摘要
用三硫代碳酸二(α,α′-二甲基-α-乙酸)酯(BDATC)作为链转移剂,苯乙烯St作为第一单体,通过可逆加成-断裂链转移聚合(RAFT)方法合成出大分子链转移剂PSt-CTA,以丙烯酸AA作为第二共聚单体合成出3个不同嵌段比的两亲性嵌段共聚物聚苯乙烯-b-聚丙烯酸-b-聚苯乙烯(PSt-b-PAA-b-PSt).通过傅里叶变换红外光谱(FTIR)和核磁共振氢谱(1H-NMR)确定了PSt-b-PAA-b-PSt结构,使用凝胶渗透色谱(GPC)测定了大分子引发剂PSt-CTA和嵌段共聚物PSt-b-PAA-b-PSt的分子量及分子量分布.将这3个不同嵌段比的两亲性嵌段共聚物在离子液体1-丁基-3-甲基咪唑六氟磷酸盐[BMIM][PF6]中进行自组装,用透射电子显微镜(TEM)观察聚合物在离子液体中自组装结构.研究发现,当PSt的链段长度固定时,胶束的自组装形态主要依赖于PAA链的长度.当PAA链段较长时,胶束呈球形;PAA链段变得较短时,胶束的形态则由球形转变为核壳结构,并且胶束形态在25℃至100℃之间不受温度影响.
The Block copolymer polystyrene-b-poly（acrylic acid）-b-polystyrene（PSt-b-PAA-b-PSt） wassynthesizedviareversible addition-fragmentation chain transfer polymerization by using styrene as the firstmonomer.The architectures of the macro-chain transfer agent PSt-CTA and the block copolymers wereconfirmed by FTIR and1H-NMR.GPC analysis was used to estimate the molecular weight and the molecularweight distribution of the copolymers,the numer-average molecular weight of macro-chain transfer agent PSt-CTA was 8320,and the molecular weight distribution was 1.05.The numer-average moleccular weight of threeblock copolymers was 13050,11130 and 9760,respectively,and the corresponding molecular weightdistribution was 1.356,1.430,1.365.The block copolymers with different molecular weights were self-assembled by co-solvent method in an ionic liquid,1-butyl-3-methylimidazolium hexafluorophosphate（[BMIM][PF6]）.The nanostructures of the PSt-b-PAA-b-PSt micelles formed in the ionic liquid wereobserved by TEM（transmission electron microscopy） and DLS（dynamic light scattering）.The self-assembledmorphologies of the copolymers are strongly dependent on the length of PAA block chains when the chainlength of PSt is fixed.With the decrease of molecular weight of PAA in block copolymers,the resultingaggregates are spheres with diameter of about 50 nm.With further decrease of PAA molecular weight incopolymers,the sphere morphology is turned to core-shell sphere micelles with diameters not more than 100nm.Compared with the aqueous solutions of the same copolymers,[BMIM] [PF6] solutions exhibit somedistinct features,such as temperature-independent micellar morphologies between 25℃ and 100℃.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2010年第1期59-64,共6页
Acta Polymerica Sinica
基金
河南省教育厅基金(基金项目2006150005)资助项目
