Resistivity measurements of carbon–polymer composites in chemical sensors: impact of carbon concentration and geometry

Hua, Lei; Pitt, William G.; McGrath, Lucas K.; Ho, Clifford K.

doi:10.1016/j.snb.2004.02.042

Cited by 40 publications

(26 citation statements)

References 32 publications

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“…The sensors and other materials (polyisobutylene, carbon black and trichloroethylene) were the same as those described in our previous work [16].…”

Section: Methodsmentioning

confidence: 99%

“…Thus, this is a fairly good model with which to simulate the current flow in the sensor. The details of this resistivity model have been published [16].…”

Section: Conductivity Modelmentioning

confidence: 99%

“…In the second step, as in our previous work, the GEM equation was used to relate the resistivity to the concentration of the various components in the composite [8,16]. This equation was developed by combining effective media theory and percolation theory, and can be applied to the entire range of carbon black content [17][18][19].…”

Section: Conductivity Modelmentioning

confidence: 99%

“…In our previous work, we proposed that an individual carbon-black/polymer composite sensor can be modeled by combining two sub-models: a conductivity model and a thermodynamic model [16]. The conductivity model was well described; the geometry of the sensor was modeled and analyzed.…”

Section: Introductionmentioning

confidence: 99%

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Modeling carbon black/polymer composite sensors

Hua

Pitt

McGrath

et al. 2007

Sensors and Actuators B: Chemical

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Conductive polymer composite sensors have shown great potential in identifying gaseous analytes. To more thoroughly understand the physical and chemical mechanisms of this type of sensor, a mathematical model was developed by combining two sub-models: a conductivity model and a thermodynamic model, which gives a relationship between the vapor concentration of analyte(s) and the change of the sensor signals. In this work, 64 chemiresistors representing eight different carbon concentrations (8-60 vol% carbon) were constructed by depositing thin films of a carbon-black/polyisobutylene composite onto concentric spiral platinum electrodes on a silicon chip. The responses of the sensors were measured in dry air and at various vapor pressures of toluene and trichloroethylene. Three parameters in the conductivity model were determined by fitting the experimental data. It was shown that by applying this model, the sensor responses can be adequately predicted for given vapor pressures; furthermore the analyte vapor concentrations can be estimated based on the sensor responses. This model will guide the improvement of the design and fabrication of conductive polymer composite sensors for detecting and identifying mixtures of organic vapors.

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“…The sensors and other materials (polyisobutylene, carbon black and trichloroethylene) were the same as those described in our previous work [16].…”

Section: Methodsmentioning

confidence: 99%

“…Thus, this is a fairly good model with which to simulate the current flow in the sensor. The details of this resistivity model have been published [16].…”

Section: Conductivity Modelmentioning

confidence: 99%

Section: Conductivity Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modeling carbon black/polymer composite sensors

Hua

Pitt

McGrath

et al. 2007

Sensors and Actuators B: Chemical

Self Cite

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“…11 Where formulation studies have been carried out, these focused on the influence of the carbon/graphite relative proportions, 12 the carbon/graphite physical and electrical characteristics, 13,14 and the proportion of conductive material required for charge percolation through the cured film. 15 A variety of binder systems are compatible with carbon/graphite materials, such as epoxy resins, alkyd resins, acrylic resins, polyurethane resins, or phenolic resins, and the choice is generally governed by the curing temperature, substrate which is being printed, film flexibility, and the resin compatibility with the final application. The choice of binder/binders is usually proprietary information held by manufacturers.…”

Section: Introductionmentioning

confidence: 99%

The impact of solvent characteristics on performance and process stability of printed carbon resistive materials

2016

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Carbon conductive pastes deposited by screen printing are used in many commercial applications including sensors, PCB, batteries, and PV, and as such represent an important value-added coating. An experimental investigation was carried out into the role of the solvent on the drying characteristics, conductivity, and process consistency in screen printed carbon pastes. Four materials with solvent boiling points between 166 and 219°C were deposited at film thickness between 6 and 16 lm, and the sheet resistance and film thickness were measured after successive passes through an industrial dryer operating with an air temperature of 155°C. Sheet resistances of 14 X/sq. were obtained with the thicker films while thinner films produced a sheet resistance of 46 X/sq. Thinner films achieved a stable resistivity within a 2.5-min residence time, while the thicker films required a residence time in excess of 12.5 min to achieve a stable resistivity. As well as prolonging drying times, the higher boiling point increased the resistivity of the cured film. It is postulated that the lower resistance of the faster drying materials is a result of film stressing increasing inter particle contact. Process models indicate that multiple thin layers are a more efficient means of manufacture for the process parameters examined.

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Field‐Structured Chemiresistors

Read

Martin

2010

Adv Funct Materials

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A significantly improved material is developed for application to chemiresistors, which are resistance‐based sensors for volatile organic compounds. This material is a polymer composite containing Au‐coated magnetic particles organized into electrically conducting pathways by magnetic fields. This improved material overcomes the various problems inherent to conventional carbon‐black chemiresistors, while achieving an unprecedented response magnitude. When exposed to chemical vapors, the polymer swells only slightly, yet this is amplified into large, reversible resistance changes, as much as (1 × 1011)% at a swelling of only 1.5%. These conductor–insulator transitions occur over such a narrow range of analyte vapor concentration that these devices can be described as chemical switches. The sensitivity and response range of these sensors can be tailored over a wide range by controlling the stress within the composite, including through the application of a magnetic field. Such tailorable sensors can be used to create sensor arrays that can accurately determine analyte concentration over a broad concentration range, or can be used to create logic circuits that signal a particular chemical environment.

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Resistivity measurements of carbon–polymer composites in chemical sensors: impact of carbon concentration and geometry

Cited by 40 publications

References 32 publications

Modeling carbon black/polymer composite sensors

Modeling carbon black/polymer composite sensors

The impact of solvent characteristics on performance and process stability of printed carbon resistive materials

Field‐Structured Chemiresistors

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