PDMS-MDI-PEG多嵌段共聚物涂层表面微相分离行为研究

采用两步溶液聚合方法合成了一系列聚二甲基硅氧烷(PDMS)-4,4′-二苯基甲烷二异氰酸酯(MDI)-聚乙二醇(PEG)多嵌段共聚物.利用轻敲模式原子力显微镜(AFM)观察了嵌段共聚物的表明形貌,研究了退火、共聚物组成以及PEG分子量和不同的官能团对涂层表面微相分离行为的影响,同时对微相分离行为的形成机理也作了相应的探讨.研究表明,该嵌段共聚物即使在PDMS含量大于50wt%时,涂层表面仍呈现出规整有序的纳米级相分离结构,其中疏水相和亲水相分别由PDMS链段和MDI-PEG组分构成.

MICRO SEPARATION BEHAVIOR OF PDMS-MDI-PEG MULTIBLOCK COPOLYMER COATING SURFACE

A series of poly(ethylene glycol)(PEG)-4,4'-diphenylmethanediisocyanate(MDI)-poly(dimethyl-siloxane)(PDMS)multiblock copolymers were synthesized by employing two step growth polymerization technique.Surface phase separation behavior of these multiblock copolymer coatings was studied by atomic force microscopy(AFM)with ultra-light tapping mode.The results showed that nanoscopically well-organized phase-separated surfaces consisting of hydrophilic domains of PEG and MDI segments and hydrophobic domains of PDMS segments were clearly observed even the concentration of PDMS segments in the copolymer was more than 50 wt%,and the microphase separation pattern depended on the annealing,weight fraction of hydrophilic domains or hydrophobic domains and composition of hydrophilic domains.Formation mechanism of surface phase separation was also discussed.