离子液体型表面活性剂C_12mimBr与普通表面活性剂混合性质的研究

Mixing Behavior of Ionic Liquid Surfactant C_(12)mimBr with Common Surfactants

研究了离子液体型表面活性剂C12mimBr与阳离子表面活性剂Gemini12-3-12,DTAB及阴离子表面活性剂SDS复配体系的性质,并分别采用Rubingh-Margules模型和Rubingh-正规溶液模型计算了临界胶束浓度和混合胶团组成.研究发现,两表面活性剂分子结构的匹配性及带电头基之间的相互作用是影响混合溶液性质的主要因素.对于分子结构差别较大的C12mimBr与Gemini12-3-12的混合,其行为远远偏离理想混合性质;对疏水链长相同仅亲水头基不同的C12mimBr与DTAB则接近于理想混合;而对C12mimBr+SDS的复配体系,正、负电荷间强烈的相互吸引使得混合体系大大偏离理想行为.计算发现,两种理论模型得到的混合胶团组成基本一致,但Rubingh-Margules模型预测的临界胶束浓度比Rubingh-正规溶液模型要好.

Properties of mixed surfactants containing ionic liquid surfactant are investigated in this paper. The other surfactants mixed with C12mimBr are several common surfactants, including Gemini 12-3-12, DTAB and SDS. Both of Rubingh-Margules model and Rubingh-regular solution model are used to calculate the critical micelle concentration and the composition of mixed micelle. It is observed that molecular structure and interaction between the charged head groups have great effects on the properties of mixed surfactants. The mixed behavior of C 12mimBr and Gemini 12-3-12 with great difference in the molecular structure is non-ideal, while it is almost ideal for mixture of C12mimBr and DTAB with the same hydrophobic chain length and different hydrophilic head group only. Due to the strong attractive interaction between the opposite charged head groups, of course the mixed behavior of Cl2mimBr and SDS is absolutely non-ideal. Moreover, results of the micelle composition from the two models are almost the same; however, the prediction result of the critical micelle concentration is obviously better from Rubingh-Margules model than from Rubingh-regular solution model.