双羟基Gemini表面活性剂的溶液性能及其聚集形态

Properties and aggregations of dual-hydroxyl Gemini surfactant in aque-ous solution

摘要:

以1-溴十二烷、2-甲氨基乙醇、1,3-二溴丙烷、1,4-二溴丁烷、1,6-二溴己烷、1,8-二溴辛烷、1,10-二溴癸烷和1,12-二溴十二烷为原料，制得含有双羟基的Gemini表面活性剂（缩写为12(OH)-s-12(OH)，其中s = 3、4、6、8、10和12）。表征了双羟基Gemini表面活性剂的热稳定性及其在水溶液中的表面张力；测试了Gemini表面活性剂的泡沫性能；采用耗散粒子动力学(DPD)方法预测了Gemini表面活性剂在水溶液中的聚集形态。结果表明，该类型Gemini表面活性剂具有较好的热稳定性和泡沫性能，随着连接基团长度的增加(s≤6)，其在水溶液中的临界胶束浓度(CMC)从0.62mmol/L（s = 3）降至0.21mmol/L（s = 6）左右，且当连接基团长度s>6后CMC基本不变。随着Gemini表面活性剂摩尔分数的增加，胶束形态从球状胶束→棒状胶束→层状胶束→反胶束网络结构逐渐转变，且连接基团长度的改变几乎不影响其在水溶液中的胶束形态转变。

Abstract:

Gemini surfactants containing two hydroxyl groups (abbreviated as 12(OH)-s-12(OH), s = 3, 4, 6, 8, 10 and 12) were synthesized using 1-Bromododecane, 2-methylaminoethanol, 1,3-Dibromopropane, 1,4-Dibromobutane, 1,6-Dibromohexane, 1,8-Dibromooctane, 1,10-Dibromodecane and 1,12-Dibromododecane. The thermal property and surface tension of Gemini surfactants in aqueous solu-tion were characterized. The results indicated that the foaming ability of the Gemini surfactants was measured. The aggregation property of Gemini surfactants in aqueous solution were simulated using dissi-pative particle dynamics (DPD). The Gemini surfactants have good thermal property and foaming property. The critical micelle concentration (CMC) of Gemini surfactants were decreased from 0.62 mmol/L(s = 3) to 0.21 mmol/L(s = 6) with the increase of spacer (s≤6), and the CMC almost keep the same when the spacer was continue increased (s >6). With the increase of Gemini surfactant concentration, the aggregate morphologies in aqueous solution were changed from spherical micelle → rod micelle → layered micelle, eventually to reverse micelle network structure. The length of spacer almost has no efficient on the micelle morphology transition in aqueous solution.