Chaisitsak, Sutichai

Preferred name

Alternative Name

Chaisitsak, S.

Main Affiliation

School of Engineering

sutichai.ch@kmitl.ac.th

Now showing 1 - 10 of 18

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Novel preparation and characterization of fe2 o3 /cnt thin films for flammable gas sensors
(2019-01-01)
Chaitongrat, Buaworn
;
Chaisitsak, Sutichai
In this work, novel preparation for Fe<inf>2</inf> O<inf>3</inf> /CNT thin films was investigated. The Fe/CNT thin films were synthesized through vertical floating-catalyst chemical vapor deposition technique (FC-CVD) and subsequently annealed in air. The various annealing temperature to create Fe<inf>2</inf> O<inf>3</inf> was examined and characterized by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Ultraviolet–visible spectroscopy (UV-Vis) and Raman spectroscopy. In addition, effect of wet/dry process on gas sensing of Fe<inf>2</inf> O<inf>3</inf> /CNTs was also investigated. The results suggest that the interfacial oxide layer helps to significantly improve LPG sensing performance with rapid response and recovery times. The proposed method can be considered as a promising approach for producing ultra-Fe<inf>2</inf> O<inf>3</inf> /CNT thin films that are appropriate for sensing application.
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Impact of Dimethylformamide/Acetone Ratios and Stirring Time on Morphology and Electrical Properties of Electrospun PVDF Fibers
(2025-01-01)
Hakimi Bin Ismail, M. I.
;
Syed Bakar, S. S.
;
Yahud, S.
;
Chaisitsak, S.
This study examines the impact of Dimethylformamide, DMF/Acetone ratio (60/40, 70/30 and 100/0) and stirring time (16 hours and 24 hours) on Polyvinylidene Fluoride electrospun fibers. Total of six samples were prepared at 12% solution con-centration were electrospun at 20 kV, 10 cm tip-to-collector distance, and 1 mL/h flow rate. Morphological analysis showed that a 70/30 ratio produced finer fibers with fewer beads than 60/40 ratio, while prolonged stirring increased fiber diameter. Electrical analysis confirmed the lowest resistance and highest conductivity for these fibers. The 70/30 ratio and 16-hour stirring time technique optimized fiber structure and electrical performance for advanced applications.
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Graphite-encapsulated iron particles grown by mist-CVD
(2009-11-30)
Chaisitsak, S.
In this paper, a novel and simple method for synthesis of iron nanoparticles using a CVD of ferrocene-ethanol mist was proposed. By using this technique, graphite-encapsulated Fe2O3 nanoparticles could be synthesized at a low temperature of ∼400°C under 1 atm. The synthesis temperature as well as the deposition position and time were found to determine the amount of carbon-filament impurities in the obtained materials. The addition of water mist in the growth atmosphere was found to be a key parameter for eliminating carbon by-products due to the water-asisted etching effect. The result of this study could be useful for the production of graphite-encapsulated iron particles since our modified CVD technique is simple and low-cost. © 2009 American Institute of Physics.
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Fabrication of SWNTs/α-Fe2O3 as room-temperature LPG sensor
(2015-12-31)
Chaitongrat, Buaworn
;
Chaisitsak, Sutichai
A simple fabrication of liquid petroleum gas sensor based on SWNTs/α-Fe2O3 nanocomposite films is reported. SWNTs/α-Fe2O3 films were successfully synthesized through the vertical floating catalyst chemical vapor deposition method using ferrocene-ethanol mist, followed by annealing in air at 350 oC to create α-Fe2O3. To fabricate a sensor, carbon conductive electrodes were directly deposited on top of the SWNTs/α-Fe2O3 films. SWNTs/α-Fe2O3 growth conditions (deposition time and ferrocene/ethanol ratio) were optimized to improve sensor response. The sensor had the capability to detect LPG at a concentration as low as 0.2% LEL (lower explosive limit), indicating possible applications in LPG monitoring at room temperature.
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Effect of the deposition condition for carbon nanotube thin films on gas sensing performance
(2008-01-01)
Chaisitsak, S.
;
Tuantranont, A.
A simple fabrication process for single-walled carbon nanotube (SWCNT)-based sensors was reported. By using chemical vapor deposition (CVD) of alcohol-ferrocene mist, SWCNT films could be directly deposited on patterned Al electrodes to fabricate a sensor. The effects of depositing position along the inner quartz reactor on the properties of SWGNT films (morphology, structure and purity) and the characteristics of sensors (response and reproducibility) were investigated. The SWCNT-film-based sensors fabricated at low substrate temperatures of 200-700 °C exhibited a reasonably good sensitivity to saturated organic vapor (ethanol, methanol and acetone) and showed a fair reproducibility even operated at a room temperature (∼28 °C). Copyright © 2008 American Scientific Publishers All rights reserved.
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Ferrocene-ethanol-mist CVD grown SWCNT films as transparent electrodes
(2014-01-01)
Jantharamatsakarn, Kittipong
;
Chaisitsak, Sutichai
The floating catalyst CVD using ferrocene-ethanol mist was successfully used to deposit single-walled carbon nanotube (SWCNT) films from the gaseous phase onto a Si substrate and a membrane filter. The home-built vertical mist-CVD system was used without the use of H<inf>2</inf> or CO gases. The tiny mist was generated using a high-frequency ultrasonic vibration. The effects of various parameters including furnace temperature, ferrocene/ethanol ratio, the deposition position in the reactor, flow rate of carrier gas, and deposition time on the SWCNTs formation were investigated using SEM, TEM and Raman spectroscopy. The furnace temperature and the flow rate of carrier gas were found to determine the diameter and crystallinity of nanotubes. The ferrocene concentration in ethanol influenced the diameter distribution of nanotubes and the amount of impurity particles in the materials. The collected SWCNT films on a filter were directly transferred to a laminate sheet by using a hot press laminator. The properties of SWCNTs were investigated by UV-Vis spectrophotometer and four-point probe measurement. The high sheet resistance was observed for the as-transferred films. However, the initial results show that a sheet resistance of 10 kΩ/cm2 and an 80% transmittance at the wavelength of 550 nm after nitric acid treatment.
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Hybrid Fe2O3/CNT thin films for gas sensor applications
(2018-08-13)
Chaitongrat, Buaworn
;
Chaisitsak, Sutichai
Thin films of Fe nanoparticles (NPs)/CNT networks were synthesized through vertical floating catalyst chemical vapor deposition technique (FC-CVD) and collected directly onto a cellulose membrane filter. Fe NPs/CNT films were transferred onto glass (or Si) substrates simply by dissolving filters, and then annealed in air at a low temperature for 8 hrs to create Fe<inf>2</inf>O<inf>3</inf> NPs. The effect of annealing temperature ranging from 150 to 550°C on the morphology and structures of the Fe<inf>2</inf>O<inf>3</inf>/CNTs films was investigated by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Fe<inf>2</inf>O<inf>3</inf>/CNTs film-based sensors were tested against LPG gas under room temperature. LPG sensing-performance (sensor response and response/recovery time) of the Fe<inf>2</inf>O<inf>3</inf>/CNTs films-based sensor varied depending on the annealing temperature. The results of this study reinforce the potential of hybrid Fe<inf>2</inf>O<inf>3</inf>/CNTs films as a sensing material for LPG detection at low operating temperature.
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Ferrocene-ethanol-mist CVD grown SWCNT films as transparent electrodes
(2014-01-01)
Jantharamatsakarn, Kittipong
;
Chaisitsak, Sutichai
The floating catalyst CVD using ferrocene-ethanol mist was successfully used to deposit single-walled carbon nanotube (SWCNT) films from the gaseous phase onto a Si substrate and a membrane filter. The home-built vertical mist-CVD system was used without the use of H2 or CO gases. The tiny mist was generated using a high-frequency ultrasonic vibration. The effects of various parameters including furnace temperature, ferrocene/ethanol ratio, the deposition position in the reactor, flow rate of carrier gas, and deposition time on the SWCNTs formation were investigated using SEM, TEM and Raman spectroscopy. The furnace temperature and the flow rate of carrier gas were found to determine the diameter and crystallinity of nanotubes. The ferrocene concentration in ethanol influenced the diameter distribution of nanotubes and the amount of impurity particles in the materials. The collected SWCNT films on a filter were directly transferred to a laminate sheet by using a hot press laminator. The properties of SWCNTs were investigated by UV-Vis spectrophotometer and four-point probe measurement. The high sheet resistance was observed for the as-transferred films. However, the initial results show that a sheet resistance of 10 kΩ/cm2 and an 80% transmittance at the wavelength of 550 nm after nitric acid treatment.
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Antibacterial activity and nanocomposite properties of monodispersed silver nanoparticles synthesized by the microwave method
(2016-01-01)
Lothongkum, Anchaleeporn W.
;
Wongparb, Kornwika
;
Sethapokin, Pinthep
;
Chaisitsak, Sutichai
Monodispersed colloidal silver nanoparticles (Ag-NPs) were synthesized by a simple and rapid microwave method. A precursor, AgNO<inf>3</inf>, was reduced by ethylene glycol (EG) and N,N-dimethylformamide (DMF) in the presence of polyvinylpyrrolidone (PVP) as a stabilizer or capping agent. It was found that the concentration of AgNO<inf>3</inf> significantly affected Ag-NPs particle sizes. The particle sizes decreased when the concentration decreased from 0.1 to 0.05 and 0.01 M, which corresponded to narrow size distribution of the particle diameters of approximately 60 to 80, 30 to 40 and 10 to 20 nm. The spherical-shaped monodispersed Ag-NPs were obtained by using a volume ratio of EG to DMF of 2.75:2.25, microwave power of 400 W and heating time of 2 min. The volume ratio of EG to DMF and the microwave power influenced the uniformity of the Ag-NPs shape and size, while the heating time had no effect. For antibacterial application, 60-80 and 10-20 nm Ag-NPs showed good disinfection ability against Escherichia coli (ATCC 25922) at the minimum inhibitory concentrations (MIC) of 32 and 16 (μg × ml-1, respectively. In addition, the electrical resistance of the nanocomposites of DMF-loaded Ag-NPs (20-50 nm) without PVP on single-walled carbon nanotubes and polyethylene terephthalate (PET) was measured. As a result, it is obvious that the Ag-NPs help to increase the electrical conductivity of the nanocomposites as the electrical resistance of the Ag-NPs nanocomposites was 4.68 kΩ × cm-2 compared to that of the nanocomposites without Ag-NPs of 8.76 kΩ × cm-2.
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Effects of three parameters on graphene synthesis by chemical vapor deposition
(2013-09-02)
Dathbun, Ajjiporn
;
Chaisitsak, Sutichai
A high quality graphene film on a copper foil was successfully grown by a CVD process using ethanol as a carbon source. The effect of growth temperatures (650-850°C), reaction times (5-50 min) and post-CVD cooling process rates (slow-cooling, fast-cooling and fast-cooling under ethanol exposure) on the formation of graphenes was investigated by Raman spectroscopy and scanning electron microscopy (SEM). The graphene film deposited under the optimal conditions showed features of a high quality such as a high I <inf>2D</inf>/I<inf>G</inf> ratio of ∼8, a low I<inf>D</inf>/I<inf>G</inf> ratio of 0.28 and a narrow full width half maximum (FWHM) of Lorentzian-shaped 2D peak of ∼35 cm-1. It was found that the quality of graphene film could be enhanced by optimizing the growth temperature and time, while the number of graphene layer was less sensitive to the cooling rate. However, the fast cooling process under ethanol exposure was found to be a key process for obtaining graphenes with a large domain size. These findings may help to fabricate high-quality graphenes on a copper foil for electronic applications. © 2013 IEEE.
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Chaisitsak, Sutichai

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