Diseño de polianilinas nanoestruturadas para aplicaciones termoeléctricas y sensores

Abstract

Among the class of materials known as intrinsically conducting polymers, polyaniline (PANI) stands out due to the great versatility of synthetic methods and properties which greatly enlarge its fields of applications. Within this context, the scope of the present doctoral thesis is the design and characterization of novel polyanilines which combine suitable physical properties (electrical conductivity, thermoelectric performance, thermal stability or piezoresistivity) with affordability and less environmental impact. In order to fulfill this aim, the first part of this work studies the influence on PANI properties of HCl, dodecylbenzenesulfonic acid (DBSA) and 5- sulfoisophtalic acid sodium salt (NaSIPA) as dopants and several simple and ecofriendly synthetic routes. Furthermore, with the purpose of improving the mechanical properties of PANI together with cost reduction, new composite materials were designed using poly(vinyl acetate) (PVAc) as polymer matrix and PANI as conductive filler. Both doped PANIs and the PANI-PVAc composites had been analyzed by means TGA, FTIR, Elemental Analysis, XRD and TEM. The electrical, thermoelectric and piezoresistive properties had been studied as a function of the type of dopant, synthetic route and PANI content, in the case of the PANI-PVAc composites, so as to evaluate the potential application of these materials as sensors and thermoelectric generators. As a conclusion, PANI doped with DBSA and synthesized either by the so called “direct” or “indirect” routes, are the best candidates for thermal sensors; however, PANI-NaSIPA offers the highest thermoelectric efficiency, whereas polyaniline–poly(vinyl acetate) latex nanocomposites (PANI– PVAc) with 30% PANI-HCl (weight%), which preserve the conductivity values of pristine PANI, present a worthy compromise between piezoresistive properties and affordability.