[en] 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.

[gl] Dentro do conxunto dos polímeros intrinsecamente condutores, a polianilina (PANI) presenta unha grande versatilidade en canto a súa síntese e propiedades que a fan axeitada para un amplo campo de aplicacións. Neste contexto, a presente tese ten como obxecto o deseño e caracterización de novas polianilinas que combinen boas propiedades (eléctricas, termoeléctricas, estabilidade térmica ou piezorresistivas) cun custo asumíbel e con menor impacto medioambiental. Para iso, estudouse a influencia do HCl, DBSA (ácido dodecilbencensulfónico) e NaSIPA (sal de sodio do ácido 5-sulfoisoftálico) coma dopantes e distintas rutas de síntese, sinxelas e respectuosas co medio ambiente, na obtención das polianilinas. Ase mesmo, co fin de mellorar as propiedades mecánicas do polímero sintetizado e reducir custos, elaboráronse novos materiais compostos empregando acetato de polivinilo como matriz polimérica e a PANI como carga condutora. Tanto as polianilinas sintetizadas coma os seus compostos, caracterizáronse por TGA, FTIR, análise elemental, XRD e TEM. As propiedades eléctricas, termoeléctricas e piezorresistivas estudáronse en función do tipo de dopante, tipo de síntese e cantidade de polianilina (no caso dos compostos), para avaliar o potencial uso destes materiais en sensores e xeradores termoeléctricos. Entre os distintos polímeros estudados: as PANIs dopadas con DBSA, obtidas tanto por ruta de síntese directa como pola indirecta, amosaron as mellores propiedades para seu uso en sensores térmicos; con todo, a PANI-NaSIPA mostra a mellor eficiencia termoeléctrica; namentres que os materiais compostos de látex cun 30% en masa de PANI-HCl presentaron a condutividade da PANI orixinal, obtendo un bo balance entre as propiedades piezorresistivas e custo económico.