The effect of varying the introduction mode of reactants on electrical, physical and thermal stability properties of polypyrrole synthesized with CTAB

Abstract

Electrical and physical properties of conducting polymers are generally enhanced via modifications in the chemical structure of the final product, there appears to be a void in facile physical means to improve the materials' properties without utilizing additives which remain in the final product as impurity. In this research, we presented the effect of altering the introduction method of reactants in emulsion polymerization of PPy with CTAB on the electrical, physical and stability properties of the final product. Three samples were prepared: one via a conventional non-emulsion polymerization method as a reference sample, the second in which the reactants were added simultaneously and the goal sample in which the monomer/surfactant mixture was allowed to be stirred separately then it was added dropwise to the oxidant solution. UV-vis, FTIR, 4-point Van Derr Paw probe, FESEM and contact angle measurements were used to investigate optical, electrical, physical, heat stability and solubility properties of the samples. The results indicate that since in the final sample a higher portion of the reaction occurred on the hydrophobic interior of the micelles, the final material had a lower number of structural and chemical defects which leads to higher conjugation lengths and thus higher properties such as a 9-fold difference in conductivity and improved solubility and thermal stability. The novelty of this work lies in the simplicity of the alterations that have been made, both in terms of optimization of the synthetic route which had been thoroughly investigated and also in terms of the differences that our work poses compared to that of the others; namely: the parameters have been thoroughly studied and analyzed but not the method of addition as in our experiments the sequence of addition and the method of addition of the reactants were altered to observe their effect on the physical and the electronic properties which has led to the conclusion that in case of drop-wise addition, a larger portion of the reaction occurs inside the micelles hence giving rise to inhibition of the defect-producing chemical bonds which is supported by the analysis in our investigations.