Copper nanowires （Cu NWs） have attracted increasing attention as building blocks for electronics due to their outstanding electrical properties and low cost. However, organic residues and oxide layers ubiquitously e...Copper nanowires （Cu NWs） have attracted increasing attention as building blocks for electronics due to their outstanding electrical properties and low cost. However, organic residues and oxide layers ubiquitously existing on the surface of Cu NWs impede good inter-wire contact. Commonly used methods such as thermal annealing and acid treatment often lead to nanowire damage. Herein, hydrogen plasma treatment at room temperature has been demonstrated to be effective for simultaneous surface cleaning and selective welding of Cu NWs at junctions. Transparent electrodes with excellent optical-electrical performance （19 ff）-sq-1 @ 90% T） and enhanced stability have been fabricated and integrated into organic solar cells. Besides, Cu NW conductors with superior stretchability and cycling stability under stretching speeds of up to 400 mm-min-＇ can also be produced by the nanowelding process, and the feasibility of their application in stretchable LED circuits has been demonstrated.展开更多
Silver nanowires （AgNWs） have emerged as a promising nanomaterial for next generation stretchable electronics. However, until now, the fabrication of AgNW- based components has been hampered by complex and time-cons...Silver nanowires （AgNWs） have emerged as a promising nanomaterial for next generation stretchable electronics. However, until now, the fabrication of AgNW- based components has been hampered by complex and time-consuming steps. Here, we introduce a facile, fast, and one-step methodology for the fabrication of highly conductive and stretchable AgNW/polyurethane （PU） composite electrodes based on a high-intensity pulsed light （HIPL） technique. HIPL simultaneously improved wire-wire junction conductivity and wire-substrate adhesion at room temperature and in air within 50 μs, omitting the complex transfer-curing-implanting process. Owing to the localized deformation of PU at interfaces with AgNWs, embedding of the nanowires was rapidly carried out without substantial substrate damage. The resulting electrode retained a low sheet resistance （high electrical conductivity） of 〈10 Ω/sq even under 100% strain, or after 1,000 continuous stretching-relaxation cycles, with a peak strain of 60%. The fabricated electrode has found immediate application as a sensor for motion detection. Furthermore, based on our electrode, a light emitting diode （LED） driven by integrated stretchable AgNW conductors has been fabricated. In conclusion, our present fabrication approach is fast, simple, scalable, and cost- efficient, making it a good candidate for a future roll-to-roll process.展开更多
Intrinsically conducting polymers(ICPs),such as polyacetylene,polyaniline,polypyrrole,polythiophene,and poly(3,4-ethylenedioxythiophene)(PEDOT),can have important application in flexible electronics owing to their uni...Intrinsically conducting polymers(ICPs),such as polyacetylene,polyaniline,polypyrrole,polythiophene,and poly(3,4-ethylenedioxythiophene)(PEDOT),can have important application in flexible electronics owing to their unique merits including high conductivity,high mechanical flexibility,low cost,and good biocompatibility.The requirements for their application in flexible electronics include high conductivity and appropriate mechanical properties.The conductivity of some ICPs can be enhanced through a postpolymerization treatment,the so-called“secondary doping.”A conducting polymer film with high conductivity can be used as flexible electrode and even as flexible transparent electrode of optoelectronic devices.The application of ICPs as stretchable electrode requires high mechanical stretchability.The mechanical stretchability of ICPs can be improved through blending with a soft polymer or plasticization.Because of their good biocompatibility,ICPs can be modified as dry electrode for biopotential monitoring and neural interface.In addition,ICPs can be used as the active material of strain sensors for healthcare monitoring,and they can be adopted to monitor food processing,such as the fermentation,steaming,storage,and refreshing of starch-based food because of the resistance variation caused by the food volume change.All these applications of ICPs are covered in this review article.展开更多
In vivo monitoring of bioelectrical and biochemical signals with implanted electrodes has received great interest over the past decades.However,this faces huge challenges because of the severe mechanical mismatch betw...In vivo monitoring of bioelectrical and biochemical signals with implanted electrodes has received great interest over the past decades.However,this faces huge challenges because of the severe mechanical mismatch between conventional rigid electrodes and soft biological tissues.In recent years,the emergence of flexible and stretchable electrodes offers seamless and conformable biological-electronic interfaces and has demonstrated significant advantages for in vivo electrochemical and electrophysiological monitoring.This review first summarizes the strategies for electrode fabrication from the point of substrate and conductive materials.Next,recent progress in electrode functionalization for improved performance is presented.Then,the advances of flexible and stretchable electrodes in exploring bioelectrical and biochemical signals are introduced.Finally,we present some challenges and perspectives ranging from electrode fabrication to application.展开更多
Stretchable and transparent electrodes(STEs)based on silver nanowires(AgNWs)have garnered considerable attention due to their unique optoelectronic features.However,the low oxidation resistance of AgNWs severely limit...Stretchable and transparent electrodes(STEs)based on silver nanowires(AgNWs)have garnered considerable attention due to their unique optoelectronic features.However,the low oxidation resistance of AgNWs severely limits the reliability and durability of devices based on such STEs.The present work reports a type of core-sheath silver@gold nanowires(Ag@Au NWs)with a morphology resembling dual-headed matchsticks and an average Au sheath thickness of 2.5 nm.By starting with such Ag@Au NWs,STEs with an optical transmittance of 78.7%,a haze of 13.0%,a sheet resistance of 13.5Ω·sq.−1,and a maximum tensile strain of 240%can be formed with the aid of capillary-force-induced welding.The resultant STEs exhibit exceptional oxidation resistance,high-temperature resistance,and chemical/electrochemical stability owing to the conformal and dense Au sheath.Furthermore,non-enzymatic glucose biosensors are fabricated employing the Ag@Au NW STEs.The electrocatalytic oxidation currents are proportional to glucose concentrations with a high sensitivity of 967μA·mM−1·cm−2 and a detection limit of 125μM over a detection range of 0.6 to 16 mM.Additionally,the biosensors demonstrate an appealing robustness and antiinterference characteristics,high repeatability,and great stability that make them adequate for practical use.展开更多
The urgent requirement of electronic skin conformably attached to nonplanar surfaces to provide sta-ble monitoring in areas of healthcare,prosthetics,and robotics promotes the development of strain-insensitive/unpertu...The urgent requirement of electronic skin conformably attached to nonplanar surfaces to provide sta-ble monitoring in areas of healthcare,prosthetics,and robotics promotes the development of strain-insensitive/unperturbed pressure sensors.The main challenges lie in:(1)stretchability and conduc-tive stability of flexible electrodes and(2)mechanical stability of heterogeneous interfaces.This study presents a highly stable strain-insensitive pressure sensor achieved by in-plane strain modulation and quasi-homogenous interfacial design.Strain modulation of stretchable electrodes by both periodic mi-crostructured engineering and pre-stretching strategies(called“island-ripple”)was employed to suppress microcracks propagation.The improvement in stretchability and cyclic conductive stability of electrodes was identified by finite element analysis and experimental verification.The pre-stretched microconed stretchable electrode with a low sheet resistance of 0.546sq^(−1) shows a maximum deformation of up to 80%and excellent cyclic conductive stability over 10000 times under 30%strain.Quasi-homogenous interface strategy by the CNTs/PDMS system was employed to enhance the mechanical and electrical sta-bility of the electrode-active materials interface,demonstrating a strong peel strength and shear strength of>40.9 N/m and>124.8 kPa,respectively.The as-prepared strain-insensitive pressure sensor provides constant sensing performance over 5000 stretching-releasing cycles within 20%stretching.In addition,a 4×4 pixel strain-insensitive pressure sensor array with reduced cross-talk circuit design was further integrated to identify the shape and weight of different objects under strains.The stretchability and sta-bility of our sensor enable it to be applied in stretchable electronics with great potential.展开更多
Electrochemical sensing faces huge challenges in characterizing the transient release of biochemical molecules from deformed cells,due to the severely mechanical mismatch between rigid electrodes and soft cells.In rec...Electrochemical sensing faces huge challenges in characterizing the transient release of biochemical molecules from deformed cells,due to the severely mechanical mismatch between rigid electrodes and soft cells.In recent years,the emergence of stretchable electrochemical sensors has made a breakthrough by complying with the deformation of living cells and simultaneous monitoring of mechanically evoked biochemical signals.This review first summarizes two fundamental strategies for the fabrication of stretchable electrodes from the points of structure and material.Next,recent progresses in construction of functionalized interface to improve the performance of stretchable electrochemical sensors are presented.Then,the application of stretchable electrochemical sensors in real-time monitoring of biomolecules released by mechanically sensitive cells is introduced.Finally,some perspectives and challenges of stretchable electrochemical sensors regarding cell detection are discussed.展开更多
Electrodes based on composites of silver nanowires(AgNWs)and elastic polymers have been widely studied and applied in various stretchable electronic devices.However,due to the high aspect ratio of nanowires,the patter...Electrodes based on composites of silver nanowires(AgNWs)and elastic polymers have been widely studied and applied in various stretchable electronic devices.However,due to the high aspect ratio of nanowires,the patterning of AgNW-based composite electrodes remains a huge challenge,especially for high-resolution complex circuit wiring on large-size elastic substrates.In this paper,we propose a method for preparing large-size stretchable circuit boards with high-resolution electrodes by the combination of screen printing and vacuum filtration of AgNWs/polydimethylsiloxane(PDMS)composite.The as-prepared stretchable electrodes have smooth edges with patterning resolution up to-50 μm.The conductivity of the composite electrode can be precisely controlled by varying deposition densities of AgNWs and have reached to 1.07 x 10^(4) S/cm when the deposition density was 2.0 mg/cm^(2).In addition,the uniformity of conductivity and the resistance-strain characteristics of composite electrodes were systematically evaluated with different AgNWs deposition densities.The composite electrodes have been successfully employed to construct a large-size programmable display system and an 18-channel surface electromyography(EMG)recording,showing great potentials for some strain-insensitive stretchable circuits in wearable and health-related electronic applications.展开更多
Stretchable transparent electrode(STE)plays a key role in numerous emerging applications as an indispensable component for future stretchable devices.The embedded STE,as a promising candidate,possesses balanced perfor...Stretchable transparent electrode(STE)plays a key role in numerous emerging applications as an indispensable component for future stretchable devices.The embedded STE,as a promising candidate,possesses balanced performances and facile preparation procedures.However,it still suffers from the defects of conductive materials caused by the transferring,which results in the irreversible failure of devices.In this work,a patternable silver nanowire(AgNW)STE was fabricated by a plasma-enhanced cryo-transferring(PEC-transferring)process.Owing to the plasma-induced sintering,the AgNW network obtained remarkable improvement in robustness,which ensured the intact network after transferring and thus led to superior tensile electrical properties of the STE.Furthermore,serpentine patterns were utilized to optimize the tensile electrical properties of the STE,which achieved a figure of merit of 292.8 and 150%resistance changing under 50%strain.As a practical application,a 4×3 array of the mutual-capacitive type stretchable touch sensors was demonstrated for future touch sensors in stretchable devices.The PEC-transferring process opened a new avenue for patternable embedded STEs and exhibited its high potential in wearable electronics and the Internet of Thing devices.展开更多
Stretchable epidermal electronics allow conformal interactions with the human body for emerging applications in wearable health monitoring and therapy.Stretchable devices are commonly constructed on submillimeter-thic...Stretchable epidermal electronics allow conformal interactions with the human body for emerging applications in wearable health monitoring and therapy.Stretchable devices are commonly constructed on submillimeter-thick elastomer substrates with limited moisture permeability,thereby leading to unpleasant sensations during long-term attachment.Although the ultrathin elastomer membrane may address this problem,the mechanical robustness is essentially lost for direct manipulations and repetitive uses.Here,we report a stretchable,breathable,and washable epidermal electrode of microfoam reinforced ultrathin conductive nanocomposite(MRUCN).The new architecture involves ultrathin conductive silver nanowire nanocomposite features supported on a porous elastomeric microfoam substrate,which exhibits high moisture permeability for pleasant perceptions during epidermal applications.As-prepared epidermal electrodes show excellent electronic conductivity(8440 S·cm^(-1)),high feature resolution(~50μm),decent stretchability,and excellent durability.In addition,the MRUCN retains stable electrical properties during washing to meet the hygiene requirements for repetitive uses.The successful implementation in an integrated electronic patch demonstrates the practical suitability of MRUCN for a broad range of epidermal electronic devices and systems.展开更多
Epilepsy is a chronic nervous disease with increasing incidence worldwide,while the accurate localization of epileptic focus and the corresponding treatment are still challenging due to the lack of effective tools to ...Epilepsy is a chronic nervous disease with increasing incidence worldwide,while the accurate localization of epileptic focus and the corresponding treatment are still challenging due to the lack of effective tools to monitor and modulate the related brain neurological activities.In this work,stretchable micro electrocorticogram(mECoG)electrodes are developed and used to investigate penicillininduced epilepsy in rats.The electrodes possess excellent stretchability,conformality,anti-interference ability and sufficient resolution to successfully monitor electroencephalogram(EEG)signals,which is superior to traditional rigid polyimide-based electrodes.Characteristic epileptic spike waves are detected and analyzed to study the epileptic focus and electrical stimulus effects during epileptic seizures.It is found that the spike waves occur first in the visual cortex which is likely to be the epileptic focus.Epileptic spike wave frequency quickly increases to 1.07 Hz where it reaches a plateau and remains stable.There is no dominant brain hemisphere that would show early warning of epileptic seizures.Electrical stimuli for various times are applied after administering penicillin.It is found that 15 min of electrical stimulus has the best restraining effect on epileptic seizures.The mECoG electrodes developed in this study show potentials for applications in stretchable biomedical devices.展开更多
In the development of wearable energy devices,polypyrrole (PPy) is considered as a promising electrode material owing to its high capacitance and good mechanical flexibility.Herein,we report a PPy-based hybrid structu...In the development of wearable energy devices,polypyrrole (PPy) is considered as a promising electrode material owing to its high capacitance and good mechanical flexibility.Herein,we report a PPy-based hybrid structure consisting of vertical PPy nanotube arrays and carbon nano-onions (CNOs) grown on textile for wearable supercapacitors.In this hybrid nanostructure,the vertical PPy nanotubes provide straight and superhighways for electron and ion transport,boosting the energy storage;while the CNOs mainly act as a conductivity retainer for the underlayered PPy film during stretching.A facile template-degrading method is developed for the large-area growth of the PPy-based hybrid nanostructures on the textile through one-step polymerization process.The fabricated stretchable supercapacitor exhibits superior energy storage capacitance with the specific capacitance of 64 F·g^-1.Also,it presents the high capacitance retention of 99% at a strain of 50% after 500 stretching cycles.Furthermore,we demonstrate that the textile-based stretchable supercapacitor device can provide a stable energy storage performance in different wearable situations for practical applications.The use of the PPy-based hybrid nanostructures as the supercapacitor electrode offers a novel structure design and a promising opportunity for wearable power supply in real applications.展开更多
The development of stretchable electronics could enhance novel interface structures to solve the stretchability-conductivity dilemma,which remains a major challenge.Herein,we report a nano-liquid metal(LM)-based highl...The development of stretchable electronics could enhance novel interface structures to solve the stretchability-conductivity dilemma,which remains a major challenge.Herein,we report a nano-liquid metal(LM)-based highly robust stretchable electrode(NHSE)with a self-adaptable interface that mimics water-tonet interaction.Based on the in situ assembly of electrospun elastic nanofiber scaffolds and electrosprayed LM nanoparticles,the NHSE exhibits an extremely low sheet resistance of 52 mΩsq^(-1).It is not only insensitive to a large degree of mechanical stretching(i.e.,350%electrical resistance change upon 570%elongation)but also immune to cyclic deformation(i.e.,5%electrical resistance increases after 330000 stretching cycles with 100%elongation).These key properties are far superior to those of the state-of-the-art reports.Its robustness and stability are verified under diverse circumstances,including long-term exposure to air(420 days),cyclic submersion(30000 times),and resilience against mechanical damages.The combination of conductivity,stretchability,and durability makes the NHSE a promising conductor/electrode solution for flexible/stretchable electronics for applications such as wearable on-body physiological signal detection,human-machine interaction,and heating e-skin.展开更多
Easy fabrication of super-stretchable electrodes can pave the way for smart and wearable electronics.Using drop casting unidirectional nickel nanowires with polyurethane matrix,we fabricated a super-stretchable film w...Easy fabrication of super-stretchable electrodes can pave the way for smart and wearable electronics.Using drop casting unidirectional nickel nanowires with polyurethane matrix,we fabricated a super-stretchable film with high electric conductivity.The as-fabricated film can withstand a 300%tensile strain in the direction perpendicular to nanowires,owing to the transformation of percolating nanowire network from 2D to 3D.In contrast to the decreased film conductivities under large tension in most stretchable electrodes,which usually associate with fractures and irreversible deformations,our film conductivity can increase with the applied strain.This probably benefits from the enhanced electrical contacts between twisted nanowires under tension.The developed super-stretchable film with unprecedented behavior in this work sheds light on the facile fabrication of super-stretchable electrodes with durable performance.展开更多
基金This work was financially supported by the National Basic Research Program of China （No. 2012CB932303）, the National Natural Science Foundation of China （No. 61301036）, Shanghai Municipal Natural Science Foundation （No. 13ZR1463600）, and the Innovation Project of Shanghai Institute of Ceramics.
文摘Copper nanowires （Cu NWs） have attracted increasing attention as building blocks for electronics due to their outstanding electrical properties and low cost. However, organic residues and oxide layers ubiquitously existing on the surface of Cu NWs impede good inter-wire contact. Commonly used methods such as thermal annealing and acid treatment often lead to nanowire damage. Herein, hydrogen plasma treatment at room temperature has been demonstrated to be effective for simultaneous surface cleaning and selective welding of Cu NWs at junctions. Transparent electrodes with excellent optical-electrical performance （19 ff）-sq-1 @ 90% T） and enhanced stability have been fabricated and integrated into organic solar cells. Besides, Cu NW conductors with superior stretchability and cycling stability under stretching speeds of up to 400 mm-min-＇ can also be produced by the nanowelding process, and the feasibility of their application in stretchable LED circuits has been demonstrated.
文摘Silver nanowires （AgNWs） have emerged as a promising nanomaterial for next generation stretchable electronics. However, until now, the fabrication of AgNW- based components has been hampered by complex and time-consuming steps. Here, we introduce a facile, fast, and one-step methodology for the fabrication of highly conductive and stretchable AgNW/polyurethane （PU） composite electrodes based on a high-intensity pulsed light （HIPL） technique. HIPL simultaneously improved wire-wire junction conductivity and wire-substrate adhesion at room temperature and in air within 50 μs, omitting the complex transfer-curing-implanting process. Owing to the localized deformation of PU at interfaces with AgNWs, embedding of the nanowires was rapidly carried out without substantial substrate damage. The resulting electrode retained a low sheet resistance （high electrical conductivity） of 〈10 Ω/sq even under 100% strain, or after 1,000 continuous stretching-relaxation cycles, with a peak strain of 60%. The fabricated electrode has found immediate application as a sensor for motion detection. Furthermore, based on our electrode, a light emitting diode （LED） driven by integrated stretchable AgNW conductors has been fabricated. In conclusion, our present fabrication approach is fast, simple, scalable, and cost- efficient, making it a good candidate for a future roll-to-roll process.
基金grateful to the Ministry of Education of Singapore for the research grant of R-284-000-197-114.
文摘Intrinsically conducting polymers(ICPs),such as polyacetylene,polyaniline,polypyrrole,polythiophene,and poly(3,4-ethylenedioxythiophene)(PEDOT),can have important application in flexible electronics owing to their unique merits including high conductivity,high mechanical flexibility,low cost,and good biocompatibility.The requirements for their application in flexible electronics include high conductivity and appropriate mechanical properties.The conductivity of some ICPs can be enhanced through a postpolymerization treatment,the so-called“secondary doping.”A conducting polymer film with high conductivity can be used as flexible electrode and even as flexible transparent electrode of optoelectronic devices.The application of ICPs as stretchable electrode requires high mechanical stretchability.The mechanical stretchability of ICPs can be improved through blending with a soft polymer or plasticization.Because of their good biocompatibility,ICPs can be modified as dry electrode for biopotential monitoring and neural interface.In addition,ICPs can be used as the active material of strain sensors for healthcare monitoring,and they can be adopted to monitor food processing,such as the fermentation,steaming,storage,and refreshing of starch-based food because of the resistance variation caused by the food volume change.All these applications of ICPs are covered in this review article.
基金This work was supported by the National Natural Science Foundation of China(Grant 22122408)the National Key R&D Program of China(2022YFA1104802).
文摘In vivo monitoring of bioelectrical and biochemical signals with implanted electrodes has received great interest over the past decades.However,this faces huge challenges because of the severe mechanical mismatch between conventional rigid electrodes and soft biological tissues.In recent years,the emergence of flexible and stretchable electrodes offers seamless and conformable biological-electronic interfaces and has demonstrated significant advantages for in vivo electrochemical and electrophysiological monitoring.This review first summarizes the strategies for electrode fabrication from the point of substrate and conductive materials.Next,recent progress in electrode functionalization for improved performance is presented.Then,the advances of flexible and stretchable electrodes in exploring bioelectrical and biochemical signals are introduced.Finally,we present some challenges and perspectives ranging from electrode fabrication to application.
基金The authors acknowledge financial support from National Natural Science Foundation of China(Nos.52073026 and U20A20264).
文摘Stretchable and transparent electrodes(STEs)based on silver nanowires(AgNWs)have garnered considerable attention due to their unique optoelectronic features.However,the low oxidation resistance of AgNWs severely limits the reliability and durability of devices based on such STEs.The present work reports a type of core-sheath silver@gold nanowires(Ag@Au NWs)with a morphology resembling dual-headed matchsticks and an average Au sheath thickness of 2.5 nm.By starting with such Ag@Au NWs,STEs with an optical transmittance of 78.7%,a haze of 13.0%,a sheet resistance of 13.5Ω·sq.−1,and a maximum tensile strain of 240%can be formed with the aid of capillary-force-induced welding.The resultant STEs exhibit exceptional oxidation resistance,high-temperature resistance,and chemical/electrochemical stability owing to the conformal and dense Au sheath.Furthermore,non-enzymatic glucose biosensors are fabricated employing the Ag@Au NW STEs.The electrocatalytic oxidation currents are proportional to glucose concentrations with a high sensitivity of 967μA·mM−1·cm−2 and a detection limit of 125μM over a detection range of 0.6 to 16 mM.Additionally,the biosensors demonstrate an appealing robustness and antiinterference characteristics,high repeatability,and great stability that make them adequate for practical use.
基金the National Key R&D Program of China(No.2018YFA0702100)the Zhejiang Provincial Key R&D Program of China(Nos.2021C05002 and 2021C01026)+3 种基金the National Natural Science Foundation of China(No.U21A2079)the Beijing Natural Science Foundation(No.2182032)the Basic R&D Program of Zhejiang(No.LGC22B050044)the Leading In-novative and Entrepreneur Team Introduction Program of Zhejiang(No.2020R01007).
文摘The urgent requirement of electronic skin conformably attached to nonplanar surfaces to provide sta-ble monitoring in areas of healthcare,prosthetics,and robotics promotes the development of strain-insensitive/unperturbed pressure sensors.The main challenges lie in:(1)stretchability and conduc-tive stability of flexible electrodes and(2)mechanical stability of heterogeneous interfaces.This study presents a highly stable strain-insensitive pressure sensor achieved by in-plane strain modulation and quasi-homogenous interfacial design.Strain modulation of stretchable electrodes by both periodic mi-crostructured engineering and pre-stretching strategies(called“island-ripple”)was employed to suppress microcracks propagation.The improvement in stretchability and cyclic conductive stability of electrodes was identified by finite element analysis and experimental verification.The pre-stretched microconed stretchable electrode with a low sheet resistance of 0.546sq^(−1) shows a maximum deformation of up to 80%and excellent cyclic conductive stability over 10000 times under 30%strain.Quasi-homogenous interface strategy by the CNTs/PDMS system was employed to enhance the mechanical and electrical sta-bility of the electrode-active materials interface,demonstrating a strong peel strength and shear strength of>40.9 N/m and>124.8 kPa,respectively.The as-prepared strain-insensitive pressure sensor provides constant sensing performance over 5000 stretching-releasing cycles within 20%stretching.In addition,a 4×4 pixel strain-insensitive pressure sensor array with reduced cross-talk circuit design was further integrated to identify the shape and weight of different objects under strains.The stretchability and sta-bility of our sensor enable it to be applied in stretchable electronics with great potential.
基金This work was supported by the National Natural Science Foundation of China(Grants 22122408,21725504 and 21721005)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA16021306)the Fundamental Research Funds for the Central Universities(2042021kf0035 and 2042022kf0030).
文摘Electrochemical sensing faces huge challenges in characterizing the transient release of biochemical molecules from deformed cells,due to the severely mechanical mismatch between rigid electrodes and soft cells.In recent years,the emergence of stretchable electrochemical sensors has made a breakthrough by complying with the deformation of living cells and simultaneous monitoring of mechanically evoked biochemical signals.This review first summarizes two fundamental strategies for the fabrication of stretchable electrodes from the points of structure and material.Next,recent progresses in construction of functionalized interface to improve the performance of stretchable electrochemical sensors are presented.Then,the application of stretchable electrochemical sensors in real-time monitoring of biomolecules released by mechanically sensitive cells is introduced.Finally,some perspectives and challenges of stretchable electrochemical sensors regarding cell detection are discussed.
基金This work was supported by the National Key R&D Program of China(No.2017YFE0112000)the National Natural Science Foundation of China(NSFC)(No.51603227).
文摘Electrodes based on composites of silver nanowires(AgNWs)and elastic polymers have been widely studied and applied in various stretchable electronic devices.However,due to the high aspect ratio of nanowires,the patterning of AgNW-based composite electrodes remains a huge challenge,especially for high-resolution complex circuit wiring on large-size elastic substrates.In this paper,we propose a method for preparing large-size stretchable circuit boards with high-resolution electrodes by the combination of screen printing and vacuum filtration of AgNWs/polydimethylsiloxane(PDMS)composite.The as-prepared stretchable electrodes have smooth edges with patterning resolution up to-50 μm.The conductivity of the composite electrode can be precisely controlled by varying deposition densities of AgNWs and have reached to 1.07 x 10^(4) S/cm when the deposition density was 2.0 mg/cm^(2).In addition,the uniformity of conductivity and the resistance-strain characteristics of composite electrodes were systematically evaluated with different AgNWs deposition densities.The composite electrodes have been successfully employed to construct a large-size programmable display system and an 18-channel surface electromyography(EMG)recording,showing great potentials for some strain-insensitive stretchable circuits in wearable and health-related electronic applications.
基金supported by the Key-Area Research and Development Program of Guangdong Province(No.2019B010934001)the Fundamental Research Funds for the Central Universities,Sun Yat-Sen University(No.19lgzd12)the Scientific and Technological Projection of Guangdong Province(No.2020B1212060030).
文摘Stretchable transparent electrode(STE)plays a key role in numerous emerging applications as an indispensable component for future stretchable devices.The embedded STE,as a promising candidate,possesses balanced performances and facile preparation procedures.However,it still suffers from the defects of conductive materials caused by the transferring,which results in the irreversible failure of devices.In this work,a patternable silver nanowire(AgNW)STE was fabricated by a plasma-enhanced cryo-transferring(PEC-transferring)process.Owing to the plasma-induced sintering,the AgNW network obtained remarkable improvement in robustness,which ensured the intact network after transferring and thus led to superior tensile electrical properties of the STE.Furthermore,serpentine patterns were utilized to optimize the tensile electrical properties of the STE,which achieved a figure of merit of 292.8 and 150%resistance changing under 50%strain.As a practical application,a 4×3 array of the mutual-capacitive type stretchable touch sensors was demonstrated for future touch sensors in stretchable devices.The PEC-transferring process opened a new avenue for patternable embedded STEs and exhibited its high potential in wearable electronics and the Internet of Thing devices.
基金This work was supported by Key Research and Development Program of Jiangsu Provincial Department of Science and Technology of China(No.BE2019002)Key Research and Development Program of Hebei Provence(No.19251804D)High-Level Entrepreneurial and Innovative Talents Program of Jiangsu Province。
文摘Stretchable epidermal electronics allow conformal interactions with the human body for emerging applications in wearable health monitoring and therapy.Stretchable devices are commonly constructed on submillimeter-thick elastomer substrates with limited moisture permeability,thereby leading to unpleasant sensations during long-term attachment.Although the ultrathin elastomer membrane may address this problem,the mechanical robustness is essentially lost for direct manipulations and repetitive uses.Here,we report a stretchable,breathable,and washable epidermal electrode of microfoam reinforced ultrathin conductive nanocomposite(MRUCN).The new architecture involves ultrathin conductive silver nanowire nanocomposite features supported on a porous elastomeric microfoam substrate,which exhibits high moisture permeability for pleasant perceptions during epidermal applications.As-prepared epidermal electrodes show excellent electronic conductivity(8440 S·cm^(-1)),high feature resolution(~50μm),decent stretchability,and excellent durability.In addition,the MRUCN retains stable electrical properties during washing to meet the hygiene requirements for repetitive uses.The successful implementation in an integrated electronic patch demonstrates the practical suitability of MRUCN for a broad range of epidermal electronic devices and systems.
基金financially supported by the National Key Scientific Research Instrument Development Project(81927804)the Major Scientific and Technological Innovation Projects of Shandong Province(2019JZZY011112)+1 种基金the Clinical Research Project of Shandong University(2020SDUCRCB004)the National Nature Science Foundation of China(81960419 and 81760416)。
文摘Epilepsy is a chronic nervous disease with increasing incidence worldwide,while the accurate localization of epileptic focus and the corresponding treatment are still challenging due to the lack of effective tools to monitor and modulate the related brain neurological activities.In this work,stretchable micro electrocorticogram(mECoG)electrodes are developed and used to investigate penicillininduced epilepsy in rats.The electrodes possess excellent stretchability,conformality,anti-interference ability and sufficient resolution to successfully monitor electroencephalogram(EEG)signals,which is superior to traditional rigid polyimide-based electrodes.Characteristic epileptic spike waves are detected and analyzed to study the epileptic focus and electrical stimulus effects during epileptic seizures.It is found that the spike waves occur first in the visual cortex which is likely to be the epileptic focus.Epileptic spike wave frequency quickly increases to 1.07 Hz where it reaches a plateau and remains stable.There is no dominant brain hemisphere that would show early warning of epileptic seizures.Electrical stimuli for various times are applied after administering penicillin.It is found that 15 min of electrical stimulus has the best restraining effect on epileptic seizures.The mECoG electrodes developed in this study show potentials for applications in stretchable biomedical devices.
基金the National Natural Science Foundation of China (No.51702233)the Natural Science Foundation of Tianjin City (No.16JCYBJC41000)support by Tianjin Key Subject for Materials Physics and Chemistry.
文摘In the development of wearable energy devices,polypyrrole (PPy) is considered as a promising electrode material owing to its high capacitance and good mechanical flexibility.Herein,we report a PPy-based hybrid structure consisting of vertical PPy nanotube arrays and carbon nano-onions (CNOs) grown on textile for wearable supercapacitors.In this hybrid nanostructure,the vertical PPy nanotubes provide straight and superhighways for electron and ion transport,boosting the energy storage;while the CNOs mainly act as a conductivity retainer for the underlayered PPy film during stretching.A facile template-degrading method is developed for the large-area growth of the PPy-based hybrid nanostructures on the textile through one-step polymerization process.The fabricated stretchable supercapacitor exhibits superior energy storage capacitance with the specific capacitance of 64 F·g^-1.Also,it presents the high capacitance retention of 99% at a strain of 50% after 500 stretching cycles.Furthermore,we demonstrate that the textile-based stretchable supercapacitor device can provide a stable energy storage performance in different wearable situations for practical applications.The use of the PPy-based hybrid nanostructures as the supercapacitor electrode offers a novel structure design and a promising opportunity for wearable power supply in real applications.
文摘The development of stretchable electronics could enhance novel interface structures to solve the stretchability-conductivity dilemma,which remains a major challenge.Herein,we report a nano-liquid metal(LM)-based highly robust stretchable electrode(NHSE)with a self-adaptable interface that mimics water-tonet interaction.Based on the in situ assembly of electrospun elastic nanofiber scaffolds and electrosprayed LM nanoparticles,the NHSE exhibits an extremely low sheet resistance of 52 mΩsq^(-1).It is not only insensitive to a large degree of mechanical stretching(i.e.,350%electrical resistance change upon 570%elongation)but also immune to cyclic deformation(i.e.,5%electrical resistance increases after 330000 stretching cycles with 100%elongation).These key properties are far superior to those of the state-of-the-art reports.Its robustness and stability are verified under diverse circumstances,including long-term exposure to air(420 days),cyclic submersion(30000 times),and resilience against mechanical damages.The combination of conductivity,stretchability,and durability makes the NHSE a promising conductor/electrode solution for flexible/stretchable electronics for applications such as wearable on-body physiological signal detection,human-machine interaction,and heating e-skin.
基金the National Key Research and Development Program of China(Grant No.2019YFA0705400)National Natural Science Foundation of China(Grant Nos.51535005,51472117,51702159)+4 种基金the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures(Grant Nos.MCMS-I-0418K01,MCMS-I-0419K01)the Fundamental Research Funds for the Central Universities(Grant Nos.NC2018001,NP2019301,NJ2019002)Natural Science Foundation of Jiangsu Province(Grant Nos.BK20170791,BK20180416)National and Jiangsu Postdoctoral Research Funds(Grant Nos.2017M610328,2018T110494 and 1701141B)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Easy fabrication of super-stretchable electrodes can pave the way for smart and wearable electronics.Using drop casting unidirectional nickel nanowires with polyurethane matrix,we fabricated a super-stretchable film with high electric conductivity.The as-fabricated film can withstand a 300%tensile strain in the direction perpendicular to nanowires,owing to the transformation of percolating nanowire network from 2D to 3D.In contrast to the decreased film conductivities under large tension in most stretchable electrodes,which usually associate with fractures and irreversible deformations,our film conductivity can increase with the applied strain.This probably benefits from the enhanced electrical contacts between twisted nanowires under tension.The developed super-stretchable film with unprecedented behavior in this work sheds light on the facile fabrication of super-stretchable electrodes with durable performance.
