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Kinetic analysis of liquid–solid contact electrification: Using adsorption models as mechanistic probes for hybrid EDL behavior
(2026-08-01)
Chaithaweep, Kanokwan
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Pharino, Utchawadee
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Pongampai, Satana
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Sriphan, Saichon
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Charoonsuk, Thitirat
Liquid–solid interfaces are central to technologies ranging from energy storage to triboelectric nanogenerators (TENGs). Whereas classical electric double layer (EDL) theory describes these interfaces mainly in terms of electrostatic ion adsorption, hybrid EDL concepts suggest that interfacial electron transfer may also contribute importantly to charge generation. However, the hybrid EDL model has so far been discussed primarily at a qualitative level or through complex theoretical and computational treatments, and a simple, experimentally accessible macroscopic kinetic handle that can discriminate, in operando, between adsorption‑dominated and ET‑influenced regimes remains lacking. By analyzing high-resolution charging dynamics over systematically varied H₂SO₄ and HNO₃ concentrations, a clear concentration-dependent kinetic transition is identified. At low ionic strengths, the charging process is described more effectively by pseudo-second-order (PSO) kinetics, consistent with a reaction-influenced interfacial step, whereas at higher concentrations the system becomes pseudo-first-order (PFO) dominated, consistent with transport- and ion-screening-controlled behavior. Although previous studies have provided compelling theoretical and spectroscopic evidence that interfacial electron transfer contributes to liquid–solid contact electrification in TENGs, these mechanisms have rarely been examined through such simple macroscopic kinetic formalisms. In this work, classical adsorption kinetic models are used as operational probes for distinguishing electron-transfer-influenced regimes from ion-transport-dominated regimes at PTFE/liquid interfaces. The PSO-to-PFO crossover reported here is interpreted within the hybrid EDL framework as a kinetic marker of a transition from an electron-transfer-influenced charging regime at low concentration to an ion-transport- and screening-dominated regime at high concentration, thereby demonstrating how adsorption kinetics can serve as a practical diagnostic language for liquid–solid triboelectric systems.
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Flexible and Self-Powered Wearable Sensors for Tremor Monitoring in Parkinson'S Disease: Recent Advances in Materials and Device Architectures
(2026-01-01)
Ukasi, Sirinya
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Hajra, Sugato
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Kim, Hoe Joon
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Sriphan, Saichon
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Pongampai, Satana
Parkinson's disease (PD) is a progressive neurodegenerative disorder where tremor remains one of the most prominent and disabling motor symptoms. Traditional clinical rating scales for disease severity rely on clinician observation and patient self-report, often failing to capture the dynamic and continuous nature of tremors in daily life. This drives the development of objective monitoring technologies, such as wearable sensors, for more accurate evaluation of PD severity. However, many existing systems use rigid materials that lack the mechanical compliance and skin conformability required for stable biointegration. This review summarizes advances in flexible wearable sensors for PD tremor assessment from material innovations to a device engineering perspective, covering inertial measurement units (IMUs), electromyography (EMG), and emerging self-powered systems such as triboelectric (TENG) and piezoelectric nanogenerators (PENG). This review highlightshow functional materials, microstructural design, and device architectures govern sensing mechanisms and performance, with particular emphasis on the transition from rigid components to soft, skin-interfaced technologies. Recent patent activity reflects a shift toward multimodal, wireless, and clinically integrated platforms. Despite progress, challenges remain, including motion artifacts, durability, and limited large-scale clinical validation. Integration of flexible materials, self-powered designs, and AI-driven analytics enables continuous, personalized monitoring, moving closer to real-world clinical deployment and improved patient care.
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A Kirigami-Engineered “Skeletal Framework” Composite for Ultralow Hysteresis and Highly Stable Strain Sensors
(2025-11-24)
Pongampai, Satana
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Chaithaweep, Kanokwan
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Pakawanit, Phakkhananan
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Charoonsuk, Thitirat
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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.
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Synergistic Integration of MgAl-LDH Nanosheets into Bacterial Cellulose for High-Performance Triboelectric Nanogenerators
(2025-08-04)
Mohsom, Phitchayaphorn
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Suktep, Natdanai
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Sae-Tang, Chanachot
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Pongampai, Satana
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Pakawanit, Phakkhananan
A novel nanocomposite design is presented in which magnesium aluminum layered double hydroxide (MgAl-LDH) nanosheets are synergistically integrated with bacterial cellulose (BC) to fabricate a flexible triboelectric nanogenerator (TENG). Utilizing a facile solution synthesis combined with a casting process, composite films with controlled MgAl-LDH loadings (0.25–5% v/v) were developed. The optimal composite, containing 1.5% v/v MgAl-LDH, exhibits an open-circuit voltage (V<inf>OC</inf>) of 88.5 V, a short-circuit current (I<inf>SC</inf>) of 87.7 μA, and a maximum output power (P<inf>max</inf>) of 1250 μW (power density ≈138 μW/cm2), which is > 35 times higher than that of pristine BC. Notably, this performance corresponds to a superior filler efficiency metric, demonstrating a highly effective use of the nanosheet additive compared to other reported systems. This performance enhancement is attributed to the multifunctional role of MgAl-LDH nanosheets in increasing the dielectric constant through improved interfacial conductivity and the formation of parallel microcapacitors under an induced electric field. Finite element simulations corroborate the proposed mechanism, and practical demonstrations show the nanocomposite powering 200 LEDs as well as functioning as a self-powered sensor for finger movement monitoring. These findings advance the development of high-performance, flexible energy-harvesting devices.
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Synergistic Piezo- and Triboelectricity in a Novel Triglycine Sulfate/Bacterial Cellulose/Chitosan Flexible Composite Nanogenerator
(2025-08-14)
Ukasi, Sirinya
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Saichompoo, Kittipan
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Sae-tang, Chanachot
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Pakawanit, Phakkhananan
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Pongampai, Satana
Organic piezoelectric materials offer sustainable alternatives for mechanical energy harvesting (MEH), yet their potential remains underexplored compared to inorganic counterparts. This study pioneers the use of triglycine sulfate (TGS), a rarely studied organic piezoelectric, within a flexible three-phase composite with bacterial cellulose (BC) and chitosan (CS) for piezoelectric (PENG) and triboelectric (TENG) nanogenerators. Unlike widely researched systems, TGS's unique hybrid organic–inorganic nature is leveraged here for the first time in MEH. Optimized at a 50:50 BC:CS ratio with 40 wt.% TGS, achieves a TENG output of 141.2 V and 93.3 µA post-poling—1.8 and 2.4 fold higher than unpoled samples—driven by TGS's dipole alignment. Separately, the configuration utilizing a 5 wt.% TGS loading yields 13.7 V and 0.19 µA. Advanced characterization (ATR-FTIR, SR-XTM) and simulations (COMSOL, DFT) reveal TGS's synergy with BC/CS roughness, enhancing charge generation. Delivering 118.65 µW cm−2, the TENG (from the 40 wt.% TGS poled sample) powers a digital watch, showcasing practical promise. This work not only introduces TGS as a novel MEH candidate but also provides mechanistic insights into its polarization, advancing bio-hybrid nanogenerator design.
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High-Performance Droplet-Based Triboelectric Nanogenerators: A Comparison of Device Configuration and Operating Parameters
(2025-05-06)
Chaithaweep, Kanokwan
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Pharino, Utchawadee
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Pongampai, Satana
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Hajra, Sugato
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Kim, Hoe Joon
Droplet-based electricity generators (DEGs) harness liquid-solid electrification to convert water droplets impacts into electrical energy. This study systematically examines how droplet height, droplet volume, flow rate, and substrate tilt angle influence DEG performance using polytetrafluoroethylene (PTFE) as a triboelectric layer and deionized water. Three electrode designs (double, top, bottom) are evaluated, revealing that the double-electrode configuration delivers the highest output. This enhanced performance arises from synergistic droplet motion, electrical double-layer formation, and charge discharge, as validated by an equivalent circuit model. By varying droplet heights from 1–20 cm, volumes of 7.7–50 µL, flow rates of 50–300 drops/min, and tilt angles of 0–90°, an optimized setup yields −70 V and 22 mA, translating to a power density of 0.28 µW cm−2. High-speed imaging correlates these outputs with droplet impact dynamics and the resulting charge transfer. Additionally, the optimized DEG can power small electronic devices, charge capacitors, and monitor artificial acid rain in real-time, displaying distinct electrical signals compared to typical rainwater. These findings underscore the potential of DEGs as renewable energy harvesters and smart environmental sensors, paving the way for advanced on-demand power generation in diverse settings.
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A highly sensitive disease pre-screening approach for glycosuria: Triboelectric sensing at the liquid-solid interface
(2025-03-15)
Pharino, Utchawadee
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Chaithaweep, Kanokwan
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Pongampai, Satana
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Chanlek, Narong
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Kothan, Suchart
Prescreening and disease detection offer significant benefits in the prevention of serious illnesses. Traditional screening methods for disease identification have been complex and expensive, often requiring invasive procedures, which can be both harmful and uncomfortable. To address these limitations, various non-invasive screening technologies have been developed. Among recent innovations, the liquid–solid interface concept has emerged as a promising avenue for nanogenerator applications, enabling the harvesting and sensing of liquid energy and substances. In this study, we introduce a liquid–solid interface triboelectric sensor (LS-TES) for non-invasive disease screening and sensing. The LS-TES, utilizing a double-electrode configuration, delivers an immediate electrical response upon droplet contact with the solid surface and top electrode. In the case of urine glucose monitoring, our findings demonstrate a significant reduction in electrical signals with increasing concentrations of glucose, as glucose molecules hinder electron transfer from water to the solid surface, thereby disrupting the formation of the electrical double layer at the liquid–solid interface. The sensor exhibits excellent glucose sensing performance within a concentration range of 0.2 mM to 14 mM, with a detection limit of 0.25 mM and a rapid response time of 5–10 s. The LS-TES is cost-effective, highly stable, and reusable, maintaining consistent electrical responses across ten cycles of alternating droplet measurements. This work presents a preclinical assessment approach, specifically for urine glucose monitoring, utilizing an innovative sensor based on the liquid–solid interface. The proposed concept has the potential to serve as an individual indicator for early medical symptom detection, offering relief to a large number of patients.
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Effective rare-earth dielectric addition and gamma ray irradiation for achieving highly efficient PDMS triboelectric nanogenerator
(2025-02-01)
Saichompoo, Kittipan
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Kingkam, Wilasinee
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Issarapanacheewin, Sudarat
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Ukasi, Sirinya
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Pongampai, Satana
This research aims to develop the flexible triboelectric nanogenerator (TENG) using PDMS polymer as the main tribo-material and composite with dielectric rare earth oxide, lanthanum chromite compound; LaCrO<inf>3</inf>, to enhance generated charge density, before add-on its higher electrical output with gamma ray irradiation. Upon study the effect of different amounts of the loaded LaCrO<inf>3</inf> and various doses of gamma ray, the optimum condition can be obtained. The PDMS/LaCrO<inf>3</inf> at 5 wt% can reach open-circuit voltage (V<inf>OC</inf>) and shot-circuit current (I<inf>SC</inf>) at 89 V and 448 μA. The impressive results of output further appear by additional irradiated gamma radiation. At 150 kGy dose of Irradiated gamma ray, V<inf>OC</inf> and I<inf>SC</inf> can jump to 161 V and 963 μA. These output signals, especially I<inf>SC</inf>, can be ∼34 times higher than that of the pristine PDMS. Scientific discussion regarding characterization, operating mechanism, dielectric properties and electrical output is provided. The practical application of being a small power source is also developed. Therefore, this research can show another useful application of gamma ray in the field of materials design for energy harvesting devices. The knowledge provided in this research can also serve as potential guidance in the field of specific TENG utilization.
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RARE EARTH OXIDE DIELECTRICS FOR FLEXIBLE TRIBOELECTRIC NANOGENERATOR
(2025-01-01)
Kingkam, Wilasinee
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Issarapanacheewin, Sudarat
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Ukasi, Sirinya
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Pulphol, Phieraya
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Pakawanit, Phakkhananan
Rare earth oxides (REO) are well known in catalysts, glass-related industries, and permanent magnets manufacturing for almost 70%, according to the mature industry. This work proposes the new developments of REO as the emergence for mechanical energy harvesting (MEH) technology. The binary-system of REO or R<inf>2</inf>O<inf>3</inf>, including La<inf>2</inf>O<inf>3</inf>, Sm<inf>2</inf>O<inf>3</inf> and Nd<inf>2</inf>O<inf>3</inf>, are used as dielectric materials to incorporate polydimethylsiloxane (PDMS) for fabricating flexible triboelectric nanogenerators (TENG), one of MEH devices. The change in REO’s amount was studied at 0.5, 2.5, 5, and 10 wt%. Upon applying mechanical force in vertical direction, the PDMS/R<inf>2</inf>O<inf>3</inf> TENG can convert mechanical energy into electricity for the best value of ~66 V and ~93 μA with power density of about ~62 μW·cm-2. The PDMS/La<inf>2</inf>O<inf>3</inf> can be used to fully charge the 0.22 and 0.33 μF capacitor within 3 seconds and power up over 100 LEDs directly. Moreover, the influence of triboelectric polarity and dielectricity on the triboelectric output performance is scientifically discussed by following the percolation point with air breakdown limitation’s theory. The researcher believes that the knowledge of this work will be inexhaustible useful to develop a group of REO in broad applications of MEH electronics in future.
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DESIGNING WEAVING PATTERN AND ENGINEERING MULTILAYER STRUCTURE OF NYLON-ACRYLIC FABRIC UTILIZING IN TRIBOELECTRIC NANOGENERATOR
(2025-01-01)
Navatragulpisit, Suchanat
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Krailadsirirattna, Praophansupa
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Khwanming, Rawiwan
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Pongampai, Satana
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Plaipichit, Suwan
In the contemporary era, the textile triboelectric nanogenerator (T-TENG) has sparked interest to be a powerful energy supply for small electronic devices and electronic component in next generation of electronic textiles. Most T-TENG is developed by adding other materials to fabric or cloths that probably limit the comfortable use. Fabrication of conformable fabrics with high triboelectric outputs remains challenging. This research is firmly focused on the development of fully-fabric T-TENG by employing woven nylon-acrylic fabrics as the main contact material and designing a weaving pattern together with engineering a multi-layered structure to amplify its electrical efficiency. Based on the experimental results, different weaving patterns provided different electrical output values owing to its different contact surface areas. The matt weave pattern can yield the best electrical output regarding the extreme deformations. A further significant enhancement in T-TENG’s performance is consistent with inserting polymer intermediate layer. Adding ball-fiber and kapok serves as a synergetic charge-trapping interlayer, rendering a high triboelectricity of both open circuit voltage (VOC) and short circuit current (ISC) for 3 to 8 times higher than that of nylon-acrylic single layer. Finally, the multilayer fabric T-TENG is integrated with the long-sleeved garments and provide output enough to fully-charge the 0.22 μF and 0.33 μF capacitors together with brightening 30 LEDs. Finally, this work demonstrates a potential way with simple procedures in achieving fully-fabric T-TENG for small-scale energy sources that can harvest biomechanical energy to power electronic component for approaching the real application in E-textile systems.

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