• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.483-486
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• 2000

In the recognition of the gases using the quartz crystal rnicrobalance (QCM) coated with the film materials, it is important to obtain the recognition ability of gases, and the stability of film coated above the QCM. Especially, the thickness of film coated above the QCM is decreased according with the using circumstance and time of QCM gas sensor. Therefore, the sensing chararcteristics of film is changed with these. In this paper, we coated the lipid GC materials varing with the blended amount of PVC(Po1y Vinyl Chloride) and solution (Tetra Hydrofan:THF) above QCM to obtain the stability of lipid PC film. QCM gas sensors coated with film materials were measured the frequency change in the chamber of stationary gas sensing system injected 1-hexane, ethyl acetate, ethanol and benzene of 20.4 respectively. Also, we measured the degradation characteristics of QCM gas sensor to show the properties of stability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.176-179
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• 2000

In the recognition of the gases using the quartz crystal microbalance (QCM) coated with the film materials, it is important to obtain the recognition ability of gases, and the stability of film coated above the QCM. Especially, the thickness of film coated above the QCM is decreased according with the using circumstance and time of QCM gas sensor. Therefore, the sensing chararcteristics of film is changed with these. In this paper, we coated the lipid PC (Phosphatidyl Choline) materials varing with the blended amount of PVC(Poly Vinyl Chloride) and solution (Tetra Hydrofan:THF) above QCM to obtain the stability of lipid PC film. QCM gas sensors coated with film materials were measured the frequency change in the chamber of stationary gas sensing system injected 1-hexane, ethyl acetate, ethanol and benzene of $20{\mu}{\ell}$, respectively. We obtained the principal component analysis (PCA) from the frequency change due to the absorption of gas. Also, we measured the degradation characteristics of QCM gas sensor to show the properties of stability.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.5
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• pp.221-226
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• 2010

Quartz crystal microbalance (QCM) gas sensor to detect methyl mercaptan ($CH_3SH$) gas was fabricated by depositing $TiO_2$ nanoparticles and polyelectrolyte on the electrode of QCM. The $TiO_2$/poly(sodium 4-styrenesulfonate) (PSS) thin film fabricated by a layer-by-layer self-assembly (LBL-SA) method showed a high surface area and increased the sensitivity of gas sensor. When the QCM sensors coated with triethanolamine (TEA) or ($TiO_2$/PSS) were exposed to methyl mercaptan gas (1.0 ppm), the frequency shifts of QCM with TEA casting film and $TiO_2$/PSS thin film were ca. 9 Hz and ca. 24 Hz, respectively. As the bilayer number of ($TiO_2$/PSS) increased, the frequency shift of QCM sensor with ($TiO_2$/PSS) thin film was gradually increased. In addition, the frequency shift of QCM sensor was gradually increased as the concentration of methyl mercaptan gas increased from 0.5 ppm to 2.0 ppm. In this study, the surface morphology and sensor property of QCM sensor coated with ($TiO_2$/PSS) thin film were measured.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05c
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• pp.218-222
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• 2002

In the recognition of the gases using the quartz crystal microbalance (QCM) coated with the PEG film materials, it is important to obtain the recognition ability of gases, and the stability of PEG film coated above the QCM. Especially, the thickness of PEG film coated above the QCM is decreased according with the using circumstance and time of QCM gas sensor. Therefore, the sensing characteristics of PEG film is changed with these. In this paper, we coated the PEG materials varing with the blended amount of PVC(Poly Vinyl Chloride) and chloroform above QCM to obtain the sensitive and the stability of PEG film. We measured the degradation characteristics of QCM gas sensor in the ethyle acetate 50[%] concentration to show the properties of stability.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.147-153
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• 2023

Metal-organic frameworks (MOFs) of cobalt gallate were synthesized and deposited on gold electrodes using self-assembly monolayers (SAMs) and hydrothermal processing. These MOF films exhibit strong adsorption capabilities for gaseous particulates, and the use of SAMs allows the synthesis and deposition processes to be completed in a single step. When cobalt gallate is mixed with SAMs, a coordination bond is formed between the cobalt ion and the carboxylate or hydroxyl groups of the SAMs, particularly under hydrothermal conditions. Additionally, the quartz crystal microbalance (QCM) gas sensor accurately measures the number of particulates adsorbed on the MOF films in real-time. Thus, the QCM gas sensor is a valuable tool for quantitatively measuring gases, such as SO₂, NO₂, and CO₂. Furthermore, the QCM MOF film gas sensor was more effective for gas adsorption than the MOF particles alone and allowed the accurate modeling of gas adsorption. Moreover, the QCM MOF films accurately detect the adsorption-desorption mechanisms of SO₂ and NO₂, which exist as gaseous particulate matter, at specific gas concentrations.

• Proceedings of the KIEE Conference
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• 2000.07e
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• pp.44-47
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• 2000

In the recognition of the gases using the quartz crystal microbalance (QCM) coated with the film materials, it is important to obtain the recognition ability of gases, and the stability of film coated above the QCM. Especially, the thickness of film coated above the QCM is decreased according with the using circumstance and time of QCM gas sensor. Therefore, the sensing characteristics of film is changed with these. In this paper, we coated the lipid PC (Phosphatidyl Choline) materials varing with the blended amount of PVC(Poly Vinyl Chloride) and solution (Tetra Hydrofan:THF) above QCM to obtain the sensitive and the stability of lipid PC film. QCM gas sensors coated with film materials were measured the frequency change in the chamber of stationary gas sensing system injected 1-hexane, ethyl acetate, ethanol and benzene of $20{\mu}{\ell}$, respectively. We also measured the degradation characteristics of QCM gas sensor to show the properties of stability.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.389-396
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• 2022

Quartz crystal microbalance (QCM) based sensors are used for various applications owing to advantages such as excellent accuracy and precision, rapid response, and tiny footprint. Traditional applications of QCM-based sensors include biological sensing and thin-film thickness monitoring. Recently, QCMs have been used as functional material for novel physical and chemical detections, and with improved device design. QCM-based sensors are garnering considerable attention in particulate matter sensing and electric nose application. This review covers the challenges and solutions in physical, chemical, and biological sensing applications. First, various physical sensing applications are introduced. Secondly, the toxic gas and chemical detection studies are outlined, focusing on introducing a coating method for uniform sensing film and sensing materials for a minimal damping effect. Lastly, the biological and medical sensing applications, which use the monomolecularly decorating method for biomolecule recognition and a brief description of the overall measuring system, are also discussed.

• Journal of Sensor Science and Technology
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• v.3 no.2
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• pp.33-39
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• 1994

A quartz crystal microbalance (QCM) sensor system for the detection of odorants, especially environmental pollutant, has been constructed by depositing various phospholipids, activated carbon and lead compound pigment onto the surface of the QCM. The characteristics of a QCM operating at 9 MHz deposited with phosphatidyl- choline were analysed. An explanation is given for different odorant affinities based on the monolayer properties of phospholipids. The identification of odorants is discussed in terms of a comparison of their normalized resonant frequency shift patterns and relative response intensities calculated from the response areas. Applying the lead compound pigment coated QCM, it was possible to detect sulfur compound specifically. Using a number of different lipid-coated QCMs, odorants could be identified by comparing the response patterns.

• Journal of the Korean Applied Science and Technology
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• v.12 no.1
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• pp.125-131
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• 1995

Ultra thin films of Tetra-3-hexadecylsulphamoylcopperphthalocyanine(HDSM-CuPc) were formed on various substrates by Langmuir-Blodgett method, where HDSM-CuPc was synthesized by attaching long-chain alkylamine(hexa-decylamine) to CuPc. The reaction product was identified with FT-IR, UV-visible absorption spectroscopies, elemental analysis and thin layer chromatography. The formation of Ultrathin Langmuir-Blodgett(LB) films of HDSM-CuPc was confirmed by FT-IR and UV-visible spectroscopies. A quartz piezoelectric crystal coated with LB films of HDSM-CuPc was examined as a gas sensor for $N0_2$ gas. HDSM-CuPc LB films were transferred to a quartz crystal microbalance(QCM) in the form of Z-type multilayers. Response characteristics of film-coated QCM to $NO_2$ gas concentrations over a range of $100{\sim}600ppm$ have been tested with a thickness of $5{\sim}20$ layers of HDSM-CuPc. Changes in frequency by adsorption of $NO_2$ were increased With the number of LB layers and $NO_2$ concentration, but the response time was slow.

• Electrical & Electronic Materials
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• v.9 no.2
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• pp.180-187
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• 1996

The use of preformed copolymers and their cross-linking have been attempted in order to improve the intrinsic fragility of monolayers and Langmuir-Blodgett (LB) films and to make their technological applications. It has shown that an imidization followed a polyion-complexation can stabilize the LB films against heat and solvents. And, when the polymer structure was properly designed, concurrent removal of the alkyl tails together with imide formation could be accomplished. In this paper, the monolayers of the polymers which were polyion-complexed with PAA at the air-water interface can be transferred onto solid substrates such as porous fluorocarbon membranes filter and quartz crystal microbalance. The properties of the monolayers and the LB films will be discussed by .pi.-A isotherms, FT-IR, DSC, deposition ratio, QCM, and SEM. In addition, it was attempted to investigate the response characteristics of polymer LB films to the organic gases by the use of QCM.