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

Abstract

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 (1 H NMR and FT-IR), electrical conductivity (E.C), optical properties (UV-VIS), and morphology (FE-SEM) of the blends was studied. 1 H 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 1 H 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 1 H 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.

Synthesis and factor affecting on the conductivity of polypyrrole: a short review

“…The most commonly used synthesis methods for PPy are chemical and electrochemical polymerization 37,38 . Recently, the ultrasonic‐irradiation‐assisted polymerization of PPy has also gained research interest 39‐41 . Other synthesis methods for PPy include vapor‐phase polymerization (VPP), electrospinning, microemulsion polymerization, mechanochemical polymerization, and photopolymerization.…”

Smart pH-Responsive Polyaniline-Coated Hollow Polymethylmethacrylate Microspheres: A Potential pH Neutralizer for Water Purification Systems

“…The findings indicate similar patterns to those in the study of dose variation and time variation. As stated in the literature, with the change in conductivity, the absorbance at 600 nm also changes inversely.…”

“…The relationship between charge and doping has been well explained by MacDiarmid and Huang as the protonation/deprotonation of PANI, which results in an increase or decrease in the amount of charge on the polymer backbone, leading to increased or decreased conductivity. 69 , 70 The relationship between charge and doping has been explained in a study reported in the literature, 71 which mentioned that during the deprotonation of PANI, the interaction between a polar molecule and PANI decreases, which results in redistribution of charge and hence reduced electrical conductivity. Thus, based on the above discussions, it can be inferred that on the addition of NaOH to the protonated PHPM dispersion, the deprotonation of PANI starts.…”

Brush-like Polyaniline with Optical and Electroactive Properties at Neutral pH and High Temperature

“…An abrupt change occurs between pH 8 and pH 9 owing to the dedoping point ( Figure 6 ). At pH 6 and pH 7, it is observed that the intensity of bipolaron decreases until pH 8, whereas, at pH 9 and pH 10, the polaron broadband shows a blue shift, presenting a new band around ~600 nm characteristic of an emeraldine base structure [ 51 ]. In our previous work, the dedoping point of the PAni doping with AMPS manifested itself at pH 4.4 [ 37 ].…”