Temperature dependence polymer electricity

Figure 25 shows the temperature dependence of electrical conductivity and molecular structure of poly-59.As evident in this figure, conductivity increases with temperature just as for other conventional nondoped conducting polymers. Above about 70 °C. in particular, the conductivity exhibits a drastic increase with temperature. However, two inflection points are observed at about 90 °C and 110... 

There are various methods of the glass transition temperature evaluation based on temperature dependence of polymer physical properties in the interval of glass transition 1) specific volume of polymer at slow cooling (dilatometric method) 2) heat capacity (calorimetric method),3) refraction index (refractometric method) 4) mechanical properties 5) electrical properties (temperature dependence of electric conductivity) or maximum of dielectric loss 6) NMR ° 7) electronic paramagnetic resonance, etc. 

Fig. 1. (a) Comparison of normalised electrical conductivity of individual MWCNTs (Langer 96 [17], Ebbesen [18]) and bundles of MWCNTs (Langer 94 [19], Song [20]). (b) Temperature dependence of resistivity of different forms (ropes and mats) of SWCNTs [21], and chemically doped conducting polymers, PAc (FeClj-doped polyacetylene [22]) and PAni (camphor sulfonic acid-doped polyaniline [2. ]) [24]. 

Nakajima, T., and K. Torii Temperature dependence of the electrical conductivity of nylon. Rep. Prog. Polymer Phys., Japan 5, 209 (1962). 

Fig. 28. Temperature dependence of the optical properties of nematic polymer A.4 (Table 9) — transparency Tr (1) and optical transmission in crossed polarizers I (2, 3) upon application of (1, 2), and without (3) an electric field 169)...

In the temperature interval of —70 to 0°C and in the low-frequency range, an unexpected dielectric relaxation process for polymers is detected. This process is observed clearly in the sample PPX with metal Cu nanoparticles. In sample PPX + Zn only traces of this process can be observed, and in the PPX + PbS as well as in pure PPX matrix the process completely vanishes. The amplitude of this process essentially decreases, when the frequency increases, and the maximum of dielectric losses have almost no temperature dependence [104]. This is a typical dielectric response for percolation behavior [105]. This process may relate to electron transfer between the metal nanoparticles through the polymer matrix. Data on electrical conductivity of metal containing PPX films (see above) show that at metal concentrations higher than 5 vol.% there is an essential probability for electron transfer from one particle to another and thus such particles become involved in the percolation process. The minor appearance of this peak in PPX + Zn can be explained by oxidation of Zn nanoparticles. 

The room-temperature conductivity of the PPN polymer was 0.2 S/cm without doping, a value almost in the middle of those of polyacetylene and graphite. The temperature dependence of the electrical conductivity was measured with the PPN whiskers synthesized at various HTT s. The measured o - T curves were fitted to m-dimensional VRH equations ... 

Weleiams, M. L. The temperature dependence of mechanical and electrical relaxation in polymers. J. Phys. Chem. 59, 95 (1955). 

Vinylidene fluoride-trifluoroethylene (VF2-F3E) copolymers exhibit a ferroelectric-paraelectric phase transition, the first such case found for a synthetic polymer. In this transition, the electric polarization and piezoelectric constant of the film disappear above the Curie point (Tcurie)- The temperature dependence of the dielectric constant, , obeys the so called Curie-Weiss law ... 

The application of temperature-dependent line shapes and the measurements of second moments in more complex organic solids like polymers followed soon after. Even nowadays, this simple method still has its place in the characterization of materials like solid polymer electrolytes where the line widths and Ti relaxation of the charge carriers provide information about their mobility that can be correlated with the electrical conductivity of the material. More detailed information can be obtained from cases in which the interaction is well defined, i.e., when an anisotropic single-spin interaction dominates the spectrum. Typical cases are the chemical shielding anisotropy (CSA) and quadrupolar interaction for which the theory is well developed. 

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