The use of linear amphiphilic block copolymers as templates is an important method for the preparation of mesoporous materials.However,the obtained assemblies are usually sensitive to synthetic conditions,which impede...The use of linear amphiphilic block copolymers as templates is an important method for the preparation of mesoporous materials.However,the obtained assemblies are usually sensitive to synthetic conditions,which impedes the preparation of such mesoporous materials in certain environments.Herein,we report a universal strategy applying an amphiphilic multiarm triblock copolymer in the preparation of mesoporous metal oxide nanofibers(NFs)using one metal oxide(TiO_(2),ZrO_(2),WO_(3),CeO_(2)),or two(TiO_(2)/WO 3,TiO_(2)/ZrO_(2),TiO_(2)/CeO_(2))and three(TiO_(2)/WO_(3)/CuO)metal oxides as composites.The template consists of modified β-cyclodextrin as the center of the macromolecule which is attached sequentially to a block of polystyrene,poly(acrylic acid),and poly(ethylene oxide).Under electrospinning conditions,stable unimolecular micelles are formed and effectively co-assemble with metal ions to form fibrous nanostructures.As indicated by various characterization methods,the synthesized TiO_(2) and its derived composite NFs maintain a straight and continuous fibrous structure after calcination,and TiO_(2) NFs exhibit uniform mesopores of 10.8 nm in diameter and a large Brunauer-Emmett-Teller surface area of 143.3 m^(2)g^(−1).Benefiting from the characteristic structure,still present after modification,Pt-decorated mesoporous TiO_(2) NFs display excellent ability in the visible-light photocatalytic degradation of tetracycline,which is superior to the commercial P25 catalyst.This study reveals a promising strategy for the preparation of fibrous mesoporous metal oxides.展开更多
Developing“green”catalytic systems with desirable performance such as good water solubility,recyclability,and switchability is a great challenge.Here,to address this challenge,we extend the concept of polymeric unim...Developing“green”catalytic systems with desirable performance such as good water solubility,recyclability,and switchability is a great challenge.Here,to address this challenge,we extend the concept of polymeric unimolecular micelles(a typical selfassembled structure)to the construction of a stimuli-responsive and recoverable molecular catalyst with single-metal atoms that exhibits switchable photocatalytic activity for water splitting.展开更多
A novel tetrafunctional initiator, C [CH_2O (CH_2)_3 OOCCH(Br)CH_3]_4 (1), was synthesized through the reaction oftetraol with α-bromopropionyl chloride, and then was used as initiator of atom transfer radical polyme...A novel tetrafunctional initiator, C [CH_2O (CH_2)_3 OOCCH(Br)CH_3]_4 (1), was synthesized through the reaction oftetraol with α-bromopropionyl chloride, and then was used as initiator of atom transfer radical polymerization (ATRP) in thepreparation of 4-armed polystyrene (PSt) with narrow polydispersity. The structure, molecular weight and molecular weightdistribution (MWD) of each arm were studied by ~1H-NMR and GPC data of hydrolyzed products of the 4-armed PSt. TheATRP of St using 1/CuBr/bpy as initiator system is of 'living' character based on the following evidence: narrow MWD,constant concentration of chain radical during the polymerization, control of molecular weight by the molar ratio of monomerconsumed to 1. The 4-armed poly(St-b-p-nitrophenyl methacrylate) [poly(St-b-NPMA)] was prepared by the ATRP ofNPMA using 4-armed PSt with terminal bromine as the initiator, and characterized by FT-IR, ~1H-NMR spectra and GPCcurves. The micelles with PSt as core, and PNPMA as shell were formed by dropping DMSO into a solution of 4-armedpoly(St-b-NPMA) in DMF, as proved by laser light scatter (LLS) method.展开更多
The self-assembling behavior of random copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate (AMPS)and hydrophobic comonomers possessing dodecyl groups linked by various spacer bonds was discussed with a focus ...The self-assembling behavior of random copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate (AMPS)and hydrophobic comonomers possessing dodecyl groups linked by various spacer bonds was discussed with a focus on theeffect of the spacer. The characterization of association behavior of such polymers in water using quasielastic light scattering,capillary electrophoresis, NMR relaxation, various fluorescence, and viscoelastic methods was described. These copolymersform a variety of self-assembled nanostructures depending on the type of the spacer. Random copolymers of AMPS and N-dodecylmethacrylamide show a strong preference for intrapolymer self-association even in concentrated aqueous solutionsforming single-macromolecular self-assemblies (unimolecular micelles). In contrast, random copolymers of AMPS anddodecyl methacrylate are prone to undergo interpolymer associations yielding multipolymer micelles. In random copolymersof AMPS and a methacrylate substituted a nonionic surfactant (HO(CH_2CH_2O)_(25)C_(12)H_(25)) (C_(12)E_(25)), dodecyl groups are muchless restricted by the polymer backbone because they are linked via a long, flexible hydrophilic spacer. Thus, the polymer-bound C_(12)E_(25) surfactant moieties form micelles similar to those formed by discrete surfactants, but they are bridged bypolymer chains forming a network structure.展开更多
Polymer systems can be designed into different structures and morphologies according to their physical and chemical performance requirements,and are considered as one of the most promising controlled delivery systems ...Polymer systems can be designed into different structures and morphologies according to their physical and chemical performance requirements,and are considered as one of the most promising controlled delivery systems that can effectively improve the cancer therapeutic index.However,the majority of the polymer delivery systems are designed to be simple spherical nanostructures.To explore morphology/size-oriented delivery performance optimization,here,we synthesized three novel cylindrical polymer brushes(CPBs)by atom transfer radical polymerization(ATRP),which were cellulose-g-(CPT-b-OEGMA)(CCO)with different lengths(~86,~40,and~21 nm).The CPBs are composed of bio-degradable cellulose as the carrier,poly(ethylene glycol)methyl ether methacrylate(OEGMA)as hydrophily block,and glutathione(GSH)-responsive hydrophobic camptothecin(CPT)monomer as loaded anticancer drug.By controlling the chain length of the initiator,three kinds of polymeric prodrugs with different lengths(CCO-1,CCO-2,and CCO-3)could be self-organized into unimolecular micelles in water.We carried out comparative studies of three polymers,whose results verified that the shorter CPBs exhibited higher drug release efficiency,more cellular uptake,and enhanced tumor permeability,accompanied by shortened blood circulation time and lower tumor accumulation.As evidenced by in vivo experiments,the shorter CPBs exhibited higher anti-tumor efficiency,revealing that the size advantage has a higher priority than the anisotropic structure advantage.This provided vital information as to design an anisotropic polymer-based drug delivery system for cancer therapy.展开更多
基金funded by the National Natural Science Foundation of China(Grants No.51822202,52173233 and 51772050)Innovation Program of Shanghai Municipal Education Commission(Grant No.2021-01-07-00-03-E00109)+8 种基金Science and Technology Commission of Shanghai Municipality(Grant No.19520713200)Shanghai Scientific and Technological Innovation Project(Grant No.19JC1410400)“Shuguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(Grant No.20SG33)Key Basic Research Program of Science and Technology Com-mission of Shanghai Municipality(Grant No.20JC1415300)DHU Distinguished Young Professor Program and Fundamental Research Funds for the Central Universitiesthe Fundamental Research Funds for the Central Universities(Grant No.2232020D-02)Shanghai Sailing program(Grant No.20YF1400500)Shanghai Natural Science Foundation(Grant No.20ZR1401500)the Opening Project of Key Laboratory of Inorganic Functional Materials and Devices,Chinese Academy of Sciences(KLIFMD202104).
文摘The use of linear amphiphilic block copolymers as templates is an important method for the preparation of mesoporous materials.However,the obtained assemblies are usually sensitive to synthetic conditions,which impedes the preparation of such mesoporous materials in certain environments.Herein,we report a universal strategy applying an amphiphilic multiarm triblock copolymer in the preparation of mesoporous metal oxide nanofibers(NFs)using one metal oxide(TiO_(2),ZrO_(2),WO_(3),CeO_(2)),or two(TiO_(2)/WO 3,TiO_(2)/ZrO_(2),TiO_(2)/CeO_(2))and three(TiO_(2)/WO_(3)/CuO)metal oxides as composites.The template consists of modified β-cyclodextrin as the center of the macromolecule which is attached sequentially to a block of polystyrene,poly(acrylic acid),and poly(ethylene oxide).Under electrospinning conditions,stable unimolecular micelles are formed and effectively co-assemble with metal ions to form fibrous nanostructures.As indicated by various characterization methods,the synthesized TiO_(2) and its derived composite NFs maintain a straight and continuous fibrous structure after calcination,and TiO_(2) NFs exhibit uniform mesopores of 10.8 nm in diameter and a large Brunauer-Emmett-Teller surface area of 143.3 m^(2)g^(−1).Benefiting from the characteristic structure,still present after modification,Pt-decorated mesoporous TiO_(2) NFs display excellent ability in the visible-light photocatalytic degradation of tetracycline,which is superior to the commercial P25 catalyst.This study reveals a promising strategy for the preparation of fibrous mesoporous metal oxides.
基金supported by the National Natural Science Foundation of China(21774076,21890730,21890733,and 51773115)the Program for Basic Research of Shanghai Science and Technology Commission(17JC1403200,19JC1410400,and 19JC1410404)+1 种基金the Program of Shanghai Academic Research Leader(19XD1421700)the Shanghai Eastern Scholar Program.The authors appreciate Shanghai Synchrotron Radiation Facility(SSRF)(Beamline BL14W1 and BL11B)for the synchrotron beam time.
文摘Developing“green”catalytic systems with desirable performance such as good water solubility,recyclability,and switchability is a great challenge.Here,to address this challenge,we extend the concept of polymeric unimolecular micelles(a typical selfassembled structure)to the construction of a stimuli-responsive and recoverable molecular catalyst with single-metal atoms that exhibits switchable photocatalytic activity for water splitting.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29774027).
文摘A novel tetrafunctional initiator, C [CH_2O (CH_2)_3 OOCCH(Br)CH_3]_4 (1), was synthesized through the reaction oftetraol with α-bromopropionyl chloride, and then was used as initiator of atom transfer radical polymerization (ATRP) in thepreparation of 4-armed polystyrene (PSt) with narrow polydispersity. The structure, molecular weight and molecular weightdistribution (MWD) of each arm were studied by ~1H-NMR and GPC data of hydrolyzed products of the 4-armed PSt. TheATRP of St using 1/CuBr/bpy as initiator system is of 'living' character based on the following evidence: narrow MWD,constant concentration of chain radical during the polymerization, control of molecular weight by the molar ratio of monomerconsumed to 1. The 4-armed poly(St-b-p-nitrophenyl methacrylate) [poly(St-b-NPMA)] was prepared by the ATRP ofNPMA using 4-armed PSt with terminal bromine as the initiator, and characterized by FT-IR, ~1H-NMR spectra and GPCcurves. The micelles with PSt as core, and PNPMA as shell were formed by dropping DMSO into a solution of 4-armedpoly(St-b-NPMA) in DMF, as proved by laser light scatter (LLS) method.
文摘The self-assembling behavior of random copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate (AMPS)and hydrophobic comonomers possessing dodecyl groups linked by various spacer bonds was discussed with a focus on theeffect of the spacer. The characterization of association behavior of such polymers in water using quasielastic light scattering,capillary electrophoresis, NMR relaxation, various fluorescence, and viscoelastic methods was described. These copolymersform a variety of self-assembled nanostructures depending on the type of the spacer. Random copolymers of AMPS and N-dodecylmethacrylamide show a strong preference for intrapolymer self-association even in concentrated aqueous solutionsforming single-macromolecular self-assemblies (unimolecular micelles). In contrast, random copolymers of AMPS anddodecyl methacrylate are prone to undergo interpolymer associations yielding multipolymer micelles. In random copolymersof AMPS and a methacrylate substituted a nonionic surfactant (HO(CH_2CH_2O)_(25)C_(12)H_(25)) (C_(12)E_(25)), dodecyl groups are muchless restricted by the polymer backbone because they are linked via a long, flexible hydrophilic spacer. Thus, the polymer-bound C_(12)E_(25) surfactant moieties form micelles similar to those formed by discrete surfactants, but they are bridged bypolymer chains forming a network structure.
基金This work was financially supported by National Natural Science Foundation of China(51703187,31671037)the Basic and Frontier Research Project of Chongqing(cstc2018jcyjAX0104).
文摘Polymer systems can be designed into different structures and morphologies according to their physical and chemical performance requirements,and are considered as one of the most promising controlled delivery systems that can effectively improve the cancer therapeutic index.However,the majority of the polymer delivery systems are designed to be simple spherical nanostructures.To explore morphology/size-oriented delivery performance optimization,here,we synthesized three novel cylindrical polymer brushes(CPBs)by atom transfer radical polymerization(ATRP),which were cellulose-g-(CPT-b-OEGMA)(CCO)with different lengths(~86,~40,and~21 nm).The CPBs are composed of bio-degradable cellulose as the carrier,poly(ethylene glycol)methyl ether methacrylate(OEGMA)as hydrophily block,and glutathione(GSH)-responsive hydrophobic camptothecin(CPT)monomer as loaded anticancer drug.By controlling the chain length of the initiator,three kinds of polymeric prodrugs with different lengths(CCO-1,CCO-2,and CCO-3)could be self-organized into unimolecular micelles in water.We carried out comparative studies of three polymers,whose results verified that the shorter CPBs exhibited higher drug release efficiency,more cellular uptake,and enhanced tumor permeability,accompanied by shortened blood circulation time and lower tumor accumulation.As evidenced by in vivo experiments,the shorter CPBs exhibited higher anti-tumor efficiency,revealing that the size advantage has a higher priority than the anisotropic structure advantage.This provided vital information as to design an anisotropic polymer-based drug delivery system for cancer therapy.