Seeharaj, Panpailin

Preferred name

Seeharaj, Panpailin

Alternative Name

Seeharaj, P.

Main Affiliation

School of Science

panpailin.se@kmitl.ac.th

Now showing 1 - 5 of 5

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Asymmetric dot-patterned wettable and antibacterial wound dressings from bacterial cellulose–alginate composites coated with stearic acid-modified ZnO/chitosan/AgNPs
(2025-01-01)
Ieamviteevanich, Pimchanok
;
Onklam, Panida
;
Kampechdee, Wariya
;
Churiwan, Achana
;
Vittayakorn, Naratip
To improve the wound dressing characteristics of bacterial cellulose-based materials and address the issue of asymmetric wound dressing with one hydrophilic side and another hydrophobic side, this study developed a new concept for the fabrication of an asymmetric wettable and antibacterial wound dressing by selective drop coating of stearic acid-modified ZnO, chitosan, and AgNPs to form a dot pattern on both surfaces of a bacterial cellulose–alginate composite (BA-ZnS/Ch/Ag). The coated surface was hydrophobic, with a WCA of 150° due to the formation of a low surface energy zinc stearate (C<inf>17</inf>H<inf>35</inf>COO)<inf>2</inf>Zn) monolayer on the ZnO particles and a high degree of hierarchical roughness. The asymmetric wettable BA-ZnS/Ch/Ag wound dressing maintained good water absorptivity (swelling rate 417%) and natural breathability (water vapor transmission rate 792 g.m−2 day−1) of the superhydrophilic bacterial cellulose-alginate composite that consisted of dense outer surfaces and porous inner layers and simultaneously possessed the superhydrophobic property of the coating area that can reduce the risk of infection from external fluids and improve the blood repellency and anti-adhesion properties. The BA-ZnS/Ch/Ag wound dressing showed good antibacterial activity against S. aureus and E. coli and non-toxicity to human keratinocyte immortal cells (HaCaT), making it suitable for clinical applications.
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The role of γ-C2H5NO2 as a new transient liquid phase in cold sintering process of BaTiO3 composites
(2024-07-01)
Noisak, Jitrawan
;
Ieamviteevanich, Pimchanok
;
Charoonsuk, Thitirat
;
Pakawanit, Phakkhananan
;
Pinpru, Nattapong
Dielectric materials, such as barium titanate (BT)-based materials, have excellent dielectric properties but require high temperatures (above 1300 °C) for ceramic fabrication, leading to high costs and energy loss. The cold sintering process (CSP) offers a solution to these issues and is gaining worldwide attention as an innovative fabrication route. In this work, we proposed an alternative organic ferroelectric phase, gamma-glycine (γ-GC), which acts as a transient liquid phase to fabricate high-density composites with barium titanate (BT) at low temperatures through CSP. Our findings show that the density of 15γ-GC/85BT reached 96.7%±1.6% when it was sintered at 120 °C for 6 h under 10 MPa uniaxial pressure. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) mappings of the composite suggested that γ-GC completely underwent the precipitation–dissolution process and, therefore, filled between BT particles. Moreover, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the preservation of γ-GC without undesired phase transformation. In addition, the ferroelectric and dielectric properties of γ-GC/BT composites have been reported. The high dielectric constant (ε<inf>r</inf>) was 3600, and the low dielectric loss (tanδ) was 1.20 at 200 °C and 100 kHz for the 15γ-GC/85BT composite. The hysteresis loop showed a remanent polarization (P<inf>r</inf>) of 0.55 µC·cm-2 and a coercive field (E<inf>c</inf>) of 7.25 kV·cm-1. Our findings reaffirmed that an organic ferroelectric material (γ-GC) can act as a transient liquid phase in a CSP that can successfully and sustainably fabricate γ-GC/BT composites at low temperatures while delivering outstandingly high performance.
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Effect of surfactant concentration on the formation of Fe2O3@SiO2 NIR-reflective red pigments
(2021-05-01)
Soranakom, Piya
;
Vittayakorn, Naratip
;
Rakkwamsuk, Pattana
;
Supothina, Sitthisuntorn
;
Seeharaj, Panpailin
High NIR-reflective red pigments were developed by encapsulating Fe<inf>2</inf>O<inf>3</inf> particles in a transparent SiO<inf>2</inf> shell layer to form Fe<inf>2</inf>O<inf>3</inf>@SiO<inf>2</inf> core-shell structures. The pigments were prepared by a sol-gel process and the effect of CTAB surfactant concentration on structural formation and optical properties was investigated. The reaction between CTAB and silica species was found to increase the yield of SiO<inf>2</inf> formation, which had a major role to control the SiO<inf>2</inf> shell thickness by ranging from 8 to 62 nm when varying CTAB concentration from 0 to 2 mM. After encapsulation, Fe<inf>2</inf>O<inf>3</inf>@SiO<inf>2</inf> pigments still had the red-brown hue of hematite and the NIR reflectivity improved to 62.7 %–65.3%, or twice that of the uncoated Fe<inf>2</inf>O<inf>3</inf>. The pigments prepared using the highest CTAB concertation changed from the original Fe<inf>2</inf>O<inf>3</inf> color (CIE Lab color space coordinates) by only ΔE 8.2% due to the formation of second phase SiO<inf>2</inf> microspheres formed from excess CTAB micelles. The NIR-reflective red Fe<inf>2</inf>O<inf>3</inf>@SiO<inf>2</inf> pigments showed good chemical stability and light resistance, thus they were suitable for use as cool pigments for coating applications.
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Correlation of urea precipitation temperature with phase formation, morphology, and catalytic activity for CO2 conversion of CeO2
(2025-08-01)
Seeharaj, Panpailin
;
Duangtanon, Jenjira
;
Sreemueang, Chanakan
;
Noppharat, Phetchphalin
;
Kulthananat, Tachatad
This study proposes a simple method for tailoring the morphology and activity of cerium oxide (CeO<inf>2</inf>) catalysts in converting carbon dioxide (CO<inf>2</inf>) and methanol to green organic carbonate, dimethyl carbonate (DMC), to utilize and reduce CO<inf>2</inf> emissions. CeO<inf>2</inf> was prepared by urea precipitation at 85, 105, and 125 °C for 2 h, then calcining at 600 °C for 2 h. The phase structure and morphology of CeO<inf>2</inf> correlated with the urea hydrolysis rate. A low degree of supersaturation at 85 °C led to heterogeneous precipitation of cerium oxycarbonate (Ce<inf>2</inf>O(CO<inf>3</inf>)<inf>2</inf>.H<inf>2</inf>O) and CeO<inf>2</inf> with spherical morphology, while a higher degree of supersaturation at 105 °C and 125 °C resulted in homogeneous precipitation of single-phase Ce<inf>2</inf>O(CO<inf>3</inf>)<inf>2</inf>.H<inf>2</inf>O with spindle and elongated octahedral morphology, respectively. The spindle-shaped CeO<inf>2</inf> prepared at 105 °C with a predominant surface (111) facet showed the highest catalytic activity, with a DMC yield of 18.81 mmol.g<inf>cat</inf>−1. The enhanced catalytic efficiency of spindle-shaped CeO<inf>2</inf> was due to the high concentration of surface-active defect sites of exposed cerium cations and oxygen vacancies, which optimized the number of acid–base sites in adsorbing and activating CO<inf>2</inf> and methanol to produce DMC.
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CeO2/CuO/TiO2heterojunction photocatalysts for conversion of CO2to ethanol
(2021-09-10)
Seeharaj, Panpailin
;
Vittayakorn, Naratip
;
Morris, John
;
Kim-Lohsoontorn, Pattaraporn
An attempt to reduce CO2 emissions has led to the development of CeO2/CuO/TiO2 heterojunction photocatalysts for photoconversion of CO2 to useful products, e.g. ethanol. Composite photocatalysts were simply prepared by mixing TiO2 (P25) with different mass ratios of CeO2 (1 wt%) and CuO (2 or 3 wt%) by ball milling. The prepared photocatalysts had uniformly distributed CeO2 and CuO phases, throughout the TiO2 phase. The integration of CeO2 and CuO into TiO2 at 1 wt% CeO2 and 3 wt% CuO produced a composite, with a reduced band gap of 2.88 eV, allowing absorption of lower energy light and a lower electron-hole recombination rate. The 1%CeO2/3%CuO/TiO2 photocatalysts yielded ethanol at 30.5 μmol gcat-1 h-1, almost three times higher than the yield from pure TiO2. This improved CO2 conversion efficiency was due to contributions from properties of both additives: CeO2 increased light absorption, while CuO acted as an electron trap and enhanced CO2 adsorption. In addition, the heterojunction at the interfaces facilitated the photogenerated charge separation, which, in turn, increased the charge participation in the catalyzed conversion reactions.

Seeharaj, Panpailin

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