Improvement of the Uniformity and Electrical Properties of Polyaniline Nanocomposite Film by Addition of Auxiliary Gases during Atmospheric Pressure Plasma Polymerization.

Jae-Young Kim,Choon-Sang Park,Soonwon Lee,Heung-Sik Tae,Bhumjae Shin,Gyutae Bae,Eunyoung Jung,Hyo-Jun Jang

doi:10.3390/nano11092315

Abstract

The morphological and chemical properties of polyaniline (PANI) nanocomposite films after adding small amounts of auxiliary gases such as argon, nitrogen, and oxygen during atmospheric pressure (AP) plasma polymerization are investigated in detail. A separate gas-supply line for applying an auxiliary gas is added to the AP plasma polymerization system to avoid plasma instability due to the addition of auxiliary gas during polymerization. A small amount of neutral gas species in the plasma medium can reduce the reactivity of monomers hyperactivated by high plasma energy and prevent excessive crosslinking, thereby obtaining a uniform and regular PANI nanocomposite film. The addition of small amounts of argon or nitrogen during polymerization significantly improves the uniformity and regularity of PANI nanocomposite films, whereas the addition of oxygen weakens them. In particular, the PANI film synthesized by adding a small amount of nitrogen has the best initial electrical resistance and resistance changing behavior with time after the ex situ iodine (I2)-doping process compared with other auxiliary gases. In addition, it is experimentally demonstrated that the electrical conductivity of the ex situ I2-doped PANI film can be preserved for a long time by isolating it from the atmosphere.

Highlights

Plasma polymerization is a process of synthesizing vaporized reactive monomers produced by gaseous plasmas into a polymeric composite [1,2,3,4,5,6,7], and the resulting polymers are generally manufactured on a substrate as a thin film [8,9,10,11,12]
We propose an additional flow of a small amount of neutral gas toward the substrate as a simple solution to reduce excessive crosslinking by suppressing the reactivity of the aniline monomer species hyperactivated by a high-voltage (HV)-driven plasma
The atmospheric pressure (AP) plasma polymerization process occurs in the space confined between the guide tube, which is connected to the plasma jet array, and the bluff body, which is the substrate stand

Summary

Introduction

Plasma polymerization is a process of synthesizing vaporized reactive monomers produced by gaseous plasmas into a polymeric composite [1,2,3,4,5,6,7], and the resulting polymers are generally manufactured on a substrate as a thin film [8,9,10,11,12]. Various radicals and reactive species generated through diverse successive interactions with charged particles, vaporized monomers, and neutral gas species remain conserved or react with each other to form crosslinks in atmospheric pressure (AP) plasma polymerization, which uses nonthermal glow discharge at AP. The crosslinking of these reactive monomers grows into polymer 4.0/). These material properties of polyaniline and the advantages of plasma polymerization are attracting the attention of researchers studying near-future electronic devices such as conductive fabrics, solar devices, displays, and sensors

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Results

Conclusion