With the rapid development of wearable electronic skin technology, flexible strain sensors have shown great application prospects in the fields of human motion and physiological signal detection, medical diagnostics, ...With the rapid development of wearable electronic skin technology, flexible strain sensors have shown great application prospects in the fields of human motion and physiological signal detection, medical diagnostics, and human-computer interaction owing to their outstanding sensing performance. This paper reports a strain sensor with synergistic conductive network, consisting of stable carbon nanotube dispersion (CNT) layer and brittle MXene layer by dip-coating and electrostatic self-assembly method, and breathable three-dimensional (3D) flexible substrate of thermoplastic polyurethane (TPU) fibrous membrane prepared through electrospinning technology. The MXene/CNT@PDA-TPU (MC@p-TPU) flexible strain sensor had excellent air permeability, wide operating range (0–450 %), high sensitivity (Gauge Factor, GFmax = 8089.7), ultra-low detection limit (0.05 %), rapid response and recovery times (40 ms/60 ms), and excellent cycle stability and durability (10,000 cycles). Given its superior strain sensing capabilities, this sensor can be applied in physiological signals detection, human motion pattern recognition, and driving exoskeleton robots. In addition, MC@p-TPU fibrous membrane also exhibited excellent photothermal conversion performance and can be used as a wearable photo-heater, which has far-reaching application potential in the photothermal therapy of human joint diseases.展开更多
Multifunctional flexible sensors as wearable electronic systems have attracted considerable attention for mimicking human skin to sense ambient stimuli.However,sensors need to have high resolution,stability and sensit...Multifunctional flexible sensors as wearable electronic systems have attracted considerable attention for mimicking human skin to sense ambient stimuli.However,sensors need to have high resolution,stability and sensitivity to realize fully biomimetic skin.Here,an assembled and welded Ag/W composite nanowire flexible electrode was prepared for body motion monitoring and flexible heaters.This Ag/W composite nanowire flexible electrode has a high transmittance of 90.1%(at 121Ω·sq^(−1) sheet resistance)and a low sheet resistance of 27Ω·sq^(−1)(at 60.1%transmittance).Although the transparency of this electrode is not high,the fluctuation in relative resistance change rate at 10%strain is only 5%after 1000 tensile cycles.It can be employed to monitor human body motions,including bending of fingers,arms,wrists,and throat action.Meanwhile,the Ag/W nanowires composite film heater achieves a steady-state temperature of up to 100℃ at a constant voltage of 3.5 V and an instantaneous heating rate of up to 36.5℃·s^(−1).展开更多
Flexible piezoresistive sensors based on biomimetic microstructures are prospective for broad application in motion monitoring.However,the design and preparation processes of most biomimetic microstructures in the exi...Flexible piezoresistive sensors based on biomimetic microstructures are prospective for broad application in motion monitoring.However,the design and preparation processes of most biomimetic microstructures in the existing studies are complicated,and there are few studies on pore size control.Herein,the porous structure of human bones was used as a biomimetic prototype,and optimally designed by creating a theoretical equivalent sensor model and a finite element model.Soluble raw materials such as sugar and salt in different particle sizes were pressed into porous templates.Based on the template method,porous structures in different pore sizes were prepared using polydimethylsiloxane(PDMS)polymer as the substrate.On this basis,graphene oxide conductive coating was prepared with the modified Hummers method and then deposited via dip coating onto the substrate.Finally,a PDMS-based porous structure biomimetic flexible piezoresistive sensor was developed.Mechanically,the deformation of the sensor under the same load increased with the pore size rising from 0.3 to 1.5 mm.Electrically,the resistance rang of the sensor was enlarged as the pore size rose.The resistance variation rates of samples with pore sizes of 0.3,1.0,and 1.5 mm at approximately the 200th cycle were 63%,79%,and 81%,respectively;at the 500th cycle,these values were 63%,77%,and 79%;and at the 1000th cycle,they stabilized at 63%,74%,and 76%.These results indicate that the fabricated sensor exhibits high stability and fatigue resistance.At the pressure of 0–25 kPa,the sensitivity rose from 0.0688 to 0.1260 kPa−1,and the performance was enhanced by 83%.After 1,000 cycles of compression testing,the signal output was stable,and no damage was caused to the substrate.Further application tests showed the biomimetic sensor accurately and effectively identified human joint motions and gestures,and has potential application value in human motion monitoring.展开更多
Wearable devices have great application potential in the next generation of smart portable electronics,especially in the fields of medical monitoring,soft robotics,artificial intelligence,and human-machine interfaces....Wearable devices have great application potential in the next generation of smart portable electronics,especially in the fields of medical monitoring,soft robotics,artificial intelligence,and human-machine interfaces.Piezoelectric flexible strain sensors are key components of wearable devices.However,existing piezoelectric flexible strain sensors have certain limitations in weak signal monitoring due to their large modulus and low sensitivity.To solve this problem,the concept of Kirigami(paper-cutting)was introduced in this study to design the sensor structure.By comparing the Kirigami structures of different basic structures,the serpentine structure was determined as the basic configuration of the sensor.The serpentine structure not only provides excellent tensile properties,but also significantly improves the sensitivity of the sensor,which performs well in monitoring weak signals.On this basis,the adhesion properties of the flexible sensor were analyzed and tested,and the optimal ratio of the substrate was selected for preparation.In addition,a low-cost and rapid prototyping process for stretchable patches was established in this study.Using this technology,we prepared the sensor device and tested its performance.Finally,we successfully developed a flexible sensor with a sensitivity of 0.128 mV/μɛand verified its feasibility for wrist joint motion monitoring applications.This result opens up new avenues for the recovery care of tenosynovitis patients after surgery.展开更多
Flexible strain sensor has promising features in successful application of health monitoring, electronic skins and smart robotics, etc.Here, we report an ultrasensitive strain sensor with a novel crack-wrinkle structu...Flexible strain sensor has promising features in successful application of health monitoring, electronic skins and smart robotics, etc.Here, we report an ultrasensitive strain sensor with a novel crack-wrinkle structure(CWS) based on graphite nanoplates(GNPs)/thermoplastic urethane(TPU)/polydimethylsiloxane(PDMS) nanocomposite. The CWS is constructed by pressing and dragging GNP layer on TPU substrate,followed by encapsulating with PDMS as a protective layer. On the basis of the area statistics, the ratio of the crack and wrinkle structures accounts for 31.8% and 9.5%, respectively. When the sensor is stretched, the cracks fracture, the wrinkles could reduce the unrecoverable destruction of cracks, resulting in an excellent recoverability and stability. Based on introduction of the designed CWS in the sensor, the hysteresis effect is limited effectively. The CWS sensor possesses a satisfactory sensitivity(GF=750 under 24% strain), an ultralow detectable limit(strain=0.1%) and a short respond time of 90 ms. For the sensing service behaviors, the CWS sensor exhibits an ultrahigh durability(high stability>2×10^(4) stretching-releasing cycles). The excellent practicality of CWS sensor is demonstrated through various human motion tests,including vigorous exercises of various joint bending, and subtle motions of phonation, facial movements and wrist pulse. The present CWS sensor shows great developing potential in the field of cost-effective, portable and high-performance electronic skins.展开更多
Due to the motion artifacts and mechanical mismatches between the conventional rigid sensor and soft skin,flexible sensors have received extensive attention in recent years.In this paper,a AgNW-based strain sensor on ...Due to the motion artifacts and mechanical mismatches between the conventional rigid sensor and soft skin,flexible sensors have received extensive attention in recent years.In this paper,a AgNW-based strain sensor on thermoplastic polyurethane(TPU)substrates was fabricated via a transfer-printing technique.The effects of AgNW content on the mechanical,electrical,transparency.展开更多
The aerostatic spindle is a key component of ultra-precision machine tools,and its error motion is crucial to machining accuracy and reliability.Spindle error motion is unavoidable,and its online monitoring and predic...The aerostatic spindle is a key component of ultra-precision machine tools,and its error motion is crucial to machining accuracy and reliability.Spindle error motion is unavoidable,and its online monitoring and prediction are quite important.Currently,there are relatively few studies on the online monitoring and prediction methods for the aerostatic spindle,and the level of intelligence is relatively low.To address this problem,an error motion monitoring system based on digital twin(DT)technology was established for the aerostatic spindle.A spindle error motion prediction method based on a mechanism and data fusion model(MDFM)was proposed.Additionally,a highly available and interactive aerostatic spindle DT service platform was developed.Experimental results have verified the good performance of this platform.The platform facilitates interaction between the physical and virtual entities of the aerostatic spindle,enabling three-dimensional visualization,monitoring,prediction,and simulation of spindle error motion,and shows good potential for engineering applications.展开更多
Piezoresistive pressure sensors have received considerable attention because of their simple structure,high sensitivity and low cost.Graphene,which is known for its outstanding mechanical and electrical properties,has...Piezoresistive pressure sensors have received considerable attention because of their simple structure,high sensitivity and low cost.Graphene,which is known for its outstanding mechanical and electrical properties,has shown great application potential as a sensor material.However,its durability and performance consistency in practical applications still require enhancement.In this study,magnetic graphene fibers(MGFs)are prepared via wet spinning,using graphene oxide(GO),doped with Fe_(3)O_(4)nanoparticles.The resulting MGFs exhibit a high tensile strength of 58.6 MPa,a strain of 5.3%and an electrical conductivity of 1.7×10^(4)S/m.These MGFs are utilised to construct a multilayer fabric for fabrication of flexible pressure sensors.The confinement within the spinning channel facilitates an ordered arrangement of GO sheets,resulting in MGFs with superior electrical and mechanical properties.The issuing MGFs pressure sensors demonstrate a wide detection range(0-120 kPa),high sensitivity(0.233 kPa^(−1),0-40 kPa)and rapid response/recovery times(121 ms/158 ms).In addition,it exhibits a remarkable durability,maintaining performance over 1300 cycles,during continuous operation,with negligible degradation.This sensor shows excellent capability in monitoring human physiological activities,indicating its substantial application potential in wearable devices.展开更多
Wearable triboelectric nanogenerators(TENGs)have emerged as a transformative technology for converting low-frequency mechanical energy into electrical power,offering promising applications in electronic skins,human-ma...Wearable triboelectric nanogenerators(TENGs)have emerged as a transformative technology for converting low-frequency mechanical energy into electrical power,offering promising applications in electronic skins,human-machine interfaces,and advanced healthcare systems.However,achieving structural robustness and multifunctionality in thermal regulation remains a persistent challenge for TENG-based skin electronics.This deficiency compromises the charge transfer efficiency and diminishes user comfort during prolonged wear.This study introduces a novel thermally regulating triboelectric nanogenerator(TR-TENG)in the form of a bilayer electronic textile(e-textile)fabricated through a semi-bonding assembly approach.The e-textile comprises two distinct layers:nonwoven styrene-ethylene-butylene-styrene(SEBS)textiles loaded with highly reflective and electronegative polyvinylidene fluoride-trifluoroethylene(PVDF-TrFE)nanoparticles(NPs)and polyvinyl alcohol(PVA)fibers embedded with emissive and electropositive SiO_(2) NPs.These layers are merged via hotpress needle punching,creating a flexible,permeable yet robust interface capable of dual functionalities—enhanced solar reflection and efficient infrared emission—while maintaining stable triboelectric performance.When utilized as a skinattachable self-powered motion sensor,this e-textile provides a remarkable passive radiative cooling effect and high-fidelity recognition of both high-frequency and subtle motions(swallowing,running,breathing,etc.).This TR-TENG e-textile presents a breakthrough in self-powered and comfortable electronics for next-generation healthcare technologies.展开更多
Flexible mechanical sensors offer extensive application prospects in the field of smart wearables.However,developing highly sensitive,flexible mechanical sensors that can simultaneously detect strain and pressure rema...Flexible mechanical sensors offer extensive application prospects in the field of smart wearables.However,developing highly sensitive,flexible mechanical sensors that can simultaneously detect strain and pressure remains a significant challenge.Herein,we present a flexible mechanical sensor based on AgNPs/MWCNTsCOOH/PDA/PU/PVB nanofiber-covered yarn(AMPPPNY)featuring a DNA-like double-helix wrinkled structure.The sensor is fabricated by electrospraying polyvinyl butyral(PVB)onto a pre-stretched double-helix elastic yarn,followed by electrospinning a polyurethane(PU)nanofiber membrane and inducing the self-polymerization of dopamine(DA)to create an adhesive layer.Then,one-dimensional carboxylated multi-walled carbon nanotubes(MWCNTs-COOH)and zero-dimensional silver nanoparticles(AgNPs)are dispersed onto the structure,synergistically forming a stable conductive network for efficient signal transmission.The integration of conductive fillers with different dimensionalities and DNA-like double-helix wrinkled structure endows the sensor with high strain sensitivity(gauge factor of 11,977)in the strain range of 0-310%and high pressure sensitivity(0.475 kPa^(-1))in the pressure range of 0-2 kPa.Moreover,the fabricated sensor exhibits rapid response and recovery times(130 ms/135 ms)and outstanding cyclic stability(over 10,000 cycles of both strain and pressure).Next,the fibrous sensor is weaved into a large-area fabric,and the developed smart textiles demonstrate impressive performance in detecting both subtle and large human movements.The proposed sensor is a promising candidate for flexible wearable applications.展开更多
Strain sensors with high stretchability, broad strain range, high sensitivity, and good reliability are desirable, owing to their promising applications in electronic skins and human motion monitoring systems. In this...Strain sensors with high stretchability, broad strain range, high sensitivity, and good reliability are desirable, owing to their promising applications in electronic skins and human motion monitoring systems. In this paper, we report a high- performance strain sensor based on printable and stretchable electrically con- ductive elastic composites. This strain sensor is fabricated by mixing silver-coated polystyrene spheres （PS@Ag） and liquid polydimethylsiloxane （PDMS） and screen-printed to a desirable geometry. The strain sensor exhibits fascinating comprehensive performances, including high electrical conductivity （1.65 × 104 S/m）, large workable strain range （〉 80%）, high sensitivity （gauge factor of 17.5 in strain of 0%-10%, 6.0 in strain of 10%-60% and 78.6 in strain of 60%-80%）, inconspicuous resistance overshoot （〈 15%）, good reproducibility and excellent long-term stability （1,750 h at 85℃/85% relative humidity） for PS@Ag/PDMS-60, which only contains - 36.7 wt.% of silver. Simultaneously, this strain sensor provides the advantages of low-cost, simple, and large-area scalable fabrication, as well as robust mechanical properties and versatility in applications. Based on these performance characteristics, its applications in flexible printed electrodes and monitoring vigorous human motions are demonstrated, revealing its tremendous potential for applications in flexible and wearable electronics.展开更多
Triboelectric nanogenerators(TENGs)have recently drawn much attention in the field of biomechanical energy harvesting and motion monitoring.However,the electrode stretchability and contact-separation model induced com...Triboelectric nanogenerators(TENGs)have recently drawn much attention in the field of biomechanical energy harvesting and motion monitoring.However,the electrode stretchability and contact-separation model induced complicated packed structure remain a problem that heavily affects output performance during various human movements and requires to be urgently addressed.Here,a single-electrode piezotriboelectric hybrid nanogenerator(SEP-TENG)integrated with stretchable liquid-metal metal electrodes is reported,which simultaneously achieves outstanding energy harvesting performance and skincomfort human motion monitoring.A polarized piezoelectric BaTiO_(3)/silicon rubber(SR)composites film is served as the effective negative tribomaterial,benefiting from the improved dielectric constant and piezoelectric charge transfer,the optimized SEP-TENG generates a high peak power density of 5.7 W/m^(2) while contacted with human skin.Besides,owing to the ultralow Young's modulus of the SR encapsulation layer and tribo-piezoelectric hybrid layer,the homogeneous integrated multilayer composite serves no break till a 745%elongation,promoting that the SEP-TENG could effectively harvest biomechanical energy and realize stable power supplying for wearable electronics even under large deformation state.Furthermore,the SEP-TENG could comfortably attach to the finger joints and collect bending energy.This work provides a novel design methodology for a single-electrode TENG to realize omnidirectional biomechanical energy harvesting and motion monitoring.展开更多
Quantitative analysis of gait parameters,such as stride frequency and step speed,is essential for optimizing physical exercise for the human body.However,the current electronic sensors used in human motion monitoring ...Quantitative analysis of gait parameters,such as stride frequency and step speed,is essential for optimizing physical exercise for the human body.However,the current electronic sensors used in human motion monitoring remain constrained by factors such as battery life and accuracy.This study developed a self-powered gait analysis system(SGAS)based on a triboelectric nanogenerator(TENG)fabricated electrospun composite nanofibers for motion monitoring and gait analysis for regulating exercise programs.The SGAS consists of a sensing module,a charging module,a data acquisition and processing module,and an Internet of Things(IoT)platform.Within the sensing module,two specialized sensing units,TENG-S1 and TENG-S2,are positioned at the forefoot and heel to generate synchronized signals in tandem with the user's footsteps.These signals are instrumental for real-time step count and step speed monitoring.The output of the two TENG units is significantly improved by systematically investigating and optimizing the electrospun composite nanofibers'composition,strength,and wear resistance.Additionally,a charge amplifier circuit is implemented to process the raw voltage signal,consequently bolstering the reliability of the sensing signal.This refined data is then ready for further reading and calculation by the micro-controller unit(MCU)during the signal transmission process.Finally,the well-conditioned signals are wirelessly transmitted to the IoT platform for data analysis,storage,and visualization,enhancing human motion monitoring.展开更多
Highly sensitive sensors with extensive applications are extremely desired in the next-generation wearable electronics for human motion monitoring,human-machine interface and intelligent robotics,while singlefunctiona...Highly sensitive sensors with extensive applications are extremely desired in the next-generation wearable electronics for human motion monitoring,human-machine interface and intelligent robotics,while singlefunctional pressure sensors cannot fulfill the growing demands of modern technological advances.Herein,an all-fabric and multilayered piezoresistive sensor based on conductive metal-organic frame-work/layered double hydroxide(cMOF/LDH)hetero-nanoforest is demonstrated to achieve multiple applications including pulse detection,joint motion detection,sound detection and information transmission.Benefiting from the synergism of cMOF/LDH hetero-nanoforest and multilayered structure,the sensor exhibits a high sensitivity(1.61×10^(9)kPa^(−1))over a broad pressure range(0-100 kPa),a fast response/recovery time(71 ms/71 ms)and a low detection limit(18 Pa),as well as reliable dynamic stability(8000 cycles).It is gratifying to note that the introduction of cMOFs endows the sensor with the potential to detect the concentration of NH_(3)(1-100 ppm)and sunlight intensity(10-100 mW cm^(−2)).This work shows great potential in multifunctional sensing,which enlightens a strategy for advancing the development process of highly sensitive intelligent wearable devices.展开更多
Flexible strain sensors have been extensively used in human motion detection,medical aids,electronic skins,and other civilian or military fields.Conventional strain sensors made of metal or semiconductor materials suf...Flexible strain sensors have been extensively used in human motion detection,medical aids,electronic skins,and other civilian or military fields.Conventional strain sensors made of metal or semiconductor materials suffer from insufficient stretchability and sensitivity,imposing severe constraints on their utilization in wearable devices.Herein,we design a flexible strain sensor based on biphasic hydrogel via an in-situ polymerization method,which possesses superior electrical response and mechanical performance.External stress could prompt the formation of conductive microchannels within the biphasic hydrogel,which originates from the interaction between the conductive water phase and the insulating oil phase.The device performance could be optimized by carefully regulating the volume ratio of the oil/water phase.Consequently,the flexible strain sensor with oil phase ratio of 80%demonstrates the best sensitivity with gauge factor of 33 upon a compressive strain range of 10%,remarkable electrical stability of 100 cycles,and rapid resistance response of 190 ms.Furthermore,the human motions could be monitored by this flexible strain sensor,thereby highlighting its potential for seamless integration into wearable devices.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52373093 and 12072325)the Outstanding Youth Fund of Henan Province(No.242300421062)+1 种基金National Key R&D Program of China(No.2019YFA0706802)the 111 project(No.D18023).
文摘With the rapid development of wearable electronic skin technology, flexible strain sensors have shown great application prospects in the fields of human motion and physiological signal detection, medical diagnostics, and human-computer interaction owing to their outstanding sensing performance. This paper reports a strain sensor with synergistic conductive network, consisting of stable carbon nanotube dispersion (CNT) layer and brittle MXene layer by dip-coating and electrostatic self-assembly method, and breathable three-dimensional (3D) flexible substrate of thermoplastic polyurethane (TPU) fibrous membrane prepared through electrospinning technology. The MXene/CNT@PDA-TPU (MC@p-TPU) flexible strain sensor had excellent air permeability, wide operating range (0–450 %), high sensitivity (Gauge Factor, GFmax = 8089.7), ultra-low detection limit (0.05 %), rapid response and recovery times (40 ms/60 ms), and excellent cycle stability and durability (10,000 cycles). Given its superior strain sensing capabilities, this sensor can be applied in physiological signals detection, human motion pattern recognition, and driving exoskeleton robots. In addition, MC@p-TPU fibrous membrane also exhibited excellent photothermal conversion performance and can be used as a wearable photo-heater, which has far-reaching application potential in the photothermal therapy of human joint diseases.
基金supported by the National Natural Science Foundation of China(Nos.51905103,52275177).
文摘Multifunctional flexible sensors as wearable electronic systems have attracted considerable attention for mimicking human skin to sense ambient stimuli.However,sensors need to have high resolution,stability and sensitivity to realize fully biomimetic skin.Here,an assembled and welded Ag/W composite nanowire flexible electrode was prepared for body motion monitoring and flexible heaters.This Ag/W composite nanowire flexible electrode has a high transmittance of 90.1%(at 121Ω·sq^(−1) sheet resistance)and a low sheet resistance of 27Ω·sq^(−1)(at 60.1%transmittance).Although the transparency of this electrode is not high,the fluctuation in relative resistance change rate at 10%strain is only 5%after 1000 tensile cycles.It can be employed to monitor human body motions,including bending of fingers,arms,wrists,and throat action.Meanwhile,the Ag/W nanowires composite film heater achieves a steady-state temperature of up to 100℃ at a constant voltage of 3.5 V and an instantaneous heating rate of up to 36.5℃·s^(−1).
基金supported by the National Natural Science Foundation of China(52175270)the Project of Scientifc and Technological Development Plan of Jilin Province(20220508130RC)+3 种基金the Science and Technology Development Program of Jilin Province(YDZJ202501ZYTS370)the Scientific Research Project of Education Department of Jilin Province(JJKH20251196KJ)the Scientific Research Project of Education Department of Jilin Province(JJKH20251195KJ)the Key Project of State Key Laboratory of Changchun City(23GZZ14).
文摘Flexible piezoresistive sensors based on biomimetic microstructures are prospective for broad application in motion monitoring.However,the design and preparation processes of most biomimetic microstructures in the existing studies are complicated,and there are few studies on pore size control.Herein,the porous structure of human bones was used as a biomimetic prototype,and optimally designed by creating a theoretical equivalent sensor model and a finite element model.Soluble raw materials such as sugar and salt in different particle sizes were pressed into porous templates.Based on the template method,porous structures in different pore sizes were prepared using polydimethylsiloxane(PDMS)polymer as the substrate.On this basis,graphene oxide conductive coating was prepared with the modified Hummers method and then deposited via dip coating onto the substrate.Finally,a PDMS-based porous structure biomimetic flexible piezoresistive sensor was developed.Mechanically,the deformation of the sensor under the same load increased with the pore size rising from 0.3 to 1.5 mm.Electrically,the resistance rang of the sensor was enlarged as the pore size rose.The resistance variation rates of samples with pore sizes of 0.3,1.0,and 1.5 mm at approximately the 200th cycle were 63%,79%,and 81%,respectively;at the 500th cycle,these values were 63%,77%,and 79%;and at the 1000th cycle,they stabilized at 63%,74%,and 76%.These results indicate that the fabricated sensor exhibits high stability and fatigue resistance.At the pressure of 0–25 kPa,the sensitivity rose from 0.0688 to 0.1260 kPa−1,and the performance was enhanced by 83%.After 1,000 cycles of compression testing,the signal output was stable,and no damage was caused to the substrate.Further application tests showed the biomimetic sensor accurately and effectively identified human joint motions and gestures,and has potential application value in human motion monitoring.
基金supported by National Natural Science Foundation of China(Nos.62301509,62304209)Key Research and Development Program of Shanxi Province(No.202302030201001)Fundamental Research Program of Shanxi Province(Nos.202203021222079,0210302123203,202103021223185).
文摘Wearable devices have great application potential in the next generation of smart portable electronics,especially in the fields of medical monitoring,soft robotics,artificial intelligence,and human-machine interfaces.Piezoelectric flexible strain sensors are key components of wearable devices.However,existing piezoelectric flexible strain sensors have certain limitations in weak signal monitoring due to their large modulus and low sensitivity.To solve this problem,the concept of Kirigami(paper-cutting)was introduced in this study to design the sensor structure.By comparing the Kirigami structures of different basic structures,the serpentine structure was determined as the basic configuration of the sensor.The serpentine structure not only provides excellent tensile properties,but also significantly improves the sensitivity of the sensor,which performs well in monitoring weak signals.On this basis,the adhesion properties of the flexible sensor were analyzed and tested,and the optimal ratio of the substrate was selected for preparation.In addition,a low-cost and rapid prototyping process for stretchable patches was established in this study.Using this technology,we prepared the sensor device and tested its performance.Finally,we successfully developed a flexible sensor with a sensitivity of 0.128 mV/μɛand verified its feasibility for wrist joint motion monitoring applications.This result opens up new avenues for the recovery care of tenosynovitis patients after surgery.
基金financially supported by the National Natural Science Foundation of China (Nos. 51773183 and U1804133)National Natural Science Foundation of China-Henan Province Joint Funds (No. U1604253)+1 种基金Henan Province University Innovation Talents Support Program (No. 20HASTIT001)Innovation Team of Colleges and Universities in Henan Province(No. 20IRTSTHN002)。
文摘Flexible strain sensor has promising features in successful application of health monitoring, electronic skins and smart robotics, etc.Here, we report an ultrasensitive strain sensor with a novel crack-wrinkle structure(CWS) based on graphite nanoplates(GNPs)/thermoplastic urethane(TPU)/polydimethylsiloxane(PDMS) nanocomposite. The CWS is constructed by pressing and dragging GNP layer on TPU substrate,followed by encapsulating with PDMS as a protective layer. On the basis of the area statistics, the ratio of the crack and wrinkle structures accounts for 31.8% and 9.5%, respectively. When the sensor is stretched, the cracks fracture, the wrinkles could reduce the unrecoverable destruction of cracks, resulting in an excellent recoverability and stability. Based on introduction of the designed CWS in the sensor, the hysteresis effect is limited effectively. The CWS sensor possesses a satisfactory sensitivity(GF=750 under 24% strain), an ultralow detectable limit(strain=0.1%) and a short respond time of 90 ms. For the sensing service behaviors, the CWS sensor exhibits an ultrahigh durability(high stability>2×10^(4) stretching-releasing cycles). The excellent practicality of CWS sensor is demonstrated through various human motion tests,including vigorous exercises of various joint bending, and subtle motions of phonation, facial movements and wrist pulse. The present CWS sensor shows great developing potential in the field of cost-effective, portable and high-performance electronic skins.
基金supported by the Program for the Ningbo Municipal Science and Technology Innovative Research Team(2016B10005)the Zhejiang Provincial Natural Science Foundation of China(LY19A020002)the National Natural Science Foundation of China(61774160)。
文摘Due to the motion artifacts and mechanical mismatches between the conventional rigid sensor and soft skin,flexible sensors have received extensive attention in recent years.In this paper,a AgNW-based strain sensor on thermoplastic polyurethane(TPU)substrates was fabricated via a transfer-printing technique.The effects of AgNW content on the mechanical,electrical,transparency.
基金supported by the National Natural Science Foundation of China(Grant No.52475494)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY22E050003)the Fundamental Research Funds for the Provincial Universities of Zhejiang(Grant No.RF-A2020005).
文摘The aerostatic spindle is a key component of ultra-precision machine tools,and its error motion is crucial to machining accuracy and reliability.Spindle error motion is unavoidable,and its online monitoring and prediction are quite important.Currently,there are relatively few studies on the online monitoring and prediction methods for the aerostatic spindle,and the level of intelligence is relatively low.To address this problem,an error motion monitoring system based on digital twin(DT)technology was established for the aerostatic spindle.A spindle error motion prediction method based on a mechanism and data fusion model(MDFM)was proposed.Additionally,a highly available and interactive aerostatic spindle DT service platform was developed.Experimental results have verified the good performance of this platform.The platform facilitates interaction between the physical and virtual entities of the aerostatic spindle,enabling three-dimensional visualization,monitoring,prediction,and simulation of spindle error motion,and shows good potential for engineering applications.
基金supported by Zhejiang Natural Science Foundation Technology Project(LGG22E030015)National Key Research and Development Program of China support by Ministry of Science and Technology(2022YFB3704504)+5 种基金Jiaxing Science and Technology Plan Project(2023AY11004)Jiaxing Project of Science and Technology(2023AY11014)Jiaxing University General Cultivation Project(00321056AL)Qinshen Youth Backbone Training Program of Jiaxing University(CD70623038)Jiaxing City Public Welfare Project(Young Talent Special Project)(2023AY40027)Key Laboratory of Yarn Materials Forming and Composite Processing Technology,Zhejiang Province(MTC-2022-06).
文摘Piezoresistive pressure sensors have received considerable attention because of their simple structure,high sensitivity and low cost.Graphene,which is known for its outstanding mechanical and electrical properties,has shown great application potential as a sensor material.However,its durability and performance consistency in practical applications still require enhancement.In this study,magnetic graphene fibers(MGFs)are prepared via wet spinning,using graphene oxide(GO),doped with Fe_(3)O_(4)nanoparticles.The resulting MGFs exhibit a high tensile strength of 58.6 MPa,a strain of 5.3%and an electrical conductivity of 1.7×10^(4)S/m.These MGFs are utilised to construct a multilayer fabric for fabrication of flexible pressure sensors.The confinement within the spinning channel facilitates an ordered arrangement of GO sheets,resulting in MGFs with superior electrical and mechanical properties.The issuing MGFs pressure sensors demonstrate a wide detection range(0-120 kPa),high sensitivity(0.233 kPa^(−1),0-40 kPa)and rapid response/recovery times(121 ms/158 ms).In addition,it exhibits a remarkable durability,maintaining performance over 1300 cycles,during continuous operation,with negligible degradation.This sensor shows excellent capability in monitoring human physiological activities,indicating its substantial application potential in wearable devices.
基金supported by National Natural Science Foundation of China,52373079,Yunpeng Huang,52161135302,Yunpeng HuangNatural Science Foundation of Jiangsu Province,BK20221540,Yunpeng HuangState Key Laboratory for Modification of Chemical Fibers and Polymer Materials,KF2512,Yunpeng Huang.
文摘Wearable triboelectric nanogenerators(TENGs)have emerged as a transformative technology for converting low-frequency mechanical energy into electrical power,offering promising applications in electronic skins,human-machine interfaces,and advanced healthcare systems.However,achieving structural robustness and multifunctionality in thermal regulation remains a persistent challenge for TENG-based skin electronics.This deficiency compromises the charge transfer efficiency and diminishes user comfort during prolonged wear.This study introduces a novel thermally regulating triboelectric nanogenerator(TR-TENG)in the form of a bilayer electronic textile(e-textile)fabricated through a semi-bonding assembly approach.The e-textile comprises two distinct layers:nonwoven styrene-ethylene-butylene-styrene(SEBS)textiles loaded with highly reflective and electronegative polyvinylidene fluoride-trifluoroethylene(PVDF-TrFE)nanoparticles(NPs)and polyvinyl alcohol(PVA)fibers embedded with emissive and electropositive SiO_(2) NPs.These layers are merged via hotpress needle punching,creating a flexible,permeable yet robust interface capable of dual functionalities—enhanced solar reflection and efficient infrared emission—while maintaining stable triboelectric performance.When utilized as a skinattachable self-powered motion sensor,this e-textile provides a remarkable passive radiative cooling effect and high-fidelity recognition of both high-frequency and subtle motions(swallowing,running,breathing,etc.).This TR-TENG e-textile presents a breakthrough in self-powered and comfortable electronics for next-generation healthcare technologies.
基金National Natural Science Foundation of China,51503168,Chengkun LiuTaishan Scholar Foundation of Shandong Province,tsqn201909100,Chengkun LiuInnovation Capability Support Plan of Shaanxi,China,2020PT-043,Chengkun Liu。
文摘Flexible mechanical sensors offer extensive application prospects in the field of smart wearables.However,developing highly sensitive,flexible mechanical sensors that can simultaneously detect strain and pressure remains a significant challenge.Herein,we present a flexible mechanical sensor based on AgNPs/MWCNTsCOOH/PDA/PU/PVB nanofiber-covered yarn(AMPPPNY)featuring a DNA-like double-helix wrinkled structure.The sensor is fabricated by electrospraying polyvinyl butyral(PVB)onto a pre-stretched double-helix elastic yarn,followed by electrospinning a polyurethane(PU)nanofiber membrane and inducing the self-polymerization of dopamine(DA)to create an adhesive layer.Then,one-dimensional carboxylated multi-walled carbon nanotubes(MWCNTs-COOH)and zero-dimensional silver nanoparticles(AgNPs)are dispersed onto the structure,synergistically forming a stable conductive network for efficient signal transmission.The integration of conductive fillers with different dimensionalities and DNA-like double-helix wrinkled structure endows the sensor with high strain sensitivity(gauge factor of 11,977)in the strain range of 0-310%and high pressure sensitivity(0.475 kPa^(-1))in the pressure range of 0-2 kPa.Moreover,the fabricated sensor exhibits rapid response and recovery times(130 ms/135 ms)and outstanding cyclic stability(over 10,000 cycles of both strain and pressure).Next,the fibrous sensor is weaved into a large-area fabric,and the developed smart textiles demonstrate impressive performance in detecting both subtle and large human movements.The proposed sensor is a promising candidate for flexible wearable applications.
基金This work was supported by the National Key R＆D Project from Minister of Science and Technology of China （No. 2016YFA0202702）, National Natural Science Foundation of China （Nos. 61701488 and 21571186）, Leading Scientific Research Project of Chinese Academy of Sciences （No. QYZDY-SSW-JSC010）, Youth Innovation Promotion Association （No. 2017411）, Guangdong Provincial Key Laboratory （No. 2014B030301014）, Guangdong TeZhi Plan Youth Talent of Science and Technology （No. 2014TQ01C102）, Shenzhen Basic Research plan （Nos. JSGG20150512145714246 and JSGG20160229155249762） and SIAT Innovation Program for Excellent Young Researchers （No. 2016005）.
文摘Strain sensors with high stretchability, broad strain range, high sensitivity, and good reliability are desirable, owing to their promising applications in electronic skins and human motion monitoring systems. In this paper, we report a high- performance strain sensor based on printable and stretchable electrically con- ductive elastic composites. This strain sensor is fabricated by mixing silver-coated polystyrene spheres （PS@Ag） and liquid polydimethylsiloxane （PDMS） and screen-printed to a desirable geometry. The strain sensor exhibits fascinating comprehensive performances, including high electrical conductivity （1.65 × 104 S/m）, large workable strain range （〉 80%）, high sensitivity （gauge factor of 17.5 in strain of 0%-10%, 6.0 in strain of 10%-60% and 78.6 in strain of 60%-80%）, inconspicuous resistance overshoot （〈 15%）, good reproducibility and excellent long-term stability （1,750 h at 85℃/85% relative humidity） for PS@Ag/PDMS-60, which only contains - 36.7 wt.% of silver. Simultaneously, this strain sensor provides the advantages of low-cost, simple, and large-area scalable fabrication, as well as robust mechanical properties and versatility in applications. Based on these performance characteristics, its applications in flexible printed electrodes and monitoring vigorous human motions are demonstrated, revealing its tremendous potential for applications in flexible and wearable electronics.
基金This work was supported by the National Key R&D Program of China(grant numbers 2019YFB2004802,2019YFE0120300)National Natural Science Foundation of China(grant numbers 51975542,52175554)+1 种基金National Defense Fundamental Research Project,Shanxi province key laboratory of quantum sensing and precision measurement(grant number 201905D121001)Natural Science Foundation of Shanxi Province(grant numbers 20210302123059,201801D121152).
文摘Triboelectric nanogenerators(TENGs)have recently drawn much attention in the field of biomechanical energy harvesting and motion monitoring.However,the electrode stretchability and contact-separation model induced complicated packed structure remain a problem that heavily affects output performance during various human movements and requires to be urgently addressed.Here,a single-electrode piezotriboelectric hybrid nanogenerator(SEP-TENG)integrated with stretchable liquid-metal metal electrodes is reported,which simultaneously achieves outstanding energy harvesting performance and skincomfort human motion monitoring.A polarized piezoelectric BaTiO_(3)/silicon rubber(SR)composites film is served as the effective negative tribomaterial,benefiting from the improved dielectric constant and piezoelectric charge transfer,the optimized SEP-TENG generates a high peak power density of 5.7 W/m^(2) while contacted with human skin.Besides,owing to the ultralow Young's modulus of the SR encapsulation layer and tribo-piezoelectric hybrid layer,the homogeneous integrated multilayer composite serves no break till a 745%elongation,promoting that the SEP-TENG could effectively harvest biomechanical energy and realize stable power supplying for wearable electronics even under large deformation state.Furthermore,the SEP-TENG could comfortably attach to the finger joints and collect bending energy.This work provides a novel design methodology for a single-electrode TENG to realize omnidirectional biomechanical energy harvesting and motion monitoring.
基金supported by the National Natural Science Foundation of China(62004083)the Fundamental Research Funds for the Central Universities(21622410)。
文摘Quantitative analysis of gait parameters,such as stride frequency and step speed,is essential for optimizing physical exercise for the human body.However,the current electronic sensors used in human motion monitoring remain constrained by factors such as battery life and accuracy.This study developed a self-powered gait analysis system(SGAS)based on a triboelectric nanogenerator(TENG)fabricated electrospun composite nanofibers for motion monitoring and gait analysis for regulating exercise programs.The SGAS consists of a sensing module,a charging module,a data acquisition and processing module,and an Internet of Things(IoT)platform.Within the sensing module,two specialized sensing units,TENG-S1 and TENG-S2,are positioned at the forefoot and heel to generate synchronized signals in tandem with the user's footsteps.These signals are instrumental for real-time step count and step speed monitoring.The output of the two TENG units is significantly improved by systematically investigating and optimizing the electrospun composite nanofibers'composition,strength,and wear resistance.Additionally,a charge amplifier circuit is implemented to process the raw voltage signal,consequently bolstering the reliability of the sensing signal.This refined data is then ready for further reading and calculation by the micro-controller unit(MCU)during the signal transmission process.Finally,the well-conditioned signals are wirelessly transmitted to the IoT platform for data analysis,storage,and visualization,enhancing human motion monitoring.
基金supported by the National Natural Science Foundation of China(Nos.52271209 and 51762013)the Key Project of Hebei Natural Science Foundation(No.E20202201030)+5 种基金the Beijing-Tianjin-Hebei Collaborative Innovation Community Construction Project(No.21344301D)the Second Batch of Young Talent of Hebei Province(Nos.70280016160250 and 70280011808)the Key Fund in Hebei Province Department of Education China(No.ZD2021014)the Central Government Guide Local Funding Projects for Scientific and Technological Development(Nos.216Z4404G and 206Z4402G)the Interdisciplinary Research Program of Natural Science of Hebei University(No.DXK202107)the Government Foundation of Clinical Medicine Talents Training Program of Hebei Province(No.361007).
文摘Highly sensitive sensors with extensive applications are extremely desired in the next-generation wearable electronics for human motion monitoring,human-machine interface and intelligent robotics,while singlefunctional pressure sensors cannot fulfill the growing demands of modern technological advances.Herein,an all-fabric and multilayered piezoresistive sensor based on conductive metal-organic frame-work/layered double hydroxide(cMOF/LDH)hetero-nanoforest is demonstrated to achieve multiple applications including pulse detection,joint motion detection,sound detection and information transmission.Benefiting from the synergism of cMOF/LDH hetero-nanoforest and multilayered structure,the sensor exhibits a high sensitivity(1.61×10^(9)kPa^(−1))over a broad pressure range(0-100 kPa),a fast response/recovery time(71 ms/71 ms)and a low detection limit(18 Pa),as well as reliable dynamic stability(8000 cycles).It is gratifying to note that the introduction of cMOFs endows the sensor with the potential to detect the concentration of NH_(3)(1-100 ppm)and sunlight intensity(10-100 mW cm^(−2)).This work shows great potential in multifunctional sensing,which enlightens a strategy for advancing the development process of highly sensitive intelligent wearable devices.
基金China Postdoctoral Science Foundation(Grant No.2021M700773)the Jiangsu Planned Projects for Postdoctoral Research Funds(Grant No.2021K509C)。
文摘Flexible strain sensors have been extensively used in human motion detection,medical aids,electronic skins,and other civilian or military fields.Conventional strain sensors made of metal or semiconductor materials suffer from insufficient stretchability and sensitivity,imposing severe constraints on their utilization in wearable devices.Herein,we design a flexible strain sensor based on biphasic hydrogel via an in-situ polymerization method,which possesses superior electrical response and mechanical performance.External stress could prompt the formation of conductive microchannels within the biphasic hydrogel,which originates from the interaction between the conductive water phase and the insulating oil phase.The device performance could be optimized by carefully regulating the volume ratio of the oil/water phase.Consequently,the flexible strain sensor with oil phase ratio of 80%demonstrates the best sensitivity with gauge factor of 33 upon a compressive strain range of 10%,remarkable electrical stability of 100 cycles,and rapid resistance response of 190 ms.Furthermore,the human motions could be monitored by this flexible strain sensor,thereby highlighting its potential for seamless integration into wearable devices.
