THERMAL-STABILITY OF POLY(THIONAPHTHENEINDOLE) - TEMPERATURE EFFECT ON DOPING AND CONDUCTIVE PROPERTIES

The thermal stability of poly(1-benzothieno[3,2-b]indole) (pTNI) was examined under controlled environmental and thermal conditions by means of thermogravimetric analysis (dynamic method) and heating at two different fixed temperatures (90 and 385-degrees-C) (static method). It was found that pTNI, other than high chemical and electrochemical properties, possesses high thermal stability. The chain decomposition takes place at T > 400-degrees-C and the dedoping starts above 200-degrees-C. The electrical conductivity, both ionic and electronic in the starting material, is essentially electronic in the heated samples. From physical and electrical considerations a structure very similar to that shown by some oxidized and deprotonated polyanilines was hypothesized for samples submitted to the thermal treatment at 385-degrees-C.