Frontiers in Science 2017, 7(1): 23-26
DOI: 10.5923/j.fs.20170701.03
Detection of Environmentally Hazardous Nitrogen Oxide
Pollutants using Polythiophene Derivative/Carbon
nanotube-based Nanocomposite
Ayesha Kausar
Nanoscience and Technology Department, National Centre for Physics, Islamabad, Pakistan
Abstract This article reports a novel effort towards the detection of environmentally hazardous NO and NO
2
gas
pollutants. The required nanocomposite sensor was designed using poly(thiophene-3-[2-(2-meth
-oxyethoxy)ethoxy]-2,5-diyl) (PThME), multi-walled carbon nanotube (MWCNT), and 3-thiopheneacetate additive. Simple
dispersion route was opted in this case. Gas sensing properties towards nitrogen oxides NO and NO
2
gases were measured.
The response of PThME/MWCNT-based sensor for NO and NO
2
gases in the concentration range of 2-5 ppm was studied.
The resistance change was found to increase with the increase in gas concentration. Moreover, the sensitivity of
PThME/MWCNT 3-based gas sensors for 2 ppm NO gas was increased with rise in temperature. Time derivative of
resistance for PThME/MWCNT was also observed higher for NO
2
gas. In a nutshell, novel PThME/MWCNT gas sensors
possess high efficiency to distinguish NO and NO
2
based environmental pollution.
Keywords Polymer, MWCNT, NOx, Sensor, Environment, Polluant
1. Introduction
By definition, an air pollutant is any material which may
harm human beings, animals, vegetation or other materials
[1, 2]. In the case of humans, air pollutants may cause or
add to mortality or serious illness. Therefore, air pollutants
may cause potential hazard to human health. The
determination of hazardous substances in atmosphere has,
therefore receives an immense research attention [3].
Carbon nanotube (CNT) is a talented material with range of
exclusive properties such as surface area, aspect ratio,
mechanical strength, and electrical conductivity [4, 5].
Uniqueness of carbon nanotubes has rendered them
competitors for specific applications. Research on
CNT-based materials have pointed to range of probable
applications in electronic devices, sensors, field emission
devices, supercapacitors, batteries, actuators, membranes,
and drug delivery systems [6-10]. It has also been an
attractive material for the sensing and detection of gases
[11]. CNT possess wide specific surface area and fine
adsorption ability, therefore can be used as a gas sensing
material. Nitrogen oxides such as nitrogen monoxide (NO)
and nitrogen dioxide (NO
2
) are typical air pollutants
causing serious environmental problems. The demands for
* Corresponding author:
asheesgreat@yahoo.com (Ayesha Kausar)
Published online at http://journal.sapub.org/fs
Copyright © 2017 Scientific & Academic Publishing. All Rights Reserved
low cost gas sensors have been rapidly grown NOx
detection. Consequently, highly sensitive and inexpensive
NOx gas sensors have been developed to detect low
concentration of NO and NO
2
gases. In this regard, polymer
and CNT-based gas sensing materials have outstanding high
sensitivity at low temperature with fast response and
selectively [12-18]. NO
2
sensors for environmental
applications have been developed using chemical vapor
deposition (CVD) technique [19]. The sensors showed good
response to low NO
2
concentrations and fine selectivity.
Such sensors have also been prepared using pulsed laser
ablation (PLA) method. The sensitivity of CNT-based gas
sensors was dependent on the deposition methods [20].
Similarly, various types of gas sensors have been prepared
using polymer and carbon nanotube [21]. The mechanism
of CNT-based gas sensors depends on the p-type
semiconducting properties of nanotubes. The electron
transfer between CNT and oxidizing or reducing gas
molecules adsorbed on nanotube surface may affect the
electrical conductance [22, 23]. In this paper, gas sensors of
a polythiophene derive polymer and multi-walled carbon
nanotube (MWCNT) have been developed for the first time.
The objective of study was to see the effect of MWCNT
loading on the performance of sensors towards the detection
of toxic nitrogen oxides. The sensor was developed on
ceramic substrate. The response of the prepared gas sensors
to NO and NO
2
gases were measured and analyzed.