Bogdan Chachulski

Properties of a polyethyleneimine-based sensor for measuring medium and high relative humidity

In this paper a method of preparing polyethyleneimine films, which improves the water resistance of polymer humidity sensors, is proposed. The polyethyleneimine was cross-linked at elevated temperature using 1,4-butanediol diglycidyl ether, both being dissolved in dimethylsulfoxide. The optimum composition of polymer and optimum reaction temperature were obtained. Resistive-type sensors have been prepared by dip coating. The sensor preserves excellent durability in high humidities or even after immersion in water. The electrical properties of the sensors were investigated by impedance spectroscopy.

Properties of a lithium solid electrolyte gas sensor based on reaction kinetics

Principle of operation, construction and properties of a gas sensor based on lithium ion-conductor solid electrolyte (Lisicon) are presented. The sensor has been prepared using thick film technology. Its working principle is based on electric current acquisition, while a voltage ramp is applied to the sensor. The current–voltage plot has a unique shape, which depends on the surrounding gas type and its concentration. Results of measurements conducted in mixtures of high purity gases—nitrogen dioxide, sulfur dioxide, carbon dioxide and synthetic air of controlled concentration—over a wide range of temperatures are presented and discussed.

The influence of the choice of the cross-linking agent on the electrical properties of polyethyleneimine-based humidity sensors

The results of impedance measurements of thin film polymer humidity sensors are presented in this paper. The sensors were made of chemically modified polyethyleneimine, spread on alumina substrate with comb type gold electrodes. Electrical properties of the sensors are strongly dependent on relative humidity (RH). The influence of the selected cross-linking agents on the properties, measuring range, and technology of preparation of the sensors is discussed.

Electrical properties of polymer humidity sensor based on polyethyleneimine

In the paper the amperometric properties of polymer humidity sensor based on polythyleneimine are presented. Usually properties of this sensor are examined by means of impedance spectroscopy. The new approach is proposed. It is shown that the current flow in the investigated sensor is a result of the electrode reaction at the anode. The quasi-static diffusion current is a linear function (in the log-lin scale) of relative humidity, so this sensor can be used as an amperometric. An equivalent circuit, containing the elements representing diffusion effect, has been proposed. The shape of impedance plots show diffusion related process.

Electrocatalytic nitrogen dioxide sensor

Construction and properties of electrocatalytic gas sensor based on samarium-doped ceria solid electrolyte are described. Electrocatalytic sensors form a new group of gas sensor, which employ kinetics of controlled chemical reaction. Measurements in mixtures of synthetic air and nitrogen dioxide are shown. Current-voltage response has unique shape, which depends on NO2 concentration. Influence of voltage sweep rate and temperature on sensor characteristics is reported. The constructed sensor can be used for nitrogen dioxide monitoring.

Investigations of a new humidity sensor with polymer film

Results of impedance measurements of humidity sensors with epoxy resins containig quarternary ammonium salts are presented in this paper. The humidity sensitive membranes were prepared from polyethyleneimine (PEI). PEI was cross-linked using 1,4-butanediol diglycidyl ether (BDDGE) and glycidyl trimethyl ammonium chloride (GTMAC) was added as a humidity sensitive epoxy monomer.

Computer simulation of current voltage response of electrocatalytic sensor

In the present paper, results of computer simulation of cyclic voltammetry applied to electrocatalytic solid state sensor are presented. The computer software developed by D.Gosser is based on explicit finite difference method. The software is devoted for the simulation of cyclic voltammetry experiments in liquid electrochemistry. However the software is based on general electrochemical rules and may be used for simulation of experiments in solid state electrochemistry. The electrocatalytic sensor does not have a reference electrode and therefore it is necessary to employ virtual reference electrode into the model of the sensor. Data obtained from simulation are similar to measurement one what confirms correctness of assumed sensing mechanism.

Preparation and properties of nanoporous alumina-based humidity sensors

In this paper preparation method of nano-porous alumina based humidity sensors is presented. Investigation of relation between technological process parameters, sensors porous layer structure and electric parameters is main aim of this study. Surface morphology was investigated by scanning electron microscopy. Impedance spectroscopy was used to identify electrical parameters of the sensor.

Investigation of solid polymer electrolyte gas sensor with different electrochemical techniques

In this work solid polymer electrolyte (SPE) amperometric sulphur dioxide sensor is investigated. Nafion was used as a membrane electrode and 1M sulphuric acid as an internal electrolyte. Sensor response to sulphur dioxide was measured. Besides traditional constant voltage amperometry also different electrochemical techniques were used. Results obtained by these methods are compared.

Properties of humidity sensors with porous Al2O3 as a dielectric layer

The effect of humidity influence on characteristics of a ceramic sensor with a porous dielectric Al2O3 layer is presented. Influence of chosen electrolytic process parameters on electrical properties of the sensor is shown. The experimental data of two groups of sensors are interpreted using two, known from literature, electric equivalent circuits.