KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 84

Some of the metrics are blocked by your
consent settings
Upcycling waste mycelium into chitosan-based biodegradable triboelectric nanogenerators with enhanced energy output
(2026-12-01)
Panpho, Phakakorn
;
Charoonsuk, Thitirat
;
Pakawanit, Phakkhananan
;
Bongkarn, Theerachai
;
Vitayakorn, Narathip
Sustainable nanogenerators require bio-based active layers that combine interfacial polarization, mechanical deformability, and stable charge generation. Herein, waste mushroom mycelium (WMM) was upcycled as a multifunctional biofiller in chitosan (CTS)-based films for piezoelectric/triboelectric energy-harvesting devices. By controlling WMM loading and glycerol plasticization, this study reveals a morphology–dielectric–compliance coupling mechanism governing device performance. FTIR, XRD, SEM, and X-ray tomographic analyses show that WMM modifies hydrogen bonding, chain packing, surface texture, and internal filler connectivity, while excessive loading causes aggregation and structural non-uniformity. The optimized 7 wt% WMM/CTS film produced a PENG-mode output of 1.87 V and 1.72 μA and a TENG output of 15.39 V and 2.54 μA. The output of the TENG was further improved to 20.35 V and 2.80 μA at a maximum power of about 44 μW with glycerol plasticization. Capacitor charging, cyclic operation, LED array illumination and seven-segment display were also shown with the optimized device. Notably, the highest low-frequency apparent permittivity was observed at 11 wt% WMM/CTS, but its output decreased because of aggregation, dielectric loss, and mechanical non-uniformity. These results demonstrate that optimum energy harvesting is governed not by dielectric permittivity alone but by balanced polar interfaces, surface asperity, moderate dielectric loss, and contact compliance. This work establishes waste mycelium as a functional biofiller for sustainable biopolymer active layers in low-power self-powered systems.
Some of the metrics are blocked by your
consent settings
Enhanced densification and thermoelectric properties of Ca3Co4O9 ceramics fabricated by solid-state combustion and hot-pressing
(2026-11-15)
Thatawong, Bhoowadol
;
Sriondee, Manlika
;
Chongsatan, Wistsarut
;
Palaporn, Dulyawich
;
Pinitsoontorn, Supree
The Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> powders were synthesized by the solid-state combustion method and then calcined at 775-875 °C for 6 h. The combination of combustion-derived fine powders and hot pressing was adopted to improve the densification and thermoelectric (TE) performance of Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> ceramics. Dense Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> ceramics were subsequently fabricated by hot-pressing to investigate the influence of hot-pressing temperature (800-950 °C, 2 h) on phase formation, microstructure, electrical, and TE properties. The Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> powder was obtained after calcination at 800 °C for 6 h and exhibited an average particle size of 0.55 μm. XRD analysis confirmed that Ca<inf>3</inf>Co<inf>4</inf>O<inf>9</inf> was the predominant phase in all hot-pressed samples. XPS analysis further confirmed the presence of oxygen vacancy (V<inf>O</inf>++)-related defects and mixed-valence cobalt species. FESEM observations revealed a dense microstructure composed of plate-like grains with an average grain size ranging from 0.61 to 0.96 μm. The bulk density ranged from 4.31 to 4.46 g/cm3, indicating dense ceramics. The electrical resistivity (ρ) decreased with increasing measured temperature for all samples. Among all samples, the ceramic hot-pressed at 900 °C exhibited the lowest ρ at 600 °C. The Seebeck coefficient (S) significantly increased from 150 μV/K to 223 μV/K, while the thermal conductivity (κ) decreased with increasing temperature. Due to the favorable combination of low ρ and high S, the sample hot-pressed at 900 °C achieved the highest power factor (PF) and a maximum dimensionless figure of merit (ZT) of 0.17 at 600 °C.
Some of the metrics are blocked by your
consent settings
Integration of CCTAO/PDMS composite films into proximity capacitive sensor devices
(2026-12-01)
Bongkarn, Theerachai
;
Panpho, Phakakorn
;
Charoonsuk, Thitirat
;
Vittayakorn, Naratip
;
Pakawanit, Phakkhananan
Flexible capacitive proximity sensors are promising for contactless sensing applications, but their performance is strongly influenced by the dielectric properties and microstructure of the sensing layer. In this work, CaCu<inf>3</inf>Ti<inf>4-x</inf>A<inf>x</inf>O<inf>12</inf>/polydimethylsiloxane (CCTAO/PDMS, A = Nd3+ or Gd3+) composite films were developed as flexible dielectric layers for interdigitated capacitive proximity sensors. Nd- and Gd-doped CCTO ceramics were synthesized by a solid-state reaction method and incorporated into a PDMS matrix at different filler loadings. Structural analysis confirmed that the CCTAO ceramics retained the cubic CCTO phase after rare-earth substitution, while the composite films preserved the characteristic amorphous structure of PDMS with embedded ceramic fillers. The FESEM, EDS mapping and X-ray tomographic microscopy analyses showed that the CCTNdO/PDMS composite had a more uniform distribution of ceramic particles than the CCTO/PDMS system. The dielectric measurements demonstrated the improvement in the dielectric constant of the PDMS-based composites upon CCTNdO incorporation and also indicated that the composites did not exhibit any significant changes in their dielectric properties across the range of frequencies examined. The CCTNdO/PDMS films were found to show the negative capacitance response as a function of distance due to the electric-field shunting mechanism when used in an interdigitated capacitor sensor. The sensor with composition 10 wt% CCTNdO/PDMS had excellent performance with a maximum normalized capacitance change equal to −8.70%, which corresponds to a proximity sensitivity of around 0.42%/mm and an effective sensing range of around 20 mm. It is concluded that the optimization of the loading of the rare-earth material in a flexible PDMS matrix is an effective approach to achieve a compromise between the dielectric enhancement of the sensor and the dispersion of the filler and fringing-field interaction in the contactless capacitive proximity sensor.
Some of the metrics are blocked by your
consent settings
Fabrication of BNBT-BS ceramics via a solid-state combustion approach for BNBT-BS/PDMS composite films in hybrid PENG/TENG applications
(2026-10-01)
Luangpangai, Anupong
;
Apirattanon, Nattapong
;
Yimsabai, Sununta
;
Sumang, Rattiphorn
;
Rittidech, Aurawan
Synthesis of (1-x)Bi<inf>0.47</inf>Na<inf>0.47</inf>Ba<inf>0.06</inf>TiO<inf>3</inf>-xBaSnO<inf>3</inf> ceramics (BNBT-xBS, where 0 ≤ x ≤ 0.05) was accomplished via a solid-state combustion approach. The influence of BaSnO<inf>3</inf> concentration on the phase structure, microstructure, dielectric, ferroelectric and strain properties was thoroughly examined. All specimens exhibited the coexistence of rhombohedral and tetragonal phases within a pure perovskite structure. The composition with x = 0.01 demonstrated optimal electrical properties, achieving a dielectric constant (ɛ<inf>m</inf>) of 6199, a maximum polarization (P<inf>max</inf>) of 41.86 μC/cm2, a maximum strain (S<inf>max</inf>) of 0.34% and a normalized strain (d<inf>33</inf>*) of 489 pm/V. The ceramic powder of BNBT-0.01BS was incorporated into a PDMS matrix at concentrations ranging from 0 to 30 wt%. The hybrid PENG/TENG devices achieved their largest electrical output at a BNBT-0.01BS loading of 20 wt%, recording a voltage of 92 V and a current of 0.50 μA. This work outlines a fabrication and development method for composite films with BNBT-0.01BS with PDMS polymers for high-efficiency nanogenerators, playing an important role in improving future energy harvesting technologies.
Some of the metrics are blocked by your
consent settings
Structure–property correlations and magnetoelectric response of lead-free BNT–BCTS/CZFMO composite ceramics
(2026-06-01)
Kornphom, Chittakorn
;
Sonchaopri, Nutkamon
;
Yimsabai, Sununta
;
Yotthuan, Surirat
;
Jantaratana, Pongsakorn
Lead-free multiferroic composite ceramics have garnered increasing attention as an eco-friendly alternative for magnetoelectric (ME) devices. In this work, (100-x) [0.93(Bi<inf>0.5</inf>Na<inf>0.5</inf>TiO<inf>3</inf>) 0.07(Ba<inf>0.945</inf>Ca<inf>0.055</inf>Ti<inf>0.91</inf>Sn<inf>0.09</inf>O<inf>3</inf>)]/xCo<inf>0.6</inf>Zn<inf>0.4</inf>Fe<inf>1.7</inf>Mn<inf>0.3</inf>O<inf>4</inf> composite ceramics, abbreviated as (100-x) BNT-BCTS/xCZFMO were synthesized via a solid-state combustion route. Analysis of XRD data using the Rietveld method confirmed the coexistence of rhombohedral and tetragonal perovskite (BNT–BCTS) phases and a cubic spinel (CZFMO) phase without additional impurity phases. The 0–3 connectivity was verified using SEM/EDS, PFM, and MFM measurements, confirming discrete CZFMO magnetic grains are embedded within a continuous BNT–BCTS piezoelectric matrix. Williamson–Hall (W–H) analysis, treated as a semi-quantitative approach due to fitting limitations in the multiphase composite system, suggested a composition-dependent microstrain trend. The reduced microstrain at intermediate CZFMO contents was consistent with enhanced crystallite growth, improved densification, and the maximum magnetoelectric response. The composition with x = 20 exhibits the highest relative density (~ 98.14%), the highest saturation magnetization (M<inf>s</inf> = 6.55 emu/g), and the maximum magnetoelectric coefficient (α<inf>ME</inf> = 7.92 mV cm−1 Oe−1), showing higher ME coefficients than many previously reported lead-free composites. This work demonstrates the potential of BNT–BCTS/CZFMO composites for multifunctional electronic devices, including magnetic sensors, energy harvesters, and magnetoelectric transducers.
Some of the metrics are blocked by your
consent settings
Piezoelectric composite films for real-time foot strike detection and energy generation
(2025-12-16)
Panpho, Phakakorn
;
Charoonsuk, Thitirat
;
Vittayakorn, Naratip
;
Charoenthai, Nipaphat
;
Bongkarn, Theerachai
Energy harvesting technology integrated into running shoes enables the conversion of mechanical energy from foot strikes into electrical signals for real-time monitoring. This approach enhances running efficiency, reduces injury risk, and eliminates the need for external power sources. In this study, composite films combining lead-free piezoelectric ceramics (KNNS-BNZ-xBF) with PDMS were developed for efficient energy harvesting and accurate detection of foot-strike patterns. XRD analysis revealed a broad R–O–T phase coexistence zone (0 ≤ x ≤ 0.006) and a transition to an R–T phase boundary for x > 0.006, with reduced grain size as xBF increased. The sample with xBF = 0.006 mol.% showed optimal electrical properties and was selected for composite film fabrication. Electrical output increased with ceramic loading, reaching maximum open-circuit voltage (V<inf>OC</inf>) and short-circuit current (I<inf>SC</inf>) at 18 wt% KBB due to enhanced piezoelectric response and uniform particle dispersion. The films, mounted on running shoe soles, successfully detected different foot-strike patterns (heel strike, midfoot, and forefoot). This system demonstrates strong potential for wearable sensors in athletic monitoring and injury prevention.
Some of the metrics are blocked by your
consent settings
Optimal Bi₀.₈Ba₀.₂FeO₃ doping in Bi₀.₅(Na₀.₇₇K₀.₂₀Li₀.₀₃)₀.₅TiO₃ multiferroic ceramics synthesized by the solid-state combustion technique
(2025-12-01)
Thawong, Pichittra
;
Prasertpalichat, Sasipohn
;
Suriwong, Tawat
;
Pinitsoontorn, Supree
;
Jantaratana, Pongsakorn
(1-x)Bi<inf>0.5</inf>(Na<inf>0.77</inf>K<inf>0.20</inf>Li<inf>0.03</inf>)<inf>0.5</inf>TiO<inf>3</inf>-xBi<inf>0.8</inf>Ba<inf>0.2</inf>FeO<inf>3</inf> ((1-x)BNKLT-xBBF) ceramics with x = 0-0.4 were synthesized by the solid-state combustion technique. X-ray diffraction (XRD) analysis confirmed a pure perovskite structure with coexisting rhombohedral and tetragonal phases. Rietveld refinement revealed that the unit cell volume increased with increased x due to the substitution of smaller Bi3+ and Ti4+ ions by larger Ba2+ and Fe3+ ions at the A- and B-sites, respectively. The average grain size and measured density also increased with increasing x, while the resistivity decreased. At room temperature, (1-x)BNKLT-xBBF ceramics with x = 0.2–0.4 exhibited multiferroic behavior, characterized by ferroelectric and ferromagnetic hysteresis loops. The 0.8BNKLT-0.2BBF ceramic exhibited the most favorable properties, including: the highest relative density (95.48%), the highest dielectric constant and low dielectric loss at room temperature (ε<inf>R</inf> = 1746 and tan δ<inf>R</inf> = 0.0296), good ferroelectric properties (P<inf>r</inf>=6.46 µC/cm2 and E<inf>c</inf>=11.84 kV/cm) and good ferromagnetic properties (M<inf>r</inf>=0.002 emu/g, H<inf>c</inf>=110 Oe and α<inf>E</inf> = 1.092 mV/Oe·cm). These results indicate that 0.8BNKLT-0.2BBF has the potential for applications in lead-free, room temperature multiferroic applications.
Some of the metrics are blocked by your
consent settings
A Kirigami-Engineered “Skeletal Framework” Composite for Ultralow Hysteresis and Highly Stable Strain Sensors
(2025-11-24)
Pongampai, Satana
;
Chaithaweep, Kanokwan
;
Pakawanit, Phakkhananan
;
Charoonsuk, Thitirat
;
Bongkarn, Theerachai
Wearable strain sensors are pivotal for next-generation human–machine interfaces, yet achieving high fidelity, robustness, and sustainability in a single platform remains a significant challenge. A primary obstacle is the inherent viscoelasticity of soft materials, which leads to signal drift and hysteresis. Here, we report a highly stretchable and ultrastable strain sensor fabricated through a synergistic integration of Kirigami-based structural engineering and nanocomposite material design. By introducing titanium dioxide nanotubes (TNTs) into a bacterial cellulose (BC) matrix, we create a composite with a unique internal “skeletal framework”. This framework substantially reduces viscoelastic losses, resulting in an exceptionally low hysteresis of 0.6% and ensuring robust performance with 99.4% signal stability over >10 000 cycles. Concurrently, the Kirigami-patterned structure enhances stretchability to ∼235% while the framework amplifies sensitivity 5.8-fold. The practical viability of this high-fidelity sensor is demonstrated through the precise and repeatable control of a robotic arm, where ultralow hysteresis proves more critical than raw sensitivity. The sensor’s eco-friendly, water-based fabrication aligns high-fidelity sensing with sustainable processing, presenting a clear design paradigm for engineering reliable and eco-conscious wearable electronic devices.
Some of the metrics are blocked by your
consent settings
Multifunctional properties of Mn and Fe co-doped lead-free BCT perovskite ceramics synthesized via solid-state combustion
(2025-10-01)
Kornphom, Chittakorn
;
Sonchaopri, Nutkamon
;
Yimsabai, Sununta
;
Jantaratana, Pongsakorn
;
Pinitsoontorn, Supree
There is a growing demand to improve the performance of multiferroic lead-free ceramics. Good ferroelectric and magnetic properties are key parameters for achieving high magnetoelectric coupling (ME). In this work, Mn and Fe were co-doped into lead-free Ba<inf>0.96</inf>Ca<inf>0.04</inf>Ti<inf>(1-x)</inf>(Mn<inf>0.5</inf>Fe<inf>0.5</inf>)<inf>x</inf>O<inf>3</inf> (BCT-xMF) ceramics with 0 ≤ x ≤ 0.030 mol%, synthesized by the solid-state combustion technique. X-ray diffraction (XRD) analysis and Rietveld refinement confirmed the formation of a pure phase with coexisting tetragonal and cubic phases in all compositions. As the Mn/Fe content increased, the percentage of the tetragonal phase decreased while the cubic phase increased, consistent with Raman spectroscopy results. Increasing Mn/Fe content also led to more oxygen vacancies and defects, and a decrease in average grain size. Analysis of the temperature-dependent dielectric constant revealed a reduction in the Curie temperature from 116 to 67 °C, corresponding to the tetragonal-to-cubic phase transformation. The ceramic with x = 0.015 showed the highest dielectric constant at the Curie temperature (ε<inf>c</inf>), maximum saturated polarization (P<inf>s</inf>), remnant polarization (P<inf>r</inf>), saturation magnetization (M<inf>s</inf>), and remnant magnetization (M<inf>r</inf>), with values of 4583, 14.09 μC/cm2, 9.31 μC/cm2, 0.0127 emu/g, and 0.006 emu/g, respectively. These results indicate that Fe/Mn co-doping into BCT ceramics enhanced both ferroelectric and ferromagnetic properties, resulting in a high magnetoelectric coefficient (α<inf>ME</inf>∼1.27 mV/cm Oe) at room temperature, making these ceramics candidates for multiferroic applications.
Some of the metrics are blocked by your
consent settings
High-performance triboelectric and piezoelectric nanogenerator enabled by BF-BT-NZN multifunctional ceramic filler
(2025-10-01)
Sumang, Rattiphorn
;
Jantaratana, Pongsakorn
;
Charoonsuk, Thitirat
;
Vittayakorn, Naratip
;
Bongkarn, Theerachai
The development of efficient and flexible energy-harvesting materials is essential for advancing self-powered electronic devices. In this study, we report the fabrication of flexible composite films by incorporating (1-x)(0.75BiFeO<inf>3</inf>-0.25BaTiO<inf>3</inf>)-xNd(Zn<inf>0.67</inf>Nb<inf>0.33</inf>)O<inf>3</inf>,abbreviated as (BF-BT-NZN), ceramic powder into a PDMS matrix, with filler contents ranging from 5 to 25 wt%. The optimized 10 wt% composite film demonstrated a maximum output voltage of 112.24 V and a current of 5.69 µA approximately 11 and 18 times higher than pure PDMS, respectively. Following a poling treatment, the output further increased to 149.54 V and 10.71 µA. The film exhibited excellent flexibility and durability, enabling practical applications such as powering LEDs, a digital watch, and charging capacitors. These results highlight the potential of BF-BT-NZN/PDMS composites as high-performance materials for wearable energy-harvesting applications.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results