Fundamentals and Emerging Applications of Polyaniline

Masoud Mozafari, Narendra Pal Singh Chauhan

• Publisher: Elsevier
• Year: 2019
• Print ISBN:
  9780128179154
• eBook ISBN:
  9780128179161
• Topic: Technology & Engineering
• Subtopic: Industrial & Technical Chemistry
• Index: Technology & Engineering

Fundamentals and Emerging Applications of Polyaniline presents in-depth coverage of synthetic routes, characterization tools, experimental procedures, and the preparation of PANI-based materials for advanced applications. Sections examine the various synthetic routes available for the polymerization of aniline, covering both conventional methods and new approaches, specific PANI-based materials, and their potential applications. Users will be able to understand how to use these methods in areas such as electromagnetic interference shielding, rechargeable batteries, light emitting diodes, super capacitors, anti-static packaging and coatings, photonics, biomedical applications, chemical and biochemical sensors. This is a highly valuable source of information for researchers, scientists and graduate students in polymer science, polymer composites, polymer chemistry, nanotechnology, physics and materials science. - Covers the latest synthetic approaches, such as ultrasound-assisted polymerization, irradiation path and electrochemical polymerization - Offers detailed information on PANI-based composites, including graphene, CNT and functionalized polyaniline - Explains how different PANI-based materials can be geared for specific cutting-edge applications across a range of fields

Chapter 1

Polyaniline: An introduction and overview

Narendra Pal Singh Chauhan^a; Masoud Mozafari^{b,c,d a} Department of Chemistry, Faculty of Science, Bhupal Nobles’ University, Udaipur, India
^b Bioengineering Research Group, Nanotechnology and Advanced Materials Department, Materials and Energy Research Center (MERC), Tehran, Iran
^c Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
^d Department of Tissue Engineering & Regenerative Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran

Abstract

Polyaniline (PANI) is a conductive polymer that is used in many applications due to its unique characteristics. Although it has been almost 150 years since this class of polymers was discovered, it has recently attracted heightened attention from the scientific community working in different fields of study, largely due to the discovery of the high electrical conductivity of PANI. Different synthesis strategies and modification techniques can be used for the optimization of PANI for specific applications. It is expected that this class of polymers play a more critical role in the future in many different fields, ranging from electronics to medicine, due to its ease of synthesis, environmental stability, and simple doping/dedoping chemistry.

Keywords

Polyaniline; PANI; Conductive polymer; Polymer synthesis

1 Introduction

In 1977, Shirakawa and coworkers [1] fabricated intrinsically conducting polymers (ICPs), trans“polyacetylene”, (CH)_x, with unique properties that made them excellent candidates for a range of emerging applications. Although this class of polymers had many advantages over other conventional polymers, there were also some drawbacks in their development, the main issues with them being their processing and poor mechanical properties. Therefore many other ICPs were proposed, including polyaniline (PANI), polythiophene (PTh), polypyrrole (Ppy), and their derivatives.

Among the various conducting polymers, PANI has attracted attention since it has nitrogen and hydrogen bonds on either side of a phenylene ring, which is highly reactive. Hence, it has immense potential for many applications due to its unique characteristics, such as [2–9] easy preparation, eco-friendliness, stability, cost effectiveness, and wide spectrum of applications. It is also a very important tool in chemistry and physics, as it undergoes protonation and deprotonation. Furthermore, it undergoes adsorption via a nitrogen, having a lone pair of electrons. But PANI has also shown some drawbacks, such as its insolublility in common solvents, its poor mechanical properties, and infusible nature (i.e., it decomposes before melting). Different techniques, namely grafting [10], blending, composites, fictionalization, etc., have been applied to provide enhanced electrochromic, sensor, catalytic, redox, processability, mechanical, and other physical properties [11–15]. The characteristic peaks for PANI using the Fourier transform infrared (FTIR) spectroscopy technique are tabulated in Table 1.

Table 1

The characteristic peaks of PANI using FTIR spectroscopy.

Type of bonds	Frequency (cm^− 1)	References
N H stretching vibration (nonhydrogen)	3460	[16–18]
N H bond between amine and imine sites	3230
C N and C C stretching modes for the quinonoid and benzenoid units	~ 1560 and 1498
C N stretching mode	1298
degree of electron delocalization	1128

2 Synthesis methods of PANI

2.1 Chemical synthesis

Chemical synthesis involves various methods, including in situ oxidation polymerization, counterion-induced processability, emulsion polymerization, inversion emulsion process, dispersion polymerization blending method, solution blending, dry blending, interfacial polymerization, melt processing, and the flux method.

2.1.1 In situ chemical polymerization

Various modified PANIs have been prepared using in situ chemical polymerization, such as PANI/bacterial cellulose nanocomposite [19–21], PANI@cellulose nanowhiskers [22, 23], PANI and iota-carrageenan biocomposites [24], and others, and these have shown excellent conductivity, tensile strength, thermal stability, decreased percolation thresholds, and oxidation reduction transition. In one study, Zhang et al. [25] prepared PANI on cellulose nanocrystals via in situ polymerization in which lyotropic chiral nematic liquid crystals were utilized as an asymmetric reaction field. The lyotropic chiral nematic liquid crystals of cellulose nanocrystals were fabricated by using a simple hydrolysis method. The content of cellulose nanocrystals influences the size of the PANI nanoparticles.

2.1.2 Bulk and slurry oxidative polymerization

This is another method for the synthesis of PANI. In one study, a bulk and slurry oxidative polymerization method was used by Alves Marins [26] for the synthesis of fiber-based nanocomposites of PANI attached with sepiolite, which could be used for electrorheological fluid applications.

2.1.3 Chemical oxidative polymerization

The performance of cellulose-PANI composites prepared by chemical oxidative polymerization depends on the acids used in the process. Mo et al. [27] reported that dibasic acid could show higher conductivity compared to that of monobasic acid. In this method, the product depends on the acidity conditions [28]. Sarauli et al. [29] chemically prepared copolymers by using methoxyaniline-5-sulfonic acid monomers and aniline monomer with different ratios and another copolymer with 3-amino-benzoic acid and aniline. They also studied the interactions of redox protein cytochrome c (cyt c) and the enzyme sulfite oxidase (SO) with electrodes made of these materials. The addition of cellulose triacetate (CTA) increased the solubility of PANI in organic solvents, with an improvement in biodegrability and flexibility [30]. The (PANI)-kaolinite nanoc...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributors
• About the editors
• Preface
• Chapter 1: Polyaniline: An introduction and overview
• Chapter 2: Synthetic route of polyaniline (I): Conventional oxidative polymerization
• Chapter 3: Synthetic route of PANI (II): Enzymatic method
• Chapter 4: Synthetic route of PANI (III): Ultrasound-assisted polymerization
• Chapter 5: Synthetic route of polyaniline (IV): Irradiation path
• Chapter 6: Synthetic route of PANI (V): Electrochemical polymerization
• Chapter 7: PANI-based nanostructures
• Chapter 8: Polyaniline/metal oxides nanocomposites
• Chapter 9: PANI-CNT nanocomposites
• Chapter 10: Polyaniline/graphene-based nanocomposites
• Chapter 11: Functionalized polyaniline and composites
• Chapter 12: Advanced characterization tools for PANI and PANI-clay nanocomposites
• Chapter 13: Experimental procedures for assessing electrical and thermal conductivity of polyaniline
• Chapter 14: Application of polyaniline and its derivatives
• Chapter 15: Polyaniline: Future perspectives
• Index