Wongwiriyapan, Winadda

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Wongwiriyapan, W.

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Integrated Innovative Technology

winadda.wo@kmitl.ac.th

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Hybrid gas sensor based on platinum nanoparticles/poly(methyl methacrylate)-coated single-walled carbon nanotubes for dichloromethane detection with a high response magnitude
(2016-05-01)
Muangrat, Worawut
;
Yordsri, Visittapong
;
Maolanon, Rungroj
;
Pratontep, Sirapat
;
Porntheeraphat, Supanit
A dichloromethane (DCM) sensor with a high response magnitude was successfully fabricated using the integration of single-walled carbon nanotubes (SWNTs), poly(methyl methacrylate) (PMMA) and platinum nanoparticles (Pt NPs). A pristine SWNT network was first formed by drop-casting onto printed circuit board (PCB) substrates. Next, PMMA was coated onto the pre-dropped SWNT network by spin coating using a PMMA-toluene solution, followed by the deposition of Pt NPs by electron-beam evaporation (hereafter referred to as Pt/PMMA/SWNT). The Pt/PMMA/SWNT enabled an approximately 69-fold improvement in DCM detection compared to pristine SWNT. The high response magnitude of the Pt/PMMA/SWNT was successfully achieved because of the incorporation of PMMA and Pt functions. Swelling of the PMMA matrix as a result of DCM adsorption leads to PMMA volume expansion, thereby increasing the SWNT-SWNT distance, which results in an increase in the resistance. Pt NPs promote the dissociation of DCM to CO, and consequently the CO oxidation on the Pt NPs catalyst and electron donation from Pt NPs to SWNTs, resulting in an increase in the resistance. Moreover, a linear relationship was obtained between the sensor response of the Pt/PMMA/SWNT and the concentration of DCM. These results suggest that the integration of SWNTs with PMMA and Pt NPs is a promising approach for improving DCM detection at room temperature.
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Hybrid graphene and poly(methyl methacrylate) for gas sensor application
(2017-01-01)
Rattanabut, Chanoknan
;
Muangrat, Worawut
;
Phonyiem, Mayuree
;
Bungjongpru, Win
;
Wongwiriyapan, Winadda
The graphene and hybrid graphene/poly(methy methacrylate) (PMMA) were fabricated for use in volatile organic compound (VOC) detection. Graphene was synthesized on copper foil by chemical vapor deposition (CVD). To remove Cu foil, PMMA was coated on graphene by spin-coating (hereafter referred to as graphene/PMMA) and transferred to silicon substrate with silicon dioxide layer (SiO<inf>2</inf>/Si) by wetting transfer process. For comparison, a PMMA layer was removed in order to achieve a pristine graphene. Graphene and hybrid graphene/PMMA sensors showed the highest sensor response to ethanol. Responses of the graphene to ethanol, dichloromethane and benzene were 5.62, 20.06 and 35.09 times higher than that of hybrid graphene/PMMA. The sensor response of graphene can be described in terms of the dielectric constant of VOC. In addition, the sensor response of hybrid graphene/PMMA to benzene and dichloromethane would be attributed to the Hansen solubility parameter (HSP), while that of ethanol is related to the molecular size. These results suggest that the integration of graphene with PMMA is a promising approach for the selectivity for VOC detection.
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Effect of metal catalysts on synthesis of carbon nanomaterials by alcohol catalytic chemical vapor deposition
(2013-12-31)
Muangrat, Worawut
;
Porntheeraphat, Supanit
;
Wongwiriyapan, Winadda
Carbon nanomaterials (CNMs) were synthesized by alcohol catalytic chemical vapor deposition (CVD) at atmospheric pressure using different metal catalysts (Ni, Co and Fe) at a growth temperature of 700°C. Ni and Fe acted as active catalysts for multi-walled carbon nanotubes (MWNTs) growth, while Co acted as an active catalyst for bamboo-like MWNTs and carbon nanofibers (CNFs) growth. The CNMs synthesized from Ni catalyst showed the highest crystallinity with a small amount of by-products. These results imply that metal catalyst is a key parameter to the structure, morphology and crystallinity of CNMs. The different effects of metal catalysts on the growth of CNMs can be explained in terms of the difference in the change in Gibbs free energy of metal carbide formation.
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A flexible formaldehyde sensor based on palladium nanoparticles-polyvinylpyrrolidone-carbon nanotubes-nanocellulose composite films
(2025-01-01)
Chobsilp, Thanattha
;
Muangrat, Worawut
;
Inpaeng, Saowaluk
;
Tedsree, Karaked
;
Yordsri, Visittapong
A flexible formaldehyde sensor with high sensitivity was successfully fabricated by integrating palladium (Pd) nanoparticles, polyvinylpyrrolidone (PVP), multi-walled carbon nanotubes (MWCNTs) and nanocellulose (NC) into composite films. The flexible composite films were fabricated via vacuum filtration. The morphology, structure, composition, crystallinity, and functional group of as-fabricated sensing materials were characterized by scanning electron microscopy, transmission electron microscopy, electron probe microanalyzer, Raman spectroscopy, and Fourier transform infrared spectrometer. Pd nanoparticles-PVP-MWCNTs-NC (Pd-PVP-MWCNTs-NC) composite films exhibited an 11-fold increase in formaldehyde sensitivity compared to MWCNTs-NC composite films. The excellent sensing performances of Pd-PVP-MWCNTs-NC sensors were attributed to the combination of Pd nanoparticles and PVP. The enhanced sensitivity is attributed to the synergistic effect of the high electron transfer from formaldehyde molecule to Pd nanoparticles and swelling of PVP due to sorption of formaldehyde molecule. Pd-PVP-MWCNTs-NC sensors still maintained good response under bending angle up to 30° and 300 bending cycles. The results demonstrate that the Pd-PVP-MWCNTs-NC composite films are highly promising in terms of sensitivity and flexibility for sub-ppm level formaldehyde detection at room temperature.
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Graphene and poly(methyl methacrylate) composite laminates on flexible substrates for volatile organic compound detection
(2018-04-01)
Rattanabut, Chanoknan
;
Wongwiriyapan, Winadda
;
Muangrat, Worawut
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Bunjongpru, Win
;
Phonyiem, Mayuree
In this paper, we present a gas sensor for volatile organic compound (VOC) detection based on graphene and poly(methyl methacrylate) (GR/PMMA) composite laminates fabricated using CVD-grown graphene. Graphene was transferred to a poly(ethylene terephthalate) (PET) substrate by PMMA-supported wet transfer process without PMMA removal in order to achieve the deposition of GR/PMMA composite laminates on PET. The GR/PMMA and graphene sensors show completely different sensitivities to VOC vapors. The GR/PMMA and graphene sensors showed the highest sensitivities to dichloromethane (DCM). The response of the GR/PMMA sensor to DCM was 3 times higher than that of the graphene sensor but the GR/PMMA sensor hardly responded to acetone, chloroform, or benzene. The sensing mechanism of the graphene sensor can be based on the dielectric constant of VOCs, the size of VOC molecule, and electron hopping effects on defect graphene, while that of the GR/PMMA sensor can be explained in terms of the polymer swelling owing to the Hansen solubility parameter.
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Sensitivity Enhancement of Benzene Sensor Using Ethyl Cellulose-Coated Surface-Functionalized Carbon Nanotubes
(2018-01-01)
Chobsilp, Thanattha
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Muangrat, Worawut
;
Issro, Chaisak
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Chaiwat, Weerawut
;
Eiad-Ua, Apiluck
A hybrid sensor based on the integration of functionalized multiwalled carbon nanotubes (MWCNTs) with ethyl cellulose (EC) was fabricated for sensitivity enhancement of benzene detection. To functionalize the surface of MWCNTs, MWCNTs were treated with hydrochloric acid for 60 min (A60-MWCNTs), while other MWCNTs were treated with oxygen plasma for 30, 60, 90, and 120 min (P30-MWCNTs, P60-MWCNTs, P90-MWCNTs, and P120-MWCNTs, resp.). Pristine MWCNTs, A-MWCNTs, and P-MWCNTs were dispersed in 1,2-dichloroethane, then dropped onto a printed circuit board consisting of Cu/Au electrodes used as the sensor platform. Next, EC was separately spin coated on the pristine MWCNTs, A-MWCNTs, and P-MWCNTs (EC/MWCNTs, EC/A-MWCNTs, and EC/P-MWCNTs, resp.). All sensors responded to benzene vapor at room temperature by increasing their electrical resistance which was sensitive to benzene vapor. The EC/P90-MWCNTs enabled an approximately 11-fold improvement in benzene detection compared to EC/MWCNTs. The sensitivity of all sensors would be attributed to the swelling of EC, resulting in the loosening of the MWCNT network after benzene vapor exposure. The differences of the sensing responses of the EC/MWCNTs, EC/A-MWCNTs, and EC/P-MWCNTs would be ascribed to the differences in crystallinity and functionalization of MWCNT sidewalls, suggesting that acid and oxygen plasma treatments of MWCNTs would be promising techniques for the improvement of benzene detection.
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Graphene and poly(methyl methacrylate) composite laminates on flexible substrates for volatile organic compound detection
(2018-04-01)
Rattanabut, Chanoknan
;
Wongwiriyapan, Winadda
;
Muangrat, Worawut
;
Bunjongpru, Win
;
Phonyiem, Mayuree
In this paper, we present a gas sensor for volatile organic compound (VOC) detection based on graphene and poly(methyl methacrylate) (GR/PMMA) composite laminates fabricated using CVD-grown graphene. Graphene was transferred to a poly(ethylene terephthalate) (PET) substrate by PMMA-supported wet transfer process without PMMA removal in order to achieve the deposition of GR/PMMA composite laminates on PET. The GR/PMMA and graphene sensors show completely different sensitivities to VOC vapors. The GR/PMMA and graphene sensors showed the highest sensitivities to dichloromethane (DCM). The response of the GR/PMMA sensor to DCM was 3 times higher than that of the graphene sensor but the GR/PMMA sensor hardly responded to acetone, chloroform, or benzene. The sensing mechanism of the graphene sensor can be based on the dielectric constant of VOCs, the size of VOC molecule, and electron hopping effects on defect graphene, while that of the GR/PMMA sensor can be explained in terms of the polymer swelling owing to the Hansen solubility parameter.
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Graphene nanosheet-grafted double-walled carbon nanotube hybrid nanostructures by two-step chemical vapor deposition and their application for ethanol detection
(2019-12-01)
Muangrat, Worawut
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Wongwiriyapan, Winadda
;
Morimoto, Shingo
;
Hashimoto, Yoshio
Here, we present a facile technique for synthesis of graphene nanosheet (GNS)-grafted double-walled carbon nanotube (DWCNT) hybrid carbon nanostructures (here after referred to as G-DWCNTs) by directly growing GNSs along the sidewalls of DWCNTs using a two-step chemical vapor deposition (CVD). DWCNTs were synthesized by floating catalyst CVD at 1300 °C using ferrocene and thiophene dissolved in ethanol. Then, GNSs were grafted onto the synthesized DWCNT bundles by thermal CVD at 1300 °C using ethanol. The sharp-edged petal-like structure of GNSs were grown along the sidewalls of DWCNT bundles while maintaining the one-dimensional structure of DWCNT. Next, DWCNTs and G-DWCNTs were dispersed in ethanol, then deposited on the paper using vacuum filtration method and used for ethanol detection. G-DWCNTs sensor exhibited a 3-fold improvement in the response to ethanol vapor compared to the DWCNTs sensor. The sensing mechanism of DWCNTs and G-DWCNTs can be described in terms of charge transfer between the gas molecules and sensing material. These results demonstrate that the facile technique by two-step CVD method provides a promising approach for simple and low-cost technique to synthesize the hybrid nanostructure of GNSs and DWCNTs. The new hybrid carbon nanostructures are attractive for gas sensing application.
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Polymer-coated single-walled carbon nanotubes for ethanol and dichloromethane discrimination
(2013-10-29)
Muangrat, Worawut
;
Maolanon, Rungroj
;
Pratontep, Sirapat
;
Porntheeraphat, Supanit
;
Wongwiriyapan, Winadda
Sensor response and pattern recognition of polymer-coated single-walled carbon nanotubes (SWNTs) were investigated. Printed circuit board (PCB) with Cu/Au interdigitated electrode was used as sensor platform. SWNTs network was firstly formed on PCB by drop-casting. For polymer-coated SWNTs preparation, poly(methyl methacrylate) (PMMA) and thiophene were employed as polymers to coat on SWNTs by spin coating; PMMA/SWNTs and thiophene/SWNTs. Raman spectra showed no obvious structure changes of SWNTs after polymer coating. Next, gas sensing test was conducted. Pristine SWNTs, PMMA/SWNTs and thiophene/SWNTs were exposed to vapors of ethanol and dichloromethane at room temperature. From normalized sensor response results, it was found that pristine SWNTs and PMMA/SWNTs showed the highest response to ethanol and dichloromethane vapors, respectively. In order to discriminate vapors between ethanol and dichloromethane, pattern recognition technique was utilized. Principal component analysis (PCA) results showed that pattern recognition of ethanol and dichloromethane vapors can be discriminated by using pristine SWNTs and polymer-coated SWNTs sensors. © (2013) Trans Tech Publications, Switzerland.
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Poly(methyl methacrylate) and thiophene-coated single-walled carbon nanotubes for volatile organic compound discrimination
(2016-02-01)
Muangrat, Worawut
;
Chodjarusawad, Thanawee
;
Maolanon, Rungroj
;
Pratontep, Sirapat
;
Porntheeraphat, Supanit
Poly(methyl methacrylate) (PMMA) and thiophene-coated single-walled carbon nanotubes (SWNTs) were fabricated for use in volatile organic compound (VOC) detection. Pristine SWNTs were separately coated with PMMA (PMMA/SWNTs) and thiophene (thiophene/SWNTs) by spincoating. Pristine SWNTs showed the highest response to methanol, while PMMA/SWNTs enabled 5.4-fold improved dichloromethane detection and thiophene/SWNTs enabled 1.4-fold improved acetone detection compared with pristine SWNTs. The sensor response of PMMA/SWNTs to dichloromethane and that of thiophene/SWNTs to acetone can be attributed to the Hildebrand solubility parameter (HSP). The more similar the HSP, the higher the sensor response. The sensor response of pristine SWNTs to methanol is related to the diffusion coefficient and molecular size. The relationships between the vapor concentration and sensor response of PMMA/SWNTs to dichloromethane and thiophene/SWNTs to acetone are based on Henry's adsorption isotherm, while that of pristine SWNTs to methanol is based on the Henry-clustering model. Principal component analysis (PCA) results show that dichloromethane, acetone, and methanol were successfully discriminated.

Wongwiriyapan, Winadda

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