Electronic skins can monitor minute physiological signal variations in the human skins and represent the body’s state,showing an emerging trend for alternative medical diagnostics and human-machine interfaces.In this...Electronic skins can monitor minute physiological signal variations in the human skins and represent the body’s state,showing an emerging trend for alternative medical diagnostics and human-machine interfaces.In this study,we designed a bioinspired directional moisture-wicking electronic skin(DMWES)based on the construction of heterogeneous fibrous membranes and the conductive MXene/CNTs electrospraying layer.Unidirectional moisture transfer was successfully realized by surface energy gradient and push-pull effect via the design of distinct hydrophobic-hydrophilic difference,which can spontaneously absorb sweat from the skin.The DMWES membrane showed excellent comprehensive pressure sensing performance,high sensitivity(maximum sensitivity of 548.09 kPa^(−1)),wide linear range,rapid response and recovery time.In addition,the single-electrode triboelectric nanogenerator based on the DMWES can deliver a high areal power density of 21.6μW m^(−2) and good cycling stability in high pressure energy harvesting.Moreover,the superior pressure sensing and triboelectric performance enabled the DMWES for all-range healthcare sensing,including accurate pulse monitoring,voice recognition,and gait recognition.This work will help to boost the development of the next-generation breathable electronic skins in the applications of AI,human-machine interaction,and soft robots.展开更多
The column wicking technique was applied to estimate the surface free energy of cellulose, the importance of which is to obtain a real effective capillary radius, Reff, initially from the plot of Washburn penetration ...The column wicking technique was applied to estimate the surface free energy of cellulose, the importance of which is to obtain a real effective capillary radius, Reff, initially from the plot of Washburn penetration distance versus time. Since the cellulose sample could not be packed with good reproducibility, therefore, Reff can not be obtained readily from the slope of the plot. A method was developed in this paper by uniting all apparent packing heights with a unique value to deduce a real effective capillary radius. Based on the defined critical packing height related to the critical packing density, the surface free energy and acid-base properties of cellulose Sigma C8002 were estimated.展开更多
After a brief review of existing methods for fabric wetting and wicking measurement,a new numerical approach based on dynamic image acquisition and analysis was proposed to study the liquid wetting and wicking propert...After a brief review of existing methods for fabric wetting and wicking measurement,a new numerical approach based on dynamic image acquisition and analysis was proposed to study the liquid wetting and wicking properties of woven fabrics.A measuring system was first developed to record on-site the images of liquid ascending in fabrics for a certain period of time.The hardware and software platforms and the experimental methods were described,and the image processing and analysis as well as other related algorithms were discussed in detail.The liquid front curves and rising rates in wetting and wicking were eventually obtained towards different fabrics.From liquid wicking curves,relationship between liquid ascending height and liquid ascending time agrees well with the Washburn theory.The data comparison between the numerical measurement and the traditional test proves the reliability of the numerical results.展开更多
Plasma etching technology is used to treat Polypropylene fiber with different fineness. The result shows that the plasma etching treatment is useful to improve the wicking property of polypropylene, although too much ...Plasma etching technology is used to treat Polypropylene fiber with different fineness. The result shows that the plasma etching treatment is useful to improve the wicking property of polypropylene, although too much time of treatment may be converse to the wicking property. A surface roughness theory is applied to explain the reason why the plasma can improve the wicking property. In this experiment, fibers with different treating time under certain voltage(180 V) and pressure(0.1 mm Hg)are used as experimental sample.展开更多
An exponential model is proposed for the description of wicking, which is suitable for describing the whole process of wicking. Results are discussed and verified by the experimental data. Exponential model can be use...An exponential model is proposed for the description of wicking, which is suitable for describing the whole process of wicking. Results are discussed and verified by the experimental data. Exponential model can be used to predict the wicking process in longitudinal and planar textiles.展开更多
In this research, the wicking characteristics of fabrics were used as an essential and effective indicator to investigate the satisfaction of heat and moisture. Due to the popularization of silk fabrics recently it ha...In this research, the wicking characteristics of fabrics were used as an essential and effective indicator to investigate the satisfaction of heat and moisture. Due to the popularization of silk fabrics recently it has become an interesting topic to know about the wicking behavior of silk fabrics in water. The absorptive capability of the silk textile makes clothing comfortable even for a hotter environment. Silk fabrics are comfortable in the summer, and warm in the winter. Silk fabric can usually contain about 11 percent of its weight in moisture but the range varies from 10% to as much as 30%. In this paper, the wicking behavior of silk fabric in both warp and weft directions was investigated in terms of wicking height, wicking rate, mass increase distribution per centimeter of wicking height, the velocity of wicking height, and durability of wicking height after removal of the wicking liquid reservoir. The experimental results show that the wicking height in both the warp and weft directions had a good correlation with the time. The wicking rate was comparable in both weft and warp directions, but at the start of the wicking phase, weft direction wicking was quicker than warp direction. The mass increase in fabric per centimeter of wicking height was inversely proportional to wicking height. The mass of moisture carried in the fabric did not significantly differ in the direction of the weft and warp.展开更多
A stochastic approach based on a 3D 3-state Potts model combined with Monte Carlo simulation was used to study the equilibrium wicking height of liquids in vertical cylindrical capillaries. The Lifshitz-van der Waals ...A stochastic approach based on a 3D 3-state Potts model combined with Monte Carlo simulation was used to study the equilibrium wicking height of liquids in vertical cylindrical capillaries. The Lifshitz-van der Waals and Lewis acid-base theories were adopted to characterize the apolar and polar interactions in the spin system. The evolution of the spin system was driven by the difference in total energy for two successive states. To verify the model, equilibrium wicking height of water, formamide, heptane, and octane in capillaries of different radii were examined and the corresponding computer simulations were implemented. Good agreement was obtained between the simulation and experimental results. It shows the potential of the proposed approach to be applied in this area.展开更多
基金support from the Contract Research(“Development of Breathable Fabrics with Nano-Electrospun Membrane,”CityU ref.:9231419)the National Natural Science Foundation of China(“Study of Multi-Responsive Shape Memory Polyurethane Nanocomposites Inspired by Natural Fibers,”Grant No.51673162)+1 种基金Startup Grant of CityU(“Laboratory of Wearable Materials for Healthcare,”Grant No.9380116)National Natural Science Foundation of China,Grant No.52073241.
文摘Electronic skins can monitor minute physiological signal variations in the human skins and represent the body’s state,showing an emerging trend for alternative medical diagnostics and human-machine interfaces.In this study,we designed a bioinspired directional moisture-wicking electronic skin(DMWES)based on the construction of heterogeneous fibrous membranes and the conductive MXene/CNTs electrospraying layer.Unidirectional moisture transfer was successfully realized by surface energy gradient and push-pull effect via the design of distinct hydrophobic-hydrophilic difference,which can spontaneously absorb sweat from the skin.The DMWES membrane showed excellent comprehensive pressure sensing performance,high sensitivity(maximum sensitivity of 548.09 kPa^(−1)),wide linear range,rapid response and recovery time.In addition,the single-electrode triboelectric nanogenerator based on the DMWES can deliver a high areal power density of 21.6μW m^(−2) and good cycling stability in high pressure energy harvesting.Moreover,the superior pressure sensing and triboelectric performance enabled the DMWES for all-range healthcare sensing,including accurate pulse monitoring,voice recognition,and gait recognition.This work will help to boost the development of the next-generation breathable electronic skins in the applications of AI,human-machine interaction,and soft robots.
基金This work is financially supported by the Chinese Education Ministry and Donghua University of China (No. 2B01).
文摘The column wicking technique was applied to estimate the surface free energy of cellulose, the importance of which is to obtain a real effective capillary radius, Reff, initially from the plot of Washburn penetration distance versus time. Since the cellulose sample could not be packed with good reproducibility, therefore, Reff can not be obtained readily from the slope of the plot. A method was developed in this paper by uniting all apparent packing heights with a unique value to deduce a real effective capillary radius. Based on the defined critical packing height related to the critical packing density, the surface free energy and acid-base properties of cellulose Sigma C8002 were estimated.
基金the Research Funds for the Central Universities,China(No.1302-1)The Project Sponsored SRF for ROCS,SEM,China
文摘After a brief review of existing methods for fabric wetting and wicking measurement,a new numerical approach based on dynamic image acquisition and analysis was proposed to study the liquid wetting and wicking properties of woven fabrics.A measuring system was first developed to record on-site the images of liquid ascending in fabrics for a certain period of time.The hardware and software platforms and the experimental methods were described,and the image processing and analysis as well as other related algorithms were discussed in detail.The liquid front curves and rising rates in wetting and wicking were eventually obtained towards different fabrics.From liquid wicking curves,relationship between liquid ascending height and liquid ascending time agrees well with the Washburn theory.The data comparison between the numerical measurement and the traditional test proves the reliability of the numerical results.
文摘Plasma etching technology is used to treat Polypropylene fiber with different fineness. The result shows that the plasma etching treatment is useful to improve the wicking property of polypropylene, although too much time of treatment may be converse to the wicking property. A surface roughness theory is applied to explain the reason why the plasma can improve the wicking property. In this experiment, fibers with different treating time under certain voltage(180 V) and pressure(0.1 mm Hg)are used as experimental sample.
文摘An exponential model is proposed for the description of wicking, which is suitable for describing the whole process of wicking. Results are discussed and verified by the experimental data. Exponential model can be used to predict the wicking process in longitudinal and planar textiles.
文摘In this research, the wicking characteristics of fabrics were used as an essential and effective indicator to investigate the satisfaction of heat and moisture. Due to the popularization of silk fabrics recently it has become an interesting topic to know about the wicking behavior of silk fabrics in water. The absorptive capability of the silk textile makes clothing comfortable even for a hotter environment. Silk fabrics are comfortable in the summer, and warm in the winter. Silk fabric can usually contain about 11 percent of its weight in moisture but the range varies from 10% to as much as 30%. In this paper, the wicking behavior of silk fabric in both warp and weft directions was investigated in terms of wicking height, wicking rate, mass increase distribution per centimeter of wicking height, the velocity of wicking height, and durability of wicking height after removal of the wicking liquid reservoir. The experimental results show that the wicking height in both the warp and weft directions had a good correlation with the time. The wicking rate was comparable in both weft and warp directions, but at the start of the wicking phase, weft direction wicking was quicker than warp direction. The mass increase in fabric per centimeter of wicking height was inversely proportional to wicking height. The mass of moisture carried in the fabric did not significantly differ in the direction of the weft and warp.
基金Science Foundation of Zhejiang Sci-Tech University(ZSTU),China(No.0901804-Y)
文摘A stochastic approach based on a 3D 3-state Potts model combined with Monte Carlo simulation was used to study the equilibrium wicking height of liquids in vertical cylindrical capillaries. The Lifshitz-van der Waals and Lewis acid-base theories were adopted to characterize the apolar and polar interactions in the spin system. The evolution of the spin system was driven by the difference in total energy for two successive states. To verify the model, equilibrium wicking height of water, formamide, heptane, and octane in capillaries of different radii were examined and the corresponding computer simulations were implemented. Good agreement was obtained between the simulation and experimental results. It shows the potential of the proposed approach to be applied in this area.
