The incorporation of flexible side chains need not be restricted to synthetic methods which chemically anchor these units to the main chains at various bonding sites. The possibility also exists for using specific dopant molecules which can contribute this functionality indirectly. A well-known prototypical conducting polymer employing this approach is the doping of polyaniline EB using various surfactants[121,122] including dodecylbenzenesulfonate (DBSA) (shown in Fig. 13) or camphor sulfonic acid. In some instances substantially improved conductivities are obtained as compared to EB samples treated with only simple inorganic halogen (HX, X= F, Cl, Br, I) acids.
Studies are also possible for PANI samples having a combination of both chemically anchored side chains and functionalized dopants. The structures of these and of the dopant-only containing host polymers are found to be qualitatively similar to those of the side chain substituted material discussed previously. In general large length scale d-spacings develop indicative of a lamellar phase. Initial studies of the systematic absences in the diffraction data from PANI-DBSA polymers suggests a Pmnm space group with lattice parameters of a=11.8Å, b=17.9Å, and c=7.2Å. Detailed structure factor calculations which would further test the validity of this model are not yet available. The quality of scattering data from other existing compounds is typically poorer than for PANI-DBSA and this permits only the identification of the most pronounced d-spacings.