Resistive Type Sensor for Humidity and Short Alcohols Detection (original) (raw)
Related papers
Thin Solid Films, 2004
The responses of resistive-type sensors based on two poly(monosubstituted)acetylenes, namely poly(N,N-dimethylpropargylamine) (Pd-PDMPA) and poly(propargylalcohol) (PPOH), to relative humidity (r.h.%) and to alcohol vapors were investigated. The polymeric materials Pd-PDMPA and PPOH were doped with HCl or with SnCl2 and I2, respectively. HCl-doped Pd-PDMPA exhibited detectable response to r.h. percentages as low as 2% and a variation of five orders of magnitude in the r.h. range 0–90%. PPOH doped with SnCl2 or I2 varied its conductivity of about four orders of magnitude in the full range of r.h. Both doped polymers showed sensitivity to methanol. A morphological characterization was carried out in order to correlate the differences in the electrical behavior.
Electrical and morphological characterisation of new π-conjugated polymer films as gas sensors
Materials Science and Engineering: C, 1998
The role of polymer films in sensor applications received recently an increasing deal of attention. In the framework of polymer film-based sensors, a considerable part of scientific interest has been devoted to humidity sensors. New π-conjugated systems have been investigated and results of the studies on poly(propargyl-alcohol) [PPOH] and poly(N,N-dimethylpropargylamine) [Pd-PDMPA] are here reported. SnCl2-PPOH and I2-PPOH show an electrical response towards relative humidity (r.h.) in the range 0–90%. The electrical response to r.h. variations of the HCl doped polymer (HCl-Pd-PDMPA) has been studied. Morphological characterisation was performed by Atomic Force Microscopy (AFM) and Scanning Tunneling Microscopy (STM) techniques on both the two polymeric systems in order to study: (a) the surface morphological variation during the chain growth, testing samples produced at different polymerisation reaction times (AFM) and (b) doped samples in order to estimate the influence of different dopants and different doping exposure times (STM and AFM).
Thin films of iodine—polyphenylacetylene as starting materials for humidity sensors
Sensors and Actuators B-chemical, 1992
A humidity sensor has been fabricated by using thin films of iodine-doped polyphenylacetylene. The electrical response of the sensor towards relative humidity variations is fast and reversible during long working periods. The investigated sensor is also sensitive to the vapours of other chemical substances.
Highly ethynylated polymers: synthesis and applications for humidity sensors
Sensors and Actuators B-chemical, 2001
The response of two novel ethynylated polymers, poly[1,4-diethynyl-2,5-bis(butyloxy)benzene] (PEBB) and poly[1,4-diethynyl-2,5-bis(octyloxy)benzene (PEOB) to relative humidity (% RH) and alcohols has been investigated. The polymers have been deposited as thin-film membranes on resistive-type devices. PEBB shows a good sensitivity to RH (%) variations in the full range (0–90%), while PEOB is less affected by moisture. Both polymers give a relevant current intensity variation (5 magnitude orders) when exposed to methanol vapours and no response to alcohols with longer alkylic chain was observed. These results suggest that the selectivity of polyynes to hydroxilated molecules can be modulated by the chemical structure, that is in this case by the length of the alkoxy substituents of the benzene moiety in the polymer chain.
Iodine-doped polyphenylacetylene thin film as a humidity sensor
Sensors and Actuators B-chemical, 1992
Thin films of iodine-doped polyphenylacetylene (PPA) have been investigated and used as humidity sensors. Measurements of resistance variations of a PPA/I2 system, induced by relative humidity variations ranging from 10 to 90%, have been performed at constant temperatures (25 and 30 °C). The behaviour of the resistance versus relative humidity is found to be approximately exponential. Our samples show a good reversibility during humidity cycles and a relatively fast response time (a few seconds).
Electrical and Morphological Characterization of New -Conjugated Polymers Films as Gas Sensors
Materials Science and Engineering C
The role of polymer films in sensor applications received recently an increasing deal of attention. In the framework of polymer film-based sensors, a considerable part of scientific interest has been devoted to humidity sensors. New 7r-conjugated systems have been investigated and results of the studies on poly(propargyI-alcohol) [PPOH] and poly(N,N-dimethylpropargylamine) [Pd-PDMPA] are here reported. SnC12-PPOH and I2-PPOH show an electrical response towards relative humidity (r.h.) in the range 0-90%. The electrical response to r.h. variations of the HCI doped polymer (HCI-Pd-PDMPA) has been studied. Morphological characterisation was performed by Atomic Force Microscopy (AFM) and Scanning Tunneling Microscopy (STM) techniques on both the two polymeric systems in order to study: (a) the surface morphological variation during the chain growth, testing samples produced at different polymerisation reaction times (AFM) and (b) doped samples in order to estimate the influence of different dopants and different doping exposure times (STM and AFM).
Conducting Polymer-Based Chemiresistive Sensor for Organic Vapours
Macromolecular Symposia, 2005
Poly(2-bromo-5-hexyloxy-p-phenylenevinylene), BHPPV, was electrochemically synthesized in 81% yield. The polymer presented high solubility in organic solvents, in spite of its relatively high molar weight (M w ¼ 80 000), and showed to be thermally resistant up to 130 8C. Gas sensors made from thin films of CSA doped BHPPV, deposited on interdigitated electrodes, responded to five different solvents. Plots of relative response versus relative recovery showed good discrimination of the five solvents.
Materials Science and Engineering B-advanced Functional Solid-state Materials, 1996
The sensitivity to relative humidity of a sensor based on I2-doped polyphenylacetylene thin film membranes has been investigated. The sensor geometry allows its application in miniature devices. The response to humidity variations (20%–80%) is fast and reproducible for long times (months).The I/V characteristics suggest that ionic type conductivity is prevailing. Current intensity measurements performed on films of different thicknesses show that surface conductivity is mainly responsible for the sensor's electrical response.
Synthesis and characterization of polymer based humidity sensor
INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE “TECHNOLOGY IN AGRICULTURE, ENERGY AND ECOLOGY” (TAEE2022)
The Humidity Polymer sensors are of great interest for the scientific communities depending on their properties and applications such as alarm clocks, smart watches and flexible wearable electronic devices. In this paper, humidity sensors have been prepared using mixture of poly (vinyl alcohol) (PVA), poly (4-styrenesulfonic acid) (PSSA) and silver nitrate (AgNO3) using solvent casting method. The ratio of PVA/PSSA is kept constant and different concentrations of AgNO3 is mixed with it. Variations in the properties was analyzed using the impedance analyser and humidity analyser was used to analyse the relative humidity. The relative humidity was measured in range of (68% to 21%) at temperature range of (25 °C to 65°C). This paper concludes that on addition of 0.6gm of AgNO3 , best results of dielectric properties and the conductivity was seen. Relevant parameter like conductivity of the membranes and relative humidity was highly affected by AgNO3 content. Incresase in conductivity of membrane was observed at low frequency and after 10 4 Hz it start decreasing as frequency increases. Highest dielectric constant of the membrane increased from 10 4 to 10 7. Decrease in relative humidity was observed with increase in temperature.