Amphiphilic star-block copolymers composed of polystyrene and poly（acrylic acid） were synthesized by iodide- mediated radical polymerization. Firstly, free radical polymerization of styrene was carried out with AIBN...Amphiphilic star-block copolymers composed of polystyrene and poly（acrylic acid） were synthesized by iodide- mediated radical polymerization. Firstly, free radical polymerization of styrene was carried out with AIBN as initiator and 1,1,1-trimethyolpropane tri（2-iodoisobutyrate） as chain transfer agent, giving iodine atom ended star-shaped polystyrene with three arm chains, R（polystyrene）3. Secondly, tert-butyl acrylate was polymerization using polystyrene obtained as macro-chain transfer agent, and star-block copolymer, R（polystyrene-b-poly（tert-butyl acrylate））3 with controlled molecular weight was obtained. Finally, amphiphilic star-block copolymer, R（polystyrene-b-poly（acrylic acid））3 was obtained by hydrolysis of R（polystyrene-b-poly（tert-butyl acrylate））3 under acidic condition.展开更多
Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly（e-caprolactoneXPCL） blocks, hydrophobic non-crystalline poly（tert-butyl acrylate）（PtBA） blocks and hydrophilic ...Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly（e-caprolactoneXPCL） blocks, hydrophobic non-crystalline poly（tert-butyl acrylate）（PtBA） blocks and hydrophilic poly（ethylene glycol）（PEG） blocks were precisely synthesized by a combination of ring-opening polymerization（ROP）, atom transfer radical polymerization（ATRP） and ＂click＂ reaction. Such star copolymers could self-assemble into ＂core-shell-corona＂ micelles and ＂multi-layer＂ vesicles depending on the fraction of each block. Meanwhile, the selective hydrolysis of middle PtBA blocks into the poly（acrylic acidXPAA） blocks allowed the star block copolymers to further change their morphologies of aqueous aggregates m response to pH values.展开更多
1 Results Amphiphilic block copolymers are capable of forming supramolecular assemblies resembling those observed in nature,such as spherical micelles,worm micelles,and vesicles.Changing the solvent composition,ionic ...1 Results Amphiphilic block copolymers are capable of forming supramolecular assemblies resembling those observed in nature,such as spherical micelles,worm micelles,and vesicles.Changing the solvent composition,ionic strength or pH of the polymer solution may induce the self-assembly of block copolymers or trigger the transition between the geometries of noncovalent assemblies.In the current work,we have synthesised starlike amphiphilic block copolymers having hydrophobic poly(methyl methacrylate),PMMA,...展开更多
基金The authors gratefully acknowledge the support from Beijing Municipal Commission of Education.
文摘Amphiphilic star-block copolymers composed of polystyrene and poly（acrylic acid） were synthesized by iodide- mediated radical polymerization. Firstly, free radical polymerization of styrene was carried out with AIBN as initiator and 1,1,1-trimethyolpropane tri（2-iodoisobutyrate） as chain transfer agent, giving iodine atom ended star-shaped polystyrene with three arm chains, R（polystyrene）3. Secondly, tert-butyl acrylate was polymerization using polystyrene obtained as macro-chain transfer agent, and star-block copolymer, R（polystyrene-b-poly（tert-butyl acrylate））3 with controlled molecular weight was obtained. Finally, amphiphilic star-block copolymer, R（polystyrene-b-poly（acrylic acid））3 was obtained by hydrolysis of R（polystyrene-b-poly（tert-butyl acrylate））3 under acidic condition.
基金Supported by the Distinguished Young Investigator Fund of Zhejiang Province, China（No.LR18B040001）, the National Natural Science Foundation of China（No.51603180）, the Fundamental Research Funds for the Central Universities, China （No.2017QNA4038） and the China Postdoctoral Science Foundation（No.2015M580517）.
文摘Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly（e-caprolactoneXPCL） blocks, hydrophobic non-crystalline poly（tert-butyl acrylate）（PtBA） blocks and hydrophilic poly（ethylene glycol）（PEG） blocks were precisely synthesized by a combination of ring-opening polymerization（ROP）, atom transfer radical polymerization（ATRP） and ＂click＂ reaction. Such star copolymers could self-assemble into ＂core-shell-corona＂ micelles and ＂multi-layer＂ vesicles depending on the fraction of each block. Meanwhile, the selective hydrolysis of middle PtBA blocks into the poly（acrylic acidXPAA） blocks allowed the star block copolymers to further change their morphologies of aqueous aggregates m response to pH values.
文摘1 Results Amphiphilic block copolymers are capable of forming supramolecular assemblies resembling those observed in nature,such as spherical micelles,worm micelles,and vesicles.Changing the solvent composition,ionic strength or pH of the polymer solution may induce the self-assembly of block copolymers or trigger the transition between the geometries of noncovalent assemblies.In the current work,we have synthesised starlike amphiphilic block copolymers having hydrophobic poly(methyl methacrylate),PMMA,...
