两亲性嵌段共聚物PMnEOS-b-PAA的可控合成及与PS-b-PAA共组装体的形貌

Controllable Synthesis of Amphiphilic Block Copolymer PMnEOS-b-PAA and co-Assembly Morphologies of PMDEOS-b-PAA/PS-b-PAA

在苯乙烯单体的对位引入具有亲水性链段的乙二醇单元,利用可逆加成断裂链转移聚合方法(RAFT),可控合成了几种新的两亲性嵌段共聚物聚(4-乙烯基苄基乙二醇单甲醚)-b-聚丙烯酸(PMnEOS-b-PAA,n=1~3),对其温敏和pH敏性质进行了初步研究.同时,研究了PMnEOS-b-PAA分别在亲水性环境下(四氢呋喃/水)和亲脂性环境下(四氢呋喃/甲苯)自组装体的形貌.将聚对二乙二醇单甲醚苯乙烯-b-聚丙烯酸与聚苯乙烯-b-聚丙烯酸按质量比1:1[m(PMDEOS-b-PAA)/m(PS-b-PAA)=1:1]共混进行共组装,在四氢呋喃/甲苯体积比为2∶1的混合溶剂中,发现了一类新型具有均匀分布内部孔道且表面光滑的球形组装体.进一步研究了该组装体的可重复性和组装机理,为其后期应用于工业上的负载催化、小分子识别与释放提供了一种新的策略.

The co-assembly of polymers has attracted increasing attention due to the ability of generating diverse assembly morphology.This paper describes the synthesis and self-assembly of several novel amphiphilic block copolymers(PMnEOS-b-PAA,n=1-3)as well as co-assembly of PMDEOS-b-PAA with typical polystyrene-b-polyacrylic acid(PS-b-PAA).Namely,these block copolymers were fabricated by reversible addition fragmentation chain transfer(RAFT)polymerization of functionalized styrene bearing different glycol units on the para-position and acrylic acid,and characterized by 1H nuclear magnetic resonance spectrum(1H NMR).The thermo-responsive and pH-responsive properties of these block copolymers were then investigated,and they showed good thermo-and pH-responsiveness.Furthermore,as a comparison,the self-assembly actions of these block copolymers were also examined in tetrahydrofuran(THF)/H2O and THF/toluene(PhMe),respectively.It was found that the different block copolymers with different glycol units displayed various morphologies,especially in two different solvent systems.More interestingly,the co-assembly action of PMDEOS-b-PAA/PS-b-PAA(mass ratio 1∶1)in a mixture of THF-PhMe(volume ratio 2∶1)was detaily studied and a new spherical nanoparticle with uniformly distributed internal channel and smooth surface was found.Also,this coassembly morphology could be well repeated.The corresponding self-and co-assembly mechanisms were also proposed.This novel co-assembly mode would have potential application for further supporting catalysts,small molecules recognition and release in industry.