Abstract: The preferred polymers comprise cyclic units having sulphur at the 1 position, nitrogen at the 3 position, a substituent R group carried off of a carbon at the 4 position, and a carbon at each of the 2 and 5 positions of the thiazole ring. Each of the units is connected through the 2 or 5 position to another thiazole unit. Intermediate units are connected through the 2 and 5 positions to thiazole units on either side, terminal (end) units are connected to a respective adjacent thiazole unit at the 2 position, hydrogen or another substituent is carried off of the 5 position of the terminal unit. The R substituent group is a hydrocarbon having more than 1 carbon atom.