Non-contact resistivity

For a characterization of materials with a low mechanical resistance and for routine measurements in industrial production, it would be of great importance to have a method which allows a contact-less, non-destmctive measurement of the resistance. One of the more recently developed techniques that is capable of such non-contact resistance measurement is the eddy current technique (Kraftmakher, 2000 Schroeder, 1998), which is mainly used in the semiconductor industry for wafer characterization (ASTM, 1996b) and is only recently entering display manufacturing as well (ASTM, 2002c). The technique is based on the effect that the quahty factor of a resonant circuit is reduced when a conducting... 

Direct contact of the dispersed SWCNTs and the conductive polymer is favorable, because this presumably decreases the non-contact resistivity between the CNTs by the formation of conductive bridges between adjacent CNTs in the CNT network. The high affinity of conjugated polymers for CNTs through it-it electronic interactions ensures a close conductive polymer-CNT contact. Applying these conductive polymers to a water-based system requires the conductive polymer to have a surfactant-like nature. Water-soluble polythiophenes have been used to disperse SWCNTs in water, but no quantitative information with regard to the level of SWCNT individualization was provided. Polymeric surfactants like poly(styrene sulfonate] (PSS] have been reported to effectively disperse CNTs in water. PSS is also used in the preparation of an aqueous dispersion (latex] of the conductive polymer poly(3,4-... 

The inclusion of a conductive polymeric component, namely PEDOT PSS, in PS/SWCNT composites to reduce the non-contact resistivity limiting is shown to reduce the percolation threshold and simultaneously increase the ultimate composite conductivity. The ability of PEDOT PSS to stabilize SWCNT dispersions (individualized SWCNTs] was shown. PEDOT PSS/PS/SWCNT composites showed lower percolation thresholds as compared to PS/SWCNT composites. This reduction was modeled assuming a homogeneous deposition of PEDOT PSS over the SWCNT surface. 

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