scholarly journals Effect of MWCNTs Functionalization on Thermal, Electrical, and Ammonia-Sensing Properties of MWCNTs/PMMA and PHB/MWCNTs/PMMA Thin Films Nanocomposites

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2625
Author(s):  
Raina Aman Qazi ◽  
Rozina Khattak ◽  
Luqman Ali Shah ◽  
Rizwan Ullah ◽  
Muhammad Sufaid Khan ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Limit Of Detection ◽  
Multiwalled Carbon ◽  
Ammonia Gas ◽  
Sensing Properties ◽  
Ammonia Sensing ◽  
Chemically Modified ◽  
Pristine Mwcnts ◽  
Effective Dispersion ◽  
Amine Groups

Partially biodegradable polymer nanocomposites Poly(3-Hydroxybutyrate) (PHB)/MultiwalledCarbon Nanotubes (MWCNTs)/Poly(Methyl Methacrylate) (PMMA)and non-biodegradable nanocomposites (MWCNTs/PMMA) were synthesized, and their thermal, electrical, and ammonia-sensing properties were compared. MWCNTs were chemically modified to ensure effective dispersion in the polymeric matrix. Pristine MWCNTs (p-MWCNTs) were functionalized with –COOH (a-MWCNTs) and amine groups (f-MWCNTs). Then, PHB grafted multiwalled carbon nanotubes (g-MWNTs) were prepared by a ‘grafting to’ technique. The p-MWCNTs, a-MWCNTs, f-MWCNTs, and g-MWCNTs were incorporated into the PMMA matrix and PMMA/PHB blend system by solution mixing. The PHB/f-MWCNTs/PMMA blend system showed good thermal properties among all synthesized nanocomposites. Results from TGA and dTGA analysis for PHB/f-MWCNTs/PMMA showed delay in T5 (about 127 °C), T50 (up to 126 °C), and Tmax (up to 65 °C) as compared to neat PMMA. Higher values of frequency capacitance were observed in nanocomposites containing f-MWCNTs and g-MWCNTs as compared to nanocomposites containing p-MWCNTs and a-MWCNTs. This may be attributed to their excellent interaction and good dispersion in the polymeric blend. Analysis of ammonia gas-sensing data showed that PHB/g-MWCNTs/PMMA nanocomposites exhibited good sensitivity (≈100%) and excellent repeatability with a constant response. The calculated limit of detection (LOD) is 0.129 ppm for PHB/g-MWCNTs/PMMA, while that of all other nanocomposites is above 40 ppm.

Synthesis, Structural and Gas Sensing Properties of Nano-Branched Coaxial Polyaniline Fibers by Electrospinning

2012 ◽  
Vol 562-564 ◽  
pp. 308-311 ◽  
Author(s):  
Cheng Chun Tang ◽  
Rong Huang ◽  
Yun Ze Long ◽  
Bin Sun ◽  
Hong Di Zhang ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Oxidative Polymerization ◽  
Impedance Analysis ◽  
Ammonia Concentration ◽  
Ammonia Gas ◽  
Sensing Properties ◽  
Ammonia Sensing ◽  
Ppm Level ◽  
Polymerization Method

Polyaniline (PANI) is a promising functional polymer in the field of toxic gas detection. In this paper, nano-branched coaxial PANI fibers were grown on electrospun poly(methyl methacrylate) (PMMA) nanofibers by an in situ chemical oxidative polymerization method. The resultant PANI/PMMA fibers were characterized by scanning electronic microscopy and Raman spectrum analysis. The conductivity of an individual coaxial PANI/PMMA fiber is about 2.123 S/cm and that of the conducting PANI coating layer is about 21.8 S/cm. The ammonia sensing properties of the samples were tested by means of impedance analysis. The nano-branched PANI fibers can response significantly to low concentration of ammonia due to large specific surface area, and the sensitivity shows good linear relationship to the ammonia concentration of ppm level. These results indicate that nano-branched coaxial PANI fibers are promising candidate for detection of toxic ammonia gas.

scholarly journals Gas sensing properties of MWCNT layers electrochemically decorated with Au and Pd nanoparticles

2017 ◽  
Vol 8 ◽  
pp. 592-603 ◽  
Author(s):  
Elena Dilonardo ◽  
Michele Penza ◽  
Marco Alvisi ◽  
Riccardo Rossi ◽  
Gennaro Cassano ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Pd Nanoparticles ◽  
Gaseous Pollutants ◽  
Gas Sensitivity ◽  
Multiwalled Carbon ◽  
Sensing Properties ◽  
Pristine Mwcnts ◽  
Wide Range ◽  
Deposited Metal ◽  
Gas Sensing Properties

Multiwalled carbon nanotube (MWCNT)-based chemiresistors were electrochemically decorated with Au and Pd nanoparticles (NPs), resulting in an improvement in the detection of gaseous pollutants as compared to sensors based on pristine MWCNTs. Electrophoresis was used to decorate MWCNTs with preformed Au or Pd NPs, thus preserving their nanometer-sized dimensions and allowing the metal content to be tuned by simply varying the deposition time. The sensing response of unmodified and metal-decorated MWCNTs was evaluated towards different gaseous pollutants (e.g., NO2, H2S, NH3 and C4H10) at a wide range of concentrations in the operating temperature range of 45–200 °C. The gas sensing results were related to the presence, type and loading of metal NPs used in the MWCNT functionalization. Compared to pristine MWCNTs, metal-decorated MWCNTs revealed a higher gas sensitivity, a faster response, a better stability, reversibility and repeatability, and a low detection limit, where all of these sensing properties were controlled by the type and loading of the deposited metal catalytic NPs. Specifically, in the NO2 gas sensing experiments, MWCNTs decorated with the lowest Au content revealed the highest sensitivity at 150 °C, while MWCNTs with the highest Pd loading showed the highest sensitivity when operated at 100 °C. Finally, considering the reported gas sensing results, sensing mechanisms have been proposed, correlating the chemical composition and gas sensing responses.

Metal-oxide based ammonia gas sensors: A review

2020 ◽  
Vol 10 ◽  
Author(s):  
Priya Gupta ◽  
Savita Maurya ◽  
Narendra Kumar Pandey ◽  
Vernica Verma
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Review Paper ◽  
Gas Sensing ◽  
Gas Sensitivity ◽  
Ammonia Gas ◽  
Ammonia Sensing ◽  
Ammonia Gas Sensors

: This review paper encompasses a study of metal-oxide and their composite based gas sensors used for the detection of ammonia (NH3) gas. Metal-oxide has come into view as an encouraging choice in the gas sensor industry. This review paper focuses on the ammonia sensing principle of the metal oxides. It also includes various approaches adopted for increasing the gas sensitivity of metal-oxide sensors. Increasing the sensitivity of the ammonia gas sensor includes size effects and doping by metal or other metal oxides which will change the microstructure and morphology of the metal oxides. Different parameters that affect the performances like sensitivity, stability, and selectivity of gas sensors are discussed in this paper. Performances of the most operated metal oxides with strengths and limitations in ammonia gas sensing application are reviewed. The challenges for the development of high sensitive and selective ammonia gas sensor are also discussed.

Enhancement in Room Temperature Ammonia Sensing Properties of Naphthalene Diimides through Core Expansion

2022 ◽  
Author(s):  
Salman Ali ◽  
Mohammed Jameel ◽  
Glenn Oldham ◽  
Akhil Gupta ◽  
Mahnaz Shafiei ◽  
...  
Keyword(s):  
Active Layer ◽  
Organic Semiconductor ◽  
Room Temperature ◽  
Ammonia Gas ◽  
Sensing Properties ◽  
Ammonia Sensing ◽  
Naphthalene Diimide ◽  
Naphthalene Diimides

An amperometric type sensor whose active layer is derived from a tetra core-substituted organic semiconductor, naphthalene diimide (NDI-CN4), has been evaluated for ammonia gas (3, 6, 25 and 50 ppm)...

Room temperature ammonia gas sensing properties of polyaniline nanofibers

2019 ◽  
Vol 30 (9) ◽  
pp. 8371-8380 ◽  
Author(s):  
S. B. Kulkarni ◽  
Y. H. Navale ◽  
S. T. Navale ◽  
F. J. Stadler ◽  
V. B. Patil
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Ammonia Gas ◽  
Sensing Properties ◽  
Polyaniline Nanofibers ◽  
Gas Sensing Properties

Synthesis and Gas-Sensing Properties of MnO2 – x and MnO2 – x/CuO-Coated Multiwalled Carbon Nanotube Nanocomposites

2019 ◽  
Vol 61 (11) ◽  
pp. 2224-2227
Author(s):  
Yu. A. Sten’kin ◽  
V. V. Bolotov ◽  
D. V. Sokolov ◽  
V. E. Roslikov ◽  
K. E. Ivlev
Keyword(s):  
Carbon Nanotube ◽  
Gas Sensing ◽  
Multiwalled Carbon Nanotube ◽  
Multiwalled Carbon ◽  
Sensing Properties ◽  
Gas Sensing Properties
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