Polyanion-assisted

Self-doped PANI are very interesting due to their unique electrochemical behavior unlike PANI, the self-doped polymer remains in its doped state in near neutral or alkaline media [28]. Fully self-doped PANIs are not easy to synthesize due to the lower reactivity of acid-functionalized anilines. Kim et al. [29, 30] introduced an alternative approach in the template-assisted enzymatic polymerization of aniline. Previously, only polyanionic templates had been used for PANI synthesis. However, acid-functionalized anilines bear a net anionic charge in aqueous solution, and attempts to use SPS as template with carboxyl-functionalized aniline resulted in red-brown colored polymers with no polaron transitions, regardless of the synthetic conditions. The use of polycationic templates, such as those shown in Figure 8.2 allowed the synthesis of linear and electrically conductive PANIs with self-doping ability due to the doping effect of the carboxyl groups present in the polymer backbone. 

Various combinations of synthetic polyelectrolytes are applied to the formation of polyelectrolyte shells onto colloid particles. Polyelectrolytes are divided into weak and strong ones. The examples of the first ones are sodium poly(styrene sulfonate) (PSS) and polyaniline propanesulfonic acid. Polyacrilic acid is an example of weak polyelectrolyte. Both examples are polyanions. Polyamines with various number of assistants at the atom of nitrogen are basically used as polycation components, for example poly(allylamine hydrochloride), polyethylenimin, etc. 

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