The Effect of pH on the Preparation of Electrically Conductive and Physically Stable PANI/Sago Blend Film via in situ Polymerization

This study attempts to prepare electrically conductive and physically stable PANI/Sago starch films by a simple one-pot synthesis method using ultrasound irradiation technique. To attain physical stability of the prepared films, the pH of the PANI/Sago dispersion was varied (2, 4, 6, 7, 9, and 11 pH) before drying. The effect of pH on the structural properties (H-1 NMR and FT-IR), electrical conductivity (E.C), optical properties (UV-VIS), and morphology (FE-SEM) of the blends was studied. H-1 NMR results revealed that at low pH (2 and 4), degradation of sago starch took place and as the pH increases, deprotonation of PANI takes place. The findings of H-1 NMR were ably supported by E.C results, which showed gradual decrease in conductivity until pH 7 and then a drastic drop was noticed for pH 9 and 11. UV-Vis findings reveals that, as the pH increases, PANI deprotonates from emeraldine salt form to emeraldine base form. The morphological results were complimentary with H-1 NMR and FT-IR, while revealing different morphologies: coral like morphology with voids in them for blends with pH 2 and 4; well-connected and smooth morphology for blends with pH 6 and 7; and well-connected but with loose flake like morphology for blends with pH 9 and 11. Overall, the PANI/Sago blend with pH 6 was found to be electrically conductive and physically stable.