Typical Properties and Behavior of Traditional Carbon Paste Electrode

2 Typical Properties and Behavior of Traditional Carbon Paste (Electrode) 

In the previous text, attention was paid to a feature of carbon pastes as a unique electrode material of heterogeneous nature, reflecting both main carbon paste constituents in rather specific behavior that differs from mixture to mixture, depending not only on the type and quality of the respective component, but also on the way in which the respective electrode or sensor is constructed and employed in practical experiments. Typical properties and some specific features of traditional carbon paste mixtures are as follows  

1) Structure and microstructural morphology The physical constitution of common carbon pastes can be described as a solid dispersion (of the individual graphite particles in liquid binder). Practically from the very beginning of carbon pastes in electrochemistry, the microscopic structure of their surface was of continuing interest (see, e.g., [7, 36, 37] and other references therein [5]). 

2) Soft/plastic consistency As the term carbon paste suggests, a mixture of powdered graphite with liquid binder is a paste-like, incompact mass whose consistency has been related - for many, amusingly - to a peanut butter by the inventor himself [ 1, 2, 7]. This characterization fits quite well for classical mixtures from mineral oils [2,4,38-40,50-52], whereas carbon pastes made of silicone fluids are markedly thicker (up to nearly solid state [16,58]) and, in contrast to the typically matte appearance of most C/MO (mineral oil) configurations, the C/SO and C/SG formulas may exhibit a fine metallic luster [5, 16]. Needless to say that the resultant thickness of carbon pastes depends on the mutual ratio of both main components. 

3) Minimal Ohmic resistance/excellent conductivity Quite surprisingly, even intimately coated graphite particles in the CP(E) configurations exhibit a very low ohmic resistance often, in tens of ohms [5,39,40, 50-52, 55] and, in special cases, even below 10 Q [5,16]. 

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