Pub Date : 2026-01-02DOI: 10.1016/j.sna.2026.117450
Xinle Han , Xiaohong Wen , Yongliang Deng , Xinyue Zhang , Xiangmei Dong , Xuefeng Zhao
Flexible multimodal sensors are essential for next-generation wearable technologies and human-machine interfaces, but their practical application has been limited by signal coupling and integration challenges. Here, we present a dual-mode sensor based on a three-layer polydimethylsiloxane (PDMS) architecture that independently measures pressure and temperature via resistance and thermoelectric effects. The sensor utilizes a porous PDMS/multi-walled carbon nanotubes (MWCNTs) composite as the piezoresistive sensing layer, with an intermediate perforated PDMS spacer to reduce modal crosstalk. The top and bottom electrodes consist of spray-embedded silver nanowires (Ag NWs)/MWCNTs composites, with the bottom electrode incorporating microcavities filled with a temperature-sensitive PDMS/MWCNTs/poly(3,4-ethylenedioxythiophene) (PEDOT: PSS) composite for localized thermal detection. The device achieves a pressure sensitivity of 0.09 kPa⁻¹ and a temperature sensitivity of 5.57 μV/℃. Furthermore, a 6 × 6 sensor array demonstrates reliable multiparameter monitoring under dynamic mechanical and thermal stimuli, highlighting its potential for wearable health monitoring and human-machine interaction.
{"title":"Crosstalk-suppressed flexible sensor for simultaneous pressure-temperature detection","authors":"Xinle Han , Xiaohong Wen , Yongliang Deng , Xinyue Zhang , Xiangmei Dong , Xuefeng Zhao","doi":"10.1016/j.sna.2026.117450","DOIUrl":"10.1016/j.sna.2026.117450","url":null,"abstract":"<div><div>Flexible multimodal sensors are essential for next-generation wearable technologies and human-machine interfaces, but their practical application has been limited by signal coupling and integration challenges. Here, we present a dual-mode sensor based on a three-layer polydimethylsiloxane (PDMS) architecture that independently measures pressure and temperature via resistance and thermoelectric effects. The sensor utilizes a porous PDMS/multi-walled carbon nanotubes (MWCNTs) composite as the piezoresistive sensing layer, with an intermediate perforated PDMS spacer to reduce modal crosstalk. The top and bottom electrodes consist of spray-embedded silver nanowires (Ag NWs)/MWCNTs composites, with the bottom electrode incorporating microcavities filled with a temperature-sensitive PDMS/MWCNTs/poly(3,4-ethylenedioxythiophene) (PEDOT: PSS) composite for localized thermal detection. The device achieves a pressure sensitivity of 0.09 kPa⁻¹ and a temperature sensitivity of 5.57 μV/℃. Furthermore, a 6 × 6 sensor array demonstrates reliable multiparameter monitoring under dynamic mechanical and thermal stimuli, highlighting its potential for wearable health monitoring and human-machine interaction.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117450"},"PeriodicalIF":4.9,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-02DOI: 10.1016/j.sna.2025.117449
Fengli Huang , Jun Gao , Zhiheng Yu , Taiyao Pan , Tianyu Zhang , Hao Xue
Hydrogel sensors with excellent mechanical and electrical properties show great potential in the field of flexible intelligent sensing. However, hydrogel sensors cannot simultaneously possess good water-holding ability, anti-freezing performance and fatigue resistance, resulting in unstable sensing performance and poor reusability. This work constructed a cross-linked hydrogel conductive network by introducing polyvinyl alcohol (PVA), ethylene glycol (EG) and MXene nanosheets into a sodium alginate (SA) hydrogel system, and fabricated SPE4M2 hydrogel strain sensors using electrohydrodynamic (EHD) printing method. Benefiting from the excellent water-holding capability of the EG/water binary solvent within the hydrogel matrix, and the orientation-introduced of the conductive medium inside the hydrogel matrix by the EHD printing process, the fabricated SPE4M2 hydrogel sensor exhibits high sensitivity (100 % strain: GF = 2.1), fast response/recovery time (142 ms / 205 ms) and detection stability (100 % strain with 2.7 % DH). Meanwhile, the fabricated hydrogel sensor exhibits excellent anti-freezing and water-holding capabilities, maintaining good flexibility and conductivity even after exposure to low temperatures (-30 ℃) or prolonged storage (50 ℃ for 3 days). Wearable applications of the fabricated sensors in both room temperature and extremely low-temperature environments (-30 ℃) were demonstrated to show the excellent wearable environmental adaptability of the fabricated hydrogel sensors.
{"title":"A freeze-resistant, highly reliable hydrogel strain sensors for ultralow-temperatures via EHD printing method","authors":"Fengli Huang , Jun Gao , Zhiheng Yu , Taiyao Pan , Tianyu Zhang , Hao Xue","doi":"10.1016/j.sna.2025.117449","DOIUrl":"10.1016/j.sna.2025.117449","url":null,"abstract":"<div><div>Hydrogel sensors with excellent mechanical and electrical properties show great potential in the field of flexible intelligent sensing. However, hydrogel sensors cannot simultaneously possess good water-holding ability, anti-freezing performance and fatigue resistance, resulting in unstable sensing performance and poor reusability. This work constructed a cross-linked hydrogel conductive network by introducing polyvinyl alcohol (PVA), ethylene glycol (EG) and MXene nanosheets into a sodium alginate (SA) hydrogel system, and fabricated SPE<sub>4</sub>M<sub>2</sub> hydrogel strain sensors using electrohydrodynamic (EHD) printing method. Benefiting from the excellent water-holding capability of the EG/water binary solvent within the hydrogel matrix, and the orientation-introduced of the conductive medium inside the hydrogel matrix by the EHD printing process, the fabricated SPE<sub>4</sub>M<sub>2</sub> hydrogel sensor exhibits high sensitivity (100 % strain: GF = 2.1), fast response/recovery time (142 ms / 205 ms) and detection stability (100 % strain with 2.7 % DH). Meanwhile, the fabricated hydrogel sensor exhibits excellent anti-freezing and water-holding capabilities, maintaining good flexibility and conductivity even after exposure to low temperatures (-30 ℃) or prolonged storage (50 ℃ for 3 days). Wearable applications of the fabricated sensors in both room temperature and extremely low-temperature environments (-30 ℃) were demonstrated to show the excellent wearable environmental adaptability of the fabricated hydrogel sensors.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117449"},"PeriodicalIF":4.9,"publicationDate":"2026-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Photothermoelectric (PTE) detectors, characterized by self-powered operation and broadband response, represent a promising alternative to conventional photodetectors. However, achieving efficient photothermal conversion and thermoelectric response within a single material remains a key challenge. In this work, we successfully constructed a flexible Ag2Te@Ag composite film of Ag2Te nanowires (NWs) decorated with Ag nanoparticles (NPs), which exhibits a pronounced PTE effect. The Ag NPs act as plasmonic nanoheaters, significantly enhancing light absorption and local heat generation through localized surface plasmon resonance, while the porous Ag2Te NW network serves as an efficient thermoelectric scaffold with low lattice thermal conductivity and optical absorption cavity. As a result, this Ag2Te@Ag film achieves a remarkable temperature difference of 73.4 K and a corresponding photovoltage of 1.41 mV under 450 nm laser irradiation, with a maximum responsivity of 17.17 mV W−1 across the 380–1550 nm range. The device operates in a fully self-powered mode, exhibiting fast response, excellent output linearity, and outstanding mechanical flexibility with negligible degradation of properties after 200 bending cycles. This work provides a viable strategy for developing high-performance, flexible PTE detectors for wearable optoelectronics and energy harvesting.
{"title":"Flexible Ag nanoparticles-decorated Ag2Te nanowire film for broad-band and self-powered Photothermoelectric detection","authors":"Chenyang Guo, Jianli Jiang, Haigang Hou, Jian Yang, Dongliang Zhang, Quanjiang Lv, Junlin Liu, Guanjun Qiao","doi":"10.1016/j.sna.2025.117448","DOIUrl":"10.1016/j.sna.2025.117448","url":null,"abstract":"<div><div>Photothermoelectric (PTE) detectors, characterized by self-powered operation and broadband response, represent a promising alternative to conventional photodetectors. However, achieving efficient photothermal conversion and thermoelectric response within a single material remains a key challenge. In this work, we successfully constructed a flexible Ag<sub>2</sub>Te@Ag composite film of Ag<sub>2</sub>Te nanowires (NWs) decorated with Ag nanoparticles (NPs), which exhibits a pronounced PTE effect. The Ag NPs act as plasmonic nanoheaters, significantly enhancing light absorption and local heat generation through localized surface plasmon resonance, while the porous Ag<sub>2</sub>Te NW network serves as an efficient thermoelectric scaffold with low lattice thermal conductivity and optical absorption cavity. As a result, this Ag<sub>2</sub>Te@Ag film achieves a remarkable temperature difference of 73.4 K and a corresponding photovoltage of 1.41 mV under 450 nm laser irradiation, with a maximum responsivity of 17.17 mV W<sup>−1</sup> across the 380–1550 nm range. The device operates in a fully self-powered mode, exhibiting fast response, excellent output linearity, and outstanding mechanical flexibility with negligible degradation of properties after 200 bending cycles. This work provides a viable strategy for developing high-performance, flexible PTE detectors for wearable optoelectronics and energy harvesting.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117448"},"PeriodicalIF":4.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.sna.2025.117443
Xiang Li , Wentong Lu , Jincheng Wang , Jiaming Chen , Long Li , Hao Tian , Peilong Zhou , Hua Zhang
This study introduces a novel multifunctional composite material composed of polyvinylidene difluoride (PVDF) fiber mats, MXene nanosheets, and superabsorbent polymer (SAP) particles, aimed at addressing limitations in traditional piezoelectric materials such as low strength and poor multifunctionality. The PVDF fiber mats were fabricated via electrospinning, with MXene nanosheets uniformly deposited on their surface through a filtration process. SAP particles were subsequently incorporated to enhance moisture absorption, functional diversity, and mechanical performance. Comprehensive characterization revealed the successful integration of MXene and SAP, achieving uniform distribution and synergy at the microstructural level. The composite exhibited excellent piezoelectric properties (4–6 V) and mechanical stability (The sample can withstand thousands of cyclic compressions with good stability within a few hundred kPa), maintaining a linear response to pressure under both dry and water-absorbed conditions. Finite element analysis (FEA) and various application tests demonstrated the material’s ability to detect a wide range of external pressures, from subtle touches to high-pressure impacts, highlighting its potential for use in flexible sensors, electronic skin, and dynamic monitoring systems. The study underscores the importance of structural optimization in enhancing piezoelectric performance and environmental adaptability. Future research could explore long-term stability and further optimization of material composition to support broader applications in wearable devices, energy harvesting, and intelligent sensing technologies.
{"title":"Multifunctional PVDF composites with MXene nanosheets and SAP particles for sensors","authors":"Xiang Li , Wentong Lu , Jincheng Wang , Jiaming Chen , Long Li , Hao Tian , Peilong Zhou , Hua Zhang","doi":"10.1016/j.sna.2025.117443","DOIUrl":"10.1016/j.sna.2025.117443","url":null,"abstract":"<div><div>This study introduces a novel multifunctional composite material composed of polyvinylidene difluoride (PVDF) fiber mats, MXene nanosheets, and superabsorbent polymer (SAP) particles, aimed at addressing limitations in traditional piezoelectric materials such as low strength and poor multifunctionality. The PVDF fiber mats were fabricated via electrospinning, with MXene nanosheets uniformly deposited on their surface through a filtration process. SAP particles were subsequently incorporated to enhance moisture absorption, functional diversity, and mechanical performance. Comprehensive characterization revealed the successful integration of MXene and SAP, achieving uniform distribution and synergy at the microstructural level. The composite exhibited excellent piezoelectric properties (4–6 V) and mechanical stability (The sample can withstand thousands of cyclic compressions with good stability within a few hundred kPa), maintaining a linear response to pressure under both dry and water-absorbed conditions. Finite element analysis (FEA) and various application tests demonstrated the material’s ability to detect a wide range of external pressures, from subtle touches to high-pressure impacts, highlighting its potential for use in flexible sensors, electronic skin, and dynamic monitoring systems. The study underscores the importance of structural optimization in enhancing piezoelectric performance and environmental adaptability. Future research could explore long-term stability and further optimization of material composition to support broader applications in wearable devices, energy harvesting, and intelligent sensing technologies.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117443"},"PeriodicalIF":4.9,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926187","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.sna.2025.117445
Zongmin Lv , Wei Guan , Yinghong Zhang , Weiyong Li , Ming Que
In this paper, an improved design method for the single-mode Lamb wave electromagnetic acoustic transducer (EMAT) is proposed by using uneven meander line coil EMAT (UMLC-EMAT) instead of the conventional even meander line coil EMAT (EMLC-EMAT). By adjusting the number of turns of each meander line in the coil, the desired mode is enhanced and the unwanted mode is suppressed. Consider the excitation of the A0 mode Lamb wave as an example. First, the working mechanisms of acoustic wave destructive interference and constructive interference in the UMLC-EMAT are described in detail. Second, numerical models for the structures of UMLC-EMAT and EMLC-EMAT are established, and the eddy current density and Lorentz force magnitude generated by the two transducers are compared. And then, the displacement amplitudes of A0 and S0 waves excited and received by the two EMATs are contrasted to verify the feasibility of generating pure A0 waves via the novel design method. Finally, comparative experiments on the two structures are carried out to validate the correctness of the theoretical analysis. The experimental results reveal that UMLC-EMAT can generate the single-mode Lamb waves with high purity. Furthermore, switching the bias magnetic field direction increases the excitation efficiency by 110 %, which is consistent with the simulation results. This design method can be further extended to the excitation of pure S0 mode Lamb waves, providing new guidance for the design of single-mode Lamb wave EMATs.
{"title":"An innovative meander line coil-based electromagnetic acoustic transducer for single-mode lamb wave excitation","authors":"Zongmin Lv , Wei Guan , Yinghong Zhang , Weiyong Li , Ming Que","doi":"10.1016/j.sna.2025.117445","DOIUrl":"10.1016/j.sna.2025.117445","url":null,"abstract":"<div><div>In this paper, an improved design method for the single-mode Lamb wave electromagnetic acoustic transducer (EMAT) is proposed by using uneven meander line coil EMAT (UMLC-EMAT) instead of the conventional even meander line coil EMAT (EMLC-EMAT). By adjusting the number of turns of each meander line in the coil, the desired mode is enhanced and the unwanted mode is suppressed. Consider the excitation of the A0 mode Lamb wave as an example. First, the working mechanisms of acoustic wave destructive interference and constructive interference in the UMLC-EMAT are described in detail. Second, numerical models for the structures of UMLC-EMAT and EMLC-EMAT are established, and the eddy current density and Lorentz force magnitude generated by the two transducers are compared. And then, the displacement amplitudes of A0 and S0 waves excited and received by the two EMATs are contrasted to verify the feasibility of generating pure A0 waves via the novel design method. Finally, comparative experiments on the two structures are carried out to validate the correctness of the theoretical analysis. The experimental results reveal that UMLC-EMAT can generate the single-mode Lamb waves with high purity. Furthermore, switching the bias magnetic field direction increases the excitation efficiency by 110 %, which is consistent with the simulation results. This design method can be further extended to the excitation of pure S0 mode Lamb waves, providing new guidance for the design of single-mode Lamb wave EMATs.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117445"},"PeriodicalIF":4.9,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conventional UV-C sensing materials face challenges such as high defect densities, complex synthesis, and low photo response. This study presents an innovative approach in Mg-doped Ga2O3 thin films, fabricated via mist chemical vapor deposition (Mist-CVD) process. By tuning the precursor composition, we achieved controllable phase transformation from the α-phase to a mixed α/κ phase, and ultimately to stabilized κ-Ga2O3. Notably, the κ-Mg:Ga2O3 photodetector, synthesized at 500°C with 60 % Mg, exhibited an exceptional photo-to-dark current ratio of 1.4 × 108, a detectivity of 1.1 × 1018 Jones, and an ultrahigh responsivity of 6821.9 A/W. These outstanding performance metrics stem from Mg-induced phase stabilization, reduced defect densities, and improved photoconductive gain, collectively leading to enhanced photo response, dark current suppression, and photo-switching stability. The findings underscore the potential of Mg-doped κ-Ga2O3 as a next-generation UV-C detection material, offering superior sensitivity and low-noise operation for advanced optoelectronic applications.
{"title":"Controlled α-to-κ phase transformation in Mg-doped Ga2O3 films for high-performance UV-C detection","authors":"Chien-Sheng Cheng , Shun-Cheng Shih , Wen-Chau Liu , Hao-Chun Hung , Wei-Chou Hsu","doi":"10.1016/j.sna.2025.117447","DOIUrl":"10.1016/j.sna.2025.117447","url":null,"abstract":"<div><div>Conventional UV-C sensing materials face challenges such as high defect densities, complex synthesis, and low photo response. This study presents an innovative approach in Mg-doped Ga<sub>2</sub>O<sub>3</sub> thin films, fabricated via mist chemical vapor deposition (Mist-CVD) process. By tuning the precursor composition, we achieved controllable phase transformation from the α-phase to a mixed α/κ phase, and ultimately to stabilized κ-Ga<sub>2</sub>O<sub>3</sub>. Notably, the κ-Mg:Ga<sub>2</sub>O<sub>3</sub> photodetector, synthesized at 500°C with 60 % Mg, exhibited an exceptional photo-to-dark current ratio of 1.4 × 10<sup>8</sup>, a detectivity of 1.1 × 10<sup>18</sup> Jones, and an ultrahigh responsivity of 6821.9 A/W. These outstanding performance metrics stem from Mg-induced phase stabilization, reduced defect densities, and improved photoconductive gain, collectively leading to enhanced photo response, dark current suppression, and photo-switching stability. The findings underscore the potential of Mg-doped κ-Ga<sub>2</sub>O<sub>3</sub> as a next-generation UV-C detection material, offering superior sensitivity and low-noise operation for advanced optoelectronic applications.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117447"},"PeriodicalIF":4.9,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.sna.2025.117440
Han Zhang, Ling Weng, Huiwen Yang, Lanyang Hao, Shichao Zuo, Mingyuan Wang, Xinpei Huang, Shixin Wang
The sensitivity and linearity of flexible capacitive tactile sensors are usually difficult to achieve simultaneously. To maintain high sensitivity in a broad pressure range, this study designed a flexible dual-mode tactile sensor with a three-level gradient micro-dome porous (TGP) structure dielectric layer. The TGP dielectric layer adopts a novel working mechanism: the porous structure operates in the low-pressure zone, while the gradient structure mainly works in the medium-high pressure zone. This pressure-adaptive mechanism successfully enables this sensor to exhibit relatively good linearity with R2= 0.986 over a wide pressure range of 0–1800 kPa, and has a high sensitivity of 0.181 kPa−1. It also maintains good linearity within the bending range of 0°–45°. Leveraging the pressure characteristics of this sensor, a gripe dynamometer that can accurately measure grip strength has been made. Its bending property enables Morse code transmission which could generate clear and independent signals through finger bending. The sensor has practical value and vast potential in multiple fields such as tactile perception and medical detection.
{"title":"Flexible dual-mode capacitive tactile sensor with wide linear range based on three-level gradient micro-dome porous structure","authors":"Han Zhang, Ling Weng, Huiwen Yang, Lanyang Hao, Shichao Zuo, Mingyuan Wang, Xinpei Huang, Shixin Wang","doi":"10.1016/j.sna.2025.117440","DOIUrl":"10.1016/j.sna.2025.117440","url":null,"abstract":"<div><div>The sensitivity and linearity of flexible capacitive tactile sensors are usually difficult to achieve simultaneously. To maintain high sensitivity in a broad pressure range, this study designed a flexible dual-mode tactile sensor with a three-level gradient micro-dome porous (TGP) structure dielectric layer. The TGP dielectric layer adopts a novel working mechanism: the porous structure operates in the low-pressure zone, while the gradient structure mainly works in the medium-high pressure zone. This pressure-adaptive mechanism successfully enables this sensor to exhibit relatively good linearity with R<sup>2</sup>= 0.986 over a wide pressure range of 0–1800 kPa, and has a high sensitivity of 0.181 kPa<sup>−1</sup>. It also maintains good linearity within the bending range of 0°–45°. Leveraging the pressure characteristics of this sensor, a gripe dynamometer that can accurately measure grip strength has been made. Its bending property enables Morse code transmission which could generate clear and independent signals through finger bending. The sensor has practical value and vast potential in multiple fields such as tactile perception and medical detection.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117440"},"PeriodicalIF":4.9,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-31DOI: 10.1016/j.sna.2025.117427
Wei Jin , Hao Lin , Jiaxing Gao , Jinhua Mou , He Zhang , Yu Zhang , Xuhao Ji , Fengjun Tian , Yifan Qin , Zhihai Liu , Longxiang Guo , Liang Zhang , Heping Shen , Libo Yuan
High-precision humidity monitoring is essential for industrial and scientific applications such as precision machining, semiconductor fabrication, and energy storage. Most fiber-optic humidity sensors rely on hygroscopic materials and microfabrication to enhance performance; however, these strategies increase structural complexity and compromise long-term robustness. Nevertheless, the intrinsic humidity sensitivity of the native coating is commonly overlooked. Here, we demonstrate that the native acrylate coating of commercial optical fibers functions as a humidity-sensitive medium. To overcome the limitation of the optical spectrum analyzer (OSA)’s insufficient resolution, which impedes the detection of coating variations induced by humidity changes, we employ the Pound–Drever–Hall (PDH) frequency-locking technique in conjunction with a fiber Bragg grating-based Fabry–Perot interferometer (FBG-FFPI). This configuration enables precise measurement of cavity length variations resulting from the hygroscopic expansion of the acrylic coating on the unmodified fiber, and as a result, the proposed sensor can measure humidity across a wide range (5–95 % RH), with a resolution of 5.62 × 10⁻⁵ %RH and an accuracy of 9.36 × 10⁻⁵ %RH. As no additional structural modifications are required, the sensor exhibits high robustness and structural simplicity. Consequently, the proposed approach holds great potential for long-term deployment in harsh industrial settings and environmental monitoring.
{"title":"Ultrahigh-resolution relative humidity sensor based on Pound-Drever-Hall technique with unmodified optical fiber","authors":"Wei Jin , Hao Lin , Jiaxing Gao , Jinhua Mou , He Zhang , Yu Zhang , Xuhao Ji , Fengjun Tian , Yifan Qin , Zhihai Liu , Longxiang Guo , Liang Zhang , Heping Shen , Libo Yuan","doi":"10.1016/j.sna.2025.117427","DOIUrl":"10.1016/j.sna.2025.117427","url":null,"abstract":"<div><div>High-precision humidity monitoring is essential for industrial and scientific applications such as precision machining, semiconductor fabrication, and energy storage. Most fiber-optic humidity sensors rely on hygroscopic materials and microfabrication to enhance performance; however, these strategies increase structural complexity and compromise long-term robustness. Nevertheless, the intrinsic humidity sensitivity of the native coating is commonly overlooked. Here, we demonstrate that the native acrylate coating of commercial optical fibers functions as a humidity-sensitive medium. To overcome the limitation of the optical spectrum analyzer (OSA)’s insufficient resolution, which impedes the detection of coating variations induced by humidity changes, we employ the Pound–Drever–Hall (PDH) frequency-locking technique in conjunction with a fiber Bragg grating-based Fabry–Perot interferometer (FBG-FFPI). This configuration enables precise measurement of cavity length variations resulting from the hygroscopic expansion of the acrylic coating on the unmodified fiber, and as a result, the proposed sensor can measure humidity across a wide range (5–95 % RH), with a resolution of 5.62 × 10⁻⁵ %RH and an accuracy of 9.36 × 10⁻⁵ %RH. As no additional structural modifications are required, the sensor exhibits high robustness and structural simplicity. Consequently, the proposed approach holds great potential for long-term deployment in harsh industrial settings and environmental monitoring.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117427"},"PeriodicalIF":4.9,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-30DOI: 10.1016/j.sna.2025.117446
George Gnonhoue, Ilyass Tabiai, Jérémie Voix, Éric David
Flexible electroencephalography (EEG) electrodes have attracted increasing attention due to their potential applications in mobile health monitoring. However, balancing electrical conductivity, flexibility, stretchability, and EEG signal recording remains challenging. Here, we fabricated polystyrene-block-poly(ethylene butylene)-block-polystyrene (SEBS) composites with carbon nanotubes (CNT) and carbon black (CB) via solvent dissolution. The percolation threshold was approximately 12 wt% for SEBS/CB composites and approximately 2 wt% for SEBS/CNT composites. At 20 wt%, SEBS/CB composite conductivity plateaued at 0.01 S/m, whereas SEBS/CNT composite conductivity reached 1.26 S/m at 16 wt%. Contact impedance was 4.2 ± 0.45 kΩ for SEBS/16 wt%CNT and 5.4 ± 0.9 kΩ for SEBS/20 wt%CB. SEBS/CNT was slightly stiffer than SEBS/CB. The electrodes reliably recorded EEG signals, demonstrating their potential for health monitoring and long-term EEG measurements.
{"title":"Electrical and thermo-mechanical properties of styrene-ethylene-butylene-styrene/carbon nanotube and styrene-ethylene-butylene-styrene/carbon black multipin electrodes for electroencephalography","authors":"George Gnonhoue, Ilyass Tabiai, Jérémie Voix, Éric David","doi":"10.1016/j.sna.2025.117446","DOIUrl":"10.1016/j.sna.2025.117446","url":null,"abstract":"<div><div>Flexible electroencephalography (EEG) electrodes have attracted increasing attention due to their potential applications in mobile health monitoring. However, balancing electrical conductivity, flexibility, stretchability, and EEG signal recording remains challenging. Here, we fabricated polystyrene-block-poly(ethylene butylene)-block-polystyrene (SEBS) composites with carbon nanotubes (CNT) and carbon black (CB) via solvent dissolution. The percolation threshold was approximately 12 wt% for SEBS/CB composites and approximately 2 wt% for SEBS/CNT composites. At 20 wt%, SEBS/CB composite conductivity plateaued at 0.01 S/m, whereas SEBS/CNT composite conductivity reached 1.26 S/m at 16 wt%. Contact impedance was 4.2 ± 0.45 kΩ for SEBS/16 wt%CNT and 5.4 ± 0.9 kΩ for SEBS/20 wt%CB. SEBS/CNT was slightly stiffer than SEBS/CB. The electrodes reliably recorded EEG signals, demonstrating their potential for health monitoring and long-term EEG measurements.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117446"},"PeriodicalIF":4.9,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We investigated the electrorheological and electromechanical properties of a polyvinyl chloride (PVC) gel actuator comprising PVC plasticized with various plasticizers including dibutyl adipate (DBA), diethyl adipate (DEA), dimethyl adipate (DMA), dibutyl phthalate (DBP), and bis (2-ethylhexyl) adipate (DEHA). PVC gel actuators fabricated with various plasticizers were evaluated in terms of electrorheology, namely, the viscoelastic change under an applied electric field. For all PVC gels, the storage modulus G' value slightly increased with increasing frequency, but the response was almost flat to frequency changes, indicating that the PVC gels were in a gel state owing to the formation of an infinite network. The observed change in storage modulus G′ under applied voltage was successfully analyzed using a deformation model of the PVC gel. This model incorporates an affine mesh framework together with the formation of a solvent- (plasticizer-) rich (S-R) layer, caused by the migration of plasticizers to the anode interface under voltage. Bending deformation experiments were also conducted for PVC gel actuators with various plasticizers by applying a step voltage ranging from 0 to 500 V and coating with conductive carbon grease on both surfaces. The observed bending deformation was successfully evaluated by an electrical response model linked to the storage modulus, revealing the contribution of the S-R layer to the electromechanical actuation. This study provides a practical approach for selecting both the optimal molecular structure and the concentration of plasticizers, which are crucial factors in improving the actuation performance of PVC-based gel devices.
{"title":"Electrorheological and electromechanical properties of polyvinyl chloride gel actuators","authors":"Kinji Asaka , Kazuki Furuse , Yuuki Ooba , Kosuke Kaneko , Tomonori Hanasaki","doi":"10.1016/j.sna.2025.117442","DOIUrl":"10.1016/j.sna.2025.117442","url":null,"abstract":"<div><div>We investigated the electrorheological and electromechanical properties of a polyvinyl chloride (PVC) gel actuator comprising PVC plasticized with various plasticizers including dibutyl adipate (DBA), diethyl adipate (DEA), dimethyl adipate (DMA), dibutyl phthalate (DBP), and bis (2-ethylhexyl) adipate (DEHA). PVC gel actuators fabricated with various plasticizers were evaluated in terms of electrorheology, namely, the viscoelastic change under an applied electric field. For all PVC gels, the storage modulus <em>G</em>' value slightly increased with increasing frequency, but the response was almost flat to frequency changes, indicating that the PVC gels were in a gel state owing to the formation of an infinite network. The observed change in storage modulus <em>G</em>′ under applied voltage was successfully analyzed using a deformation model of the PVC gel. This model incorporates an affine mesh framework together with the formation of a solvent- (plasticizer-) rich (S-R) layer, caused by the migration of plasticizers to the anode interface under voltage. Bending deformation experiments were also conducted for PVC gel actuators with various plasticizers by applying a step voltage ranging from 0 to 500 V and coating with conductive carbon grease on both surfaces. The observed bending deformation was successfully evaluated by an electrical response model linked to the storage modulus, revealing the contribution of the S-R layer to the electromechanical actuation. This study provides a practical approach for selecting both the optimal molecular structure and the concentration of plasticizers, which are crucial factors in improving the actuation performance of PVC-based gel devices.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"399 ","pages":"Article 117442"},"PeriodicalIF":4.9,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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