Electrical, mechanical and piezo-resistive behavior of a polyaniline/poly(n-butyl methacrylate) composite

Dodecilbenzene sulfonate doped-polyaniline/poly(n-butyl methacrylate) composites were prepared by cast molding. The electrical, mechanical and morphological behaviors of composite films were studied. The tensile strength of the composite increased by approximately a 66% for 15 wt.% of polyaniline and this increase is attributed to the homogeneous distribution and improved interface properties between the conducting particles and the matrix. Qualitative analysis of tensile fracture surfaces reveals the presence of conductive agglomerates with matrix polymer still coating them after failure, giving an indication of a good interfacial interaction of the conducting particles and the thermoplastic matrix. The piezo-resistive behavior of the films at different compositions was measured under tensile loading and the composite shows higher electromechanical sensitivity for films compositions slightly above the percolation threshold i.e. contents of 4 wt.% and 5 wt.%. The piezo-resistive response had a good reproducibility over five cycles of loading/unloading in the elastic region of deformation. In general, the reversibility of the piezo-resistive behavior revealed that there is a very small hysteresis of the composites, with particle contents close to the threshold and it becomes smaller for higher polyaniline contents, suggesting a potential application of this material in electromechanical devices.