New conducting thermally stable blends of polyaniline (PANi) with sulfonated poly(ether sulfone) as a matrix were prepared by a solution-blending method. Camphorsulfonic acid (CSA) was used as a protonic agent for PANi. A sulfonyl group was introduced into the poly(ether sulfone) to enhance the coulomb interaction among the blends. The influence of the sulfonated group in poly(ether sulfone) was monitored with electrical property measurements. Ultraviolet-visible spectra of the blend compositions showed a well-developed polaron band. The compatibility of the blends, that is, hydrogen bonding and dispersion at the molecular level, was ascertained with X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy; these supported intermolecular interaction. A smooth and uniform morphology was observed in the blends. The electrical conductivity of the blends increased up to 14 S/cm with the protonation of the PANi complex with CSA, and the percolation threshold was found to be 2 wt % PANi. These new blends showed increases in conductivity and compatibility over other PANi-poly(ether sulfone) blends.

Poly(vinyl acetate) (PVAc) is used extensively in coatings, adhesives and films. The carbonyl group (C=O) in the structure of PVAc forms hydrogen bonding with amine and hydroxyl groups and this may also enhance miscibility with polyaniline. Hence, PVAc has been chosen for blending with PANI. Further, PVAc can be used in moisture sensors and after blending with PANI its conductivity would be in semi conducting range with moisture response, which will be suitable for easy measurement. It was expected that, the given blend may give higher conductivity because 1) PVAc and PANI solubility parameter values match closely: the Hilde Brand solubility parameter (δ) of aniline is 21.1 Mpa1/2 and PVAc is found to be 20 Mpa1/2, 2) Its miscibility also increases due to H-bonding forces of attraction observed in amine group of PANI and ‘CO’ group of PVAc. 3) PVAc has excellent sticking properties to different substrates which makes it useful as an adhesive and 4) Work function values of PANI as well as PVAc match closely. It is interesting to mention that PVAc has a low Tg (28 °C) and thus may serve as a polymeric plasticizer for PANI, which would help to improve processability and/or film formation. There are many methods of blending polymers but only limited techniques can be applicable for conducting polymers. PVAc is soluble in high dielectric constant solvent such as methanol. However, PANI is not soluble in this solvent even after modification with suitable dopants. Hence, a new method has been adopted for blending these two components; i.e. the in situ blending method. This system also explains ex-situ blending method, electrical properties and charge transport processes in the blend.

Thermally stable new conducting polymer blends of polyaniline/polyethersulfone were prepared by solution blending method in which N-methyl-2-pyrrolidone and m-cresol were used as solvent for polyaniline doped with camphorsulfonic acid, respectively. These blends show no phase separation with low percolation threshold (*2 wt% polyaniline) and well-developed polaron band. Scanning electron microscopy images of these blends exhibit uniform and smooth morphology. In these conducting blends electrical conductivity increased up to 0.7 S/cm.