一个高粘弹的阴离子蠕虫胶束体系(英文)  

A Highly Viscoelastic Anionic Wormlike Micellar System

作　　者：谢丹华[1] 赵剑曦[1] 刘琳[1] 游毅[1] 魏西莲[2] 

机构地区：[1]福州大学化学化工学院,胶体与界面化学研究所,福州350108 [2]聊城大学化学化工学院化学系,山东聊城252059

出　　处：《物理化学学报》2013年第7期1534-1540,共7页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China(20873024,21273040)~~

摘　　要：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 carboxylate gemini surfactant O,O＇-bis（sodium 2- tetradecylcarboxylate）-p-dibenzenediol （referred to as C14ФC14） with a concentration of 140 mmol. L-1 in aqueous solution in the presence of 100 mmol- L-＇ NaBr was investigated by frequency sweep and steady rate sweep measurements. The solution showed the characteristics of a Maxwell fluid with a single stress relaxation time at low shear frequencies. Analysis by the living polymer model indicated thatC14ФC14 formed long （3.6-6.8 pm） wormlike micelles at 25 ℃, which were observed by cryo-transmission electron microscopy （cryo-TEM）. The micelles were entangled with each other, resulting in a very viscous solution （the zero-shear viscosity was as high as 1.10× 104 Pa. s） that looked like a gel. On raising the temperature to 70 ℃, the relative viscosity was still as high as 1.8 × 10^4, which is very rare for anionic wormlike micelle systems. The flow activation energy （Eo） was estimated to be （141＋5） kJ· mol^-1. The size distribution of C14ФC14 was determined by dynamic light scattering. Large aggregates with a size of of-100 nm were observed at low concentrations of 5-10 mmol. L^-1. These large aggregates readily transformed into rodlike and then wormlike micelles as the surfactant concentration increased.

关 键 词：羧酸盐gemini表面活性剂 对联苯二酚联接链 蠕虫胶束 高粘弹性 温度效应 胶束形成机理 

分 类 号：O648[理学—物理化学]