Structure and properties of melt-processed PVDF/PMMA/polyaniline blends

Ternary blends composed of the matrix polymer poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) with different proportions of thermally doped polyaniline (PAni) using an alkylated dopant (dodecylbenzenesulfonic acid) (DBSA) were prepared by melt mixing. The effectiveness of these blends was compared with the corresponding binary blends of PVDF or PMMA with PAni-DBSA complex. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) measurements, thermal analysis by differential scanning calorimetry (DSC) and morphological studies by optical microscopy and scanning electron microscopy (SEM) were carried out to characterize the blends in light of the interactions between their components and on the resulting electrical conductivity. Though a notable dispersion of PAni-DBSA in the PMMA matrix was incurred along with better conductivity with respect to PVDF/PAni-DBSA and PVDF/PMMA/PAni-DBSA blends, the thin films based on PMMA/PAni-DBSA were found to be fragile in nature. However, the presence of PMMA in the ternary blends of PVDF/PMMA/PAni-DBSA provided improved dispersion of PAni-DBSA in the PVDF/PMMA host matrix as compared to PVDF/PAni-DBSA binary blends. An enhancement in the conductivity by about two orders of magnitude at > 5 wt% PAni-DBSA was witnessed in the ternary blends than that of PVDF/PAni-DBSA binary blends. Thin films made of ternary blends of PVDF/PMMA/PAni-DBSA also offered superior mechanical properties and flexibility than that of PMMA/PAni-DBSA binary blends due to the contribution of PVDF in the blend. (C) 2008 Elsevier B.V. All rights reserved.