Floating catalysis chemical vapor deposition(FCCVD)direct spinning process is an attractive method for fabrication of carbon nanotube fibers(CNTFs).However,the intrinsic structural defects,such as entanglement of the ...Floating catalysis chemical vapor deposition(FCCVD)direct spinning process is an attractive method for fabrication of carbon nanotube fibers(CNTFs).However,the intrinsic structural defects,such as entanglement of the constituent carbon nanotubes(CNTs)and inter-tube gaps within the FCCVD CNTFs,hinder the enhancement of mechanical/electrical properties and the realization of practical applications of CNTFs.Therefore,achieving a comprehensive reassembly of CNTFs with both high alignment and dense packing is particularly crucial.Herein,an efficient reinforcing strategy for FCCVD CNTFs was developed,involving chlorosulfonic acid-assisted wet stretching for CNT realigning and mechanical rolling for densification.To reveal the intrinsic relationship between the microstructure and the mechanical/electrical properties of CNTFs,the microstructure evolution of the CNTFs was characterized by cross-sectional scanning electron microscopy(SEM),wide angle X-ray scattering(WAXS),polarized Raman spectroscopy and Brunauer–Emmett–Teller(BET)analysis.The results demonstrate that this strategy can improve the CNT alignment and eliminate the inter-tube voids in the CNTFs,which will lead to the decrease of mean distance between CNTs and increase of inter-tube contact area,resulting in the enhanced inter-tube van der Waals interactions.These microstructural evolutions are beneficial to the load transfer and electron transport between CNTs,and are the main cause of the significant enhancement of mechanical and electrical properties of the CNTFs.Specifically,the tensile strength,elastic modulus and electrical conductivity of the high-performance CNTFs are 7.67 GPa,230 GPa and 4.36×10^(6)S/m,respectively.It paves the way for further applications of CNTFs in high-end functional composites.展开更多
Natural biopolymers feature natural abundance,diverse chemical compositions,tunable properties,easy processability,excellent biocompatibility and biodegradability,as well as nontoxicity,providing new opportunities for...Natural biopolymers feature natural abundance,diverse chemical compositions,tunable properties,easy processability,excellent biocompatibility and biodegradability,as well as nontoxicity,providing new opportunities for the development of flexible sensing and energy devices.Generally,biopolymers are utilized as the passive and active building blocks to endow the flexible devices with mechanical robustness and good biocompatibility.This review aims to provide a comprehensive review on natural biopolymer-based sensing and energy devices.The diverse structures and fabrication processes of three typical biopolymers,including silk,cellulose,and chitin/chitosan,are presented.We review their utilities as the supporting substrates/matrix,active middle layers,separators,electrolytes,and active components of flexible sensing devices(sensors,actuators,transistors)and energy devices(batteries,supercapacitors,triboelectric nanogenerators).Finally,the remaining challenges and future research opportunities are discussed.展开更多
Stretchable and flexible supercapacitors are highly desired due to their many potential applications in wearable devices. However, it is challenging to fabricate supercapacitors that can withstand large tensile strain...Stretchable and flexible supercapacitors are highly desired due to their many potential applications in wearable devices. However, it is challenging to fabricate supercapacitors that can withstand large tensile strain while maintaining high performance. Herein, we report an ultra-stretchable wire-shaped supercapacitor based on carbon nanotube@graphene@MnO2 fibers wound around a superelastic core fiber. The supercapacitor can sustain tensile strain up to 850%, which is the highest value reported for this type of device to date, while maintaining stable electrochemical performance. The energy density of the supercapacitor is 3.37 mWh·cm^-3 at a power density of 54.0 mW·cm^-3. The results show that 82% of the specific capacitance is retained after 1,000 stretch-release cycles with strains of 700%, demonstrating the superior durability of the elastic supercapacitor and showcasing its potential application in ultra-stretchable flexible electronics.展开更多
Silkworm silk fbers have been woven into textiles for thousands of years,because of their attractive luster,good mechanical properties,excellent biocompatibility,and large-scale production.With the development of huma...Silkworm silk fbers have been woven into textiles for thousands of years,because of their attractive luster,good mechanical properties,excellent biocompatibility,and large-scale production.With the development of human society,preparation of silk fbers with modifed or enhanced properties are highly desirable for potential applications in structural materials and smart textiles.Herein,we realized the reinforcement of multiple properties of silk fbers by feeding silkworms with Ag nanowire(Ag NW)modifed diets.The obtained silk fbers show obviously enhanced comprehensive mechanical properties,including improved tensile strength,elongation at break,tensile modulus,and toughness,which are increased by 37.2%,37.6%,68.3%,and 69.8%,respectively.Furthermore,compared with unmodifed silk,the electrical conductivity and thermal conductivity of modifed silk fbers are improved by 246.4%and 32.1%,respectively.The analysis on the components and structure shows that the incorporated Ag NWs lead to increased content of random coil/α-helix,improved orientation of crystallites,and increased content of Ag compared to pristine silk fbers,which may contribute to the enhanced mechanical,electrical,and thermal properties.展开更多
Silkworm silk,which is obtained from domesticated Bombyx mori(B.mori),can be produced in a large scale.However,the mechanical properties of silkworm silk are inferior to its counterpart,spider dragline silk.Therefore,...Silkworm silk,which is obtained from domesticated Bombyx mori(B.mori),can be produced in a large scale.However,the mechanical properties of silkworm silk are inferior to its counterpart,spider dragline silk.Therefore,researchers are continuously exploring approaches to reinforce silkworm silk.Herein,we report a facile and scalable hot stretching process to reinforce natural silk fibers obtained from silkworm cocoons.Experimental results show that the obtained hot-stretched silk fibers(HSSFs)retain the chemical components of the original silk fibers while being endowed with increasedβ-sheet nanocrystal content and crystalline orientation,leading to enhanced mechanical properties.Significantly,the average modulus of the HSSFs reaches 21:6±2:8 GPa,which is about twice that of pristine silkworm silk fibers(11:0±1:7 GPa).Besides,the tensile strength of the HSSFs reaches 0:77±0:13 GPa,which is also obviously higher than that of the pristine silk(0:56±0:08 GPa).The results show that the hot stretching treatment is effective and efficient for producing superstiff,strong,and tough silkworm silk fibers.We anticipate this approach may be also effective for reinforcing other natural or artificial polymer fibers or films containing abundant hydrogen bonds.展开更多
基金supported by the National Natural Science Foundation of China(52125201 and 21975141)the National Key Basic Research and Development Program of China(2020YFA0210702)。
基金support of the National Key Research and Development Program of China(No.2022YFA1203303)the National Natural Science Foundation of China(Nos.52162007,52163032 and 52202032)+3 种基金the China Postdoctoral Science Foundation(No.2022M712321)the Beijing Natural Science Foundation(No.2222094)the Jiangsu Province Postdoctoral Research Funding Program(No.2021K473C)the Jiangxi Provincial Natural Science Foundation(Nos.20224ACB204011 and 20202BAB204006).
文摘Floating catalysis chemical vapor deposition(FCCVD)direct spinning process is an attractive method for fabrication of carbon nanotube fibers(CNTFs).However,the intrinsic structural defects,such as entanglement of the constituent carbon nanotubes(CNTs)and inter-tube gaps within the FCCVD CNTFs,hinder the enhancement of mechanical/electrical properties and the realization of practical applications of CNTFs.Therefore,achieving a comprehensive reassembly of CNTFs with both high alignment and dense packing is particularly crucial.Herein,an efficient reinforcing strategy for FCCVD CNTFs was developed,involving chlorosulfonic acid-assisted wet stretching for CNT realigning and mechanical rolling for densification.To reveal the intrinsic relationship between the microstructure and the mechanical/electrical properties of CNTFs,the microstructure evolution of the CNTFs was characterized by cross-sectional scanning electron microscopy(SEM),wide angle X-ray scattering(WAXS),polarized Raman spectroscopy and Brunauer–Emmett–Teller(BET)analysis.The results demonstrate that this strategy can improve the CNT alignment and eliminate the inter-tube voids in the CNTFs,which will lead to the decrease of mean distance between CNTs and increase of inter-tube contact area,resulting in the enhanced inter-tube van der Waals interactions.These microstructural evolutions are beneficial to the load transfer and electron transport between CNTs,and are the main cause of the significant enhancement of mechanical and electrical properties of the CNTFs.Specifically,the tensile strength,elastic modulus and electrical conductivity of the high-performance CNTFs are 7.67 GPa,230 GPa and 4.36×10^(6)S/m,respectively.It paves the way for further applications of CNTFs in high-end functional composites.
基金supported by the National Basic Research Program of China(No.2016YFA0200103)the National Natural Science Foundation of China(Nos.51520105003,51432002,51672153 and 21975141)the China Postdoctoral Science Foundation(No.2019M660322).
文摘Natural biopolymers feature natural abundance,diverse chemical compositions,tunable properties,easy processability,excellent biocompatibility and biodegradability,as well as nontoxicity,providing new opportunities for the development of flexible sensing and energy devices.Generally,biopolymers are utilized as the passive and active building blocks to endow the flexible devices with mechanical robustness and good biocompatibility.This review aims to provide a comprehensive review on natural biopolymer-based sensing and energy devices.The diverse structures and fabrication processes of three typical biopolymers,including silk,cellulose,and chitin/chitosan,are presented.We review their utilities as the supporting substrates/matrix,active middle layers,separators,electrolytes,and active components of flexible sensing devices(sensors,actuators,transistors)and energy devices(batteries,supercapacitors,triboelectric nanogenerators).Finally,the remaining challenges and future research opportunities are discussed.
基金This work was supported by the National Natural Science Foundation of China （Nos. 51422204, 51372132, and 51672153） and the National Basic Research Program of China （Nos. 2016YFA0200103 and 2013CB228506）.
文摘Stretchable and flexible supercapacitors are highly desired due to their many potential applications in wearable devices. However, it is challenging to fabricate supercapacitors that can withstand large tensile strain while maintaining high performance. Herein, we report an ultra-stretchable wire-shaped supercapacitor based on carbon nanotube@graphene@MnO2 fibers wound around a superelastic core fiber. The supercapacitor can sustain tensile strain up to 850%, which is the highest value reported for this type of device to date, while maintaining stable electrochemical performance. The energy density of the supercapacitor is 3.37 mWh·cm^-3 at a power density of 54.0 mW·cm^-3. The results show that 82% of the specific capacitance is retained after 1,000 stretch-release cycles with strains of 700%, demonstrating the superior durability of the elastic supercapacitor and showcasing its potential application in ultra-stretchable flexible electronics.
基金This work was financially supported by the National Natural Science Foundation of China(21975141 and 52125201)the National Key Basic Research and Development Program(2020YFA0210702).
文摘Silkworm silk fbers have been woven into textiles for thousands of years,because of their attractive luster,good mechanical properties,excellent biocompatibility,and large-scale production.With the development of human society,preparation of silk fbers with modifed or enhanced properties are highly desirable for potential applications in structural materials and smart textiles.Herein,we realized the reinforcement of multiple properties of silk fbers by feeding silkworms with Ag nanowire(Ag NW)modifed diets.The obtained silk fbers show obviously enhanced comprehensive mechanical properties,including improved tensile strength,elongation at break,tensile modulus,and toughness,which are increased by 37.2%,37.6%,68.3%,and 69.8%,respectively.Furthermore,compared with unmodifed silk,the electrical conductivity and thermal conductivity of modifed silk fbers are improved by 246.4%and 32.1%,respectively.The analysis on the components and structure shows that the incorporated Ag NWs lead to increased content of random coil/α-helix,improved orientation of crystallites,and increased content of Ag compared to pristine silk fbers,which may contribute to the enhanced mechanical,electrical,and thermal properties.
基金the National Natural Science Foundation of China(52125201 and 21975141)the National Key Basic Research and Development Program(2020YFA0210702).
文摘Silkworm silk,which is obtained from domesticated Bombyx mori(B.mori),can be produced in a large scale.However,the mechanical properties of silkworm silk are inferior to its counterpart,spider dragline silk.Therefore,researchers are continuously exploring approaches to reinforce silkworm silk.Herein,we report a facile and scalable hot stretching process to reinforce natural silk fibers obtained from silkworm cocoons.Experimental results show that the obtained hot-stretched silk fibers(HSSFs)retain the chemical components of the original silk fibers while being endowed with increasedβ-sheet nanocrystal content and crystalline orientation,leading to enhanced mechanical properties.Significantly,the average modulus of the HSSFs reaches 21:6±2:8 GPa,which is about twice that of pristine silkworm silk fibers(11:0±1:7 GPa).Besides,the tensile strength of the HSSFs reaches 0:77±0:13 GPa,which is also obviously higher than that of the pristine silk(0:56±0:08 GPa).The results show that the hot stretching treatment is effective and efficient for producing superstiff,strong,and tough silkworm silk fibers.We anticipate this approach may be also effective for reinforcing other natural or artificial polymer fibers or films containing abundant hydrogen bonds.
基金This work was supported by the National Natural Science Foundation of China (Nos.21203107,51422204,and 51372132) and the National Basic Research Program of China (No.2013CB228506).
