Eliminating Non-Contact Resistivity

CNTs are near perfect electron conductors. When conductivities are measured for CNT/polymer composites, and even for CNT mats [often called buckypapers], however, they are always orders of magnitude lower than the conductivity measured for an individual CNT. This 

Polymer Carbon Nanotube Composites Tbe Polymer Latex Concept Nadia Grossiord, Marie Claire Hermant, and Cor Koning Copyright 2012 Pan Stanford Publishing Pte. Ltd. 

In this equation, the connectedness criterion [A] embraces the nature of the inter-tube junctions, as it describes the efficiency of electron tunneling between adjacent tubes. The value of A is set by the electron tunneling distance [f], the value of which presumably is influenced by the temperature and by the electronic states of the CNTs, the contact potential barrier, and the electrostatic 

1 CNT/Polymer Composites with Added Conductive Polymers 

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- 

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Furthermore, any contact of the supporting material (Si, Nb, W, Ta and especially Ti) of BDD anodes to a non-aqueous electrolyte has to be strictly eliminated (Malkowsky et al. 2006d), due to the low corrosion resistance of these materials under these conditions. If water is used as electrolyte, the common materials passivate themselves with a metal-oxide layer, preventing further corrosion. The absence of water prevents formation of such a protective layer. 

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