Overcoming high conductivity

The proximity of the anodes to structures is also important. For example, if the sacrificial anodes are placed on, or very close to, steel pipework in soil then the output from the face of the anodes next to the steelwork can be severely limited. Alternatively, in high conductivity environments, corrosion products may build up and wedge between the anode and the structure. The resulting stresses can lead to mechanical failure of the anode. On the other hand, when anodes are located at an appreciable distance from the steelwork, part of the potential difference will be consumed in overcoming the environmental resistance between the anode and cathode. 

At very low temperatures and for high conductivity materials, Rc may become of the order of the thermal resistance of the sample. To overcome this problem, for samples of... 

To achieve high conductivities, the polythiophene paradox must be overcome. The polymerization process and conductivity of the resultant material are influenced by the concentration of monomer used during polymerization116 because, if this is too low, the overoxidation reaction predominates, at least when galvanostatic polymerization is used. Synthesis at reduced temperatures will help avoid overoxidation and can be used to increase the conductivity of the resultant material.117... 

Another area of intense interest in conducting-polymer nanomaterials for chemical sensing is their combination with carbon nanostructures, most particularly carbon nanotubes, either single-walled (SWNT) or multiwaUed (MWNT). This again reflects the desire to combine the beneficial properties of both types of material to create new combinations with novel properties. CNTs empart high conductivity and high aspect ratios, which yield low percolation thresholds with nanodimensional stmctural order. This has led to their application as chemical sensors. However, CNT-based devices are difficult to fabricate, an issue which may be overcome by their dispersion in a conductive polymeric matrix. 

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