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
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
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
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
Yarn-based flexible strain sensors with advantages in wearability and integrability have attracted wide at-tention.However,it is still a big challenge to achieve yarn-based strain sensors with a wide linear strain ran...Yarn-based flexible strain sensors with advantages in wearability and integrability have attracted wide at-tention.However,it is still a big challenge to achieve yarn-based strain sensors with a wide linear strain range,low hysteresis,and durability synchronously that can be used for full range detection of human body motions.Herein,a new structure,double-threaded conductive yarn with rhythmic strain distribu-tion,is reported to markedly widen the linear strain range of microcrack-based stretchable strain sensors.A new method of winding and thermally adhering hot-melt filaments on the surface of the elastic fiber is used to achieve double-threaded yarn(DTY)with rhythmic strain distribution.The proposed strategy,the integration of heterogeneous materials,is reported to significantly reduce the mechanical hysteresis of composite yarns.Rhythmic strain distribution of the DTY during stretching causes multi-level micro-cracks in different regions of the carbon nanotube(CNT)conductive layer deposited on the surface of the DTY.Besides,the sensing performance of DTY-based strain sensor can be adjusted by designing the structural parameters.The final prepared flexible strain sensor has the advantages of a wide linear strain range(100%),great sensitivity(GF=12.43),low hysteresis,rapid response(158 ms),high repeatability(>2000 cycles at 50%strain),and hydrophobicity,etc.The sensor can monitor human motion repeatedly and stably well,and shows great advantages in flexible 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
Triboelectric nanogenerator(TENG)has been proved as a promising energy harvester in recent years,but the challenges of exploring economically triboelectric materials still exist and have aroused interests of many rese...Triboelectric nanogenerator(TENG)has been proved as a promising energy harvester in recent years,but the challenges of exploring economically triboelectric materials still exist and have aroused interests of many researchers.In this paper,chitosan-silk fibroin-airlaid paper composite film(CSA film)was fabricated and then the CSA film based-triboelectric nanogenerator(CSA-TENG)was constructed,which presents an opportunity for natural polymers to be applied in triboelectric materials.Due to the excellent electron donating ability of CSA film,the CSA-TENG can harvest environmental energy with a high efficiency.More importantly,the as-designed CSA film based dual-electrode triboelectric nanogenerator(CSA-D-TENG)is successfully assembled into hand clapper and trampoline to harvest mechanical energies generated by human bodies,it is also capable of monitoring human movement while harvesting biomechanical energies.This work provides a simple and environmental-friendly way to develop TENG for biomechanical energies harvesting and human motion monitoring.展开更多
Flexible and wearable strain sensors for human-computer interaction,health monitoring,and soft robotics have drawn widespread attention to promising applications in the next generation of artificial intelligence devic...Flexible and wearable strain sensors for human-computer interaction,health monitoring,and soft robotics have drawn widespread attention to promising applications in the next generation of artificial intelligence devices.However,conventional semiconductor sensors are difficult to meet the requirements of flexibility and stretchability.Here,we reported a kind of novel and simple sensor based on layer-by-layer(LBL)method.Carbon nanotubes(CNTs)layer provides high ductility and stability in the process of tension sensing,while silver layer provides low initial resistance and fast reflecting in the process of tension sensing.LBL method ensures the uniformity of the conductive layer.The sensor has superior sheet resistance of 9.44Ω/sq.,high elongation at break of 104%.For sensing capability,the sensor has wide reflecting range of 60%,high gauge factor(GF)of 1000 up to 60%strain,fast reflecting time of 165 ms.Excellent reliability and stability have also been verified.It is also worth mentioning that the entire process does not require any expensive equipments,complicated processes or harsh experimental conditions.The above features provide an idea for large-scale application of flexible stretchable sensors.展开更多
Advanced soft ion-conducting hydrogels have been developed rapidly in the integrated portable health monitoring equipment due to their higher sensitivity,sensory traits,tunable conductivity,and stretchability for phys...Advanced soft ion-conducting hydrogels have been developed rapidly in the integrated portable health monitoring equipment due to their higher sensitivity,sensory traits,tunable conductivity,and stretchability for physiological activities and personal healthcare detection.However,traditional hydrogel conductors are normally susceptible to large deformation and strong mechanical stress,which leads to inferior electro-mechanical stability for real application scenarios.Herein,a strong ionically conductive hydrogel(poly(vinyl alcohol)-boric acid-glycerol/sodium alginate-calcium chloride/electrolyte ions(PBG/SC/EI))was designed by engineering the covalently and ionically crosslinked networks followed by the salting-out effect to further enhance the mechanical strength and ionic conductivity of the hydrogel.Owing to the collective effects of the energy-dissipation mechanism and salting-out effect,the designed PBG/SC/EI with excellent structural integrity and robustness exhibits exceptional mechanical properties(elongation at break for 559.1%and tensile strength of 869.4 kPa)and high ionic conductivity(1.618 S·m^(-1)).As such,the PBG/SC/EI strain sensor features high sensitivity(gauge factor=2.29),which can effectively monitor various kinds of human motions(joint motions,facial micro-expression,faint respiration,and voice recognition).Meanwhile,the hydrogel-based Zn||MnO_(2)battery delivers a high capacity of 267.2 mAh·g^(-1)and a maximal energy density of 356.8 Wh·kg^(-1)associated with good cycle performance of 71.8%capacity retention after 8000 cycles.Additionally,an integrated bio-monitoring system with the sensor and Zn||MnO_(2)battery can accurately identify diverse physiological activities in a real-time and non-invasive way.This work presents a feasible strategy for designing high-performance conductive hydrogels for highly-reliable integrated bio-monitoring systems with excellent practicability.展开更多
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.
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 Natural Science Foundation of Shanghai(Nos.20ZR1400500,22ZR1400800)the Fundamental Research Funds for the Central Universities and Graduate Student Innovation Fund of Donghua University(No.CUSF-DH-D-2022043).
文摘Yarn-based flexible strain sensors with advantages in wearability and integrability have attracted wide at-tention.However,it is still a big challenge to achieve yarn-based strain sensors with a wide linear strain range,low hysteresis,and durability synchronously that can be used for full range detection of human body motions.Herein,a new structure,double-threaded conductive yarn with rhythmic strain distribu-tion,is reported to markedly widen the linear strain range of microcrack-based stretchable strain sensors.A new method of winding and thermally adhering hot-melt filaments on the surface of the elastic fiber is used to achieve double-threaded yarn(DTY)with rhythmic strain distribution.The proposed strategy,the integration of heterogeneous materials,is reported to significantly reduce the mechanical hysteresis of composite yarns.Rhythmic strain distribution of the DTY during stretching causes multi-level micro-cracks in different regions of the carbon nanotube(CNT)conductive layer deposited on the surface of the DTY.Besides,the sensing performance of DTY-based strain sensor can be adjusted by designing the structural parameters.The final prepared flexible strain sensor has the advantages of a wide linear strain range(100%),great sensitivity(GF=12.43),low hysteresis,rapid response(158 ms),high repeatability(>2000 cycles at 50%strain),and hydrophobicity,etc.The sensor can monitor human motion repeatedly and stably well,and shows great advantages in flexible 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the National Key R&D Project from Ministry of Science and Technology(Nos.2016YFA0202702 and 2016YFA0202701)the Key Research Program of Frontier Sciences,CAS(No.ZDBS-LY-DQC025)。
文摘Triboelectric nanogenerator(TENG)has been proved as a promising energy harvester in recent years,but the challenges of exploring economically triboelectric materials still exist and have aroused interests of many researchers.In this paper,chitosan-silk fibroin-airlaid paper composite film(CSA film)was fabricated and then the CSA film based-triboelectric nanogenerator(CSA-TENG)was constructed,which presents an opportunity for natural polymers to be applied in triboelectric materials.Due to the excellent electron donating ability of CSA film,the CSA-TENG can harvest environmental energy with a high efficiency.More importantly,the as-designed CSA film based dual-electrode triboelectric nanogenerator(CSA-D-TENG)is successfully assembled into hand clapper and trampoline to harvest mechanical energies generated by human bodies,it is also capable of monitoring human movement while harvesting biomechanical energies.This work provides a simple and environmental-friendly way to develop TENG for biomechanical energies harvesting and human motion monitoring.
基金financially supported by the National Natural Science Foundation of China(No.51403115)。
文摘Flexible and wearable strain sensors for human-computer interaction,health monitoring,and soft robotics have drawn widespread attention to promising applications in the next generation of artificial intelligence devices.However,conventional semiconductor sensors are difficult to meet the requirements of flexibility and stretchability.Here,we reported a kind of novel and simple sensor based on layer-by-layer(LBL)method.Carbon nanotubes(CNTs)layer provides high ductility and stability in the process of tension sensing,while silver layer provides low initial resistance and fast reflecting in the process of tension sensing.LBL method ensures the uniformity of the conductive layer.The sensor has superior sheet resistance of 9.44Ω/sq.,high elongation at break of 104%.For sensing capability,the sensor has wide reflecting range of 60%,high gauge factor(GF)of 1000 up to 60%strain,fast reflecting time of 165 ms.Excellent reliability and stability have also been verified.It is also worth mentioning that the entire process does not require any expensive equipments,complicated processes or harsh experimental conditions.The above features provide an idea for large-scale application of flexible stretchable sensors.
基金support from the National Natural Science Foundation of China(Nos.21965033,U2003216,22269023,and U2003132)the Key Research and Development Task Special Program of Xinjiang Uygur Autonomous Region(No.2022B01040-3)+2 种基金the Special Projects on Regional Collaborative Innovation-SCO Science and Technology Partnership Program,and the International Science and Technology Cooperation Program(Nos.2022E01020 and 2022E01056)Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01C25)gratefully acknowledged.Z.C.W.acknowledges the European Research Executive Agency(Project 101079184-FUNLAYERS).
文摘Advanced soft ion-conducting hydrogels have been developed rapidly in the integrated portable health monitoring equipment due to their higher sensitivity,sensory traits,tunable conductivity,and stretchability for physiological activities and personal healthcare detection.However,traditional hydrogel conductors are normally susceptible to large deformation and strong mechanical stress,which leads to inferior electro-mechanical stability for real application scenarios.Herein,a strong ionically conductive hydrogel(poly(vinyl alcohol)-boric acid-glycerol/sodium alginate-calcium chloride/electrolyte ions(PBG/SC/EI))was designed by engineering the covalently and ionically crosslinked networks followed by the salting-out effect to further enhance the mechanical strength and ionic conductivity of the hydrogel.Owing to the collective effects of the energy-dissipation mechanism and salting-out effect,the designed PBG/SC/EI with excellent structural integrity and robustness exhibits exceptional mechanical properties(elongation at break for 559.1%and tensile strength of 869.4 kPa)and high ionic conductivity(1.618 S·m^(-1)).As such,the PBG/SC/EI strain sensor features high sensitivity(gauge factor=2.29),which can effectively monitor various kinds of human motions(joint motions,facial micro-expression,faint respiration,and voice recognition).Meanwhile,the hydrogel-based Zn||MnO_(2)battery delivers a high capacity of 267.2 mAh·g^(-1)and a maximal energy density of 356.8 Wh·kg^(-1)associated with good cycle performance of 71.8%capacity retention after 8000 cycles.Additionally,an integrated bio-monitoring system with the sensor and Zn||MnO_(2)battery can accurately identify diverse physiological activities in a real-time and non-invasive way.This work presents a feasible strategy for designing high-performance conductive hydrogels for highly-reliable integrated bio-monitoring systems with excellent practicability.
