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以频率扫描和稳态剪切实验研究了140mmol·L-1羧酸盐gemini表面活性剂(C14φ2C14)在100mmol·L-1NaBr条件下溶液的流变行为.在低剪切频率时,溶液呈现出具有单一松弛时间特性的Maxwell流体行为.通过活的高分子模型(living polymer model)分析,C14φ2C14体系在25℃时形成了很长的蠕虫胶束(3.6-6.8μm).冷冻透射电镜也观察到蠕虫胶束的形成.这些胶束相互缠绕,形成了很黏稠的溶液(零剪切粘度高达1.10×104Pa·s),外观呈现胶状.随着温度升高至70℃,体系的相对粘度仍旧保持很高(1.8×104),这在阴离子表面活性剂蠕虫胶束溶液中是很少见的.体系的流动活化能(Ea)约为(141±5)kJ·mol-1.利用动态光散射测定了C14φ2C14聚集体的尺寸分布,证实了这个表面活性剂在5-10mmol·L-1的低浓度时生成了约100nm的大聚集体,这些大聚集体随着表面活性剂浓度的增加很容易转化成棒状直至蠕虫胶束.
The rheological behavior of a solution of 140 mmol·L-1 carboxylate gemini surfactant (C14φ2C14) at 100 mmol·L-1NaBr was investigated by frequency sweep and steady-state shear experiments. At low shear frequencies, the solution exhibited a Maxwell fluid behavior with a single relaxation time characteristic. Through the living polymer model analysis, the C14φ2C14 system formed very long worm micelles (3.6-6.8μm) at 25 ° C. Cryo-TEM was also observed Worm micelles formed.They were entangled with each other to form a very viscous solution (zero shear viscosity of 1.10 × 104Pa · s), the appearance of a gel.With the temperature rises to 70 ℃, the relative viscosity of the system is still (1.8 × 104), which is very rare in the anionic surfactant micellar solution.The activation energy (Ea) of the system is about (141 ± 5) kJ · mol -1 .Using the dynamic light The size distribution of the C14φ2C14 aggregates was determined by scattering, confirming that this surfactant produced large aggregates of about 100 nm at a low concentration of 5-10 mmol·L-1, and that these large aggregates increased with increasing surfactant concentration Easily transformed into sticks until worm micelles.