十四烷基三甲基溴化铵蠕虫状胶束的形成及其线性黏弹性

Study on linear viscoelasticity of wormlike micelles formed by tetradecyl trimethyl ammonium bromided

以阳离子表面活性剂十四烷基三甲基溴化铵(TTAB)溶液作为反应主剂,油酸钠(NaOA)溶液作为反应助剂,制备得到了TTAB/NaOA蠕虫状胶束,并研究了表面活性剂摩尔比、主剂质量分数对蠕虫状胶束线性黏弹性的影响。结果表明,当主剂TTAB与助剂NaOA的摩尔比为2.6∶1~4.6∶1,TTAB质量分数在7%~16%之间时,溶液中均有蠕虫状胶束形成。当主剂TTAB与助剂NaOA的摩尔比为4.2∶1,TTAB质量分数为14%时,零剪切黏度可达到最大值即为η_(0)=15324 mPa·s,且溶液体系的平台模量G_(0)和弛豫时间τ_(R)也达到最大值,此时溶液体系中蠕虫状胶束长度最长,网络结构最为紧密,并呈现出良好的线性黏弹性。由上述溶液体系的实际Cole-Cole图表明本文探讨研究的蠕虫状胶束体系是符合麦克斯韦模型的线性黏弹性流体。

The cationic surfactant tetradecyl trimethyl ammonium bromide(TTAB) solution was used as the reaction main agent and sodium oleate(NaOA) solution was used as the reaction auxiliary to prepare TTAB/NaOA wormlike micelles,and the effects of surfactant molar ratio and main agent mass fraction on the linear viscoelasticity of wormlike micelles were investigated.The results showed that wormlike micelles were formed in the solution when the molar ratio of the main agent TTAB to the auxiliary NaOA was 2.6∶1~4.6∶1 and the mass fraction of TTAB was between 7%~16%.When the molar ratio of TTAB to NaOA is 4.2∶1 and the mass fraction of TTAB is 14%,the zero shear viscosity reaches the maximum value of η_0=15 324 mPa·s,and the platform modulus G_(0) and relaxation time τ_(R) of the solution system also reach the maximum value,at which time the wormlike micelles in the solution system have the longest length and the tightest network structure,and show good linear viscoelasticity.The actual Cole-Cole diagram of the above solution system indicates that the wormlike micelle system studied in this paper is a linear viscoelastic fluid in accordance with Maxwell's model.