Highly Conductive and Dispersible Polyaniline Microtubes Controlled by Methyl Orange

Polyaniline (PANI) is one of the best-known conductive polymers that has been widely studied due to its ease of synthesis, low cost, and tunable conductivity. However, it is still challenging to synthesize dispersible and highly electroconductive PANIs with high aspect ratios. This research provides a facile one-step synthetic method assisted by an organic dye, methyl orange (MO), to obtain high aspect ratios (the ratio could reach 20) in PANI structures. The presence of MO contributes to microtubes’ morphology, enhancing their electrical conductivity from 0.5 to 4.6 S cm–1, which is 8 times that of spherical PANI nanoparticles. The electrical properties and processability of the PANI microtubes were well explored simultaneously. The PANI microtubes can reach high conductive levels and maintain stable electrical performance for over 30 days. In addition, the PANI microtubes could be dispersed in a wide range of organic solvents and water. These functionalities enable them to act as conductive fillers to be effectively combined with silver flakes in thermoplastic polyurethane resins for fabricating conductive composites. Adding the PANI microtubes combined with silver flakes as conductive fillers in polyurethane, the resistivity of the composites can decrease to 1/1900 of those filled only with the same mass ratio of silver flakes, showing their great potential in reinforcing resins.