Transport properties of polymers

Calculation of the vibrational spectrum of doped PA, in which electron-electron interaction is included for the first time in a self-consistent way, shows that the infrared spectrum can be explained in terms of defects which invoke a local relaxation of the bond alternation. The interpretation is not uniquely in favor of the soliton picture. The polaron defect can serve as an alternative explanation. The broad band between 800 and 900 cm results from in-plane C-C-H bending and C-H out-of-plane bending motions involving relaxed bond lengths of the defect site. 

Both the theoretical and experimental determination of charge transport, even in a periodic polymer, is a rather formidable task. In the case of the theory, one has to start with the dispersion curves of the different normal modes (see Sections 9.1 and 9.2) and, after calculating scattering of the electrons on these phonons, one has to conduct several rather complicated calculations to arrive at reliable values of the quantities (such as mean free path, mobility, and specific conductivity) which 

9 Vibrational Spectra and Transport Properties of Polymers 

One could ask whether it is worthwhile discussing in this book the theory of charge transport in polymers if only very few serious calculations are available and there are no very reliable experimental measurements on the same systems, which hinders comparison of the results. The answer is yes, because the theory itself is sufficiently developed for 

Here the second term in the eqnation arises from the electron-electron interaction and third term is the correction to c(0) dne to localisation effects. 

The value of p is determined by the temperature dependence of the scattering rate of the dominant dephasing mechanism. 

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Using Eq. (2.6.18) the temperature dependence of various transport properties of polymers, such as diffusion coefficient D, ionic conductivity a and fluidity (reciprocal viscosity) 1/rj are described, since all these quantities are proportional to p. Except for fluidity, the proportionality constant (pre-exponential factor) also depends, however, on temperature,... 

Viscoelastic and transport properties of polymers in the liquid (solution, melt) or liquid-like (rubber) state determine their processing and application to a large extent and are of basic physical interest [1-3]. An understanding of these dynamic properties at a molecular level, therefore, is of great importance. However, this understanding is complicated by the facts that different motional processes may occur on different length scales and that the dynamics are governed by universal chain properties as well as by the special chemical structure of the monomer units [4, 5],... 

Siu, A. 2007. Influence of water and membrane morphology on the transport properties of polymers for proton exchange membrane fuel cells. Ph. D. Dissertation, Department of Chemistry, Simon Fraser University. 

Kalnins, R. V., Emergency Preparedness and Response, Symposium on the Characterization of Thermodynamic and Transport Properties of Polymer Systems, American Institute of Chemical Engineers, New York, 1986. 

TABLE II Transport Properties of Polymers Obtained from SDS Microemulsions... 

Riedel I, Dyakonov V (2004) Influence of electronic transport properties of polymer-fullerene blends on the performance of bulk heterojimction photovoltaic devices. Phys Status Solidi A 201 1332... 

Information on how orientation during melt crystallization affects the transport properties of polymers is sparse however, increases in the permeability have been attributed to the "shish kebab" morphology (ill). Most of the work involving barrier properties of oriented semicrystalline polymers has dealt with materials drawn at temperatures well below the melting point. The transport properties of cold-drawn polyethylene (34f 42-46), polypropylene (42,42), poly(ethylene terephthalate) (12,42-4 9), and nylon 66 (22) among others have been reported. 

Howsmon, G.J., andN.A. Peppas, "Mathematical Analysis of Transport Properties of Polymer Films for Food Packaging. VI Coupling of Moisture and Oxygen Transport Using Langmuir Sorption Isotherms", J Appl Poly Sci 1986, 31, pp 2071-2082. 

The purpose of this chapter is to outline some of the basic Issues and principles that pertain to the transport of small molecules in polymers and to introduce a few examples in which transport properties of polymers may be important or lead to new uses for polymers. 

O. Hatozaki, T. Osaka and N. Oyama, Charge-transport properties of polymer complex films composed of poly(alkyleneviologen) and poly(p-styrenesulfonate), J. Phys. Chem., 1992, 96, 10492. 

The transport properties of polymer blends are of interest both for the practical application of blends and for providing insight into the morphology of the blend. Measurement of the effect of blend composition on permeability in various mbbers has been described (Barrier, 1956). The permeability of... 

An overview of the physics of glassy polymers and the relationships between molecular mechanisms and macroscopic physical, mechanical and transport properties of polymer glasses is presented. The importance of local translational and/or rotational motions of molecular segments in the glass is discussed in terms of the implications for thermodynamic descriptions of the glass (configurational states and energy surfaces) as well as history dependent properties such as expansivity, refractive index, gas permeability, and viscoelastic mechanical behaviour. 

D. Hands, The thermal transport properties of polymers. Rubber Chem. Technol. 50,480-522. 

Oberta, A., Wasilewski, J., and Wodzki, R. 2011. Structure and transport properties of polymer inclusion membranes for Pb(II) separation. Desalination 271 132-138. 

Kim DH, Kim SC (2008) Transport properties of polymer blend membranes of sulfimated and nonsulfonated polysulfones for direct methanol fuel cell application. Macromol Res... 

A question of great interest is the influence of disorder in the medium on the universality class of dissolved flexible polymers, namely ire the imiversal exponents (1) in this c ise the same as in the pure case The question of how line tr polymers behave in disordered media is not only interesting from a theoretical point of view, but is also relevant for understanding transport properties of polymer chains in porous media, such as an oil recovery, gel electrophoresis, gel permeation chromatography, etc. [14]. 

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