polyelectrolyte conductivity [129]. Generally, the equivalent conductivity (Eq. (17)) can be written as [128]... 

Fig. 10 Temperature dependent conductivity a for Me-PVP1940I, cp=5 glT1, Q=80%. a Raw data (y) with salt reference measurements (solid line 0.03 M Nal). b Polyelectrolyte conductivity Act after subtraction of the reference measurement. (A, O) repeated measurements...

To show the same general pattern of conductance behavior of polyelectrolytes, conductance curves for another type of polyelectrolyte, made by quaternization with n-butyl bromide of poly(styrene-co-4-vinylpyridine) in... 

As a powerful methodology to assemble various components into soft supramolecular organizations, the LbL assembly method shows continuous progresses in the fields of drug delivery under the supramolecular concept (Fig. 2.2.5). The LbL method has excellent versatility for the assembly of various kinds of substances [13]. This method covers a wide range of available materials including proteins, nucleic acids, saccharides, virus particles micelles, vesicles, LB films, and other lipid membranes as well as conventional polyelectrolytes, conductive polymers, inorganic nanomaterials, nanocarbons, and dye... 

With added electrolyte, the polyelectrolyte conductance can be derived from the measured solution conductance by subtracting the measured conductance of a polyelectrolyte-free solution containing the same level of added electrolyte. The polyelectrolyte equivalent conductance is then defined exactly as before, substituting the corrected polyelectrolyte conductance into equation 56. Trends in A vs Cp in this case do not match those of a salt-free solution, demonstrating that electrostatic interactions disallow additivity laws in this case, additivity would suppose that the solution conductivity is simply the sum of independent conductances of... 

Colby RH, Boris DC, Krause WE, Tan JS (1997) Polyelectrolyte conductivity. J Polym Sci B... 

Because of the aqueous solubiUty of polyelectrolyte precursor polymers, another method of polymer blend formation is possible. The precursor polymer is co-dissolved with a water-soluble matrix polymer, and films of the blend are cast. With heating, the fully conjugated conducting polymer is generated to form the composite film. This technique has been used for poly(arylene vinylenes) with a variety of water-soluble matrix polymers, including polyacrjiamide, poly(ethylene oxide), polyvinylpyrroHdinone, methylceUulose, and hydroxypropylceUulose (139—141). These blends generally exhibit phase-separated morphologies. 

Conducting polymer composites have also been formed by co-electrodeposition of matrix polymer during electrochemical polymerization. Because both components of the composite are deposited simultaneously, a homogenous film is obtained. This technique has been utilized for both neutral thermoplastics such as poly(vinyl chloride) (159), as well as for a large variety of polyelectrolytes (64—68, 159—165). When the matrix polymer is a polyelectrolyte, it serves as the dopant species for the conducting polymer, so there is an intimate mixing of the polymer chains and the system can be appropriately termed a molecular composite. 

A membrane ionomer, in particular a polyelectrolyte with an inert backbone such as Nation . They require a plasticizer (typically water) to achieve good conductivity levels and are associated primarily, in their protonconducting form, with solid polymer-electrolyte fuel cells. 

While the condition of stoichiometric neutrality invariably must hold for a macroscopic system such as a space-network polyelectrolyte gel, its application to the poly electrolyte molecule in an infinitely dilute solution may justifiably be questioned. In a polyelectrolyte gel of macroscopic size the minute excess charge is considered to occur in the surface layer (the gel being conductive), which is consistent with the assumption that the potential changes abruptly at the surface. This change is never truly abrupt, for it must take place throughout a layer extending to a depth which is of the order of magnitude of the... 

Another example of ion conducting polymer/ion/solvent systems are polyelectrolytes based on ion-exchange polymers, also called ionomers. The ionic conductivity of ion-exchange polymers is usually very low in the dry state, but increases abruptly by orders of magnitude upon addition of a... 

Ion-exchanger membranes with fixed ion-exchanger sites contain ion conductive polymers (ionomers) the properties of which have already been described on p. 128. These membranes are either homogeneous, consisting only of a polyelectrolyte that may be chemically bonded to an un-ionized polymer matrix, and heterogeneous, where the grains of polyelectrolyte are incorporated into an un-ionized polymer membrane. The electrochemical behaviour of these two groups does not differ substantially. 

A separate continuous DAF operation conducted by Krofta and Wang59 under 33.3% recycle flow pressurization mode demonstrated that aluminum sulfate, sodium aluminate, and polyelectrolyte combination at pH 6.2 also effectively recovered both fibers and titanium dioxide from the same white water containing 500mg/L of titanium dioxide and 1000 mg/L of cotton fibers. 

A strongly anionic, polyelectrolyte can be made from lignin by conducting a graft polymerization in the presence of 2-propenamide and 2,2-dimethyl-3-imino-4-oxohex-5- ene-1-sulfonic acid or its salts. 

No attempt will be made here to extend our results beyond the simple lowest-order limiting laws the often ad hoc modifications of these laws to higher concentrations are discussed in many excellent books,8 11 14 but we shall not try to justify them here. As a matter of fact, for equilibrium as well as for nonequilibrium properties, the rigorous extension of the microscopic calculation beyond the first term seems outside the present power of statistical mechanics, because of the rather formidable mathematical difficulties which arise. The main interests of a microscopic theory lie both in the justification qf the assumptions which are involved in the phenomenological approach and in the possibility of extending the mathematical techniques to other problems where a microscopic approach seems necessary in the particular case of the limiting laws, obvious extensions are in the direction of other transport coefficients of electrolytes (viscosity, thermal conductivity, questions involving polyelectrolytes) and of plasma physics, as well as of quantum phenomena where similar effects may be expected (conductivity of metals and semi-... 

Fang, J., Guo, X., Harada, S., Watari, T., Tanaka, K., Kita, H. and Okamoto, K. 2002. Novel sulfonated polyimides as polyelectrolytes for fuel cell applications. 1. Synthesis, proton conductivity, and water stability of polyimides from 4,4 -diaminophenyl ether-2,2 -disulfonic acid. Macromolecules 35 9022-9028. 

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