The investigation of sensing mechanism of ethanol vapour in polymer-nanostructured carbon composite (original) (raw)
Related papers
Sensors and Actuators B: Chemical, 2011
Poly(vinyl alcohol) was modified by esterification to prepare poly(vinyl alcohol) copolymers. The degree of esterification on poly(vinyl alcohol) was elucidated by FTIR, 1 H NMR, and elemental analysis. The obtained products were poly(vinyl benzoate)-co-poly(vinyl alcohol) (B-PVA) and poly(vinyl p-toluoate)co-poly(vinyl alcohol) (P-PVA). The chemical vapor sensors were fabricated by the mixtures of polymer and carbon black in dimethyl sulfoxide and their subsequent preparation as thin films onto the interdigited electrodes by the application of the spin-coating technique. The chemical vapor sensing properties of the sensors were examined with various solvents, such as hexane, toluene, methanol, ethanol, isopropanol, tetrahydrofuran, ethyl acetate, acetonitrile, dimethyl sulfoxide, and water. The experimental results indicated that modifying the chemical structure of PVA results in the decreased polarity of the obtained products. The composites of modified PVA consequently responded well to low polarity solvents, such as THF or ethyl acetate.
Response of poly(vinyl acetate)/carbon black composites to ethanol vapour and temperature
2004 24th International Conference on Microelectronics (IEEE Cat. No.04TH8716), 2004
Ahxtsrmcr -The effect of ethanol vapour and temperature was investigatcd on gas sensors fabricated from poly(viny1 acetate)\carbon black composites based around a predetermined percolation threshold. Samples with 8% carbon black loading displayed the best response to the ethanol vapour. Typical response and recovery times of 140s and 45s respectively were recorded. In addition, bridge structures were fabricated, where all four resistive elements were prepared from the same composite material and in which a novel passivation process was employed. It was observed that these bridge stmchres were significantly less affected by variations in temperature in comparison to the single sensor structures.
Fabrication and Characterization of Carbon Nanotube/Poly(vinyl alcohol) Composites
Advanced Materials, 1999
The working principle of composite polymer vapor sensors is basically to exploit the vapor absorption properties of an insulating polymer whose electrical properties are modulated by a conductive "filler". Carbon black and graphite powder have already been used as "filler" materials [Sens. In this work we fabricate and characterize vapor sensors with a new type of "filler": carbon nanoparticles obtained by flame synthesis. Electrochemically prepared porous silicon with a 40% porosity has been used as the substrate for the carbon growth. Carbon nanoparticles have been characterized by AFM, SEM, FTIR; XRD, diffraction laser spectroscopy, nitrogen isothermal adsorption and visible optical micrography. The carbon structures seem composed of "units" whose size is in the range 5-20 nm. Composite thin films have been realized using mainly poly(methyl-methacrylate) (PMMA) as polymeric insulating matrix. Thin films of the composite are used to realize chemiresistor sensing devices. The characteristics of the sensors responses to volatile organic compounds (VOCs) are related to filler types in order to optimize the sensing device and show the importance of the filler characteristics.
Journal of Nanoscience and Nanotechnology, 2011
We investigate the chemical sensing behavior of composites prepared with polyvinyl alcohol and carbon materials (undoped multiwalled carbon nanotubes, nitrogen-doped multiwalled carbon nanotubes and carbon nanocoils). We determine the sensitivity of thin films of these composites for ethanol, methanol and toluene vapor, comparing their conductance and capacitance responses. The composite that exhibits highest sensitivity depends on specific vapor, vapor concentration and measured electrical response, showing that the interactivity of the carbon structure with chemical species depend on structural specificities of the carbon structure and doping.
Study of Ethanol Vapour Sensing Behaviour by Polypyrrole-multiwall Carbon Nanotubes Nanocomposites
Journal of Physical Science
Polypyrrole-multiwall carbon nanotubes (PPy/MWCNT) nanocomposites were synthesised by in-situ chemical oxidative polymerisation method. The MWCNTs were functionalised prior to the formation of nanocomposites. These nanocomposites were characterised by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) to study the effect of incorporation of functionalised MWCNT in PPy matrix. The results showed the successful formation of PPy/MWCNT nanocomposite and there is significant interaction between PPy and MWCNTs. The response of the prepared PPy/ MWCNT nanocomposites sensors was studied in the form of sensitivity towards ethanol vapours. Results showed that the response increases with ethanol concentration and it is also affected by the MWCNT content in PPy matrix.
Journal of Nanoscience and Nanotechnology, 2011
We report the preparation of inexpensive ethanol sensor devices using multiwalled carbon nanotube-polyvinyl alcohol composite films deposited onto interdigitated electrodes patterned on phenolite substrates. We investigate the frequency dependent response of the device conductance and capacitance showing that higher sensitivity is obtained at higher frequency if the conductance is used as sensing parameter. In the case of capacitance measurements, higher sensitivity is obtained at low frequency. Ethanol detection at a concentration of 0.3 ppm in air is demonstrated. More than 80% of the sensor conductance and capacitance variation response occurs in less than 20 s.
Poly(m-aminophenol)/amine groups functionalized multi-walled carbon nanotube composite was prepared by in-situ chemical polymerization and the film of the nanocomposite have been demonstrated as chemo-resistive sensor for ethanol. The functionalization of nanotube and the interfacial interaction between the poly(m-aminophenol) and functionalized nanotube within their composite was confirmed by Fourier transform infrared spectroscopy, X-beam photoelectron spectroscopy and Raman spectroscopy. Formation of polymer layers on the surfaces of nanotube was demonstrated form the morphological analysis of the nanocomposite by scanning electron microscopy and transmission electron microscopy. The percentage of functionalized nanotube was optimized as 2 wt% within the polymer matrix in terms of highest average DC-conductivity achieved as 32×10 −2 S cm −1 for that composition. The responses of nanocomposite with optimized composition toward various aliphatic alcohols vapor under dynamic flow with air were examined. The good response times and reasonable recovery times with significantly selective response for ethanol vapor was recorded.
Fabrication and characterization of carbon nanoparticles for polymer based vapor sensors
Sensors and Actuators B-chemical, 2004
The working principle of composite polymer vapor sensors is basically to exploit the vapor absorption properties of an insulating polymer whose electrical properties are modulated by a conductive "filler". Carbon black and graphite powder have already been used as "filler" materials [Sens. In this work we fabricate and characterize vapor sensors with a new type of "filler": carbon nanoparticles obtained by flame synthesis. Electrochemically prepared porous silicon with a 40% porosity has been used as the substrate for the carbon growth. Carbon nanoparticles have been characterized by AFM, SEM, FTIR; XRD, diffraction laser spectroscopy, nitrogen isothermal adsorption and visible optical micrography. The carbon structures seem composed of "units" whose size is in the range 5-20 nm. Composite thin films have been realized using mainly poly(methyl-methacrylate) (PMMA) as polymeric insulating matrix. Thin films of the composite are used to realize chemiresistor sensing devices. The characteristics of the sensors responses to volatile organic compounds (VOCs) are related to filler types in order to optimize the sensing device and show the importance of the filler characteristics.
Properties of multifunctional polymers – carbon black composite vapor
Publishing House of Lviv Polytechnic National University, 2011
In this work the electrical properties of vapor detectors, formed from composites of conductive carbonblack and insulating organic multifunctional polymers having metal ions complexing ability, were investigated. The new composites are tailored to produce increased sensitivity toward specific classes of analyte vapors. Resonant frequency shift of a Quartz Crystal Microbalance (QCM) and dc resistance measurements have been also performed simultaneously on polymer-carbon black composite materials. For comparison purpose, poly(vinyl chloride) (PVC) with di(2-ethylhexyl)phthalate (DOP), a traditional low molecular weight plasticizer, is used as a representative of the behaviour of a traditional composite vapor detector. These new detectors showed an enhanced sensitivity upon exposure to acetic acid and amines vapors; the performances of our systems are 10 3 times higher than those of a traditional composite vapor detector. Moreover the extent of such responses is beyond that expected by mass uptake upon exposure to the same vapors and cannot be attributed solely to differences in polymer/gas partition coefficients. In this respect, several different chemical factors determine the dc electrical response of this system: in our opinion changes in polymer conformation during the adsorption process also play a significant role. The effects of the temperature on the electric resistance of the vapor detectors have also been studied. These materials showed a discontinuity in the temperature dependence of their resistance, and this discontinuity provided a simple method for determining the T g of the composites.
Materials Science in Semiconductor Processing, 2015
We report for the first time, development of an efficient ethanol sensor using mild functionalized multiwalled carbon nanotubes (MWCNTs). A unique technique to functionalize MWCNT is reported to enhance the performance of the ethanol sensor based on it. The conventional functionalization techniques tend to damage physical structure of carbon nanotubes (CNTs) to a large extent and convert most of their sp 2 bonds into sp 3 bonded carbon atoms. This results in reduction of the available adsorption sites for ethanol vapors on the CNT surface and hence deteriorates the sensitivity. In this work, the functionalization of nanotubes is achieved through direct cycloaddition to π electrons of the CNT that does not hamper the physical structure of the nanotube. High resolution transmission electron microscopy (HRTEM) and Raman spectroscopy studies were employed to confirm the appropriate functionalization for better performance of the sensor. Electrical transport properties of the composites were also studied to understand the quality of the established CNT network. Out of the other functionalization technique, Diels Alder cyclo addition reaction based composite sensor was found to exhibit excellent performance and has an edge over the other reported CNT based sensor.