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以结构明确的两端为短的聚苯乙烯(PS)或聚甲基丙烯酸甲酯(PMMA)链段,中间为长的聚乙二醇(PEG)链段的PS-b-PEG-b-PS和PMMA-b-PEG-b-PMMA两亲性三嵌段共聚物为对象,研究了PS和PMMA链段对其在水中形成胶束和凝胶的影响.两种三嵌段共聚物在水中形成以PS或PMMA链段为核、PEG链段为壳的球形胶束,流体力学半径Rh,app为15.3~24.3 nm,并随PEG链段长度增长而增大.临界胶束浓度CMC均小于0.01 mg/mL,随着PS和PMMA链段长度的增加而减小.PS-b-PEG-b-PS浓度高于4.5 wt%可形成较强的疏水缔合的物理凝胶,平衡模量Ge可达到103Pa;PMMA-b-PEG-b-PMMA浓度高于7.5 wt%可以形成弱的凝胶,Ge<10 Pa.凝胶的储存模量G′和损耗模量G″均随着PS或PMMA链段的增长而增大.
With a well-defined polystyrene (PS) or polymethylmethacrylate (PMMA) segment short in both ends and PS-b-PEG-b-PEG in the middle with long polyethylene glycol (PEG) segments, PS and PMMA-b-PEG-b-PMMA amphiphilic triblock copolymers were investigated for the influence of PS and PMMA segments on the formation of micelles and gels in water.The two triblock copolymers In the water, spherical micelles with PS or PMMA segments as the core and PEG segments as the shell were formed. The hydrodynamic radius, Rh, app, was 15.3-24.3 nm and increased with the PEG segment length increasing. Less than 0.01 mg / mL, with the length of PS and PMMA segments decreasing.PS-b-PEG-b-PS concentration higher than 4.5 wt% can form a strong hydrophobic association physical gel, balance mode Ge can reach 103Pa; PMMA-b-PEG-b-PMMA concentration higher than 7.5wt% can form a weak gel, Ge <10Pa gel storage modulus G ’and loss modulus G " PS or PMMA segment increases.