Directional fluid transport is of significan</span><span style="font-family:Verdana;">ce</span><span style="font-family:Verdana;"> to many physical processes in nature. How ...Directional fluid transport is of significan</span><span style="font-family:Verdana;">ce</span><span style="font-family:Verdana;"> to many physical processes in nature. How to manipulate this process by man-made material is still a key challenge to scientists. In this study, Janus fabric was constructed by electrospinning a layer of polyvinylidene fluoride (PVDF) nanofibers on woven cotton or gauze. The chemical composition, morphology and surface wettability of two sides of Janus fabric were characterized by infrared spectroscopy, scanning electron microscope (SEM) and contact angle measurement. By controlling the PVDF electrospinning time, the maximum hydrostatic pressure of Janus fabric with different PVDF thickness was measured. It was found that PVDF/gauze is more favorable for unidirectional water transportation, and the moisture also can transfer from hydrophobic side to hydrophilic side. With the advantages of facile preparation, low-cost and one-way water/moisture transportation, the Janus fabric prepared in this study can be applied for water separation, humidity transfer and water collection from the air.展开更多
Unidirectional liquid transport without any need of external energy has drawn worldwide attention for its potential applications in various fields such as microfluidics,biomedicine and mechanical engineering.In nature...Unidirectional liquid transport without any need of external energy has drawn worldwide attention for its potential applications in various fields such as microfluidics,biomedicine and mechanical engineering.In nature,numerous creatures have evolved such extraordinary unidirectional liquid transport ability such as spider sik,Sarracenia's trichomes,and Nepenthes alata's peristome,etc.This review summarizes the current progresses of natural unidirectional liquid transport on 1-Dimensional(1D)linear structure and 2-Dimensional(2D)surface stucture.The driving force of unidirectional liquid transport which is determined by unique structure exist distinct differences in physics.The fundamental understanding of 1D and 2D unidirectionaliquid transport especially about hierarchical structural characteristics and their transport mechanism were concentrated,and various bioinspired fabrication methods are also introduced.The applications of bioinspired directional liquid transport are demonstrated especially in fields of microfluidies,biomedical devices and anti-icing surfaces.With newly developed smart materials,various liquid transport regulation strategies are also summarized for the control of transport speed,direction guiding,etc.Finally,we provide new insights and future perspectives of the directional transport materials.展开更多
Some true bug species use droplet-shaped,open-capillary structures for passive,unidirectional fluid transport on their body surface in order to spread a defensive fluid to protect themselves against enemies.In this pa...Some true bug species use droplet-shaped,open-capillary structures for passive,unidirectional fluid transport on their body surface in order to spread a defensive fluid to protect themselves against enemies.In this paper we investigated if the shape of the structures found on bugs(bug-structure)could be optimised with regard to better performance in unidirectional fluid transportation.Furthermore,to use this kind of surface structure in technical applications where fluid surface interaction occurs,it is necessary to adapt the structure geometry to the contact angle between fluid and surface.Based on the principal of operation of the droplet-shaped structures,we optimised the structure shape for better performance in targeted fluid flow and increase in flexibility in design of the structure geometry.To adapt the structure geometry and the structure spacing to the contact angle,we implemented an equilibrium simulation of the,the structure surrounding,fluid.In order to verify the functionality of the optimised structure,we designed and manufactured a prototype.By testing this prototype with pure water used as fluid,the functionality of the optimised structure and the simulation could be proved.This kind of structure may be used on technical surfaces where targeted fluid transport is needed,e.g.evacuation of condensate in order to prevent the surface from mold growth,microfluidics,lab-on-a-chip applications and on microneedles for efficient drug/vaccine coating.展开更多
Wicking textiles are known to be superior to conventional textiles in body sweat management.However,many existingwicking textiles suffer inadequate durability and perspiration performance after repeated abrasion and w...Wicking textiles are known to be superior to conventional textiles in body sweat management.However,many existingwicking textiles suffer inadequate durability and perspiration performance after repeated abrasion and washing.Herein,aninterfacial interlocking strategy was demonstrated to prepare a durable self-pumping textile with strong interfacial adhesion(up to 21.47±1.73 N/cm)between the hydrophilic and hydrophobic layers.Unlike conventional transfer prints,the sequencedcombination of powder-patterning and hot-pressing enables the in situ formation of the interfacial interlocking structuresbetween the hydrophobic thermoplastic polyurethane(TPU)layer with the cotton fabric.The durable self-pumping textilesexhibit excellent abrasion-proof performance and enduring liquid unidirectional transport compared with the commercialwicking textiles.Furthermore,they show a liquid unidirectional transport capacity of(1385±155)%,much higher than thepreviously reported wicking textiles.This work provides valuable insights for developing future high-performance wickingtextiles,emphasizing enhanced liquid transport efficiency,and durability in demanding conditions.展开更多
Developing electronic skin(e-skin)with extraordinary sensing capabilities through biomimetic strategies holds significant potential for distributed wearable electronics in the Internet of Things and human-machine inte...Developing electronic skin(e-skin)with extraordinary sensing capabilities through biomimetic strategies holds significant potential for distributed wearable electronics in the Internet of Things and human-machine interaction.However,moisture accumulation at the surface between e-skin and human skin severly affects the stability and accuracy of sensing signals.Thermal-moisture comfort and stable functional interfaces of e-skins are still great challenges that need to be addressed.Herein,inspired by the dual-sided structure of lotus leaf,we demonstrate an unidirectional water transport e-skin(UWTES)by constructing a gradient structure of porosity and hydrophilicity using one-step electrospinning thermoplastic polyurethane/poly(vinylidene fluoride-co-hexafluoropropylene)(TPU/PVDF-HFP)with an alloyed liquid metal-based(LM-Ag)electrode.A UWTES textile-based triboelectric nanogenerator(UT-TENG)exhibits a maximum open-circuit voltage,short-circuit current and power density of 188.7 V,18.89μA and 4.73 mW/m^(2),respectively.Additionally,a temperature visualization system for UWTES textile(TUWTES)enables real-time monitoring and displays of body temperature during intense physical activity.Through a one-dimensional convolutional neural network(1D-CNN),the gait motion recognition system achieves a highly accuracy of 99.7%.This design strategy provides new insights into the development of integrated smart textiles with improved thermal-moisture comfort and user-friendliness.展开更多
Excessive energy consumption,especially space heating and cooling,is one of the major challenges facing mankind.Smart heat-moisture management textiles can effectively regulate heat-moisture comfort between the enviro...Excessive energy consumption,especially space heating and cooling,is one of the major challenges facing mankind.Smart heat-moisture management textiles can effectively regulate heat-moisture comfort between the environment and skin,greatly reducing energy consumption;these results are in line with sustainable development goals.In this work,a skin-inspired adaptive heat-regulating fabric based on heat-responsive shape-memory ethylene vinyl acetate copolymer fibres and traditional cotton fabric is used.Furthermore,single-sided hydrophobic finishing is introduced to provide the fabric with unidirectional moisture transport.Owing to the shape memory effect,the smart fabric has an environment-adaptive and responsive dynamic structure in the form of a heat-induced gap opening and cool-induced gap closing.As a result,the heat conductivity of the smart textile can be switched from 0.086 to 0.089 W/m·K.Moreover,the air permeability and moisture evaporation can be regulated between 443.5 mm/s,1761.81 g/(d·m^(2))and 461.7 mm/s,1963.8 g/(d·m^(2)),reversibly and repeatedly;the unidirectional moisture transport capacity with a unidirectional moisture index of 193.2 can also be regulated to synergistically improve the heat-moisture comfort,and the entire process results in zero carbon emission.Moreover,we demonstrate the application of the smart adaptive fabric in heat-moisture management fields,attaining a cooling effect of 4.35℃and a breathability difference of 89.6 mm/s;these values correspond to more than 30%building cooling and heating energy savings,and these results are in line with the sustainable and zero-carbon trends.The shape memory adaptive heat-moisture management fabric will likely have broad prospects in smart thermoregulation textiles,wearable fields,electronic skin,outdoor,medical,military,and energy-saving fields.展开更多
Passive cooling strategy with zero-energy consumption is effective in preventing people from heat stress.However,most of the existing radiative cooling textiles are fabricated with non-degradable hydrophobic synthetic...Passive cooling strategy with zero-energy consumption is effective in preventing people from heat stress.However,most of the existing radiative cooling textiles are fabricated with non-degradable hydrophobic synthetic polymers and lack the functions of sweat management.Herein,a hierarchically designed dual Janus nanofibrous textile with superior thermal-wet management capability is proposed by targeted selection of spinning solvents with different properties during electrospinning.The embedded Al_(2)O_(3)nanoparticles and BN nanosheets in silk fibroin nanofibers endow the textile with high solar reflectivity(97.12%)and infrared emissivity(98.69%),alongside improved in-plane and through-plane thermal conductivity(1.593 and 0.1187 W・K^(−1)・m^(−1),respectively).Benefiting from the asymmetric characteristics of the two sides in terms of fiber diameter and wettability,the nanofibrous textile exhibits unparalleled water transport index(R=1028.93%)and exceptional water vapor transmission rate(141.34 g・m^(−2)・h^(−1)).The textile integrates radiative cooling,rapid heat conduction,and unidirectional sweat evaporation,achieving a cooling effect exceeding 9°C under direct sunlight when worn.Moreover,the Janus textile has good biocompatibility,satisfactory wearability and air breathability,ensuring its comfort in wearable applications.Computer simulations complement experimental results,providing insights into the deep-seated mechanisms of nanofiber formation,Mie scattering,and water transport.This innovative design offers promising prospects for the development of next-generation passive-cooling textiles.展开更多
文摘Directional fluid transport is of significan</span><span style="font-family:Verdana;">ce</span><span style="font-family:Verdana;"> to many physical processes in nature. How to manipulate this process by man-made material is still a key challenge to scientists. In this study, Janus fabric was constructed by electrospinning a layer of polyvinylidene fluoride (PVDF) nanofibers on woven cotton or gauze. The chemical composition, morphology and surface wettability of two sides of Janus fabric were characterized by infrared spectroscopy, scanning electron microscope (SEM) and contact angle measurement. By controlling the PVDF electrospinning time, the maximum hydrostatic pressure of Janus fabric with different PVDF thickness was measured. It was found that PVDF/gauze is more favorable for unidirectional water transportation, and the moisture also can transfer from hydrophobic side to hydrophilic side. With the advantages of facile preparation, low-cost and one-way water/moisture transportation, the Janus fabric prepared in this study can be applied for water separation, humidity transfer and water collection from the air.
基金the National Key R&D Program of China(No.2019YFB1309702)the National Natural Science Foundation of China(Nos.51935001,51725501 and 51905022).
文摘Unidirectional liquid transport without any need of external energy has drawn worldwide attention for its potential applications in various fields such as microfluidics,biomedicine and mechanical engineering.In nature,numerous creatures have evolved such extraordinary unidirectional liquid transport ability such as spider sik,Sarracenia's trichomes,and Nepenthes alata's peristome,etc.This review summarizes the current progresses of natural unidirectional liquid transport on 1-Dimensional(1D)linear structure and 2-Dimensional(2D)surface stucture.The driving force of unidirectional liquid transport which is determined by unique structure exist distinct differences in physics.The fundamental understanding of 1D and 2D unidirectionaliquid transport especially about hierarchical structural characteristics and their transport mechanism were concentrated,and various bioinspired fabrication methods are also introduced.The applications of bioinspired directional liquid transport are demonstrated especially in fields of microfluidies,biomedical devices and anti-icing surfaces.With newly developed smart materials,various liquid transport regulation strategies are also summarized for the control of transport speed,direction guiding,etc.Finally,we provide new insights and future perspectives of the directional transport materials.
基金This work was supported by the European Union's Horizon 2020 research and innovation program within the project“BioComb4Nanofibers”(grant agreement No.862016)the Linz Center of Mechatronics(LCM).
文摘Some true bug species use droplet-shaped,open-capillary structures for passive,unidirectional fluid transport on their body surface in order to spread a defensive fluid to protect themselves against enemies.In this paper we investigated if the shape of the structures found on bugs(bug-structure)could be optimised with regard to better performance in unidirectional fluid transportation.Furthermore,to use this kind of surface structure in technical applications where fluid surface interaction occurs,it is necessary to adapt the structure geometry to the contact angle between fluid and surface.Based on the principal of operation of the droplet-shaped structures,we optimised the structure shape for better performance in targeted fluid flow and increase in flexibility in design of the structure geometry.To adapt the structure geometry and the structure spacing to the contact angle,we implemented an equilibrium simulation of the,the structure surrounding,fluid.In order to verify the functionality of the optimised structure,we designed and manufactured a prototype.By testing this prototype with pure water used as fluid,the functionality of the optimised structure and the simulation could be proved.This kind of structure may be used on technical surfaces where targeted fluid transport is needed,e.g.evacuation of condensate in order to prevent the surface from mold growth,microfluidics,lab-on-a-chip applications and on microneedles for efficient drug/vaccine coating.
基金National Natural Science Foundation of China,21972155,Shutao Wang,22035008,Shutao Wang,22475223,Lianxin ShiBeijing Outstanding Young Scientist Program,JWZQ20240102014,Shutao WangYouth Innovation Promotion Association CAS,2022027,Lianxin Shi.
文摘Wicking textiles are known to be superior to conventional textiles in body sweat management.However,many existingwicking textiles suffer inadequate durability and perspiration performance after repeated abrasion and washing.Herein,aninterfacial interlocking strategy was demonstrated to prepare a durable self-pumping textile with strong interfacial adhesion(up to 21.47±1.73 N/cm)between the hydrophilic and hydrophobic layers.Unlike conventional transfer prints,the sequencedcombination of powder-patterning and hot-pressing enables the in situ formation of the interfacial interlocking structuresbetween the hydrophobic thermoplastic polyurethane(TPU)layer with the cotton fabric.The durable self-pumping textilesexhibit excellent abrasion-proof performance and enduring liquid unidirectional transport compared with the commercialwicking textiles.Furthermore,they show a liquid unidirectional transport capacity of(1385±155)%,much higher than thepreviously reported wicking textiles.This work provides valuable insights for developing future high-performance wickingtextiles,emphasizing enhanced liquid transport efficiency,and durability in demanding conditions.
基金support received from the National Natural Science Foundation of China(52473178,52473275)the Natural Science Foundation of Jiangsu Province(BK20221539)+4 种基金Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)the Program of Introducing Talents of Jiangnan University(1065219032210150)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_2474)the Science and Technology Program of Jiangsu Administration for Market Regulation(KJ2024013)the Taihu Talent Program-Innovative Individual(2024)。
文摘Developing electronic skin(e-skin)with extraordinary sensing capabilities through biomimetic strategies holds significant potential for distributed wearable electronics in the Internet of Things and human-machine interaction.However,moisture accumulation at the surface between e-skin and human skin severly affects the stability and accuracy of sensing signals.Thermal-moisture comfort and stable functional interfaces of e-skins are still great challenges that need to be addressed.Herein,inspired by the dual-sided structure of lotus leaf,we demonstrate an unidirectional water transport e-skin(UWTES)by constructing a gradient structure of porosity and hydrophilicity using one-step electrospinning thermoplastic polyurethane/poly(vinylidene fluoride-co-hexafluoropropylene)(TPU/PVDF-HFP)with an alloyed liquid metal-based(LM-Ag)electrode.A UWTES textile-based triboelectric nanogenerator(UT-TENG)exhibits a maximum open-circuit voltage,short-circuit current and power density of 188.7 V,18.89μA and 4.73 mW/m^(2),respectively.Additionally,a temperature visualization system for UWTES textile(TUWTES)enables real-time monitoring and displays of body temperature during intense physical activity.Through a one-dimensional convolutional neural network(1D-CNN),the gait motion recognition system achieves a highly accuracy of 99.7%.This design strategy provides new insights into the development of integrated smart textiles with improved thermal-moisture comfort and user-friendliness.
基金supported by the National Natural Science Foundation of China[52103066]Young Talent Fund of Association for Science and Technology in Shaanxi,China(20230430)Natural Science Basic Research Program of Shaanxi[2021JQ-678].
文摘Excessive energy consumption,especially space heating and cooling,is one of the major challenges facing mankind.Smart heat-moisture management textiles can effectively regulate heat-moisture comfort between the environment and skin,greatly reducing energy consumption;these results are in line with sustainable development goals.In this work,a skin-inspired adaptive heat-regulating fabric based on heat-responsive shape-memory ethylene vinyl acetate copolymer fibres and traditional cotton fabric is used.Furthermore,single-sided hydrophobic finishing is introduced to provide the fabric with unidirectional moisture transport.Owing to the shape memory effect,the smart fabric has an environment-adaptive and responsive dynamic structure in the form of a heat-induced gap opening and cool-induced gap closing.As a result,the heat conductivity of the smart textile can be switched from 0.086 to 0.089 W/m·K.Moreover,the air permeability and moisture evaporation can be regulated between 443.5 mm/s,1761.81 g/(d·m^(2))and 461.7 mm/s,1963.8 g/(d·m^(2)),reversibly and repeatedly;the unidirectional moisture transport capacity with a unidirectional moisture index of 193.2 can also be regulated to synergistically improve the heat-moisture comfort,and the entire process results in zero carbon emission.Moreover,we demonstrate the application of the smart adaptive fabric in heat-moisture management fields,attaining a cooling effect of 4.35℃and a breathability difference of 89.6 mm/s;these values correspond to more than 30%building cooling and heating energy savings,and these results are in line with the sustainable and zero-carbon trends.The shape memory adaptive heat-moisture management fabric will likely have broad prospects in smart thermoregulation textiles,wearable fields,electronic skin,outdoor,medical,military,and energy-saving fields.
基金the National Natural Science Foundation of China(22371094)Phadcalc(www.phadcalc.com)for computer simulations support.
文摘Passive cooling strategy with zero-energy consumption is effective in preventing people from heat stress.However,most of the existing radiative cooling textiles are fabricated with non-degradable hydrophobic synthetic polymers and lack the functions of sweat management.Herein,a hierarchically designed dual Janus nanofibrous textile with superior thermal-wet management capability is proposed by targeted selection of spinning solvents with different properties during electrospinning.The embedded Al_(2)O_(3)nanoparticles and BN nanosheets in silk fibroin nanofibers endow the textile with high solar reflectivity(97.12%)and infrared emissivity(98.69%),alongside improved in-plane and through-plane thermal conductivity(1.593 and 0.1187 W・K^(−1)・m^(−1),respectively).Benefiting from the asymmetric characteristics of the two sides in terms of fiber diameter and wettability,the nanofibrous textile exhibits unparalleled water transport index(R=1028.93%)and exceptional water vapor transmission rate(141.34 g・m^(−2)・h^(−1)).The textile integrates radiative cooling,rapid heat conduction,and unidirectional sweat evaporation,achieving a cooling effect exceeding 9°C under direct sunlight when worn.Moreover,the Janus textile has good biocompatibility,satisfactory wearability and air breathability,ensuring its comfort in wearable applications.Computer simulations complement experimental results,providing insights into the deep-seated mechanisms of nanofiber formation,Mie scattering,and water transport.This innovative design offers promising prospects for the development of next-generation passive-cooling textiles.
