This study aims to investigate the effects of using different small molecule dopants based on phosphoric acid such as nitrilotrimethylphosphonic (NTMPA), 1,1’-binaphthyl-2,2’-diyl hydrogenphosphate (BNHP) and pyrophosphoric acid (PPA) in a polyaniline/poly(2-acrylamido-2-methylpropane sulfonic acid (PANI/PAAMPSA) polymer complex. The impact of size, structure, and number of acid groups of these small molecule dopants on the resulting solvent-casted film properties are examined. The polymer film is synthesized through a templated oxidative polymerization of aniline, where the resulting complex is non-covalently bonded via hydrogen bonding and electrostatic interactions. Fourier transform infrared spectroscopy confirmed the presence of a greater degree of hydrogen bonding in the PANI/PAAMPSA/PPA film, resulting in greater elongation at break (ϵ =3750%) and a higher percent water content (17.2% w/w). The stronger hydrogen bonding in PANI/PAAMPSA/PPA created a robust cross-linking within the material which reduced the material’s ability to self-heal. On the other hand, PANI/PAAMPSA/NTMPA film achieved high self-healing efficiencies of 98% (conductive self-healability) and 77.3% (mechanical self-healability) due to its more dynamic hydrogen bonding and electrostatic interactions. Furthermore, PANI/PAAMPSA/BNHP has shown less hydrogen bonding, stretchability, and self-healing capabilities due to the steric hindrance caused by its rigid bulky structure compared to the more linear structure of other dopants investigated.
