Aggregation-induced emission(AIE)is a unique phenomenon whereby aggregation of molecules induces fluorescence emission as opposed to the more commonly known aggregation-caused quenching(ACQ).AIE has the potential to b...Aggregation-induced emission(AIE)is a unique phenomenon whereby aggregation of molecules induces fluorescence emission as opposed to the more commonly known aggregation-caused quenching(ACQ).AIE has the potential to be utilized in the large-scale production of AIE-active polymeric materials because of their wide range of practical applications such as stimuli-responsive sensors,biological imaging agents,and drug delivery systems.This is evident from the increasing number of publications over the years since AIE was first discovered.In addition,the evergrowing interest in this field has led many researchers around the world to develop new and creative methods in the design of monomers,initiators and crosslinkers,with the goal of broadening the scope and utility of AIE polymers.One of the most promising approaches to the design and synthesis of AIE polymers is the use of the reversible-deactivation radical polymerization(RDRP)techniques,which enabled the production of well-controlled AIE materials that are often difficult to achieve by other methods.In this review,a summary of some recent works that utilize RDRP for AIE polymer design and synthesis is presented,including(i)the design of AIE-related monomers,initiators/crosslinkers;the achievements in preparation of AIE polymers using(ii)reversible addition–fragmentation chain transfer(RAFT)technique;(iii)atom transfer radical polymerization(ATRP)technique;(iv)other techniques such as Cu(0)-RDRP technique and nitroxide-mediated polymerization(NMP)technique;(v)the possible applications of these AIE polymers,and finally(vi)a summary/perspective and the future direction of AIE polymers.展开更多
Reversible addition-fragmentation chain transfer(RAFT)-mediated polymerization-induced self-assembly(PISA)of star block copolymer and linear block copolymer using a binary mixture of a star-like macro-RAFT agent and a...Reversible addition-fragmentation chain transfer(RAFT)-mediated polymerization-induced self-assembly(PISA)of star block copolymer and linear block copolymer using a binary mixture of a star-like macro-RAFT agent and a linear macro-RAFT agent is reported.With this formulation,star block copolymer and diblock copolymer were formed simultaneously to generate colloidally stable star/linear block copolymer assemblies.Size exclusion chromatography(SEC)analysis confirmed the presence of two types of polymers in the final samples.The molar ratio of the star-like macro-RAFT agent and the linear macro-RAFT agent has a significant impact on the morphology of polymer assemblies.It was found that increasing the amount of star-like macro-RAFT agent facilitated the formation of higher-order morphologies.Additionally,effects of other reaction parameters including the length/number of the arm of the star-like macro-RAFT agent,degree of polymer(DP),monomer concentration on the morphology of star/linear block copolymer assemblies were also investigated.We expect that this work will offer new possibilities for the scalable preparation of polymer assemblies with unique structures and functions.展开更多
Polymerization-induced self-assembly(PISA)is an emerging method for the preparation of block copolymer nano-objects at high concentrations.However,most PISA formulations have oxygen inhibition problems and inert atmos...Polymerization-induced self-assembly(PISA)is an emerging method for the preparation of block copolymer nano-objects at high concentrations.However,most PISA formulations have oxygen inhibition problems and inert atmospheres(e.g.argon,nitrogen)are usually required.Moreover,the large-scale preparation of block copolymer nano-objects at room temperature is challenging.Herein,we report an enzyme-assisted photoinitiated polymerization-induced self-assembly(photo-PISA)in continuous flow reactors with oxygen toleranee.The addition of glucose oxidase(GOx)and glucose into the reaction mixture can consume oxygen efficiently and constantly,allow the flow photo-PISA to be performed under open-air conditions.Polymerization kinetics indicated that only a small amount of GOx(0.5 μmol/L)was needed to achieve the oxygen tolerance.Block copolymer nano-objects with different morphologies can be prepared by varying reaction conditions including the degree of polymerization(DP)of core-forming block,monomer concentration,reaction temperature,and solvent composition.We expect this study will provide a facile platform for the large-scale production of block copolymer nano-objects with different morphologies at room temperature.展开更多
Usually,the aniline-based late-transition-metal catalysts often require bulky steric substituents on both sides of the ortho-aryl position to achieve efficient suppression of chain transfer in ethylene polymerization....Usually,the aniline-based late-transition-metal catalysts often require bulky steric substituents on both sides of the ortho-aryl position to achieve efficient suppression of chain transfer in ethylene polymerization.In this contribution,we demonstrated thatα-diimine catalysts based on naphthylamine with only one bulky ortho-aryl substituent also demonstrated excellent capabilities to suppress the chain transfer.Firstly,a class ofα-diimine nickel and palladium complexes with only one o-aryl-dibenzhydryl or o-aryl-dibenzosuberyl substituent were synthesized and characterized.Secondly,the as-prepared naphthylamine-based nickel catalysts demonstrated outstanding activities(up to 13.02×106 g·mol–1·h–1)and yielded lightly branched(16-40/1000C)polyethylenes with very high molecular weights(445.8-854.3 kg/mol)in ethylene polymerization.In comparison,the corresponding palladium catalysts showed moderate activities(level of 104-105 g·mol–1·h–1),generating moderately branched(47-78/1000C)polyethylenes with moderate molecular weights(21.6-82.0 kg/mol).Moreover,the palladium catalysts could also copolymerize ethylene and methyl acrylate(MA),albeit in low activities(level of 103 g·mol–1·h–1),providing E-MA copolymers with low to moderate molecular weights(1.4-16.3 kg/mol)and a moderate level of incorporation ratio(2.4-7.4 mol%)and branching density(53-84/1000C).As compared with aniline-based nickel and palladium catalysts,the naphthylamine-based catalysts displayed a superior ability to suppress the chain transfer reactions and could give access to(co)polymers with orders of magnitude higher molecular weight in ethylene(co)polymerization.展开更多
Suppressing the chain transfer reactions during polymerization in late-transition metal-catalyzed olefin polymerization systems is the key to obtaining high molecular weight polyolefin materials. In this work, two eff...Suppressing the chain transfer reactions during polymerization in late-transition metal-catalyzed olefin polymerization systems is the key to obtaining high molecular weight polyolefin materials. In this work, two efficient strategies(“sandwich” and rotation-restricted strategies)to retard chain transfer reactions in ethylene(co)polymerization were employed for the iminopyridyl system. Herein, a family of iminopyridyl Ni(Ⅱ)and Pd(Ⅱ) complexes with a flexible backbone and rigid axial bulky aryl substituents were designed, synthesized and characterized. In ethylene polymerization, the iminopyridyl Ni(Ⅱ) and Pd(Ⅱ) catalysts using the two strategies exhibited reasonable activities and generated highly branched polyethylenes with high molecular weights, where catalysts with dibenzosuberyl substituents exhibited significantly higher activities and produced higher molecular weight polyethylene than catalysts with 8-arylnaphthalenyl substituent. A similar trend of activities and molecular weights was also found in the copolymerization of ethylene with MA using the Pd(Ⅱ) catalysts. Moreover, highly branched E-MA copolymers with moderate to high molecular weights and high incorporation ratios(up to 17.4 mol%) were generated with the two Pd(Ⅱ) catalysts. Most interestingly, as compared with the dibenzhydryl Ni(Ⅱ) and Pd(Ⅱ) catalysts, the catalysts using the two strategies exhibited a superior ability to retard the chain transfer reactions and generated polymers and copolymers with 1-2 orders of magnitude higher molecular weights during ethylene(co)polymerization.展开更多
Through neodymium-mediated coordinative chain transfer copolymerizaiton(CCTcoP),polyisoprenes bearing dual hydroxylated mini-blocky chain-ends were prepared via a three-step strategy.Kinetic studies revealed that,the ...Through neodymium-mediated coordinative chain transfer copolymerizaiton(CCTcoP),polyisoprenes bearing dual hydroxylated mini-blocky chain-ends were prepared via a three-step strategy.Kinetic studies revealed that,the polymerization demonstrated typical features of CCTcoP across the whole polymerization process,i.e.,quasi-living polymerization characteristic,tunable molecular weights,narrow molecular weight distributions,and atom economies.Comparing to previously reported CCTP homopolymerization systems,the presence of oxygen-containing IpOAl polar comonomer slowed down chain transfer rates obviously,rendering slightly higher molecular weights of the resultant PIps and smaller Np(number of polymer chains per Nd atom)values.Moreover,to mimic the structure of natural rubber,the hydroxyl end groups can be facilely modified into phosphonate,amide,and UPy,whose structures were further confirmed by NMR spectra.Incorporation these functionalities could greatly improve the hydrophilic properties of the polymers,as revealed from the significantly reduced static water contact angles.展开更多
基金Australian Research Council,Grant/Award Number:CE200100009。
文摘Aggregation-induced emission(AIE)is a unique phenomenon whereby aggregation of molecules induces fluorescence emission as opposed to the more commonly known aggregation-caused quenching(ACQ).AIE has the potential to be utilized in the large-scale production of AIE-active polymeric materials because of their wide range of practical applications such as stimuli-responsive sensors,biological imaging agents,and drug delivery systems.This is evident from the increasing number of publications over the years since AIE was first discovered.In addition,the evergrowing interest in this field has led many researchers around the world to develop new and creative methods in the design of monomers,initiators and crosslinkers,with the goal of broadening the scope and utility of AIE polymers.One of the most promising approaches to the design and synthesis of AIE polymers is the use of the reversible-deactivation radical polymerization(RDRP)techniques,which enabled the production of well-controlled AIE materials that are often difficult to achieve by other methods.In this review,a summary of some recent works that utilize RDRP for AIE polymer design and synthesis is presented,including(i)the design of AIE-related monomers,initiators/crosslinkers;the achievements in preparation of AIE polymers using(ii)reversible addition–fragmentation chain transfer(RAFT)technique;(iii)atom transfer radical polymerization(ATRP)technique;(iv)other techniques such as Cu(0)-RDRP technique and nitroxide-mediated polymerization(NMP)technique;(v)the possible applications of these AIE polymers,and finally(vi)a summary/perspective and the future direction of AIE polymers.
基金the National Natural Science Foundation of China(Grant 22171055,52222301,and 21971047)the Guangdong Natural Science Foundation for Distinguished Young Scholar(Grant 2022B1515020078)the Science and Technology Program of Guangzhou(Grant SL2023A04J00142).
文摘Reversible addition-fragmentation chain transfer(RAFT)-mediated polymerization-induced self-assembly(PISA)of star block copolymer and linear block copolymer using a binary mixture of a star-like macro-RAFT agent and a linear macro-RAFT agent is reported.With this formulation,star block copolymer and diblock copolymer were formed simultaneously to generate colloidally stable star/linear block copolymer assemblies.Size exclusion chromatography(SEC)analysis confirmed the presence of two types of polymers in the final samples.The molar ratio of the star-like macro-RAFT agent and the linear macro-RAFT agent has a significant impact on the morphology of polymer assemblies.It was found that increasing the amount of star-like macro-RAFT agent facilitated the formation of higher-order morphologies.Additionally,effects of other reaction parameters including the length/number of the arm of the star-like macro-RAFT agent,degree of polymer(DP),monomer concentration on the morphology of star/linear block copolymer assemblies were also investigated.We expect that this work will offer new possibilities for the scalable preparation of polymer assemblies with unique structures and functions.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21971047 and 21504017)Innovation Project of Education Department in Guangdong(No.2018KTSCX053)+1 种基金Y.C.acknowledges the support from Guangdong Special Support Program(No.2017TX04N371)J.T.acknowledges the support from Pearl River Young Scholar of Guangdong.
文摘Polymerization-induced self-assembly(PISA)is an emerging method for the preparation of block copolymer nano-objects at high concentrations.However,most PISA formulations have oxygen inhibition problems and inert atmospheres(e.g.argon,nitrogen)are usually required.Moreover,the large-scale preparation of block copolymer nano-objects at room temperature is challenging.Herein,we report an enzyme-assisted photoinitiated polymerization-induced self-assembly(photo-PISA)in continuous flow reactors with oxygen toleranee.The addition of glucose oxidase(GOx)and glucose into the reaction mixture can consume oxygen efficiently and constantly,allow the flow photo-PISA to be performed under open-air conditions.Polymerization kinetics indicated that only a small amount of GOx(0.5 μmol/L)was needed to achieve the oxygen tolerance.Block copolymer nano-objects with different morphologies can be prepared by varying reaction conditions including the degree of polymerization(DP)of core-forming block,monomer concentration,reaction temperature,and solvent composition.We expect this study will provide a facile platform for the large-scale production of block copolymer nano-objects with different morphologies at room temperature.
基金supported by Natural Science Foundation of Anhui Province(2108085Y06)Anhui Provincial Key Laboratory Open Project Foundation(LCECSC-01)Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology(BM2012110).
文摘Usually,the aniline-based late-transition-metal catalysts often require bulky steric substituents on both sides of the ortho-aryl position to achieve efficient suppression of chain transfer in ethylene polymerization.In this contribution,we demonstrated thatα-diimine catalysts based on naphthylamine with only one bulky ortho-aryl substituent also demonstrated excellent capabilities to suppress the chain transfer.Firstly,a class ofα-diimine nickel and palladium complexes with only one o-aryl-dibenzhydryl or o-aryl-dibenzosuberyl substituent were synthesized and characterized.Secondly,the as-prepared naphthylamine-based nickel catalysts demonstrated outstanding activities(up to 13.02×106 g·mol–1·h–1)and yielded lightly branched(16-40/1000C)polyethylenes with very high molecular weights(445.8-854.3 kg/mol)in ethylene polymerization.In comparison,the corresponding palladium catalysts showed moderate activities(level of 104-105 g·mol–1·h–1),generating moderately branched(47-78/1000C)polyethylenes with moderate molecular weights(21.6-82.0 kg/mol).Moreover,the palladium catalysts could also copolymerize ethylene and methyl acrylate(MA),albeit in low activities(level of 103 g·mol–1·h–1),providing E-MA copolymers with low to moderate molecular weights(1.4-16.3 kg/mol)and a moderate level of incorporation ratio(2.4-7.4 mol%)and branching density(53-84/1000C).As compared with aniline-based nickel and palladium catalysts,the naphthylamine-based catalysts displayed a superior ability to suppress the chain transfer reactions and could give access to(co)polymers with orders of magnitude higher molecular weight in ethylene(co)polymerization.
基金Natural Science Foundation of Anhui Province(No.2108085Y06)Anhui Provincial Key Laboratory Open Project Foundation(No.LCECSC-01).
文摘Suppressing the chain transfer reactions during polymerization in late-transition metal-catalyzed olefin polymerization systems is the key to obtaining high molecular weight polyolefin materials. In this work, two efficient strategies(“sandwich” and rotation-restricted strategies)to retard chain transfer reactions in ethylene(co)polymerization were employed for the iminopyridyl system. Herein, a family of iminopyridyl Ni(Ⅱ)and Pd(Ⅱ) complexes with a flexible backbone and rigid axial bulky aryl substituents were designed, synthesized and characterized. In ethylene polymerization, the iminopyridyl Ni(Ⅱ) and Pd(Ⅱ) catalysts using the two strategies exhibited reasonable activities and generated highly branched polyethylenes with high molecular weights, where catalysts with dibenzosuberyl substituents exhibited significantly higher activities and produced higher molecular weight polyethylene than catalysts with 8-arylnaphthalenyl substituent. A similar trend of activities and molecular weights was also found in the copolymerization of ethylene with MA using the Pd(Ⅱ) catalysts. Moreover, highly branched E-MA copolymers with moderate to high molecular weights and high incorporation ratios(up to 17.4 mol%) were generated with the two Pd(Ⅱ) catalysts. Most interestingly, as compared with the dibenzhydryl Ni(Ⅱ) and Pd(Ⅱ) catalysts, the catalysts using the two strategies exhibited a superior ability to retard the chain transfer reactions and generated polymers and copolymers with 1-2 orders of magnitude higher molecular weights during ethylene(co)polymerization.
基金financially supported by the National Natural Science Foundation of China(No.U1862206)Jilin Province Department of Education(No.JJKH20200665KJ)+3 种基金Dr.W.Zhao thanks for the financial support from China Postdoctoral Science Foundation(No.2021M701818)Shandong Provincial Natural Science Foundation,China(No.ZR2022QE237)Qingdao Postdoctoral Applied Research Project,PetroChina Company Limited(No.2020B-2711)H.Liu sincerely acknowledges the financial support from the Taishan Scholars Program。
文摘Through neodymium-mediated coordinative chain transfer copolymerizaiton(CCTcoP),polyisoprenes bearing dual hydroxylated mini-blocky chain-ends were prepared via a three-step strategy.Kinetic studies revealed that,the polymerization demonstrated typical features of CCTcoP across the whole polymerization process,i.e.,quasi-living polymerization characteristic,tunable molecular weights,narrow molecular weight distributions,and atom economies.Comparing to previously reported CCTP homopolymerization systems,the presence of oxygen-containing IpOAl polar comonomer slowed down chain transfer rates obviously,rendering slightly higher molecular weights of the resultant PIps and smaller Np(number of polymer chains per Nd atom)values.Moreover,to mimic the structure of natural rubber,the hydroxyl end groups can be facilely modified into phosphonate,amide,and UPy,whose structures were further confirmed by NMR spectra.Incorporation these functionalities could greatly improve the hydrophilic properties of the polymers,as revealed from the significantly reduced static water contact angles.
