TRIBOLOGICAL CHARACTERISTICS,

ELECTRICAL PROPERTIES

SETHULAKSHMI KV

II MSc BPS

CBPST,KOCHI

TRIBOLOGICAL CHARACTERISTICS

Wear resistance

Coefficient of friction

Lubricating properties

ELECTRICAL PROPERTIES

Dieletric strength

Dielectric constant

Dissipation factor

Surface and Volume resistivity

Arc resistance

Comparative tracking index

Polycarbazole Nanocomposites with Conducting Metal Oxides for Transparent Electrode Applications

The preparation and characterization of conducting polycarbazole (PCz) hybrid films with a colorless transparency are described. They were prepared by the vacuum evaporation of tin, aluminum, or gallium onto anion-doped green-colored PCz films, or by applying gallium to the films, followed by their exposure to ambient air.

The resultant hybrid films consisting of an undoped PCz backbone and metal compounds exhibited good transparencies (90−95% at a wavelength of 550 nm). The hybrid films have a specific cross-sectional structure in which the small regions of the metal compounds are dispersed in the PCz backbone. The hybridization reaction was mechanistically explained on the basis of the combination of a metal corrosion reaction and polymer dedoping reaction, which was successfully supported by the chemical analyses of the hybrid films.

The electric conductivities of the hybrid films, measured by a four-point-probe method, ranged from 2.2 × 10−4 to 6.0 × 10−3 S cm−1, which are considered to be the lowest limit because the use of the hybrid films as an electrochemical electrode reveals that a network of conductive paths is preferentially formed in the film thickness direction rather than in the in-plane direction.

Conducting Polymer Nanocomposites

Inorganic nanoparticles of different nature and size can be combined with the conducting polymers, giving rise to a host of nanocomposites with interesting physical properties and important application potential. Such nanocomposites have been discussed in this review, throwing light on their synthesis techniques, properties, and applications.

A large variety of nanoparticles have been chosen in this respect with inclusion techniques utilizing both chemical and electrochemical routes. The nature of the association between the components can be studied from TEM pictures.

upon the synthesis techniques and the characteristics of the inorganic materials, ultimate properties of the resulting composite are controlled. In this way, the exceptional colloidal stability of different silica sols have been utilized to form stable PPy-silica and PAn-silica nanocomposite colloids. Similarly the magnetic susceptibility of γ-Fe2O3, the elctrochromic property of WO3, and the catalytic activity of Pd, Pt, etc. metals have been successfully combined with existing electrical conductivity of conducting polymers in the hybrid nanocomposite materials. Functional groups viz. −NH2 and −COOH have also been added to the composite particles and all these combinations and modifications have improved the applicability of conducting polymers in different fields, e.g., electrodes of batteries, display devices, immunodiagnostic assay, etc

Microstructural characterisation and electrical properties of multiwalled carbon nanotubes/glass-ceramic nanocomposites

In the present investigation the electrical resistivity of CNT/glass composites was measured and it was demonstrated that higher electrical conductivity values were obtained compared to previous similar materials fabricated by conventional powder processing.

Enhanced Thermoelectric Performance of Single-Walled Carbon Nanotubes/Polyaniline Hybrid Nanocomposites

Hybrid nanocomposites containing carbon nanotubes (CNTs) and ordered polyaniline (PANI) have been prepared through an in situpolymerization reaction using a single-walled nanotube (SWNT) as template and aniline as reactant.

TEM, SEM, XRD, and Raman analyses show that the polyaniline grew along the surface of CNTs forming an ordered chain structure during the SWNT-directed polymerization process.

The SWNT/PANI nanocomposites show both higher electrical conductivity and Seebeck coefficient as compared to pure PANI, which could be attributed to the enhanced carrier mobility in the ordered chain structures of the PANI. The maximum electrical conductivity and Seebeck coefficient of composites reach 1.25 × 104 S m−1 and 40 μV K−1, respectively, and the maximum power factor is up to 2 × 10−5 W m−1 K−2, more than 2 orders of magnitude higher than the pure polyaniline.

Highly ordered chain structure is a novel and effective way for improving the thermoelectric properties of conducting polymers.