Flexible hydrogels are receiving significant attention for their application in wearable sensors.However,most hydrogel materials exhibit weak and one-time adhesion,low sensitivity,ice crystallization,water evaporation...Flexible hydrogels are receiving significant attention for their application in wearable sensors.However,most hydrogel materials exhibit weak and one-time adhesion,low sensitivity,ice crystallization,water evaporation,and poor self-recovery,thereby limiting their application as sensors.These issues are only partly addressed in previous studies.Herein,a multiplecrosslinked poly(2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide-co-acrylamide)(P(SBMA-co-AAm))multifunctional hydrogel is prepared via a one-pot synthesis method to overcome the aforementioned limitations.Specifically,ions,glycerol,and 2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide are incorporated to reduce the freezing point and improve the moisture retention ability.The proposed hydrogel is superior to existing hydrogels because it exhibits good stretchability(a strain of 2900%),self-healing properties,and transparency through effective energy dissipation in its dynamic crosslinked network.Further,2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide as a zwitterion monomer results in an excellent gauge factor of 43.4 at strains of 1300-1600%by improving the ion transportability and achieving a strong adhesion of 20.9 kPa owing to the dipole-dipole moment.The proposed hydrogel is promising for next-generation biomedical applications,such as soft robots,and health monitoring.展开更多
The capability to sense complex pressure variations comprehensively is vital for wearable electronics and flexible human–machine interfaces.In this paper,inspired by button switches,a duplex tactile sensor based on t...The capability to sense complex pressure variations comprehensively is vital for wearable electronics and flexible human–machine interfaces.In this paper,inspired by button switches,a duplex tactile sensor based on the combination of triboelectric and piezoresistive effects is designed and fabricated.Because of its excellent mechanical strength and electrical stability,a double-networked ionic hydrogel is used as both the conductive electrode and elastic current regulator.In addition,micro-pyramidal patterned polydimethylsiloxane(PDMS)acts as both the friction layer and the encapsulation elastomer,thereby boosting the triboelectric output performance significantly.The duplex hydrogel sensor demonstrates comprehensive sensing ability in detecting the whole stimulation process including the dynamic and static pressures.The dynamic stress intensity(10–300 Pa),the action time,and the static variations(increase and decrease)of the pressure can be identified precisely from the dual-channel signals.Combined with a signal processing module,an intelligent visible door lamp is achieved for monitoring the entire“contact–hold–release–separation”state of the external stimulation,which shows great application potential for future smart robot e-skin and flexible electronics.展开更多
Flexible hydrogels have shown promise as strain sensors in medical monitoring,human motion detection and intelligent robotics.For a hydrogel strain sensor,certain challenges need to be urgently addressed for practical...Flexible hydrogels have shown promise as strain sensors in medical monitoring,human motion detection and intelligent robotics.For a hydrogel strain sensor,certain challenges need to be urgently addressed for practical applications,such as the damage caused by external effects,leading to equipment failure,and the inability to perceive ambient temperature,resulting in single functionality.Herein,a stretchable,self-healing and dual temperature-strain sensitive hydrogel,with a physically-crosslinked network,is designed by constructing multiple dynamic reversible bonds.Graphene oxide(GO)and iron ions(Fe^(3+))act as dynamic bridges in the cross-linked network and are mediated by the covalent and hydrogen bonding,rendering excellent stretchability to the hydrogel.The reversible features of coordination interactions and hydrogen interactions endow excellent recoverability and self-healing properties.Moreover,the incorporated N-isopropyl acrylamide(NIPAM)provides excellent temperature responsiveness to the hydrogel,facilitating the detection of external temperature changes.Meanwhile,the hydrogels exhibited strain-sensitivity,with a wide working range of 1%-300%,fast response and electrical stability,which can be used as flexible sensors to monitor body motions,e.g.,speaking and the bending of finger,wrist,elbow and knee.Overall,the hydrogel possesses dual sensory capabilities,combining external temperature and strain,for potential applications in wearable multifunctional sensing devices.展开更多
The rapid developments of artificial intelligence have attracted attention in designing electronic skin(e-skin)to realize the mechanical and sensory properties of human skin.To better imitate the tactile sensing prope...The rapid developments of artificial intelligence have attracted attention in designing electronic skin(e-skin)to realize the mechanical and sensory properties of human skin.To better imitate the tactile sensing properties of human skin,a stretchable and transparent hydrogel is produced.Thus,an elastic and capacitive strain sensor was successfully produced through the as-prepared hydrogel.The sensor was elastic with a high conductive stability and could detect the strain changes in different states,which had very short response time that could be applied into the detection of large and small deformations and would shed light on its application in e-skin.展开更多
The development of bioinspired gradient hydrogels with self-sensing actuated capabilities for remote interaction with soft-hard robots remains a challenging endeavor. Here, we propose a novel multifunctional self-sens...The development of bioinspired gradient hydrogels with self-sensing actuated capabilities for remote interaction with soft-hard robots remains a challenging endeavor. Here, we propose a novel multifunctional self-sensing actuated gradient hydrogel that combines ultrafast actuation and high sensitivity for remote interaction with robotic hand. The gradient network structure, achieved through a wettability difference method involving the rapid precipitation of MoO_(2) nanosheets, introduces hydrophilic disparities between two sides within hydrogel. This distinctive approach bestows the hydrogel with ultrafast thermo-responsive actuation(21° s^(-1)) and enhanced photothermal efficiency(increase by 3.7 ℃ s^(-1) under 808 nm near-infrared). Moreover, the local cross-linking of sodium alginate with Ca^(2+) endows the hydrogel with programmable deformability and information display capabilities. Additionally, the hydrogel exhibits high sensitivity(gauge factor 3.94 within a wide strain range of 600%), fast response times(140 ms) and good cycling stability. Leveraging these exceptional properties, we incorporate the hydrogel into various soft actuators, including soft gripper, artificial iris, and bioinspired jellyfish, as well as wearable electronics capable of precise human motion and physiological signal detection. Furthermore, through the synergistic combination of remarkable actuation and sensitivity, we realize a self-sensing touch bioinspired tongue. Notably, by employing quantitative analysis of actuation-sensing, we realize remote interaction between soft-hard robot via the Internet of Things. The multifunctional self-sensing actuated gradient hydrogel presented in this study provides a new insight for advanced somatosensory materials, self-feedback intelligent soft robots and human–machine interactions.展开更多
To realize continuously and stably work in a“moist/hot environment”,flexible electronics with excellent humid resistance,antiswelling,and detection sensitivity are demanding.Herein,a solvent-resistant and temperatur...To realize continuously and stably work in a“moist/hot environment”,flexible electronics with excellent humid resistance,antiswelling,and detection sensitivity are demanding.Herein,a solvent-resistant and temperature-ultrasensitive hydrogel sensor was prepared by combining MXene and quaternized chitosan(QCS)with the binary polymer chain.The strong electrostatic interaction between the QCS chain and the poly(acrylic acid)(PAA)network endows the hydrogel stability against solvent erosion,high temperature,and high humidity.The strong dynamic interaction between MXene and polymer matrix significantly improves the mechanical properties and sensing(strain and temperature)sensitivity of the hydrogel.The hydrogel strain sensor exhibits a high gauge factor(5.53),temperature/humidity tolerance(equilibrium swelling ratio of 2.5%at 80℃),and excellent cycle stability,which could achieve a remote and accurate perception of complex human motion and environment fluctuation under aquatic conditions.Moreover,the hydrogel sensor exhibits impressive thermal response sensitivity(-3.183%/℃),ultrashort response time(<2.53 s),and a low detection limit(<0.5℃)in a wide temperature range,which is applied as an indicator of the body surface and ambient temperature.In short,this study broadens the application scenarios of hydrogels in persistent extreme thermal and wet environments.展开更多
In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving force.Among them,acrylamide(AM)and 3-acrylam...In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving force.Among them,acrylamide(AM)and 3-acrylamidophenylboronic acid(AAPBA)were the main body,and the numerous hydroxyl groups in the trehalose(Treh)molecule and other polymer groups formed strong hydrogen bonding interactions to improve the mechanical properties of the PAM/PAAPBA/Treh(PAAT)hydrogel and ensured the simplicity of the synthesis process.The hydrogel possessed high strain at break(1239%),stress(64.7 kPa),low hysteresis(100%to 500%strain,corresponding to dissipation energy from 1.37 to 7.80 kJ/m^(3)),and outstanding cycling stability(retained more than 90%of maximum stress after 200 ten-sile cycles).By integrating carbon nanotubes(CNTs)into PAAT hydrogel(PAATC),the PAATC hydrogel with excellent strain response performance was successfully constructed.The PAATC conductive hydro-gel exhibited high sensitivity(gauge factor(GF)=10.58 and sensitivity(S)=0.304 kPa^(-1)),wide strain response range(0.5%-1000%),fast response time(450 ms),and short recovery time(350 ms),excellent fatigue resistance,and strain response stability.Furthermore,the PAATC-based triboelectric nanogener-ator(TENG)displayed outstanding energy harvesting performance,which shows its potential for appli-cation in self-powered electronic devices.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
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2020R1I1A3054824)supported by the Basic Research Program through the National Research Foundation of Korea(NRF)funded by the MSIT(2021R1A4A1032762)+1 种基金supported under the framework of international cooperation program managed by the National Research Foundation of Korea(2019K2A9A1A06091737)supported by the Technology Development Program to Solve Climate Changes of the Korean NRF(2021M1A2A2061335).
文摘Flexible hydrogels are receiving significant attention for their application in wearable sensors.However,most hydrogel materials exhibit weak and one-time adhesion,low sensitivity,ice crystallization,water evaporation,and poor self-recovery,thereby limiting their application as sensors.These issues are only partly addressed in previous studies.Herein,a multiplecrosslinked poly(2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide-co-acrylamide)(P(SBMA-co-AAm))multifunctional hydrogel is prepared via a one-pot synthesis method to overcome the aforementioned limitations.Specifically,ions,glycerol,and 2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide are incorporated to reduce the freezing point and improve the moisture retention ability.The proposed hydrogel is superior to existing hydrogels because it exhibits good stretchability(a strain of 2900%),self-healing properties,and transparency through effective energy dissipation in its dynamic crosslinked network.Further,2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide as a zwitterion monomer results in an excellent gauge factor of 43.4 at strains of 1300-1600%by improving the ion transportability and achieving a strong adhesion of 20.9 kPa owing to the dipole-dipole moment.The proposed hydrogel is promising for next-generation biomedical applications,such as soft robots,and health monitoring.
基金supported by the National Natural Science Foundation of China(Grant Nos.51705429 and 61801525)the Fundamental Research Funds for the Central Universities,Guangdong Natural Science Funds(Grant No.2018A030313400).
文摘The capability to sense complex pressure variations comprehensively is vital for wearable electronics and flexible human–machine interfaces.In this paper,inspired by button switches,a duplex tactile sensor based on the combination of triboelectric and piezoresistive effects is designed and fabricated.Because of its excellent mechanical strength and electrical stability,a double-networked ionic hydrogel is used as both the conductive electrode and elastic current regulator.In addition,micro-pyramidal patterned polydimethylsiloxane(PDMS)acts as both the friction layer and the encapsulation elastomer,thereby boosting the triboelectric output performance significantly.The duplex hydrogel sensor demonstrates comprehensive sensing ability in detecting the whole stimulation process including the dynamic and static pressures.The dynamic stress intensity(10–300 Pa),the action time,and the static variations(increase and decrease)of the pressure can be identified precisely from the dual-channel signals.Combined with a signal processing module,an intelligent visible door lamp is achieved for monitoring the entire“contact–hold–release–separation”state of the external stimulation,which shows great application potential for future smart robot e-skin and flexible electronics.
基金financially supported by the National Natural Science Foundation of China(No.52173301)International Science and Technology Cooperation Project of Sichuan Province(No.2022YFH0019)Innovative Research Team of Southwest Petroleum University(No.2017CXTD01)。
文摘Flexible hydrogels have shown promise as strain sensors in medical monitoring,human motion detection and intelligent robotics.For a hydrogel strain sensor,certain challenges need to be urgently addressed for practical applications,such as the damage caused by external effects,leading to equipment failure,and the inability to perceive ambient temperature,resulting in single functionality.Herein,a stretchable,self-healing and dual temperature-strain sensitive hydrogel,with a physically-crosslinked network,is designed by constructing multiple dynamic reversible bonds.Graphene oxide(GO)and iron ions(Fe^(3+))act as dynamic bridges in the cross-linked network and are mediated by the covalent and hydrogen bonding,rendering excellent stretchability to the hydrogel.The reversible features of coordination interactions and hydrogen interactions endow excellent recoverability and self-healing properties.Moreover,the incorporated N-isopropyl acrylamide(NIPAM)provides excellent temperature responsiveness to the hydrogel,facilitating the detection of external temperature changes.Meanwhile,the hydrogels exhibited strain-sensitivity,with a wide working range of 1%-300%,fast response and electrical stability,which can be used as flexible sensors to monitor body motions,e.g.,speaking and the bending of finger,wrist,elbow and knee.Overall,the hydrogel possesses dual sensory capabilities,combining external temperature and strain,for potential applications in wearable multifunctional sensing devices.
基金Fundamental Research Funds for the Central Universities,China(Nos.2232020G-01 and 2232019D3-15)。
文摘The rapid developments of artificial intelligence have attracted attention in designing electronic skin(e-skin)to realize the mechanical and sensory properties of human skin.To better imitate the tactile sensing properties of human skin,a stretchable and transparent hydrogel is produced.Thus,an elastic and capacitive strain sensor was successfully produced through the as-prepared hydrogel.The sensor was elastic with a high conductive stability and could detect the strain changes in different states,which had very short response time that could be applied into the detection of large and small deformations and would shed light on its application in e-skin.
基金The financial support from the National Natural Science Foundation of China (32201179)Guangdong Basic and Applied Basic Research Foundation (2020A1515110126 and 2021A1515010130)+1 种基金the Fundamental Research Funds for the Central Universities (N2319005)Ningbo Science and Technology Major Project (2021Z027) is gratefully acknowledged。
文摘The development of bioinspired gradient hydrogels with self-sensing actuated capabilities for remote interaction with soft-hard robots remains a challenging endeavor. Here, we propose a novel multifunctional self-sensing actuated gradient hydrogel that combines ultrafast actuation and high sensitivity for remote interaction with robotic hand. The gradient network structure, achieved through a wettability difference method involving the rapid precipitation of MoO_(2) nanosheets, introduces hydrophilic disparities between two sides within hydrogel. This distinctive approach bestows the hydrogel with ultrafast thermo-responsive actuation(21° s^(-1)) and enhanced photothermal efficiency(increase by 3.7 ℃ s^(-1) under 808 nm near-infrared). Moreover, the local cross-linking of sodium alginate with Ca^(2+) endows the hydrogel with programmable deformability and information display capabilities. Additionally, the hydrogel exhibits high sensitivity(gauge factor 3.94 within a wide strain range of 600%), fast response times(140 ms) and good cycling stability. Leveraging these exceptional properties, we incorporate the hydrogel into various soft actuators, including soft gripper, artificial iris, and bioinspired jellyfish, as well as wearable electronics capable of precise human motion and physiological signal detection. Furthermore, through the synergistic combination of remarkable actuation and sensitivity, we realize a self-sensing touch bioinspired tongue. Notably, by employing quantitative analysis of actuation-sensing, we realize remote interaction between soft-hard robot via the Internet of Things. The multifunctional self-sensing actuated gradient hydrogel presented in this study provides a new insight for advanced somatosensory materials, self-feedback intelligent soft robots and human–machine interactions.
基金The work was supported by the National Key R&D Program of China(No.2020YFA0709900)“Taishan scholars”construction special fund of Shandong Province。
文摘To realize continuously and stably work in a“moist/hot environment”,flexible electronics with excellent humid resistance,antiswelling,and detection sensitivity are demanding.Herein,a solvent-resistant and temperature-ultrasensitive hydrogel sensor was prepared by combining MXene and quaternized chitosan(QCS)with the binary polymer chain.The strong electrostatic interaction between the QCS chain and the poly(acrylic acid)(PAA)network endows the hydrogel stability against solvent erosion,high temperature,and high humidity.The strong dynamic interaction between MXene and polymer matrix significantly improves the mechanical properties and sensing(strain and temperature)sensitivity of the hydrogel.The hydrogel strain sensor exhibits a high gauge factor(5.53),temperature/humidity tolerance(equilibrium swelling ratio of 2.5%at 80℃),and excellent cycle stability,which could achieve a remote and accurate perception of complex human motion and environment fluctuation under aquatic conditions.Moreover,the hydrogel sensor exhibits impressive thermal response sensitivity(-3.183%/℃),ultrashort response time(<2.53 s),and a low detection limit(<0.5℃)in a wide temperature range,which is applied as an indicator of the body surface and ambient temperature.In short,this study broadens the application scenarios of hydrogels in persistent extreme thermal and wet environments.
基金the financial support from the National Natural Science Foundation of China (52002356)the China Postdoctoral Science Foundation (2020M672269)the National Key R&D program of China (2019YFA0706802)
文摘In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving force.Among them,acrylamide(AM)and 3-acrylamidophenylboronic acid(AAPBA)were the main body,and the numerous hydroxyl groups in the trehalose(Treh)molecule and other polymer groups formed strong hydrogen bonding interactions to improve the mechanical properties of the PAM/PAAPBA/Treh(PAAT)hydrogel and ensured the simplicity of the synthesis process.The hydrogel possessed high strain at break(1239%),stress(64.7 kPa),low hysteresis(100%to 500%strain,corresponding to dissipation energy from 1.37 to 7.80 kJ/m^(3)),and outstanding cycling stability(retained more than 90%of maximum stress after 200 ten-sile cycles).By integrating carbon nanotubes(CNTs)into PAAT hydrogel(PAATC),the PAATC hydrogel with excellent strain response performance was successfully constructed.The PAATC conductive hydro-gel exhibited high sensitivity(gauge factor(GF)=10.58 and sensitivity(S)=0.304 kPa^(-1)),wide strain response range(0.5%-1000%),fast response time(450 ms),and short recovery time(350 ms),excellent fatigue resistance,and strain response stability.Furthermore,the PAATC-based triboelectric nanogener-ator(TENG)displayed outstanding energy harvesting performance,which shows its potential for appli-cation in self-powered electronic devices.
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.
