温度对十六烷基三甲基溴化铵胶束盐溶液粘度的影响

The Effect of Temperature on the Viscosity of Cetyltrimethylammonium Bromide Micellar Solutions in the Presence of Added Salt

研究了温度对十六烷基三甲基溴化铵胶束盐溶液粘度的影响．发现随温度的上升溶液的粘度由于圆柱形长棒胶束解体为小的球形胶束而下降．从ΔＧ／Ｔ对１／Ｔ作图法求得的ΔＨ值较从Ｅｙｒｉｎｇ粘度理论计算的ΔＧ值要大得多．胶束的棒球转变不是一步而是分多步实现的，在转变过程中大胶束处于一系列的“活化结构”状态．认为与温度有关的ΔＧ值是粘流过程中形成空穴的自由能变，而ΔＨ值为包含有大胶束解体为小胶束过程粘性流动的总活化能．

:The effect of temperature on the viscosities of cetyltrimethylammonium bromide(CTAB) in the presence of different added salt was investigated.It was found that the viscosities of CTAB micelle solutions decrease with increasing temperature due to the break up of the cylindrical rodlike micelles.The value of ΔH obtained from the plot of ΔG/T versus 1/T are much larger than the values of ΔG calculated from Eyring equation at various temperatures.It is proposed that the transition of rod to spherical micelles can not be conceivable in only one step but in infinite steps,and in each step the rodlike micelles are always in equilibrium with activated micelle aggregates which can rapidly translate into smaller cylindrical micelles,and finally into spherical micelles.ΔH consistently larger than ΔG is associated with a breakdown of cylinderical micelles into smaller spherical micelles since this transition also requires energy to weaken the intermolecular forces and to increase the area of interface.