Superconductivity, organic polymers

So far no organic polymers have been confirmed to show superconductivity, in spite of several unconfirmed polymer superconductors mentioned below. It should be remembered that the sample should be well oriented, otherwise the disorder inherent to organic polymers will destroy the superconductivity. 

As was mentioned above, conjugated organic polymers in their pristine state, are electrical insulators or, at best, semi-conductors. Their conductivity can be increased by orders of magnitude by a doping process. In the "doped" state, the backbone of a conducting polymer consists of a delocalised 7i-system. Early in the twenty-first century Schon et al. (2001) discovered super-conduction in solution cast doped regioregular poly(3-hexylthio-phene) at temperatures below 2.35 K The appearance of superconductivity seems to be... 

Schon, J.H. Dodabalapur, A. Bao, Z. Kloc, C. Schenker, O. Batlogg, B. Gate-induced superconductivity in a solution-processed organic polymer film. Nature 2001, 410, 189. 

There are a vast number of different sorts of superconducting compound. Examples of these are summarized in Table 7.2. They include organic polymers and intercalation compounds (such as RbjCgjj), as well as ceramic oxides and sulfides. In all these compounds the critical temperature is still below the boiling point of liquid nitrogen. Hence, these materials would be very expensive to use in everyday life (as a litre of liquid helium costs 20 times as much as liquid nitrogen). 

Little proposes room-temperature superconductivity in organic polymer [29]... 

FIGURE 18.24 Part of a possible polymer system for organic conductivity and superconductivity. Organic molecules, staged by a DNA backbone, form a set of easily oxidizable molecules for the creation of carriers. 

Organic polymers such as (SN), "poly(thiazyl)", wdiich is highly conducting at room temperature and even superconducting below 0.26 K, but whose different conduction mechanism yields high conductivity along the S-N chain but poor conductivity in other directions. 

---