scholarly journals Method to Study Water Diffusion into Polymers

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 812
Author(s):  
Jamila Boudaden ◽  
Matthias Steinmaßl ◽  
Hanns-Erik Endres ◽  
Peter Müller-Buschbaum
Keyword(s):  
Chemical Sensors ◽  
Room Temperature ◽  
Diffusion Processes ◽  
Low Cost ◽  
Capacitive Sensor ◽  
Gas Diffusion ◽  
Water Molecules ◽  
Capacitance Change ◽  
Simple Method ◽  
Sensing Material

We designed and realized a low cost relative humidity (RH) capacitive sensor having an interdigitated transducer coated with a cheap sensing material working at room temperature (polyimide). Thermally perturbed diffusion of water molecules into the polyimide layer is studied by heating the sensor locally and measuring the sensor capacitance change. The swelling and deswelling model is applied to determine the time constant of involved processes. This simple method, using an evaluation kit developed by our group, to measure the sensor capacitance and to study the diffusion process of water molecules into polyimide could be generalized to analyze the gas diffusion processes into polymer based sensing layer generally used in the field of gas chemical sensors.

A New Simple Method for Fabrication of Fine Metal Patterns

2000 ◽  
Vol 636 ◽  
Author(s):  
Yasuyuki Hotta ◽  
Koji Asakawa ◽  
Shigeru Matake ◽  
Toshiro Hiraoka
Keyword(s):  
Room Temperature ◽  
Low Cost ◽  
New Method ◽  
Processing Temperature ◽  
Electroless Copper Plating ◽  
Simple Method ◽  
Ion Exchange Reaction ◽  
Micrometer Scale ◽  
Line Patterns ◽  
Hydrophobic Patterns

AbstractWe developed a new method for easy fabrication of micrometer-scale fine metal patterns on substrates. The patterns can be fabricated at low cost, at low processing temperature, and on uneven substrates as well as on plane surfaces. The method involves, first, forming hydrophilic and hydrophobic patterns on the substrates, and, second, depositing metal by electroless plating on the hydrophilic area. Hydrophilic and hydrophobic patterns were formed on a sensitizer containing naphthoquinonediazide (NQD) units coated on the substrates by the exposure. In the exposed areas, metal particles that are catalysts for electroless copper plating were adsorbed in the ion-exchange reaction and then the reduction treatment was performed. Copper was selectively deposited by the self-catalyst mechanism, according to the exposed patterns. All experimental processes can be carried out at room temperature. Using this new method, copper line patterns of 25 μm and copper dot patterns of 15 μm diameter were fabricated on the substrate.

scholarly journals A Highly Sensitive FET-Type Humidity Sensor with Inkjet-Printed Pt-In2O3 Nanoparticles at Room Temperature

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Meile Wu ◽  
Zhanyu Wu ◽  
Xiaoshi Jin ◽  
Jong-Ho Lee
Keyword(s):  
Room Temperature ◽  
Humidity Sensor ◽  
Fast Response ◽  
Water Molecules ◽  
Potential Candidate ◽  
Baseline Drift ◽  
Sensing Material ◽  
Adsorption Processes ◽  
Depth Study ◽  
The Difference

Abstract In this work, Pt-doped In2O3 nanoparticles (Pt-In2O3) were inkjet printed on a FET-type sensor platform that has a floating gate horizontally aligned with a control gate for humidity detection at room temperature. The relative humidity (RH)-sensing behavior of the FET-type sensor was investigated in a range from 3.3 (dry air in the work) to about 18%. A pulsed measurement method was applied to the transient RH-sensing tests of the FET-type sensor to suppress sensor baseline drift. An inkjet-printed Pt-In2O3 resistive-type sensor was also fabricated on the same wafer for comparison, and it showed no response to low RH levels (below 18%). In contrast, the FET-type sensor presented excellent low humidity sensitivity and fast response (32% of response and 58 s of response time for 18% RH) as it is able to detect the work-function changes of the sensing material induced by the physisorption of water molecules. The sensing mechanism of the FET-type sensor and the principle behind the difference in sensing performance between two types of sensors were explained through the analysis on the adsorption processes of water molecules and energy band diagrams. This research is very useful for the in-depth study of the humidity-sensing behaviors of Pt-In2O3, and the proposed FET-type humidity sensor could be a potential candidate in the field of real-time gas detection.

scholarly journals A Room-Temperature CNT/Fe3O4 Based Passive Wireless Gas Sensor

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3542 ◽  
Author(s):  
Tao Guo ◽  
Tianhao Zhou ◽  
Qiulin Tan ◽  
Qianqian Guo ◽  
Fengxiang Lu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
Fast Response ◽  
Sensing Material ◽  
Recovery Times ◽  
Response And Recovery ◽  
Good Repeatability

A carbon nanotube/Fe3O4 thin film-based wireless passive gas sensor with better performance is proposed. The sensitive test mechanism of LC (Inductance and capacitance resonant) wireless sensors is analyzed and the reason for choosing Fe3O4 as a gas sensing material is explained. The design and fabrication process of the sensor and the testing method are introduced. Experimental results reveal that the proposed carbon nanotube (CNT)/Fe3O4 based sensor performs well on sensing ammonia (NH3) at room temperature. The sensor exhibits not only an excellent response, good selectivity, and fast response and recovery times at room temperature, but is also characterized by good repeatability and low cost. The results for the wireless gas sensor’s performance for different NH3 gas concentrations are presented. The developed device is promising for the establishment of wireless gas sensors in harsh environments.

scholarly journals Hexanal Gas Detection Using Chitosan Biopolymer as Sensing Material at Room Temperature

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Devi Shantini ◽  
Irwana Nainggolan ◽  
Tulus Ikhsan Nasution ◽  
Mohd Nazree Derman ◽  
Roshida Mustaffa ◽  
...  
Keyword(s):  
Dairy Products ◽  
Room Temperature ◽  
Gas Sensing ◽  
Low Cost ◽  
Chitosan Film ◽  
Gas Detection ◽  
Film Sensor ◽  
Sensing Material ◽  
Good Repeatability ◽  
Chitosan Biopolymer

Hexanal was identified as one of the major volatile gases which are produced in degraded dairy products and wood industries. Therefore, preliminary study on hexanal gas detection with the laboratory scale was carried out in this paper. Electrical testing with chitosan as a sensing material to sense hexanal gas in low concentration was carried out at room temperature. Chitosan sensor was fabricated by using electrochemical deposition technique to form active sensing layer. The response of the chitosan film sensor (CFS) towards hexanal was tested via electrical testing by exposing different hexanal concentrations ranging between 20 ppm, 100 ppm, 200 ppm, and 300 ppm using air as a carrier gas. Sensing properties of the CFS toward hexanal exposure including responsibility, recovery, repeatability, stability, and selectively were studied. Overall, our result suggested that hexanal sensor based on chitosan was able to perform well at room temperature demonstrated by good response, good recovery, good repeatability, good stability, and good selectively. This simple and low cost sensor has high potential to be utilized in early quality degradation detection in dairy products and can be used to monitor the level of hexanal exposure in wood industries.

Graphene Modified Molecular Imprinting Electrochemical Sensor for Determining the Content of Dopamine

2019 ◽  
Vol 15 (6) ◽  
pp. 628-634
Author(s):  
Rong Liu ◽  
Jie Li ◽  
Tongsheng Zhong ◽  
Liping Long
Keyword(s):  
Electrochemical Sensor ◽  
Molecular Imprinting ◽  
Neurological Disorders ◽  
Room Temperature ◽  
Low Cost ◽  
Differential Pulse ◽  
Current Response ◽  
Specific Selectivity ◽  
Pulse Voltammetry

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.

Single–atom manganese and nitrogen co-doped graphene as low-cost catalysts for the efficient CO oxidation at room temperature

2021 ◽  
Vol 536 ◽  
pp. 147809
Author(s):  
Mingming Luo ◽  
Zhao Liang ◽  
Chao Liu ◽  
Xiaopeng Qi ◽  
Mingwei Chen ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Room Temperature ◽  
Low Cost ◽  
Single Atom ◽  
Doped Graphene ◽  
Co Doped

scholarly journals Synthesis and characterization of a new ZIF-67@MgAl2O4 nanocomposite and its adsorption behaviour

RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13245-13255
Author(s):  
Mehdi Davoodi ◽  
Fatemeh Davar ◽  
Mohammad R. Rezayat ◽  
Mohammad T. Jafari ◽  
Mehdi Bazarganipour ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnesium Aluminate ◽  
Synthesis And Characterization ◽  
Magnesium Aluminate Spinel ◽  
Adsorption Behaviour ◽  
Zeolitic Imidazolate Framework ◽  
Simple Method

New nanocomposite of zeolitic imidazolate framework-67@magnesium aluminate spinel (ZIF-67@MgAl2O4) has been fabricated by a simple method at room temperature with different weight ratios.

A simple method to construct a low-cost immunosensor based on a dithiol-functionalized polydopamine platform

2021 ◽  
Author(s):  
Bo Liu ◽  
Luanying Yang ◽  
Gang Wang ◽  
Sha He ◽  
Xiaobo Wang ◽  
...  
Keyword(s):  
Detection Limit ◽  
Linear Response ◽  
Low Cost ◽  
Covalent Immobilization ◽  
The Self ◽  
Simple Method ◽  
Low Detection Limit

A simple and low-cost electrochemical CEA immunosensor was investigated via the self-polymerization of dopamine and a dithiol compound spacer for the covalent immobilization of antibodies. The designed CEA immunosensor exhibited a linear response and a low detection limit.

scholarly journals EPR Spectra of Sintered Cd1−xCrxTe Powdered Crystals with Various Cr Content

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3449
Author(s):  
Ireneusz Stefaniuk ◽  
Werner Obermayr ◽  
Volodymyr D. Popovych ◽  
Bogumił Cieniek ◽  
Iwona Rogalska
Keyword(s):  
Curie Temperature ◽  
Room Temperature ◽  
Integral Intensity ◽  
Resonance Field ◽  
Epr Spectra ◽  
Paramagnetic Resonance ◽  
Simple Method ◽  
Paramagnetic Curie Temperature ◽  
Cr Content ◽  
Electron Paramagnetic

In this paper, we show a simple method of producing ferromagnetic materials with a Curie temperature above room temperature. The electron paramagnetic resonance (EPR) spectra of Cd1−xCrxTe (0.002 < x < 0.08) were measured with a dependence on temperature (82 K < T < 381 K). Obtained EPR lines were fitted to a Lorentz-shaped curve. The temperature dependencies of the parameters of the EPR lines, such as the peak-to-peak linewidth (Hpp), the intensity (A), as well as the resonance field (Hr), were studied. Ferromagnetism was noticed in samples at high temperatures (near room temperature). For a sample with a nominal concentration of chrome of x = 0.05, a very strong intrinsic magnetic field is observed. The value of the effective gyromagnetic factor for this sample is ge = 30 at T = 240 K. An increase of chrome concentration above x = 0.05 reduces the ferromagnetic properties considerably. Analysis of the temperature dependencies of the integral intensity of EPR spectra was carried out using the Curie–Weiss law and the paramagnetic Curie temperature was obtained.

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