KMITL

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

Browse

Search Results

Now showing 1 - 10 of 10

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
Synergistic Enhancement of Mechanical and Dielectric Properties in BaTiO3/PDMS Composites for Flexible Energy Harvesting Devices
(2026-01-01)
Rerngroen, Nakulkarn
;
Sasipongpan, Apinya
;
Vittayakorn, Wanwilai
This study presents the fabrication, characterization, and performance evaluation of flexible piezoelectric composites based on polydimethylsiloxane embedded with varying volume fractions (0–25 vol%) of barium titanate nanoparticles. The composites were prepared via a conventional casting method and systematically analyzed to investigate the synergistic enhancement of their mechanical, dielectric, and piezoelectric properties. Structural and morphological analyses confirmed the retention of the crystalline BaTiO<inf>3</inf> phase and its uniform dispersion within the PDMS matrix, with some agglomeration observed at higher filler loadings. Mechanical testing revealed that the 20 vol% BaTiO<inf>3</inf> composite exhibited optimal tensile strength and flexibility. Dielectric measurements showed significant increase in the dielectric constant with increasing BaTiO<inf>3</inf> content, with the 25 vol% composite achieving a 100% enhancement compared to pure PDMS. Theoretical modeling was employed to compare experimental results with established effective medium theories. Under cyclic compression, the composites demonstrated a progressive increase in output voltage, reaching up to ~426 V at 25 vol% BaTiO<inf>3</inf>, surpassing performance reported in previous studies. Additionally, the incorporation of carbon nanotubes further enhanced dielectric efficiency and mechanical stretchability, although a slight reduction in piezoelectric output was observed. These results underscore the potential of BaTiO<inf>3</inf>/PDMS nanocomposites, with and without CNTs, for next-generation flexible energy harvesting devices.
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.
Some of the metrics are blocked by your
consent settings
High-performance flexible lead-free piezo-antiferroelectric based on NaNbO3/PDMS composites for energy harvesting application
(2024-12-01)
Sumang, Rattiphorn
;
Charoonsuk, Thitirat
;
Vittayakorn, Naratip
;
Panpho, Phakakorn
To bring the rapidly advancing technology of energy harvesters into commercial use, further development is required for devices that can enhance output performance, flexibility, ease of fabrication, and low cost. A hybrid concept is a promising method. It combines between the piezoelectric nanogenerator (PENG) and the triboelectric nanogenerator (TENG) to provide a high-performance nanogenerator. This study introduced a high-performance hybrid PENG and TENG device that operates using a NN-BNT/PDMS composite film. The NN-BNT/PDMS composite based nanogenerators were fabricated with varying NN-BNT content. Then, dielectric test and electrical properties were investigated. Adding NN-BNT into the PDMS composite film resulted in a higher dielectric constant compared to pure PDMS, leading to increase of electrical output. Under the optimal condition of a 3 wt%. NN-BNT composite based hybrid nanogenerator, the electrical output was significantly enhanced, reaching 40 V, 0.95 μA/cm2, and 200 μW/cm2 compared to pure PDMS. This nanogenerator further used to the charging of a capacitor to a voltage of around 1 V within 5 s and also powered multiple LEDs. The successful development of this highly efficient NN-BNT/PDMS composite film-based hybrid concept sheds light on energy harvesting devices.
Some of the metrics are blocked by your
consent settings
Flexible hybrid piezo/triboelectric energy harvester based on a lead-free BNT-BT-KNN ceramic-polymer composite film
(2024-12-01)
Panpho, Phakakorn
;
Charoonsuk, Thitirat
;
Vittayakorn, Naratip
;
Bongkarn, Theerachai
;
Sumang, Rattiphorn
Environment-friendly piezoelectric micro/nanogenerators have attracted tremendous attention due to the increasing demand for portable self-power devices. Here, the [(0.94−x)Bi<inf>0.5</inf>Na<inf>0.5</inf>TiO<inf>3</inf>–0.06BaTiO<inf>3</inf>–xK<inf>0.5</inf>Na<inf>0.5</inf>NbO<inf>3</inf>; BNT-BT-xKNN] lead-free ceramic, at x = 0, 0.02, 0.04, 0.06, 0.08 and 0.10 mol%, was prepared via the solid-state method. The doping concentration x = 0.02 mol% shows the highest dielectric properties and the lowest dielectric loss. The active layer of the hybrid device is made by mixing BNT-BT-2KNN into the PDMS to form a series of polymer-ceramic composite films ranging from 7 to 19 wt% of BNT-BT-2KNN. The electrical response of the composite film is systematically studied with the addition of different weight percentages of the particles to the PDMS matrix. It was found that incorporating BNT-BT-2KNN at 11 wt% into the PDMS matrix exhibited the optimum harvesting performance, resulting in an output voltage and current density of about 30 V and 0.28 μA/cm2, respectively. The hybridized PENG and TENG devices could operate in a long-term cyclic mode, charge the capacitor for energy storage, and also light up LEDs. This research proposed a simple device fabrication and provided a guideline for the development of high-performance microgenerators, which is crucial for device development and practical use in the future.
Some of the metrics are blocked by your
consent settings
Enhancement of Bacterial Anti−Adhesion Properties on Robust PDMS Micro−Structure Using a Simple Flame Treatment Method
(2022-02-01)
Houngkamhang, Nongluck
;
Chaisawat, Ploymanee
;
Joksathit, Waisaree
;
Samart, Sutichai
;
Chutipaijit, Sutee
Biofilm−associated infections caused by an accumulation of micro−organisms and pathogens significantly impact the environment, health risks, and the global economy. Currently, a non−biocide−releasing superhydrophobic surface is a potential solution for antibacterial purposes. This research demonstrated a well−designed robust polydimethylsiloxane (PDMS) micro−structure and a flame treatment process with improved hydrophobicity and bacterial anti−adhesion proper-ties. After the flame treatment at 700 ± 20 °C for 15 s, unique flower−petal re−entrant nano−structures were formed on pillars (PIL−F, width: 1.87 ± 0.30 μm, height: 7.76 ± 0.13 μm, aspect ratio (A.R.): 4.14) and circular rings with eight stripe supporters (C−RESS−F, width: 0.50 ± 0.04 μm, height: 3.55 ± 0.11 μm, A.R.: 7.10) PDMS micro−patterns. The water contact angle (WCA) and ethylene glycol contact angle (EGCA) of flame−treated flat−PDMS (FLT−F), PIL–F, and C–RESS−F patterns were (133.9 ± 3.8°, 128.6 ± 5.3°), (156.1 ± 1.5°, 151.5 ± 2.1°), and (146.3 ± 3.5°, 150.7 ± 1.8°), respectively. The Escherichia coli adhesion on the C−RESS−F micro−pattern with hydrophobicity and superoleophobicity was 42.6%, 31.8%, and 2.9% less than FLT−F, PIL−F, and Teflon surfaces. Therefore, the flame−treated C−RESS−F pattern is one of the promising bacterial anti−adhesion micro−structures in practical utilization for various applications.
Some of the metrics are blocked by your
consent settings
Piezoelectric-Induced Triboelectric Hybrid Nanogenerators Based on the ZnO Nanowire Layer Decorated on the Au/polydimethylsiloxane-Al Structure for Enhanced Triboelectric Performance
(2018-02-21)
Jirayupat, Chaiyanut
;
Wongwiriyapan, Winadda
;
Kasamechonchung, Panita
;
Wutikhun, Tuksadon
;
Tantisantisom, Kittipong
Here, we demonstrate a novel device structure design to enhance the electrical conversion output of a triboelectric device through the piezoelectric effect called as the piezo-induced triboelectric (PIT) device. By utilizing the piezopotential of ZnO nanowires embedded into the polydimethylsiloxane (PDMS) layer attached on the top electrode of the conventional triboelectric device (Au/PDMS-Al), the PIT device exhibits an output power density of 50 μW/cm2, which is larger than that of the conventional triboelectric device by up to 100 folds under the external applied force of 8.5 N. We found that the effect of the external piezopotential on the top Au electrode of the triboelectric device not only enhances the electron transfer from the Al electrode to PDMS but also boosts the internal built-in potential of the triboelectric device through an external electric field of the piezoelectric layer. Furthermore, 100 light-emitting diodes (LEDs) could be lighted up via the PIT device, whereas the conventional device could illuminate less than 20 LED bulbs. Thus, our results highlight that the enhancement of the triboelectric output can be achieved by using a PIT device structure, which enables us to develop hybrid nanogenerators for various self-power electronics such as wearable and mobile devices.
Some of the metrics are blocked by your
consent settings
AFM force distance curve measurement for surface investigation of polymers compound blend with metal nanoparticles
(2017-01-01)
Koetniyom, W.
;
Suhatcho, T.
;
Treetong, A.
;
Thiwawong, T.
The atomic force microscopy (AFM) has been used to perform surface force measurements in contact mode to investigate surface properties of model systems in the nanoscale. Two different polymers compound are observed include Polydimethylsiloxane (PDMS) and Polyvinylidene fluoride (PVDF). Both polymers compound are blended with metal nanoparticles consist of gold and silver by compare with the pristine polymer. The results from adhesion force and surface roughness tests are inversed. The adhesion force is increased with the NPs concentration whereas the surface roughness is decreased. Hydrophobic and hydrophilic properties of the polymer have been studied by employing contact angle. However, variation of contact angle of polymer nanocomposites is confirmed the hydrophobicity of PDMS while PVDF is certainly different around 70-77° of Ag NPs and 70-81° of Au NPs.
Some of the metrics are blocked by your
consent settings
Study of PDMS compounds using the adhesion force determined by AFM force distance curve measurements
(2010-02-05)
Vanitparinyakul, S.
;
Pattamang, P.
;
Chanhom, A.
;
Tunhoo, B.
;
Thiwawong, T.
The atomic force microscope(AFM) was used to perform surface force measurements in contact mode to investigate surface properties of model systems at the nanoscale. Three different Polydimethylsiloxane (PDMS) compounds were observed. The first consisted of pure PDMS, the second of PDMS blend with the nanoparticles Zinc Oxide(PDMS/ZnO) and the third of PDMS blend with the nanoparticles Zinc Oxide and toluene solvent(PDMS/ZnO/toluene), respectively. Surface morphology and the adhesion force were investigated by using atomic force microscopy. Force - distance curve measurement was performed in a contact mode, which used tip as silicon nitride. Moreover, we found a significantly different of the adhesion force when modified by nanoparticles ZnO and toluene solvent. © (2010) Trans Tech Publications.
Some of the metrics are blocked by your
consent settings
A disposable polydimethylsiloxane microdevice for DNA amplification
(2010-02-05)
Lekwichai, A.
;
Porntheeraphat, S.
;
Bunjongpru, W.
;
Sripumkhai, W.
;
Supadech, J.
In this study, we demonstrate the disposable polydimethylsiloxane (PDMS) microchip provided for DNA amplification. The device consists of two main parts. The first part is PDMS/glass stationary chamber, the other part is a temperature-control microdevice on SiO<inf>2</inf>/Si substrate. This device consists of a thin film Pt-microheater and a Pt-temperature sensor, which were fabricated with CMOS compatible process. The performance of the device in the DNA amplification shows that, with 10 μl of PCR mixture volume, the approximately 700 bp DNA were successfully amplified within 50 minutes by 30 PCR cycles. The amplified products were comparable with those of a conventional method using electrophoresis. The PCR chip is also suitable for mass production. © (2010) Trans Tech Publications.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results