Room temperature gas multisensor system based on a novel polymer nanocomposite material (original) (raw)
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Gas sensing properties of conductive polymer nanocomposites
Nanocomposites consisted of carbon nanotubes (CNT) dispersed in various polymer matrices were prepared for the investigation of their sensing properties. The results from morphology study and electrical/dielectric characterization showed good dispersion of the filler with low percolation threshold. The response to water and ethanol vapour, at different concentration, was also studied showing better response for the more hydrophilic polymers and those with glass transition temperature below room temperature.
Conductive Polymer-Composite Sensor for Gas Detection
Conductive polymers with carbon black filler were prepared for gas sensor application utilising ultrasonic mixing. The composite sensors were exposed to different types of gases and the resulting changes in the resistivity were recorded. The effects of ultrasonic mixing and sensitivity of the composite sensor to various organic gases were examined.
“Nanocomposite based flexible ultrasensitive resistive gas sensor for chemical reactions studies”.
Nature Scientific Reports, 2013
Room temperature operation, low detection limit and fast response time are highly desirable for a wide range of gas sensing applications. However, the available gas sensors suffer mainly from high temperature operation or external stimulation for response/recovery. Here, we report an ultrasensitive-flexiblesilver-nanoparticle based nanocomposite resistive sensor for ammonia detection and established the sensing mechanism. We show that the nanocomposite can detect ammonia as low as 500 parts-per-trillion at room temperature in a minute time. Furthermore, the evolution of ammonia from different chemical reactions has been demonstrated using the nanocomposite sensor as an example. Our results demonstrate the proof-of-concept for the new detector to be used in several applications including homeland security, environmental pollution and leak detection in research laboratories and many others.
Nanofibrous PANI-based conductive polymers for trace gas analysis
Thin Solid Films
Electrospun nanofibres have been confirmed to be very good candidates for ultra-sensitive gas sensors since they greatly improve surface area to volume ratios of coatings, which in turn affect two additional and crucial features for sensors: high sensitivity and fast response time. Electrospinning is a simple method for the deposition of long (up to several centimetres) nanofibres, aligned or non-woven, directly onto suitable transducers. Such a structured layer may have better properties than a compact film, providing faster adsorption and minimising some bulk effects (i.e. long diffusion–desorption time, analyte entrapment, etc.). Electrospun conductive polymers (CPs) have been specifically investigated for developing smart sensors whose electrical properties change upon interactions with the analytes. Polyaniline is one of the most interesting CPs for gas sensing, because of its conductive features, when doped, as well as its thermal stability and sensing performance. The sensing mechanisms are different, depending on the nature of both PANi and the targeting analytes. Thus, various blends of polyaniline and insulating host polymers have been planned, prepared, deposited and studied to optimise the properties of sensors consequent to the combination of the electrical conductivity of CP and of the physical properties of the host polymer. Host polymer carriers cause great modifications to the topology of the interacting surface (diameter and length of the fibres, roughness, porosity, presence of beads and grains, non-woven framework and branched junctions, adhesion, etc.), in addition to the different affinity to the analytes tested. However, they enable electrodes to function over a wider dynamic range of gas or vapour concentrations. The polymer features have been also characterised over a range of water vapour concentrations and temperatures.
Progress in Solid State Chemistry, 2005
This paper investigates the use of NiO particles to enhance the vapour sensing properties of polyethylene adipate (PEA)\carbon black (CB) composite materials. Four PEA\CB suspensions were prepared with 0, 10, 20 and 30 w/w% NiO, respectively. Hypermer PS3 surfactant was shear mixed into each of the suspensions for 300 s to achieve a homogenous dispersion and to prevent reagglommeration of both the CB and NiO particles. A 0.1 ml drop of each composite was deposited between Cu electrodes on a printed circuit board (PCB) substrate using a microlitre syringe. The samples were allowed to dry for 24 h in an oven at 333 K to remove any remaining solvent. After preparation, the sensors were exposed to propanol and butanol at concentrations ranging from 0 to 25 000 ppm in steps of 5000 ppm. The response of the PEA\CB sensors improved significantly as the concentration of NiO particles in the material increased and maximum relative differential responses as high as 37% and 92.8% were recorded after exposure to 25 000 ppm propanol and butanol, respectively. This high response can be explained using the FloryeHuggins interaction parameter along with structural changes in the polymer composite caused by the addition of NiO. This paper concludes that NiO particles can be used as a method to increase the sensitivity of existing conducting polymer composite gas sensing materials.
Crystals
Among nanocomposite materials, multifunctional polymer nanocomposites have prompted important innovations in the field of sensing technology. Polymer-based nanocomposites have been successfully utilized to design high-tech sensors. Thus, conductive, thermoplast, or elastomeric, as well as natural polymers have been applied. Carbon nanoparticles as well as inorganic nanoparticles, such as metal nanoparticles or metal oxides, have reinforced polymer matrices for sensor fabrication. The sensing features and performances rely on the interactions between the nanocomposites and analytes like gases, ions, chemicals, biological species, and others. The multifunctional nanocomposite-derived sensors possess superior durability, electrical conductivity, sensitivity, selectivity, and responsiveness, compared with neat polymers and other nanomaterials. Due to the importance of polymeric nanocomposite for sensors, this novel overview has been expanded, focusing on nanocomposites based on conducti...
Gas Sensors Based on Conducting Polymers
The gas sensors fabricated by using conducting polymers such as polyaniline (PAni), polypyrrole (PPy) and poly (3,4-ethylenedioxythiophene) (PEDOT) as the active layers have been reviewed. This review discusses the sensing mechanism and configurations of the sensors. The factors that affect the performances of the gas sensors are also addressed. The disadvantages of the sensors and a brief prospect in this research field are discussed at the end of the review.
Conducting polymer composites: novel materials for gas sensing
Sensors and Actuators B: Chemical, 2001
A polypyrrole (PPy)-based conducting composite was prepared by electropolymerising pyrrole within crosslinked matrix of poly(vinyl alcohol) (PVA). It was obtained in the form of coherent ®lm and was characterised with respect to different electrical properties. The composite was found to possess signi®cant NH 3 sensing capacity; results of some preliminary investigations regarding the NH 3 sensing is reported here.
Development of Conductive Nanocomposite Sensors for Anticipated Diagnostic of Diseases
2014
The analysis of specific VOC in exhaled breath (identified as biomarkers of specific disease like cancer)give an idea of metabolic and physiological activities of an individual and can provide non-invasive andpotentially inexpensive anticipated diagnosis of several diseases including cancer. The invention of afast, reliable, economic and portable technique is highly required before breath testing become a clinicalreality. Nanomaterial based sensor arrays can fulfill all these requirements and can form a solidfoundation for identification of disease related VOC patterns in exhaled breath. The objective of thisthesis was to fabricate different chemo-resistive sensors based on conductive nanocomposites withability to differentiate and discriminate a set of disease (such as lung cancer) biomarker VOC. Thereforein order to fabricate high performance sensors with high sensitivity and required selectivity towardstargeted VOC, adoption of different methodologies for the synthesis of conduct...