To date,hydrogels have gained increasing attentions as a flexible conductive material in fabricating soft electronics.However,it remains a big challenge to integrate multiple functions into one gel that can be used wi...To date,hydrogels have gained increasing attentions as a flexible conductive material in fabricating soft electronics.However,it remains a big challenge to integrate multiple functions into one gel that can be used widely under various conditions.Herein,a kind of multifunc-tional hydrogel with a combination of desirable characteristics,including remarkable transparency,high conductivity,ultra-stretchability,tough-ness,good fatigue resistance,and strong adhesive ability is presented,which was facilely fabricated through multiple noncovalent crosslinking strategy.The resultant versatile sensors are able to detect both weak and large deformations,which owns a low detection limit of 0.1%strain,high stretchability up to 1586%,ultrahigh sensitivity with a gauge factor up to 18.54,as well as wide pressure sensing range(0-600 kPa).Meanwhile,the fabrication of conductive hydrogel-based sensors is demonstrated for various soft electronic devices,including a flexible human-machine interactive system,the soft tactile switch,an integrated electronic skin for unprecedented nonplanar visualized pressure sensing,and the stretchable triboelectric nanogenerators with excellent biomechanical energy harvesting ability.This work opens up a simple route for multifunctional hydrogel and promises the practical application of soft and self-powered wearable electronics in various complex scenes.展开更多
Wearable biosensors have received great interest as patient-friendly diagnostic technologies because of their high flexibility and conformability.The growing research and utilization of novel materials in designing we...Wearable biosensors have received great interest as patient-friendly diagnostic technologies because of their high flexibility and conformability.The growing research and utilization of novel materials in designing wearable biosensors have accelerated the development of point-of-care sensing platforms and implantable biomedical devices in human health care.Among numerous potential materials,conjugated polymers(CPs)are emerging as ideal choices for constructing high-performance wearable biosensors because of their outstanding conductive and mechanical properties.Recently,CPs have been extensively incorporated into various wearable biosensors to monitor a range of target biomolecules.However,fabricating highly reliable CP-based wearable biosensors for practical applications remains a significant challenge,necessitating novel developmental strategies for enhancing the viability of such biosensors.Accordingly,this review aims to provide consolidated scientific evidence by summarizing and evaluating recent studies focused on designing and fabricating CP-based wearable biosensors,thereby facilitating future research.Emphasizing the superior properties and benefits of CPs,this review aims to clarify their potential applicability within this field.Furthermore,the fundamentals and main components of CP-based wearable biosensors and their sensing mechanisms are discussed in detail.The recent advancements in CP nanostructures and hybridizations for improved sensing performance,along with recent innovations in next-generation wearable biosensors are highlighted.CPbased wearable biosensors have been—and will continue to be—an ideal platform for developing effective and user-friendly diagnostic technologies for human health monitoring.展开更多
Conductive hydrogels have attracted extensive attention owing to their promising application prospects in flexible and wearable electronics.However,achieving both high sensitivity and mechanical robustness remains cha...Conductive hydrogels have attracted extensive attention owing to their promising application prospects in flexible and wearable electronics.However,achieving both high sensitivity and mechanical robustness remains challenging.Herein,a novel and versatile conductive hydrogel based on the hybrid assem-bly of conductive cellulose nanofiber(CNF)networks has been designed and fabricated.Assisted by the templating effect of CNFs and stabilizing effect of negatively charged poly(styrene sulfonate)(PSS),conducting polymer poly(3,4-ethylenedioxythiophene)(PEDOT)was self-organized into three-dimensional nanostructures which constructed a robust conductive network after in-situ oxidative polymerization.The unique structure derived from CNF bio-template endowed polyacrylamide(PAM)hydrogels with improved electrical conductivity and excellent mechanical performance.As a result,the as-fabricated CNF/PEDOT:PSS/PAM hydrogel exhibited an ultimate tensile strain of 1881%and toughness of 3.72 MJ/m^(3),which were 4.07 and 8.27 times higher than the CNF-free hydrogel,respectively.More significantly,the resultant hydrogel sensor showed highly desirable sensing properties,including remarkable sensing range(1100%),high gauge factor(GF=5.16),fast response time(185 ms),and commendable durability,as well as good adhesiveness.Moreover,the hydrogel sensor was able to distinguish subtle physiological activities including phonation and facial expression,and monitor large human body motions such as finger flexion and elbow blending.Besides,it was feasible to integrate the strain sensor on the joints of robots to recognize complicated machine motion signals,showing potential in advanced human-machine interactions.展开更多
Flexible sensors have great potential for monitoring human body motion signals. This paper presents a flexible sensor that uses zinc oxide (ZnO) to improve the mechanical properties and electrical conductivity of PVA ...Flexible sensors have great potential for monitoring human body motion signals. This paper presents a flexible sensor that uses zinc oxide (ZnO) to improve the mechanical properties and electrical conductivity of PVA hydrogel. The composite hydrogel has excellent conductive properties and high strain sensitivity, making it suitable for motion monitoring. The PVA/ZnO conductive hydrogel is tested on various body parts, showing effective feedback on movement changes and good electrical signal output effects for different motion degrees, confirming its feasibility in flexible sensors. The sensor exhibits good mechanical properties, electrical conductivity, and tensile strain sensing performance, making it a promising sensor material. It can accurately monitor wrist bending, finger deformation, bending, and large-scale joint movements due to its wide monitoring range and recoverable strain. The results show that the PVA/ZnO conductive hydrogel can provide effective feedback in flexible sensors, which is suitable for use in motion monitoring.展开更多
Conductive polymers(CPs)are generally insoluble,and developing hydrophilic CPs is significant to broaden the applications of CPs.In this work,a mussel-inspired strategy was proposed to construct hydrophilic CP nanopar...Conductive polymers(CPs)are generally insoluble,and developing hydrophilic CPs is significant to broaden the applications of CPs.In this work,a mussel-inspired strategy was proposed to construct hydrophilic CP nanoparticles(CP NPs),while endowing the CP NPs with redox activity and biocompatibility.This is a universal strategy applicable for a series of CPs,including polyaniline,polypyrrole,and poly(3,4-ethylenedioxythiophene).The catechol/quinone contained sulfonated lignin(LS)was doped into various CPs to form CP/LS NPs with hydrophilicity,conductivity,and redox activity.These CP/LS NPs were used as versatile nanofillers to prepare the conductive hydrogels with long-term adhesiveness.The CP/LS NPs-incorporated hydrogels have a good conductivity because of the uniform distribution of the hydrophilic NPs in the hydrogel network,forming a well-connected electric path.The hydrogel exhibits long-term adhesiveness,which is attributed to the mussel-inspired dynamic redox balance of catechol/quinone groups on the CP/LS NPs.This conductive and adhesive hydrogel shows good electroactivity and biocompatibility and therefore has broad applications in electrostimulation of tissue regeneration and implantable bioelectronics.展开更多
Conductive ionic hydrogels(CIH)have been widely studied for the development of stretchable electronic devices,such as sensors,electrodes,and actuators.Most of these CIH are made into 3D or 2D shape,while 1D CIH(hydrog...Conductive ionic hydrogels(CIH)have been widely studied for the development of stretchable electronic devices,such as sensors,electrodes,and actuators.Most of these CIH are made into 3D or 2D shape,while 1D CIH(hydrogel fibers)is often difficult to make because of the low mechanical robustness of common CIH.Herein,we use gel spinning method to prepare a robust CIH fiber with high strength,large stretchability,and good conductivity.The robust CIH fiber is drawn from the composite gel of sodium polyacrylate(PAAS)and sodium carboxymethyl cellulose(CMC).In the composite CIH fiber,the soft PAAS presents good conductivity and stretchability,while the rigid CMC significantly enhances the strength and toughness of the PAAS/CMC fiber.To protect the conductive PAAS/CMC fiber from damage by water,a thin layer of hydrophobic polymethyl acrylate(PMA)or polybutyl acrylate(PBA)is coated on the PAAS/CMC fiber as a water-resistant and insulating cover.The obtained PAAS/CMC-PMA and PAAS/CMC-PBA CIH fibers present high tensile strength(up to 28 MPa),high tensile toughness(up to 43 MJ/m~3),and good electrical conductivity(up to 0.35 S/m),which are useful for textile-based stretchable electronic devices.展开更多
Owing to their excellent mechanical flexibility, electrical conductivity, and biocompatibility, conductive hydrogels(CHs) are widely used in the fields of energy and power, and biomedical technology. To arrive at a be...Owing to their excellent mechanical flexibility, electrical conductivity, and biocompatibility, conductive hydrogels(CHs) are widely used in the fields of energy and power, and biomedical technology. To arrive at a better understanding of the design methods and development trends of CHs, this paper summarizes and analyzes related research published in recent years. First,we describe the properties and characteristics of CHs. Using Scopus, the world’s largest abstract and citation database, we conducted a quantitative analysis of the related literature from the past 15 years and summarized development trends in the field of CHs. Second, we describe the types of CH network crosslinking and basic functional design methods and summarize the three-dimensional(3D) structure-forming methods and conductive performance tests of CHs. In addition, we introduce applications of CHs in the fields of energy and power, biomedical technology, and others. Lastly, we discuss several problems in current CH research and introduce some prospects for the future development of CHs.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
Soft strain sensors that can transduce stretch stimuli into electrical readouts are promising as sustainable wearable electronics.However,most strain sensors cannot achieve highly-sensitive and wide-range detection of...Soft strain sensors that can transduce stretch stimuli into electrical readouts are promising as sustainable wearable electronics.However,most strain sensors cannot achieve highly-sensitive and wide-range detection of ultralow and high strains.Inspired by bamboo structures,anti-freezing microfibers made of conductive poly(vinyl alcohol)hydrogel with poly(3,4-ethylenedioxythiphene)-poly(styrenesulfonate)are developed via continuous microfluidic spinning.The microfibers provide unique bamboo-like structures with enhanced local stress to improve both their length change and resistance change upon stretching for efficient signal conversion.The microfibers allow highlysensitive(detection limit:0.05%strain)and wide-range(0%-400%strain)detection of ultralow and high strains,as well as features of good stretchability(485%strain)and anti-freezing property(freezing temperature:-41.1°C),fast response(200 ms),and good repeatability.The experimental results,together with theoretical foundation analysis and finite element analysis,prove their enhanced length and resistance changes upon stretching for efficient signal conversion.By integrating microfluidic spinning with 3D-printing technique,the textiles of the microfibers can be flexibly constructed.The microfibers and their 3D-printed textiles enable highperformance monitoring of human motions including finger bending and throat vibrating during phonation.This work provides an efficient and general strategy for developing advanced conductive hydrogel microfibers as highperformance wearable strain sensors.展开更多
The wide-spread proliferation of aqueous MXene-based supercapacitor has been largely shadowed by the limited cell potential window(typically in the range of 0-0.6 V).To address this baffling issue,designing asymmetric...The wide-spread proliferation of aqueous MXene-based supercapacitor has been largely shadowed by the limited cell potential window(typically in the range of 0-0.6 V).To address this baffling issue,designing asymmetric supercapacitor(ASC)is proposed as a rational strategy to enlarge the potential window(thus energy density)of individual cell in aqueous electrolytes.To this date,however,it still remains a great challenge to develop easy fabricating,3D nanostructured,and pseudocapacitive cathode materials that can perfectly match with MXene anodematerials.In this work,we propose a supramolecular strategy to construct conducting polymer hydrogel(CPH)with highly interconnected 3D nanostructures and large pseudocapacitance,which can finely match with 2D Ti_(3)C_(2)T_(x).The as-assembled CPH//Ti_(3)C_(2)T_(x) ASCwith CPH cathode and MXene anode can operate in a broadened potential window of 1.15 V in aqueous PVA/H_(2)SO_(4) gel electrolyte with remarkably improved energy density of 16.6μWh/cm^(2)(nine times higher than that of symmetric MXene supercapacitor).Additionally,this ASC exhibits outstanding cyclic stability with no trackable performance decay over 30,000 galvanostatic charge and discharge cycles.It is demonstrated in this work that employing positive CPH electrode is a feasible yet promising strategy to enhance the potential window and energy density of aqueous MXene supercapacitors.展开更多
The capacitance performances of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT-PSS) supramolecular hydrogels have been investigated systematically. The materials show a specific capacitance of 67 ...The capacitance performances of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT-PSS) supramolecular hydrogels have been investigated systematically. The materials show a specific capacitance of 67 F/g and display excellent rate capability at the scan rate as high as 5000 m V/s in the cyclic voltammogram measurements, accompanied by good cycle stability. On the basis of the measurements of the microscale morphologies, specific areas and electrical conductivities, the mechanisms for the improvement of the electrochemical properties are discussed and ascribed to the novel porous microstructures of the hydrogels and the synergetic effect of the rigid PEDOT and soft PSS components. Furthermore, polyaniline(PAn) is compounded with the PEDOT-PSS hydrogels through an interfacial polymerization process, endowing the hydrogel materials with a higher specific capacitance of 160 F/g at the scan rate of 5000 m V/s. The significance of this work lies in the demonstration of a novel method to solve the problems of conducting polymers in electrochemical applications.展开更多
As one of the most rapidly expanding materials,hydrogels have gained increasing attention in a variety of fields due to their biocompatibility,degradability and hydrophilic properties,as well as their remarkable adhes...As one of the most rapidly expanding materials,hydrogels have gained increasing attention in a variety of fields due to their biocompatibility,degradability and hydrophilic properties,as well as their remarkable adhesion and stretchability to adapt to different surfaces.Hydrogels combined with carbon-based materials possess enhanced properties and new functionalities,in particular,conductive hydrogels have become a new area of research in the field of materials science.This review aims to provide a comprehensive overview and up-to-date examination of recent developments in the synthesis,properties and applications of conductive hydrogels incorporating several typical carbon nanoparticles such as carbon nanotubes,graphene,carbon dots and carbon nanofibers.We summarize key techniques and mechanisms for synthesizing various composite hydrogels with exceptional properties,and represented applications such as wearable sensors,temperature sensors,supercapacitors and human-computer interaction reported recently.The mechanical,electrical and sensing properties of carbon nanoparticles conductive hydrogels are thoroughly analyzed to disclose the role of carbon nanoparticles in these hydrogels and key factors in the microstructure.Finally,future development of conductive hydrogels based on carbon nanoparticles is discussed including the challenges and possible solutions in terms of microstructure optimization,mechanical and other properties,and promising applications in wearable electronics and multifunctional materials.展开更多
In recent years,electrically conductive hydrogel-based nerve guidance conduits(NGCs)have yielded promising results for treating peripheral nerve injuries(PNIs).However,developed ones are generally pre-manufactured and...In recent years,electrically conductive hydrogel-based nerve guidance conduits(NGCs)have yielded promising results for treating peripheral nerve injuries(PNIs).However,developed ones are generally pre-manufactured and exhibit a limited ability to achieve good contact with nerve tissue with irregu-lar surfaces.Herein,we developed a plasticine-like electrically conductive hydrogel consisting of gelatin,conducting polypyrrole,and tannic acid(named GPT)and assessed its ability to promote peripheral nerve regeneration.The shape-persistent GPT hydrogel exhibited good self-healing properties and could easily be molded to form a conduit that could match any injured nerve tissue.Their electrical properties could be tuned by changing the PPy concentration.In vitro,the improved conductivity of the hydrogel pro-moted dorsal root ganglion(DRG)axonal extension.More importantly,we found that the GPT hydrogel enhanced axonal regeneration and remyelination in vivo,preventing denervation atrophy and enhancing functional recovery in a mice model of sciatic nerve injury.These results suggest that our plasticine-like NGC has huge prospects for clinical application in the repair of PNI.展开更多
Conductive hydrogels have shown great prospects as wearable flexible sensors.Nevertheless,it is still a challenge to construct hydrogel-based sensor with great mechanical strength and high strain sensitivity.Herein,an...Conductive hydrogels have shown great prospects as wearable flexible sensors.Nevertheless,it is still a challenge to construct hydrogel-based sensor with great mechanical strength and high strain sensitivity.Herein,an ion-conducting hydrogel was fabricated by introducing gelatin-dialdehydeβ-cyclodextrin(Gel-DACD)into polyvinyl alcohol-borax(PVA-borax)hydrogel network.Natural Gel-DACD network acted as mechanical deformation force through non-covalent cross-linking to endow the polyvinyl alcoholborax/gelatin-dialdehydeβ-cyclodextrin hydrogel(PGBCDH)with excellent mechanical stress(1.35 MPa),stretchability(400%),toughness(1.84 MJ/m3)and great fatigue resistance(200%strain for 100 cycles).Surprisingly,PGBCDH displayed good conductivity of 0.31 S/m after adding DACD to hydrogel network.As sensor,it showed rapid response(168 ms),high strain sensitivity(gage factor(GF)=8.57 in the strain range of 200%-250%)and reliable sensing stability(100%strain for 200 cycles).Importantly,PGBCDHbased sensor can accurately monitor complex body movements(knee,elbow,wrist and finger joints)and large-scale subtle movements(speech,swallow,breath and facial expressions).Thus,PGBCDH shows great potential for human monitoring with high precision.展开更多
To achieve smart and personalized medicine, the development of hydrogel dressings with sensing properties and biotherapeutic properties that can act as a sensor to monitor of human health in real-time while speeding u...To achieve smart and personalized medicine, the development of hydrogel dressings with sensing properties and biotherapeutic properties that can act as a sensor to monitor of human health in real-time while speeding up wound healing face great challenge. In the present study, a biocompatible dual-network composite hydrogel(DNCGel) sensor was obtained via a simple process. The dual network hydrogel is constructed by the interpenetration of a flexible network formed of poly(vinyl alcohol)(PVA) physical cross-linked by repeated freeze-thawing and a rigid network of iron-chelated xanthan gum(XG) impregnated with Fe^(3+) interpenetration. The pure PVA/XG hydrogels were chelated with ferric ions by immersion to improve the gel strength(compressive modulus and tensile modulus can reach up to 0.62 MPa and0.079 MPa, respectively), conductivity(conductivity values ranging from 9 × 10^(-4) S/cm to 1 × 10^(-3)S/cm)and bacterial inhibition properties(up to 98.56%). Subsequently, the effects of the ratio of PVA and XG and the immersion time of Fe^(3+) on the hydrogels were investigated, and DNGel3 was given the most priority on a comprehensive consideration. It was demonstrated that the DNCGel exhibit good biocompatibility in vitro, effectively facilitate wound healing in vivo(up to 97.8% healing rate) under electrical stimulation, and monitors human movement in real time. This work provides a novel avenue to explore multifunctional intelligent hydrogels that hold great promise in biomedical fields such as smart wound dressings and flexible wearable sensors.展开更多
Hard magnetic soft robots have been widely used in biomedical engineering.In these applications,it is crucial to sense the movement of soft robots and their interaction with target objects.Here,we propose a strategy t...Hard magnetic soft robots have been widely used in biomedical engineering.In these applications,it is crucial to sense the movement of soft robots and their interaction with target objects.Here,we propose a strategy to fabricate a self-sensing bilayer actuator by combining magnetic and ionic conductive hydrogels.The magnetic hydrogel containing NdFeB particles exhibits rapid response to magnetic field and achieve bending deformation.Meanwhile,the polyacrylamide(PAAm)hydrogel with lithium chloride(LiCl)allows for the sensing of deformation.The bending behavior of the bilayer under magnetic field is well captured by theoretical and simulated models.Additionally,the bilayer strain sensor shows good sensitivity,stability and can endure a wide-range cyclic stretching(0-300%).These merits qualify the self-sensing actuator to monitor the motion signals,such as bending of fingers and grasping process of an intelligent gripper.When subject to an external magnetic field,the gripper can grab a cube and sense the resistance change simultaneously to detect the object size.This work may provide a versatile strategy to integrate actuating and self-sensing ability in soft robots.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
Conducting polymer hydrogel can address the challenges of stricken biocompatibility and durability.Nevertheless,conventional conducting polymer hydrogels are often brittle and weak due to the intrinsic quality of the ...Conducting polymer hydrogel can address the challenges of stricken biocompatibility and durability.Nevertheless,conventional conducting polymer hydrogels are often brittle and weak due to the intrinsic quality of the material,which exhibits viscoelasticity.This property may cause a delay in sensor response time due to hysteresis.To overcome these limitations,we have designed a wrinkle morphology three-dimensional(3D)substrate using digital light processing technology and then followed by in situ polymerization to form interpenetrating polymer network hydrogels.This novel design results in a wrinkle morphology conducting polymer hydrogel elastomer with high precision and geometric freedom,as the size of the wrinkles can be controlled by adjusting the treating time.The wrinkle morphology on the conducting polymer hydrogel effectively reduces its viscoelasticity,leading to samples with quick response time,low hysteresis,stable cyclic performance,and remarkable resistance change.Simultaneously,the 3D gradient structure augmented the sensor's sensitivity under minimal stress while exhibiting consistent sensing performance.These properties indicate the potential of the conducting polymer hydrogel as a flexible sensor.展开更多
Adhesive hydrogels have broad applications ranging from tissue engineering to bioelectronics;however,fabricating adhesive hydrogels with multiple functions remains a challenge.In this study,a mussel-inspired tannic ac...Adhesive hydrogels have broad applications ranging from tissue engineering to bioelectronics;however,fabricating adhesive hydrogels with multiple functions remains a challenge.In this study,a mussel-inspired tannic acid chelated-Ag(TA-Ag)nanozyme with peroxidase(POD)-like activity was designed by the in situ reduction of ultrasmall Ag nanoparticles(NPs)with TA.The ultrasmall TA-Ag nanozyme exhibited high catalytic activity to induce hydrogel self-setting without external aid.The nanozyme retained abundant phenolic hydroxyl groups and maintained the dynamic redox balance of phenol-quinone,providing the hydrogels with long-term and repeatable adhesiveness,similar to the adhesion of mussels.The phenolic hydroxyl groups also afforded uniform distribution of the nanozyme in the hydrogel network,thereby improving its mechanical properties and conductivity.Furthermore,the nanozyme endowed the hydrogel with antibacterial activity through synergistic effects of the reactive oxygen species generated via POD-like catalytic reactions and the intrinsic bactericidal activity of Ag.Owing to these advantages,the ultrasmall TA-Ag nanozyme-catalyzed hydrogel could be effectively used as an adhesive,antibacterial,and implantable bioelectrode to detect bio-signals,and as a wound dressing to accelerate tissue regeneration while preventing infection.Therefore,this study provides a promising approach for the fabrication of adhesive hydrogel bioelectronics with multiple functions via mussel-inspired nanozyme catalysis.展开更多
Flexible electronics have emerged as an exciting research area in recent years,serving as ideal interfaces bridging biological systems and conventional electronic devices.Flexible electronics can not only collect phys...Flexible electronics have emerged as an exciting research area in recent years,serving as ideal interfaces bridging biological systems and conventional electronic devices.Flexible electronics can not only collect physiological signals for human health monitoring but also enrich our daily life with multifunctional smart materials and devices.Conductive hydrogels(CHs)have become promising candidates for the fabrication of flexible electronics owing to their biocompatibility,adjustable mechanical flexibility,good conductivity,and multiple stimuli-responsive properties.To achieve on-demand mechanical properties such as stretchability,compressibility,and elasticity,the rational design of polymer networks via modulating chemical and physical intermolecular interactions is required.Moreover,the type of conductive components(eg,electron-conductive materials,ions)and the incorporation method also play an important role in the conductivity of CHs.Electron-CHs usually possess excellent conductivity,while ion-CHs are generally transparent and can generate ion gradients within the hydrogel matrices.This mini review focuses on the recent advances in the design of CHs,introducing various design strategies for electron-CHs and ion-CHs employed in flexible electronics and highlighting their versatile applications such as biosensors,batteries,supercapacitors,nanogenerators,actuators,touch panels,and displays.展开更多
基金supported by the National Natural Science Foundation of China(51973166)the Key Research and Development Program of Hubei Province(2020BCA079).
文摘To date,hydrogels have gained increasing attentions as a flexible conductive material in fabricating soft electronics.However,it remains a big challenge to integrate multiple functions into one gel that can be used widely under various conditions.Herein,a kind of multifunc-tional hydrogel with a combination of desirable characteristics,including remarkable transparency,high conductivity,ultra-stretchability,tough-ness,good fatigue resistance,and strong adhesive ability is presented,which was facilely fabricated through multiple noncovalent crosslinking strategy.The resultant versatile sensors are able to detect both weak and large deformations,which owns a low detection limit of 0.1%strain,high stretchability up to 1586%,ultrahigh sensitivity with a gauge factor up to 18.54,as well as wide pressure sensing range(0-600 kPa).Meanwhile,the fabrication of conductive hydrogel-based sensors is demonstrated for various soft electronic devices,including a flexible human-machine interactive system,the soft tactile switch,an integrated electronic skin for unprecedented nonplanar visualized pressure sensing,and the stretchable triboelectric nanogenerators with excellent biomechanical energy harvesting ability.This work opens up a simple route for multifunctional hydrogel and promises the practical application of soft and self-powered wearable electronics in various complex scenes.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea Government(MSIT)(No.NRF-2021R1A2C2004109)the Korea Institute for Advancement of Technology(KIAT)grant funded by the Korea Government(MOTIE)(No.P0020612,2022 The Competency Development Program for Industry Specialist).
文摘Wearable biosensors have received great interest as patient-friendly diagnostic technologies because of their high flexibility and conformability.The growing research and utilization of novel materials in designing wearable biosensors have accelerated the development of point-of-care sensing platforms and implantable biomedical devices in human health care.Among numerous potential materials,conjugated polymers(CPs)are emerging as ideal choices for constructing high-performance wearable biosensors because of their outstanding conductive and mechanical properties.Recently,CPs have been extensively incorporated into various wearable biosensors to monitor a range of target biomolecules.However,fabricating highly reliable CP-based wearable biosensors for practical applications remains a significant challenge,necessitating novel developmental strategies for enhancing the viability of such biosensors.Accordingly,this review aims to provide consolidated scientific evidence by summarizing and evaluating recent studies focused on designing and fabricating CP-based wearable biosensors,thereby facilitating future research.Emphasizing the superior properties and benefits of CPs,this review aims to clarify their potential applicability within this field.Furthermore,the fundamentals and main components of CP-based wearable biosensors and their sensing mechanisms are discussed in detail.The recent advancements in CP nanostructures and hybridizations for improved sensing performance,along with recent innovations in next-generation wearable biosensors are highlighted.CPbased wearable biosensors have been—and will continue to be—an ideal platform for developing effective and user-friendly diagnostic technologies for human health monitoring.
基金supported by the National Natural Sci-ence Foundation of China(No.32260359)the Guangxi Sci-ence and Technology Base and Talent Special Project(No.GUIKE AD23026179).
文摘Conductive hydrogels have attracted extensive attention owing to their promising application prospects in flexible and wearable electronics.However,achieving both high sensitivity and mechanical robustness remains challenging.Herein,a novel and versatile conductive hydrogel based on the hybrid assem-bly of conductive cellulose nanofiber(CNF)networks has been designed and fabricated.Assisted by the templating effect of CNFs and stabilizing effect of negatively charged poly(styrene sulfonate)(PSS),conducting polymer poly(3,4-ethylenedioxythiophene)(PEDOT)was self-organized into three-dimensional nanostructures which constructed a robust conductive network after in-situ oxidative polymerization.The unique structure derived from CNF bio-template endowed polyacrylamide(PAM)hydrogels with improved electrical conductivity and excellent mechanical performance.As a result,the as-fabricated CNF/PEDOT:PSS/PAM hydrogel exhibited an ultimate tensile strain of 1881%and toughness of 3.72 MJ/m^(3),which were 4.07 and 8.27 times higher than the CNF-free hydrogel,respectively.More significantly,the resultant hydrogel sensor showed highly desirable sensing properties,including remarkable sensing range(1100%),high gauge factor(GF=5.16),fast response time(185 ms),and commendable durability,as well as good adhesiveness.Moreover,the hydrogel sensor was able to distinguish subtle physiological activities including phonation and facial expression,and monitor large human body motions such as finger flexion and elbow blending.Besides,it was feasible to integrate the strain sensor on the joints of robots to recognize complicated machine motion signals,showing potential in advanced human-machine interactions.
文摘Flexible sensors have great potential for monitoring human body motion signals. This paper presents a flexible sensor that uses zinc oxide (ZnO) to improve the mechanical properties and electrical conductivity of PVA hydrogel. The composite hydrogel has excellent conductive properties and high strain sensitivity, making it suitable for motion monitoring. The PVA/ZnO conductive hydrogel is tested on various body parts, showing effective feedback on movement changes and good electrical signal output effects for different motion degrees, confirming its feasibility in flexible sensors. The sensor exhibits good mechanical properties, electrical conductivity, and tensile strain sensing performance, making it a promising sensor material. It can accurately monitor wrist bending, finger deformation, bending, and large-scale joint movements due to its wide monitoring range and recoverable strain. The results show that the PVA/ZnO conductive hydrogel can provide effective feedback in flexible sensors, which is suitable for use in motion monitoring.
基金This work was financially supported by the R&D Program in Key Areas of Guangdong(2019B010941002)National Key Research and Development Program of China(2016YFB0700802),NSFC(81671824,31700841)Fundamental Research Funds for the Central Universities(2682019JQ03).
文摘Conductive polymers(CPs)are generally insoluble,and developing hydrophilic CPs is significant to broaden the applications of CPs.In this work,a mussel-inspired strategy was proposed to construct hydrophilic CP nanoparticles(CP NPs),while endowing the CP NPs with redox activity and biocompatibility.This is a universal strategy applicable for a series of CPs,including polyaniline,polypyrrole,and poly(3,4-ethylenedioxythiophene).The catechol/quinone contained sulfonated lignin(LS)was doped into various CPs to form CP/LS NPs with hydrophilicity,conductivity,and redox activity.These CP/LS NPs were used as versatile nanofillers to prepare the conductive hydrogels with long-term adhesiveness.The CP/LS NPs-incorporated hydrogels have a good conductivity because of the uniform distribution of the hydrophilic NPs in the hydrogel network,forming a well-connected electric path.The hydrogel exhibits long-term adhesiveness,which is attributed to the mussel-inspired dynamic redox balance of catechol/quinone groups on the CP/LS NPs.This conductive and adhesive hydrogel shows good electroactivity and biocompatibility and therefore has broad applications in electrostimulation of tissue regeneration and implantable bioelectronics.
基金supported by the National Natural Science Foundation of China(No.21778052 and No.21975240)by the Natural Science Foundation of Anhui Province(No.1908085J19)the Talent Research Foundation of Hefei University(No.18-19RC08)。
文摘Conductive ionic hydrogels(CIH)have been widely studied for the development of stretchable electronic devices,such as sensors,electrodes,and actuators.Most of these CIH are made into 3D or 2D shape,while 1D CIH(hydrogel fibers)is often difficult to make because of the low mechanical robustness of common CIH.Herein,we use gel spinning method to prepare a robust CIH fiber with high strength,large stretchability,and good conductivity.The robust CIH fiber is drawn from the composite gel of sodium polyacrylate(PAAS)and sodium carboxymethyl cellulose(CMC).In the composite CIH fiber,the soft PAAS presents good conductivity and stretchability,while the rigid CMC significantly enhances the strength and toughness of the PAAS/CMC fiber.To protect the conductive PAAS/CMC fiber from damage by water,a thin layer of hydrophobic polymethyl acrylate(PMA)or polybutyl acrylate(PBA)is coated on the PAAS/CMC fiber as a water-resistant and insulating cover.The obtained PAAS/CMC-PMA and PAAS/CMC-PBA CIH fibers present high tensile strength(up to 28 MPa),high tensile toughness(up to 43 MJ/m~3),and good electrical conductivity(up to 0.35 S/m),which are useful for textile-based stretchable electronic devices.
基金supported by the Research Project Funding of National University of Defense Technology of China (No.ZK19-33)the National Postdoctoral International Exchange Program Funding for Incoming Postdoctoral Students (Postdoctoral No.48127)+1 种基金the Science and Technology Innovation Program of Hunan Province (No.2020RC2036)the National Natural Science Foundation of China (Nos.52105039 and 52175069)。
文摘Owing to their excellent mechanical flexibility, electrical conductivity, and biocompatibility, conductive hydrogels(CHs) are widely used in the fields of energy and power, and biomedical technology. To arrive at a better understanding of the design methods and development trends of CHs, this paper summarizes and analyzes related research published in recent years. First,we describe the properties and characteristics of CHs. Using Scopus, the world’s largest abstract and citation database, we conducted a quantitative analysis of the related literature from the past 15 years and summarized development trends in the field of CHs. Second, we describe the types of CH network crosslinking and basic functional design methods and summarize the three-dimensional(3D) structure-forming methods and conductive performance tests of CHs. In addition, we introduce applications of CHs in the fields of energy and power, biomedical technology, and others. Lastly, we discuss several problems in current CH research and introduce some prospects for the future development of CHs.
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.
基金support from the National Natural Science Foundation of China(Nos.22278281 and 21991101)Sichuan University(2020SCUNG112)
文摘Soft strain sensors that can transduce stretch stimuli into electrical readouts are promising as sustainable wearable electronics.However,most strain sensors cannot achieve highly-sensitive and wide-range detection of ultralow and high strains.Inspired by bamboo structures,anti-freezing microfibers made of conductive poly(vinyl alcohol)hydrogel with poly(3,4-ethylenedioxythiphene)-poly(styrenesulfonate)are developed via continuous microfluidic spinning.The microfibers provide unique bamboo-like structures with enhanced local stress to improve both their length change and resistance change upon stretching for efficient signal conversion.The microfibers allow highlysensitive(detection limit:0.05%strain)and wide-range(0%-400%strain)detection of ultralow and high strains,as well as features of good stretchability(485%strain)and anti-freezing property(freezing temperature:-41.1°C),fast response(200 ms),and good repeatability.The experimental results,together with theoretical foundation analysis and finite element analysis,prove their enhanced length and resistance changes upon stretching for efficient signal conversion.By integrating microfluidic spinning with 3D-printing technique,the textiles of the microfibers can be flexibly constructed.The microfibers and their 3D-printed textiles enable highperformance monitoring of human motions including finger bending and throat vibrating during phonation.This work provides an efficient and general strategy for developing advanced conductive hydrogel microfibers as highperformance wearable strain sensors.
基金National Natural Science Foundation of China,Grant/Award Numbers:51977185,51972277Sichuan Science and Technology Program,Grant/Award Numbers:20ZDYF2478,20ZDYF2833,21ZDYF3951。
文摘The wide-spread proliferation of aqueous MXene-based supercapacitor has been largely shadowed by the limited cell potential window(typically in the range of 0-0.6 V).To address this baffling issue,designing asymmetric supercapacitor(ASC)is proposed as a rational strategy to enlarge the potential window(thus energy density)of individual cell in aqueous electrolytes.To this date,however,it still remains a great challenge to develop easy fabricating,3D nanostructured,and pseudocapacitive cathode materials that can perfectly match with MXene anodematerials.In this work,we propose a supramolecular strategy to construct conducting polymer hydrogel(CPH)with highly interconnected 3D nanostructures and large pseudocapacitance,which can finely match with 2D Ti_(3)C_(2)T_(x).The as-assembled CPH//Ti_(3)C_(2)T_(x) ASCwith CPH cathode and MXene anode can operate in a broadened potential window of 1.15 V in aqueous PVA/H_(2)SO_(4) gel electrolyte with remarkably improved energy density of 16.6μWh/cm^(2)(nine times higher than that of symmetric MXene supercapacitor).Additionally,this ASC exhibits outstanding cyclic stability with no trackable performance decay over 30,000 galvanostatic charge and discharge cycles.It is demonstrated in this work that employing positive CPH electrode is a feasible yet promising strategy to enhance the potential window and energy density of aqueous MXene supercapacitors.
基金financially supported by the National Natural Science Foundation of China(Nos.21174059 and 21374046)China Postdoctoral Science Foundation(No.2013M530249)+1 种基金Program for Changjiang Scholars and Innovative Research Teams in Universities,Open Project of State Key Laboratory of Superamolecular Structure and Materials(No.SKLSSM201416)the Testing Foundation of Nanjing University
文摘The capacitance performances of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)(PEDOT-PSS) supramolecular hydrogels have been investigated systematically. The materials show a specific capacitance of 67 F/g and display excellent rate capability at the scan rate as high as 5000 m V/s in the cyclic voltammogram measurements, accompanied by good cycle stability. On the basis of the measurements of the microscale morphologies, specific areas and electrical conductivities, the mechanisms for the improvement of the electrochemical properties are discussed and ascribed to the novel porous microstructures of the hydrogels and the synergetic effect of the rigid PEDOT and soft PSS components. Furthermore, polyaniline(PAn) is compounded with the PEDOT-PSS hydrogels through an interfacial polymerization process, endowing the hydrogel materials with a higher specific capacitance of 160 F/g at the scan rate of 5000 m V/s. The significance of this work lies in the demonstration of a novel method to solve the problems of conducting polymers in electrochemical applications.
基金This work was supported by the National Key R&D Program of China(grant No.2020YFA0210702)National Natural Science Foundation of China(grant No.51872267)+2 种基金the Natural Science Foundation of Henan Province,China(grant No.202300410371)Program for Science&Technology Innovation Talents in Universities of Henan Province(grant No.21HASTIT017)Foundation of Henan Province Educational Committee(grant No.23A140005).
文摘As one of the most rapidly expanding materials,hydrogels have gained increasing attention in a variety of fields due to their biocompatibility,degradability and hydrophilic properties,as well as their remarkable adhesion and stretchability to adapt to different surfaces.Hydrogels combined with carbon-based materials possess enhanced properties and new functionalities,in particular,conductive hydrogels have become a new area of research in the field of materials science.This review aims to provide a comprehensive overview and up-to-date examination of recent developments in the synthesis,properties and applications of conductive hydrogels incorporating several typical carbon nanoparticles such as carbon nanotubes,graphene,carbon dots and carbon nanofibers.We summarize key techniques and mechanisms for synthesizing various composite hydrogels with exceptional properties,and represented applications such as wearable sensors,temperature sensors,supercapacitors and human-computer interaction reported recently.The mechanical,electrical and sensing properties of carbon nanoparticles conductive hydrogels are thoroughly analyzed to disclose the role of carbon nanoparticles in these hydrogels and key factors in the microstructure.Finally,future development of conductive hydrogels based on carbon nanoparticles is discussed including the challenges and possible solutions in terms of microstructure optimization,mechanical and other properties,and promising applications in wearable electronics and multifunctional materials.
基金financially supported by the National Natural Science Foundation of China(Nos.51932002 and 51903087)the Science and Technology Innovation Team Project of Foshan(No.2018IT100101)the Joint Fund of Ministry of Education for Equipment Preresearch(No.6141A02022632).
文摘In recent years,electrically conductive hydrogel-based nerve guidance conduits(NGCs)have yielded promising results for treating peripheral nerve injuries(PNIs).However,developed ones are generally pre-manufactured and exhibit a limited ability to achieve good contact with nerve tissue with irregu-lar surfaces.Herein,we developed a plasticine-like electrically conductive hydrogel consisting of gelatin,conducting polypyrrole,and tannic acid(named GPT)and assessed its ability to promote peripheral nerve regeneration.The shape-persistent GPT hydrogel exhibited good self-healing properties and could easily be molded to form a conduit that could match any injured nerve tissue.Their electrical properties could be tuned by changing the PPy concentration.In vitro,the improved conductivity of the hydrogel pro-moted dorsal root ganglion(DRG)axonal extension.More importantly,we found that the GPT hydrogel enhanced axonal regeneration and remyelination in vivo,preventing denervation atrophy and enhancing functional recovery in a mice model of sciatic nerve injury.These results suggest that our plasticine-like NGC has huge prospects for clinical application in the repair of PNI.
基金supported by National Key R&D Program of China(Nos.2019YFC1905500 and 2021ZD0201604)National Natural Science Foundation of China(Nos.U20A20261,31870948,31971250 and 21922409)Seed Foundation of Tianjin University(No.2022XYY-0009)。
文摘Conductive hydrogels have shown great prospects as wearable flexible sensors.Nevertheless,it is still a challenge to construct hydrogel-based sensor with great mechanical strength and high strain sensitivity.Herein,an ion-conducting hydrogel was fabricated by introducing gelatin-dialdehydeβ-cyclodextrin(Gel-DACD)into polyvinyl alcohol-borax(PVA-borax)hydrogel network.Natural Gel-DACD network acted as mechanical deformation force through non-covalent cross-linking to endow the polyvinyl alcoholborax/gelatin-dialdehydeβ-cyclodextrin hydrogel(PGBCDH)with excellent mechanical stress(1.35 MPa),stretchability(400%),toughness(1.84 MJ/m3)and great fatigue resistance(200%strain for 100 cycles).Surprisingly,PGBCDH displayed good conductivity of 0.31 S/m after adding DACD to hydrogel network.As sensor,it showed rapid response(168 ms),high strain sensitivity(gage factor(GF)=8.57 in the strain range of 200%-250%)and reliable sensing stability(100%strain for 200 cycles).Importantly,PGBCDHbased sensor can accurately monitor complex body movements(knee,elbow,wrist and finger joints)and large-scale subtle movements(speech,swallow,breath and facial expressions).Thus,PGBCDH shows great potential for human monitoring with high precision.
基金supported by Physical Chemical Materials Analytical&Testing Center of Shandong University at Weihai,Natural Science Foundation of Shandong Province(No.ZR2022QD057)Open Project Fund for Hubei Key Laboratory of Oral and Maxillofacial Development and Regeneration(No.2021kqhm003)+1 种基金State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology)the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing(Yantai,No.AMGM2021F02)。
文摘To achieve smart and personalized medicine, the development of hydrogel dressings with sensing properties and biotherapeutic properties that can act as a sensor to monitor of human health in real-time while speeding up wound healing face great challenge. In the present study, a biocompatible dual-network composite hydrogel(DNCGel) sensor was obtained via a simple process. The dual network hydrogel is constructed by the interpenetration of a flexible network formed of poly(vinyl alcohol)(PVA) physical cross-linked by repeated freeze-thawing and a rigid network of iron-chelated xanthan gum(XG) impregnated with Fe^(3+) interpenetration. The pure PVA/XG hydrogels were chelated with ferric ions by immersion to improve the gel strength(compressive modulus and tensile modulus can reach up to 0.62 MPa and0.079 MPa, respectively), conductivity(conductivity values ranging from 9 × 10^(-4) S/cm to 1 × 10^(-3)S/cm)and bacterial inhibition properties(up to 98.56%). Subsequently, the effects of the ratio of PVA and XG and the immersion time of Fe^(3+) on the hydrogels were investigated, and DNGel3 was given the most priority on a comprehensive consideration. It was demonstrated that the DNCGel exhibit good biocompatibility in vitro, effectively facilitate wound healing in vivo(up to 97.8% healing rate) under electrical stimulation, and monitors human movement in real time. This work provides a novel avenue to explore multifunctional intelligent hydrogels that hold great promise in biomedical fields such as smart wound dressings and flexible wearable sensors.
基金support from the National Natural Science Foundation of China(No.12172272 and 11820101001).
文摘Hard magnetic soft robots have been widely used in biomedical engineering.In these applications,it is crucial to sense the movement of soft robots and their interaction with target objects.Here,we propose a strategy to fabricate a self-sensing bilayer actuator by combining magnetic and ionic conductive hydrogels.The magnetic hydrogel containing NdFeB particles exhibits rapid response to magnetic field and achieve bending deformation.Meanwhile,the polyacrylamide(PAAm)hydrogel with lithium chloride(LiCl)allows for the sensing of deformation.The bending behavior of the bilayer under magnetic field is well captured by theoretical and simulated models.Additionally,the bilayer strain sensor shows good sensitivity,stability and can endure a wide-range cyclic stretching(0-300%).These merits qualify the self-sensing actuator to monitor the motion signals,such as bending of fingers and grasping process of an intelligent gripper.When subject to an external magnetic field,the gripper can grab a cube and sense the resistance change simultaneously to detect the object size.This work may provide a versatile strategy to integrate actuating and self-sensing ability in soft robots.
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Fundamental Research Funds for the Central UniversitiesBasic and Applied Basic Research Foundation of Guangdong Province,Grant/Award Number:2022A1515111227+1 种基金Natural Science Foundation of Shaanxi Province,Grant/Award Number:2023‐JC‐QN‐0598China Postdoctoral Science Foundation,Grant/Award Number:2023T160529。
文摘Conducting polymer hydrogel can address the challenges of stricken biocompatibility and durability.Nevertheless,conventional conducting polymer hydrogels are often brittle and weak due to the intrinsic quality of the material,which exhibits viscoelasticity.This property may cause a delay in sensor response time due to hysteresis.To overcome these limitations,we have designed a wrinkle morphology three-dimensional(3D)substrate using digital light processing technology and then followed by in situ polymerization to form interpenetrating polymer network hydrogels.This novel design results in a wrinkle morphology conducting polymer hydrogel elastomer with high precision and geometric freedom,as the size of the wrinkles can be controlled by adjusting the treating time.The wrinkle morphology on the conducting polymer hydrogel effectively reduces its viscoelasticity,leading to samples with quick response time,low hysteresis,stable cyclic performance,and remarkable resistance change.Simultaneously,the 3D gradient structure augmented the sensor's sensitivity under minimal stress while exhibiting consistent sensing performance.These properties indicate the potential of the conducting polymer hydrogel as a flexible sensor.
基金This work was financially supported by the National Key Research and Development Program of China(2016YFB0700800)Key-Area Research and Development Program of Guang Dong Province(2019B010941002)+3 种基金NSFC(82072071,82072073)Fundamental Research Funds for the Central Universities(2682020ZT79)Sichuan Science and Technology Program(2020YJ0009)Young Scientific and Technological Innovation Research Team Funds of Sichuan Province(20CXTD0106).
文摘Adhesive hydrogels have broad applications ranging from tissue engineering to bioelectronics;however,fabricating adhesive hydrogels with multiple functions remains a challenge.In this study,a mussel-inspired tannic acid chelated-Ag(TA-Ag)nanozyme with peroxidase(POD)-like activity was designed by the in situ reduction of ultrasmall Ag nanoparticles(NPs)with TA.The ultrasmall TA-Ag nanozyme exhibited high catalytic activity to induce hydrogel self-setting without external aid.The nanozyme retained abundant phenolic hydroxyl groups and maintained the dynamic redox balance of phenol-quinone,providing the hydrogels with long-term and repeatable adhesiveness,similar to the adhesion of mussels.The phenolic hydroxyl groups also afforded uniform distribution of the nanozyme in the hydrogel network,thereby improving its mechanical properties and conductivity.Furthermore,the nanozyme endowed the hydrogel with antibacterial activity through synergistic effects of the reactive oxygen species generated via POD-like catalytic reactions and the intrinsic bactericidal activity of Ag.Owing to these advantages,the ultrasmall TA-Ag nanozyme-catalyzed hydrogel could be effectively used as an adhesive,antibacterial,and implantable bioelectrode to detect bio-signals,and as a wound dressing to accelerate tissue regeneration while preventing infection.Therefore,this study provides a promising approach for the fabrication of adhesive hydrogel bioelectronics with multiple functions via mussel-inspired nanozyme catalysis.
基金support from the Natural Sciences and Engineering Research Council of Canada(NSERC)the Canada Foundation for Innovation(CFI),and the Canada Research Chairs Program(H.Zeng).
文摘Flexible electronics have emerged as an exciting research area in recent years,serving as ideal interfaces bridging biological systems and conventional electronic devices.Flexible electronics can not only collect physiological signals for human health monitoring but also enrich our daily life with multifunctional smart materials and devices.Conductive hydrogels(CHs)have become promising candidates for the fabrication of flexible electronics owing to their biocompatibility,adjustable mechanical flexibility,good conductivity,and multiple stimuli-responsive properties.To achieve on-demand mechanical properties such as stretchability,compressibility,and elasticity,the rational design of polymer networks via modulating chemical and physical intermolecular interactions is required.Moreover,the type of conductive components(eg,electron-conductive materials,ions)and the incorporation method also play an important role in the conductivity of CHs.Electron-CHs usually possess excellent conductivity,while ion-CHs are generally transparent and can generate ion gradients within the hydrogel matrices.This mini review focuses on the recent advances in the design of CHs,introducing various design strategies for electron-CHs and ion-CHs employed in flexible electronics and highlighting their versatile applications such as biosensors,batteries,supercapacitors,nanogenerators,actuators,touch panels,and displays.