Applications of PANI Thin Films

Applications of PANI Thin Films

DOI: 10.4018/978-1-5225-9896-1.ch006

Abstract

Polypyrrole, polythiophene, and PANI are inherently conducting polymers (ICPs), which show electrical properties just like metals and semiconductors. Aniline has low cost, so it makes PANI the least expensive and thermally stable from all ICPs. PANI is conducting in nature, but due to its less solubility and melting processability, it has not much attention for commercial purposes. PANI might be used for commercial purposes following by some additional improvements. It can be synthesized by electrochemical and chemical oxidative polymerization. PANI thin films can be used in the detection of gases as gas sensors, chemical and biological sensors, optical pH sensors, etc. These films can also be used in supercapacitors, electrochromic devices, solar cells, dye-sensitized solar cells, rechargeable batteries, electrochemical filter, protection of metal surface from corrosion, etc. PANI thin films can also be used in biological applications such as antimicrobial properties, and the various researchers across the globe have the most widely studied tissue engineering applications.
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Introduction

Polypyrrole (Ppy), polythiophene (PTh), and polyanilines (PANI) are inherently conducting polymers (ICPs) that show electrical properties just like metals and semiconductors. These ICPs can replace conducting materials due to their lower density, higher mechanical flexibility, low manufacturing cost, and better process ability. ICPs can be used for electromagnetic shielding and antistatic coatings. PANI can be synthesized by using aniline monomer unit, and this aniline can be obtained by benzene and can be extracted as a by-product from coal tar refining and oil (Endemann, 1886). Aniline has low cost, so it makes PANI least expensive and thermally stable from all ICPs (Li et al., 2008). PANI is conducting in nature, but due to its less solubility and meting processability, it has not much attention for commercial purposes (Li & Kaner, 2005). PANI can be used for commercial purpose followed by some additional improvements. PANI can synthesize by electrochemical & chemical oxidative polymerization (Tren et al., 2009). Synthesized PANI has been soluble in some organic solvent such as meta-cresol or hexafluoroisopropanol (HFIP), dimethylformamide (DMF), N-methyl-pyrrolidinone (NMP), etc. (Baker et al., 2017). PANI thin films can be formed by a chemical and physical deposition method, which has been discussed in chapter 2 along with the characterization tools. There are various applications associated with PANI thin films shown in this flowchart (Figure 1) and will be addressed in this chapter.

Figure 1.

Applications of PANI thin films

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Applications Of Pani Thin Film

Gas Sensors

PANI thin films can be used in sensors just because of its high surface area, and fast response time. These are used in the detection of many gases such as ammonia, LPG, CO, etc. In gas detection process, PANI thin films are inserted vertically in the gas chamber, and observed changes are measured. It has been seen that absorbance on thin film increases when gas is purged in chamber, and it indicates a reaction between gaseous molecules and PANIs. This relation S = (Ag-Aa)/Aa where Ag and Aa are the absorptions of films in gas and air, and S describes the sensitivity of the sensor, where the sensitivity increases with an increase in the concentration of gas (Joshi, 2016).

Key Terms in this Chapter

Supercapacitors: Supercapacitor is a capacitor which has a high value of capacitance then another capacitor.

Gas Sensors: These are gas detectors that measure the concentration of target gas by reduction or oxidation of gas at the electrode and measure the current.

Solar Cells: It is also known as a photovoltaic cell, which is an electrical device. Solar cells convert solar energy into electrical energy.

Antimicrobial Properties: These properties are shown by some compounds which are known as an antimicrobial agent. Antimicrobial agents killed the microorganisms or stopped their growth. Antibiotics are used against bacteria and antifungals are used against the fungi.

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