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Hydroxypropyl methylcellulose/carboxymethyl starch/zinc oxide porous nanocomposite films for wound dressing application
(2022-12-15)
Pitpisutkul, Vipawan
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Prachayawarakorn, Jutarat
Because of low moisture uptake, water vapor transmission rate, oxygen transmission rate, swelling capacity and no antibacterial activity of hydroxypropyl methylcellulose (HPMC) film, carboxymethyl starch (CMS) and zinc oxide nanoparticles (ZnO-NPs) were incorporated in order to improve its limitations for wound dressing application. The infrared shifted peak of O–H stretching and O–H bending in HPMC/CMS blended films was detected due to hydrogen bond formation between HPMC and CMS. Scanning electron images of HPMC/CMS blended films exhibited porous structure. In addition, swelling degree, moisture uptake, water vapor transmission rate and oxygen transmission rate of HPMC/CMS blended films with various contents of CMS clearly increased compared to HPMC film. Moreover, HPMC/CMS nanocomposite films loaded with ZnO-NPs showed good antibacterial activity against Staphylococcus aureus and Escherichia coli, revealing their potential for wound dressing application. Percentage of crystallinity, cytotoxicity, mechanical and thermal properties were also examined.
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Ga-doped ZnO nanoparticles synthesized by sonochemical-assisted process
(2018-01-01)
Santibenchakul, S.
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Sirijaturaporn, P.
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Mekprasart, W.
;
Pechrapa, W.
In this work, the experimental work has been conducted on the synthesis of Gallium (Ga)- doped zinc oxide (ZnO) nanoparticles with different doping concentration (0-5% at.) via sonochemical process. The precursors of Ga-doped ZnO nanoparticle were sourced by zinc acetate dehydrate and gallium (III) nitrate hydrate, respectively. Ammonia (NH<inf>3</inf>) was chosen as a precipitating agent in sonochemical process. The sonochemical time was operated for 10 min by a direct-immersion ultrasonic horn using Sonic model VCX 750 (750W, 20 KHz). Structural properties and morphologies were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that Ga doped ZnO powder after the synthesis were obtained in ultrafine structure that different form with pure ZnO. XRD analysis revealed that the pattern of Ga doped ZnO powder showed good crystallinity with the wurtzite structure due to the preferred orientation direction and crystallization. Ga doping concentration plays a key role in significant change of ZnO structures.
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Effect of F incorporation on physical and optical properties of hydrothermally grown ZnO nanorods
(2018-01-01)
Sinornate, Wuttichai
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Chongsri, Krisana
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Boonyarattanakalin, Kanokthip
;
Pecharapa, Wisanu
F-doped ZnO nanorods were synthesized via hydrothermal process with variation of Fluorine doping contents (0-10%) starting from zinc oxide thin film as a seeding layer for nanorod growth. The zinc oxide seeding thin film was prepared by sol-gel spin coating at 2000 rpm on glass substrate using zinc acetate precursor with annealing at 500°C in air for 2 h. Ammonium fluoride (NH<inf>4</inf>F) was used as F doping precursor. The properties of F-doped ZnO nanorods were characterized by field emission electron microscope (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and UV-Visible spectrophotometer. Corresponding results indicated that growth of ZnO:F nanorods with good crystallinity and grown in (002) plane in undoped ZnO and F-doped ZnO 5%. The average size diameter of undoped and F-doped ZnO nanorods at 3%, 5% and 10% are 56, 96, 70 and 103 nm, respectively. From cross section images the average length of undoped and F-doped ZnO nanorods at 3%, 5% and 10% are 400, 375, 199 and 478 nm, respectively. The transmittance spectra shows moderate transparency (<80%) of the ZnO nanorod film in visible region with corresponding band gap range of 3.25-3.28 eV.
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Dielectric properties of natural ester based nanofluid
(2017-11-29)
Jariyanurat, K.
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Potivejkul, S.
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Pattanadech, N.
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Chotigo, S.
In this paper, AC breakdown and standard impulse breakdown characteristics of natural ester oil and natural ester base nano fluids are investigated. Three types of nanoparticles such as Zinc oxide (ZnO), Barium titanate (BaTiO3), and Titanium dioxide (TiO2) which have their diameter less than 100 nm are used to prepare the nanofluid samples which consist of the natural ester mixed with 0.01% volume fraction of each nanoparticle type. To measure AC breakdown voltage of the natural ester and natural ester based nanofluids, the oil breakdown tester (FOSTER OTS 60AF) is employed by sphere-sphere electrode system according to IEC 60156. The gap distance between electrodes is set at 2.5 mm. Furthermore, the needle-sphere electrode configuration with gap spacing of 40 mm is used for impulse breakdown voltage investigation of the dielectric liquids by the needle is tungsten and 40 μ m tip radius. The test circuit is set up in accordance with IEC 60897 and the test experiment is conducted at room temperature. The test results show that the AC breakdown voltages of the natural ester with nanopaticles is markedly higher than those of the unmodified natural ester. Additionally, TiO2, BaTiO3, and ZnO nanoparticles show their properties to increase impulse breakdown voltages of the nanofluids compared with those of the unmodified natural ester. From the test results, it is found that nanoparticles are good candidates to enhance the dielectric properties of natural ester for dielectric applications.
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Electrical characteristics of natural ester based nanofluid
(2017-10-19)
Potivejkul, S.
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Jariyanurat, K.
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Pattanadech, N.
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Wattakapaiboon, W.
In this paper, the dielectric properties of natural ester based nanofluids were investigated. This research represents the improvement of the electrical properties, AC breakdown and negative lightning impulse breakdown strength, of the natural ester (FR3) by amalgamation with nanoparticles. Two types of nanoparticles i.e., Titanium dioxide (TiO2) and Zinc Oxide (ZnO), with a mean diameter of less than 100 nm were used in this experiment. The nanofluid samples, a natural ester merged with nanoparticles, were prepared in three steps. First, the natural ester was divided into four groups. The first group was merged with 0.01% concentration of TiO2 and the second group was merged with 0.03% concentration of TiO2. The third group was merged with 0.01% concentration of ZnO and the fourth group was merged with 0.03% concentration of ZnO. Second, the nanofluid samples were dispersed using a magnetic stirrer. Finally, the ultrasonic dispersant technique was applied to the prepared nanofluids to be homogeneity. To measure AC breakdown voltage of the natural ester based nanofluids, the oil breakdown tester was employed and the testing experiment was performed according to IEC 60156. In addition, the negative lightning impulse breakdown characteristic of the natural ester based nanofluid was investigated with the needle-sphere electrodes in accordance with IEC 60897. A tungsten needle with tip radius of 40m was utilized as the high voltage electrode and the 13 mm diameter brass sphere was used as the grounded electrode. The gap distance was fixed as 15 mm. The test results showed that the AC breakdown property of the modified liquids was clearly influenced by the type of nanoparticles added. The AC breakdown voltage of the natural ester with nanopaticles was slightly higher than that of the unmodified natural ester. Additionally, both TiO2 and ZnO nanoparticles demonstrated their ability to increase negative impulse breakdown voltage of the nanofluids. These tests indicated that such nanoparticles have good potential to be used with natural ester to improve the dielectric properties.
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The influence of annealing temperature on structural properties of zinc oxide nanoparticles synthesized by precipitation method
(2017-01-01)
Chaithanatkun, Natpasit
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Onlaor, Korakot
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Tunhoo, Benchapol
In the present work, the precipitation method was used to prepare zinc oxide nanoparticles in the presence of zinc nitrate and potassium hydroxide as zinc precursor and hydroxide precursor, respectively. The influence of annealing temperature on the structural, morphological, and vibrational properties of zinc oxide nanoparticles was studied by X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Fourier transform Raman spectroscopy (FT-Raman), and Fourier transform infrared spectroscopy (FT-IR) techniques. The effects of annealing temperature on the crystallite size of zinc oxide nanoparticles were investigated. The XRD results represented that the zinc oxide nanoparticles exhibited high crystallinity of hexagonal wurtzite crystal structure. The average crystallite size of nanoparticles increased from 25 nm to 31 nm with an increase in annealing temperature from 600°C to 800°C. The SEM images showed that the prepared zinc oxide nanoparticles in this present work were spherical in shape and had the larger size with increasing annealing temperature. FT-Raman and FT-IR spectra confirmed that the quality of Zn-O vibrational mode was stronger at higher annealing temperature.
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Influence of post-annealing temperature on the morphological, structural and optical properties of spin coated zinc oxide thin films
(2017-01-01)
Chaithanatkun, Natpasit
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Fujihara, Takeshi
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Kamano, Masaru
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Konishi, Tomoya
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Uehara, Nobutomo
In this study, zinc oxide films were fabricated on quartz glass substrate using spin coating technique with 2 molar of zinc oxide in organic solvent as starting materials. The fabricated sample was post-annealed at different temperature from 350 °C to 750 °C for 60 minutes. The energy dispersive x-ray spectroscopy (EDS) confirmed that zinc oxide coating film was fabricated on the quartz glass substrate. The crystallography of zinc oxide films were analyzed by X-ray diffraction (XRD). The crystallite size of zinc oxide nanoparticles was determined from the full-width at half maximum (FWHM) of XRD peaks using Debye-Scherrer's equation and showed that the zinc oxide films had highly crystalline quality in hexagonal wurtzite crystal structure. The morphological property of films was observed by scanning electron microscopy (SEM). Surface morphology of films shows regularly spread all of zinc oxide films. The optical property of various zinc oxide films was measured using UV-Visible spectrophotometer.
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Photoresponse of composites of zinc oxide and poly(3-hexythiophene) under selective UV and white-light illumination
(2016-12-01)
Pattamang, Pattaraluck
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Jiramitmonkon, Kanpitcha
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Piyakulawat, Phimwipha
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Asawapirom, Udom
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Tantisantisom, Kittitpong
We investigate charge transport in UV sensing devices based on organic-inorganic semiconductor composites with the metal-semiconductor-metal (MSM) structure. Composite materials of zinc oxide (ZnO) nanoparticles and poly(3-hexylthiophene) (P3HT) were prepared by drop-casting their colloidal mixture in chloroform onto low-cost interdigitated copper electrodes. The current-voltage characteristics of the devices were investigated under both dark and illuminated conditions in the UV–visible range. The highest photoresponse was observed for an optimal P3HT:ZnO ratio of 1:8 w/w in the wavelength range between 310 and 380 nm. The dynamic response was investigated by pulsing a 365 nm UV light with a long period to reveal the response time of 4 s and the recovery time of less than 1 s. The photoresponse of the materials was also investigated for a shorter period of UV pulsing, using a rotating chopper. The response time and recovery time for the short UV pulse were found to be approximately 20 m and 25 m, respectively. The dual response times should stem from the presence of two types of semiconductor materials, namely ZnO with a high electron mobility and P3HT with a moderate hole mobility. To probe the charge generation and transport mechanisms, we further investigate the photoresponse using UV pulsing under background white light of different intensities, and vice versa. The background white light was found to deteriorate the UV photoresponse of the materials. On the other hand, the background UV illumination produced an anomalous photoresponse pattern with the white light pulsing. Understanding the charge transport mechanisms for composite materials is highly important for future applications in low-cost UV sensors and tunable optoelectronic devices.
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Hydrothermal synthesis and characterization of ZnO:F nanorod structure
(2016-01-01)
Sinornate, Wuttichai
;
Chongsri, Krisana
;
Pecharapa, Wisanu
F-doped ZnO nanorod structures were synthesized via hydrothermal process with variation of doping content starting from zinc nitrate solution and zinc oxide thin film used as seeding layer. The zinc oxide seeding film was fabricated by spin coating on glass substrate using zinc acetate precursor and annealed at 500 °C for 2 h. Relevant properties of ZnO:F nanorod structures were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and UV-VIS spectrophotometer. Corresponding results indicated that ZnO:F nanorod array, grown in (002) plane, has the characteristics of good crystallinity. In addition, this study showed that ZnO:F nanorod with exceptional structure can be obtained by hydrothermal process, operated at proper treatment time, temperature and F-doping content.
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Characterization and phase formation study of ZnO:Sn nanoparticles synthesized by co-precipitation method
(2014-09-02)
Noonuruk, R.
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Mekprasart, W.
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Supparattanasamai, T.
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Kanyapan, T.
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Techitdheera, W.
ZnO:Sn were successfully prepared by co-precipitation method using zinc acetate dihydrate and tin (IV) chloride hexahydrate as host and dopant precursor sources, respectively. The ratio of Sn doping content in ZnO was designated at 0, 5, 10 and 20 wt.% and calcined at different temperatures at 200, 300, 400 and 500°C. Physical properties and composition of Sn-doped ZnO powder were monitored by X-ray diffraction and scanning electron microscope. Chemical bonding of as-synthesized powders were investigated by Fourier transform spectroscopy. The preliminary results indicate that the crystallinity and morphologies of ZnO nanoparticle are significantly affected by Sn dopant. The phase formation of Zn-Sn-O was observed depending on the Sn-doping composition and calcination temperature. Meanwhile, FTIR results indicate the existence of mixture phases of ZnO:Sn in the compounds which were obtained via precipitation process. © 2014 Taylor & Francis Group, LLC.

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