Low friction ice sliding interfaces were critical for ski performance optimization.Traditional fluorinated ski waxes have attracted considerable attention for enhancing the hydrophobicity,anti-wearing,and oxidation re...Low friction ice sliding interfaces were critical for ski performance optimization.Traditional fluorinated ski waxes have attracted considerable attention for enhancing the hydrophobicity,anti-wearing,and oxidation resistance of ski–ice base.However,the toxicity and complexity of the waxing process limited batch manufacturing of low-cost and non-toxic ski–ice base,what is more,the wax covering on the base wore and failed during skiing due to the friction between ski and ice.Herein,we demonstrated a novel ultra-high molecular weight polyethylene(UHMWPE)composite that could maintain a low coefficient of friction(COF)with about 0.026 for at least 160 min when skiing on the ice.Microcapsule(MS)could release liquid(liquid paraffin(LP)).The released LP further enhanced the hydrophobicity of UHMWPE’s surfaces when friction occurred,which would maintain the stability and durability of the water film,and achieved superior and long-lasting friction resistance.Compared with other microcapsules with lower hydrophobic core,microcapsules with LP performed the best in reducing the friction of ski base from 0.126 to 0.024.Meanwhile,the COF of the surface kept at about 0.02 even after 12 rapid temperature changes.The presented UHMWPE composite of encapsulated liquids showed great potential and broad application owing to its simplicity and efficiency in winter sports.展开更多
Electromagnetic interference shielding and thermal management by wearable devices show great po-tential in emerging digital healthcare.Conventional metal films implementing the functions must sacri-fice either flexibi...Electromagnetic interference shielding and thermal management by wearable devices show great po-tential in emerging digital healthcare.Conventional metal films implementing the functions must sacri-fice either flexibility or permeability,which is far from optimal in practical applications.In this work,an ultra-thin(15μm),flexible,and porous Cu/PLLA fibrous membrane is developed by depositing cop-per particles on the polymer substrate.With novel acetone&heat treatment procedure,the mem-brane is considerably stronger while maintaining the porous fibre structure.Its fantastic breathabil-ity and super high electrical conductivity(9471.8130 S/cm)enable the composites to have fast electri-cal heating characteristics and excellent thermal conductivity for effective thermal management.Mean-while,the porous polymer substrate structure greatly enhances the diffusion of conductive substances and increases the electromagnetic interference shielding effectiveness of the membranes(7797.98 dB cm^(2)/g at the H band and 8072.73 dB cm^(2)/g at the Ku band respectively).The composites present high flexibility,breathability,and strength with the functions of thermal management and electromag-netic shielding,showing great potential for future portable electronic devices and wearable integrated garments.展开更多
基金funded by the National Key R&D Program of China(Nos.2020YFF0304600 and 2019YFF0302100)the National Natural Science Foundation of China(No.52275200).
文摘Low friction ice sliding interfaces were critical for ski performance optimization.Traditional fluorinated ski waxes have attracted considerable attention for enhancing the hydrophobicity,anti-wearing,and oxidation resistance of ski–ice base.However,the toxicity and complexity of the waxing process limited batch manufacturing of low-cost and non-toxic ski–ice base,what is more,the wax covering on the base wore and failed during skiing due to the friction between ski and ice.Herein,we demonstrated a novel ultra-high molecular weight polyethylene(UHMWPE)composite that could maintain a low coefficient of friction(COF)with about 0.026 for at least 160 min when skiing on the ice.Microcapsule(MS)could release liquid(liquid paraffin(LP)).The released LP further enhanced the hydrophobicity of UHMWPE’s surfaces when friction occurred,which would maintain the stability and durability of the water film,and achieved superior and long-lasting friction resistance.Compared with other microcapsules with lower hydrophobic core,microcapsules with LP performed the best in reducing the friction of ski base from 0.126 to 0.024.Meanwhile,the COF of the surface kept at about 0.02 even after 12 rapid temperature changes.The presented UHMWPE composite of encapsulated liquids showed great potential and broad application owing to its simplicity and efficiency in winter sports.
基金We acknowledge the support of the Electron Microscopy Centre at The University of Manchester.
文摘Electromagnetic interference shielding and thermal management by wearable devices show great po-tential in emerging digital healthcare.Conventional metal films implementing the functions must sacri-fice either flexibility or permeability,which is far from optimal in practical applications.In this work,an ultra-thin(15μm),flexible,and porous Cu/PLLA fibrous membrane is developed by depositing cop-per particles on the polymer substrate.With novel acetone&heat treatment procedure,the mem-brane is considerably stronger while maintaining the porous fibre structure.Its fantastic breathabil-ity and super high electrical conductivity(9471.8130 S/cm)enable the composites to have fast electri-cal heating characteristics and excellent thermal conductivity for effective thermal management.Mean-while,the porous polymer substrate structure greatly enhances the diffusion of conductive substances and increases the electromagnetic interference shielding effectiveness of the membranes(7797.98 dB cm^(2)/g at the H band and 8072.73 dB cm^(2)/g at the Ku band respectively).The composites present high flexibility,breathability,and strength with the functions of thermal management and electromag-netic shielding,showing great potential for future portable electronic devices and wearable integrated garments.
