Poly（vinylidene fluoride） （PVDF） has become one of the most popular materials for membrane preparation via nonsolvent induced phase separation （NIPS） process. In this study, an amphiphilic block copolymer, Pluro...Poly（vinylidene fluoride） （PVDF） has become one of the most popular materials for membrane preparation via nonsolvent induced phase separation （NIPS） process. In this study, an amphiphilic block copolymer, Pluronic F127, has been used as both a pore-former and a surface-modifier in the fabrication of PVDF hollow fibermembranes to enhance the membrane permeability and hydrophilicity. The effects of 2nd additive and coagulant temperature on the formation of PVDF/Pluronic F 127 membranes have also been investigated. The as-spun hollow fibers were characterized in terms of cross-sectional morphology, pure water permeation （PWP）, relative molecular mass cut-off （MWCO）, membrane chemistry, and hydrolphilicity. It was obsered that the addition of Pluronic F 127 significantly increased the PWP of as-spun fibers, while the membrane contact angle was reduced. However, the size of macrovoids in the membranes was undesirably large. The addition of a 2nd additive, including lithium chloride （LiC1） and water, or an increase in coagulant temperature was found to effectively suppress the macrovoid for- mation in the Pluronic-containing membranes. In addition, the use of LiC1 as a 2nd additive also further enhanced the PWP and hydrophilicity of the membranes, while the surface pore size became smaller. PVDF hollow fiber with a PWP as high as 2330 L·m-2·h-1·MPa-1, a MWCO of 53000 and＇a contact angle of 71 o was successfully fabricated with 3% （by mass） of Pluronic F127 and 3% （by mass） of LiC1 at a coagulant temperature of 25 ℃, which shows better performance as compared with most of PVDF hollow fiber membranes made by NIPS method.展开更多
Controllable fabrication of mesoporous carbon nanoparticles(MCNs)with tunable pore structures is of great interest,due to the remarkable effect of pore structure on electrochemical performance of the materials.However...Controllable fabrication of mesoporous carbon nanoparticles(MCNs)with tunable pore structures is of great interest,due to the remarkable effect of pore structure on electrochemical performance of the materials.However,it has remained a major challenge.Here,we demonstrate the controlled synthesis of MCNs with tunable closed pore structures via a silica-assisted coassembly strategy,which employs polystyrene-block-poly(ethylene oxide)diblock copolymers as soft template,phenolic resol and tetraethyl orthosilicate as carbon and silica precursors,respectively.Through simply varying the sequential cross-linking of the silica and carbon precursors or the copolymer composition,novel MCNs with alluring spherical,hollow-hoop-structured,or yolk-shell-like closed mesopores are tunably prepared.In particular,serving as cathode materials of lithium-sulfur batteries,the resultant silica-hybridized MCNs with the exceptional hollow-hoop mesopores and a moderate sulfur-loading content of 46 wt%exhibit top-level electrochemical performance.This study opens an avenue for tunable construction of mesoporous particles with closed pores and provides clues for the effect of pore geometry on the electrochemical performance of porous cathode materials for lithium-sulfur batteries.展开更多
Based on block copolymer assisted topochemical polymerization,a new strategy for facilely producing robust nanoporous membranes with controlled incorporation of functional groups onto nanopores is developed.As exempli...Based on block copolymer assisted topochemical polymerization,a new strategy for facilely producing robust nanoporous membranes with controlled incorporation of functional groups onto nanopores is developed.As exemplified by preparing nanoporous polypyrrole decorated with amino acids,this strategy exhibits a high degree of freedom for tailoring the surface functionality in the created pores.展开更多
文摘Poly（vinylidene fluoride） （PVDF） has become one of the most popular materials for membrane preparation via nonsolvent induced phase separation （NIPS） process. In this study, an amphiphilic block copolymer, Pluronic F127, has been used as both a pore-former and a surface-modifier in the fabrication of PVDF hollow fibermembranes to enhance the membrane permeability and hydrophilicity. The effects of 2nd additive and coagulant temperature on the formation of PVDF/Pluronic F 127 membranes have also been investigated. The as-spun hollow fibers were characterized in terms of cross-sectional morphology, pure water permeation （PWP）, relative molecular mass cut-off （MWCO）, membrane chemistry, and hydrolphilicity. It was obsered that the addition of Pluronic F 127 significantly increased the PWP of as-spun fibers, while the membrane contact angle was reduced. However, the size of macrovoids in the membranes was undesirably large. The addition of a 2nd additive, including lithium chloride （LiC1） and water, or an increase in coagulant temperature was found to effectively suppress the macrovoid for- mation in the Pluronic-containing membranes. In addition, the use of LiC1 as a 2nd additive also further enhanced the PWP and hydrophilicity of the membranes, while the surface pore size became smaller. PVDF hollow fiber with a PWP as high as 2330 L·m-2·h-1·MPa-1, a MWCO of 53000 and＇a contact angle of 71 o was successfully fabricated with 3% （by mass） of Pluronic F127 and 3% （by mass） of LiC1 at a coagulant temperature of 25 ℃, which shows better performance as compared with most of PVDF hollow fiber membranes made by NIPS method.
基金This work was supported by the National Natural Science Foundation of China(nos.21774076,61774102,and 51573091)the National Key Research and Development Program of China(no.2017YFE0195800)+2 种基金the Program of the Shanghai Committee of Science and Technology(no.17JC1403200)the Program of Shanghai Academic Research Leader(no.19XD1421700)the Program of Shanghai Eastern Scholar.
文摘Controllable fabrication of mesoporous carbon nanoparticles(MCNs)with tunable pore structures is of great interest,due to the remarkable effect of pore structure on electrochemical performance of the materials.However,it has remained a major challenge.Here,we demonstrate the controlled synthesis of MCNs with tunable closed pore structures via a silica-assisted coassembly strategy,which employs polystyrene-block-poly(ethylene oxide)diblock copolymers as soft template,phenolic resol and tetraethyl orthosilicate as carbon and silica precursors,respectively.Through simply varying the sequential cross-linking of the silica and carbon precursors or the copolymer composition,novel MCNs with alluring spherical,hollow-hoop-structured,or yolk-shell-like closed mesopores are tunably prepared.In particular,serving as cathode materials of lithium-sulfur batteries,the resultant silica-hybridized MCNs with the exceptional hollow-hoop mesopores and a moderate sulfur-loading content of 46 wt%exhibit top-level electrochemical performance.This study opens an avenue for tunable construction of mesoporous particles with closed pores and provides clues for the effect of pore geometry on the electrochemical performance of porous cathode materials for lithium-sulfur batteries.
基金financial support from the Ministry of Science and Technology of the People's Republic of China(MOST,Nos.2017YFA0204501,2013CB834502)National Natural Science Foundation of China(NSFC,Nos.21773135,21473098 and 21421064)。
文摘Based on block copolymer assisted topochemical polymerization,a new strategy for facilely producing robust nanoporous membranes with controlled incorporation of functional groups onto nanopores is developed.As exemplified by preparing nanoporous polypyrrole decorated with amino acids,this strategy exhibits a high degree of freedom for tailoring the surface functionality in the created pores.
