Chaisitsak, Sutichai

Preferred name

Alternative Name

Chaisitsak, S.

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School of Engineering

sutichai.ch@kmitl.ac.th

Now showing 1 - 8 of 8

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Fast-LPG Sensors at Room Temperature by α -Fe2O3/CNT Nanocomposite Thin Films
(2018-01-01)
Chaitongrat, B.
;
Chaisitsak, S.
We present performance of a room temperature LPG sensor based on α-Fe2O3/CNT (carbon nanotube) nanocomposite films. The nanocomposite film was fabricated via the metallic Fe catalyst particle on CNTs in which both the catalyst particles and the CNT were simultaneously synthesized by chemical vapor deposition (CVD) synthesis and were subsequently annealed in air to create α-Fe2O3. These methods are simple, inexpensive, and suitable for large-scale production. The structure, surface morphologies, and LPG response of nanocomposite films were investigated. Raman spectroscopy and XPS analysis showed the formation of α-Fe2O3 on small CNTs (SWNTs). Morphological analysis using FE-SEM and AFM revealed the formation of the porous surface along with roughness surface. Additionally, the sensing performance of α-Fe2O3/CNTs showed that it could detect LPG concentration at lower value than 25% of LEL with response/recovery time of less than 30 seconds at room temperature. These results suggest that the α-Fe2O3/CNTs films are challenging materials for monitoring LPG operating at room temperature.
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Comparison Between Wet and Dry Transfer FE2O3-CNT Hybrid Thin Films as Room-Temperature Liquefied Petroleum Gas (LPG) Sensors
(2023-12-01)
Chaisitsak, Sutichai
;
Chaitongrat, Buaworn
;
Yahud, Shuhaida
;
Salleh, Ahmad Faizal
FE<inf>2</inf>O<inf>3</inf>-CNT hybrid thin films are promising candidates for room-temperature gas sensors with high sensitivity, rapid response, and recovery times. In this work, we reported the suitable fabrication strategies of FE<inf>2</inf>O<inf>3</inf>-CNT hybrid thin films as liquefied petroleum gas (LPG) sensors by comparing the dry (without using aqueous solutions) and wet processes. Fe-CNT hybrid thin films were used as the primary material for synthesizing FE<inf>2</inf>O<inf>3</inf>-CNT hybrid thin films, which were then annealed in air at 350oC to create α-FE<inf>2</inf>O<inf>3</inf>. Characterizations by X-ray photoelectron spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy (FE-SEM) confirmed the decoration of α-FE<inf>2</inf>O<inf>3</inf> nanoparticles on CNT surfaces. The transfer process had effects on the surface morphology and sensor characteristics. FE-SEM presents that the surface morphology of the wet-transfer FE<inf>2</inf>O<inf>3</inf>-CNT films was web-like structures with a highly porous morphology. Whereas the surface morphology of the dry-transferred FE<inf>2</inf>O<inf>3</inf>-CNT films was a branch-like structure. The I-V relationship of both annealed wet-and dry-films was non-linear indicating the present of n-type α-FE<inf>2</inf>O<inf>3</inf>. Under 5 vol.% of LPG, the wet-transferred FE<inf>2</inf>O<inf>3</inf>-CNT films have higher sensitivity (S = ~ 3% Tresp.= 10 s, trec.= 59s) compared to the dry-transferred FE<inf>2</inf>O<inf>3</inf>-CNT films (S = ~ 1.4%, Tresp.=90s, trec.= incomplete recovery). Moreover, the wet-transferred FE<inf>2</inf>O<inf>3</inf>-CNTs could detect LPG concentration at a lower value than 25% of LEL (Lower Explosive Limit) with rapid response and recovery time of 23 s and 49 s, respectively.
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Fabrication of amorphous silicon nanocones by bias-enhanced microwave plasma CVD
(2007-02-25)
Chaisitsak, Sutichai
We present a simple growth of highly aligned silicon nanocones by using bias-enhanced microwave plasma CVD of gas mixture of hydrogen and methane. SiO<inf>2</inf> and nickel films were used as a silicon precursor and a seeding material for patterning cone structure, respectively. SEM studies showed that the nanocones have nanometer-size tips and sub micrometer-size bases. TEM analysis revealed that the nanocones have amorphous structure with nickel on the tips. The model for formation of silicon nanostructures will also be suggested. © 2006 Elsevier B.V. All rights reserved.
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Parametric study of atmospheric-pressure single-walled carbon nanotubes growth by ferrocene-ethanol mist CVD
(2007-11-01)
Chaisitsak, S.
;
Nukeaw, J.
;
Tuantranont, A.
Uniform web-like films consisting single-walled carbon nanotubes (SWCNTs) were deposited on a silicon substrate using the chemical vapor deposition (CVD) of ferrocene-ethanol mist at atmospheric pressure (∼ 1 atm). The tiny mist was generated using a high-frequency ultrasonic vibration. The effects of various parameters including deposition position in the reactor, temperature, ferrocene/ethanol ratio, flow rate of carrier gas (argon), and deposition time on the formation of SWCNTs was investigated using high-resolution scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The worm region outside the furnace was found to be a suitable position for the formation of SWCNT films. The furnace temperature and the flow rate of carrier gas were found to determine the diameter and crystallinity of nanotube. The ferrocene concentration in ethanol strongly influenced the amount of impurity particles in the material. Moreover, the intensity of metallic tail in D-band was found to decrease with increasing the flow rate, showing a possibility of the formation of semiconducting SWCNTs. Results of this study can be used to improve understanding of the growth of SWCNTs by floating catalyst CVD of alcohol mist. © 2007 Elsevier B.V. All rights reserved.
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Nanocrystalline SnO2: F thin films for liquid petroleum gas sensors
(2011-07-01)
Chaisitsak, Sutichai
This paper reports the improvement in the sensing performance of nanocrystalline SnO2-based liquid petroleum gas (LPG) sensors by doping with fluorine (F). Un-doped and F-doped tin oxide films were prepared on glass substrates by the dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer). The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. The effect of F concentration on the structural, surface morphological and LPG sensing properties of the SnO<inf>2</inf> films was investigated. Atomic Force Microscopy (AFM) and X-ray diffraction pattern measurements showed that the obtained thin films are nanocrystalline SnO<inf>2</inf> with nanoscale-textured surfaces. Gas sensing characteristics (sensor response and response/recovery time) of the SnO2:F sensors based on a planar interdigital structure were investigated at different operating temperatures and at different LPG concentrations. The addition of fluorine to SnO<inf>2</inf> was found to be advantageous for efficient detection of LPG gases, e.g., F-doped sensors are more stable at a low operating temperature (300 °C) with higher sensor response and faster response/recovery time, compared to un-doped sensor materials. The sensors based on SnO2:F films could detect LPG even at a low level of 25% LEL, showing the possibility of using this transparent material for LPG leak detection. © 2011 by the authors.
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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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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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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.

Chaisitsak, Sutichai

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