非离子型Y形两亲性聚氨酯水溶液的自组装研究

Self-assemble Research of Nonionic Y-Shaped Amphiphilic Polyurethane in Aqueous

设计并制备了Y形两亲性嵌段聚合物(mPEG)2-HDI-PEA。以六亚甲基二异氰酸酯三聚体为反应物,分别与聚乙二醇单甲醚、聚醚胺进行官能团偶合生成Y形聚氨酯,其结构和自组装形貌经1H NMR、FT-IR、GPC、透射电镜(TEM)和原子力显微镜(AFM)表征。聚合物(mPEG)2-HDI-PEA在不同温度和不同浓度下自组装形成的聚集体形貌,表明分子间的氢键作用对聚集体形貌起着重要作用。(mPEG)2-HDI-PEA嵌段聚合物在室温下自组装,形成新颖的形貌,表面具有“沟壑”的球状胶束,随着浓度增加形成的球状胶束表面“沟壑”越明显,排列越有序;当嵌段聚合物(mPEG)2-HDI-PEA在60℃水溶液中自组装时,形成蠕虫状胶束,并随着浓度的增加从蠕虫状转变成网状;聚合物溶液在60℃环境中静置1 mon后,在AFM下观测到蠕虫状胶束长度增加,当蠕虫装胶束从60℃冷却至室温胶束形貌、尺寸未改变;当稀释并于60℃静置3 d后胶束从蠕虫状转变成棒状或者椭球状,展现出动态组装与解离的过程。

Y-shaped amphiphilic block polymer(mPEG)2-HDI-PEA was designed and prepared.hexanethylene diisocyanate(HDI)trimer coupled with hydroxyl and amino group exceptly.We exported the amphiphilic block copolymer which has two methoxypolyethylene glycols(mPEG)and a amino-terminated polyxoypropylene(PEA)self-assembly behavior in aqueous solution.The chemical structure of the copolymer was well characterized by 1H-NMR,FT-IR and GPC.The morphology of the copolymer was verified by Transmission Electron Microscope(TEM)and atomic force microscopy(AFM).The sizes of micelles were measured by dynamic light scattering(DLS).Self-assembly of(mPEG)2-HDI-PEA at different temperature and polymer concentrations indicated that the hydrogen bonding plays a important role in determining the self-assembly structure.When it assemblied at room temperature,the morphology of(mPEG)2-HDI-PEA in water was spherical micelles under TEM.When it under AFM we observed a interesting phenomenon,the surfaces of those spherical micelles with a number of bulges and cracks which looks like“gullys”.Moreover,concentration of the polymer from 0.1 mg/mL to 1 mg/mL the“gullys”on spherical micelles surfaces become more obvious and more regular.The sizes of micelles at 1mg/mL increase toμm degree.Furthermore,When the temperature of copolymer aqueous solution up to 60℃the morphology of the self-assembly copolymer become to worm-like micelles.Along with the polymer concentration increasing the morphology of micelles changed from worm-like to mesh-like.We also studied the stability of the worm-like micelles.The new polymer aqueous solution stationary stored at 60℃for a month the length of micelles from 1~2μm and the longest to 5μm.After then stationary solution from 60℃to room temperature the morphology changed a little,then the diluted solution stored at 60℃environment the self-assembly structure changed from worm-like to rod-like or ellipsoid-like after 3 d.This process showed a dynamic assemble and disassemble phenomenon.