Nanofibers of polyaniline synthesized by interfacial polymerization

The average diameter of polyaniline nanofibers obtained by interfacial polymerization using a solution of aniline in toluene as the top organic phase and acidic ammonium peroxydisulfate as the bottom aqueous phase can be controlled by using surface active dopants and/or surfactants in the aqueous phase. The average diameter of polyaniline nanofibers doped with camphorsulfortic acid (CSA) synthesized by interfacial polymerization decreases when twin-tailed anionic surfactants, based on the cis-1,2-alkylethene sulfonate structure (alkyl = C5H11 or C7H13), are used. For example, the average diameter of polyaniline. CSA nanofibers decreases in the order 48 nm (no surfactant) > 35 nm (C5H11-twin-tailed) > 28 nm (C7H13-twin-tailed). This effect is reversed in polyaniline nanotibers synthesized using 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) as the dopant, e.g., the average fiber diameter of polyaniline. AMPSA increases in the order 23 nm (no surfactant) < 35 nm (C5H11-twin-tailed) < 55 nm (C7H13-twin-tailed). The doping percentage is reduced when surfactants are used although there is no significant change in the pressed-pellet room temperature 4-probe DC conductivity compared to conventional (single-phase) polyaniline-HCl (sigma similar to 1-5 S/cm). Polyaniline nanofibers also show increased capacitance consistent with their high surface area, e.g., a capacitance value of 277 F/g was observed in nanofibers of polyaniline-AMPSA (23 nm average diameter) compared to 11 F/g in non-fibrillar polyaniline. AMPSA powder. Further optimization and surfactant structure-function evaluation is needed to uncover the mechanism associated with this phenomenon. (C) 2004 Elsevier B.. All rights reserved.