Inoue Tohru, Misono Takeshi
Department of Chemistry, Faculty of Science, Fukuoka University, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
J Colloid Interface Sci. 2008 Oct 15;326(2):483-9. doi: 10.1016/j.jcis.2008.04.047. Epub 2008 Apr 26.
The cloud point phenomenon has been investigated for the solutions of polyoxyethylene (POE)-type nonionic surfactants (C(12)E(5), C(12)E(6), C(12)E(7), C(10)E(6), and C(14)E(6)) in 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)), a typical room temperature ionic liquid (RTIL). The cloud point, T(c), increases with the elongation of the POE chain, while decreases with the increase in the hydrocarbon chain length. This demonstrates that the solvophilicity/solvophobicity of the surfactants in RTIL comes from POE chain/hydrocarbon chain. When compared with an aqueous system, the chain length dependence of T(c) is larger for the RTIL system regarding both POE and hydrocarbon chains; in particular, hydrocarbon chain length affects T(c) much more strongly in the RTIL system than in equivalent aqueous systems. In a similar fashion to the much-studied aqueous systems, the micellar growth is also observed in this RTIL solvent as the temperature approaches T(c). The cloud point curves have been analyzed using a Flory-Huggins-type model based on phase separation in polymer solutions.
对聚氧乙烯（POE）型非离子表面活性剂（C(12)E(5)、C(12)E(6)、C(12)E(7)、C(10)E(6)和C(14)E(6)）在典型的室温离子液体1-丁基-3-甲基咪唑四氟硼酸盐（bmimBF(4)）中的浊点现象进行了研究。浊点T(c)随POE链的延长而升高，随烃链长度的增加而降低。这表明表面活性剂在室温离子液体中的亲溶剂性/疏溶剂性源于POE链/烃链。与水体系相比，室温离子液体体系中T(c)对POE链和烃链的链长依赖性都更大；特别是，烃链长度在室温离子液体体系中对T(c)的影响比在等效水体系中要强得多。与研究较多的水体系类似，当温度接近T(c)时，在这种室温离子液体溶剂中也观察到了胶束生长。已使用基于聚合物溶液相分离的弗洛里-哈金斯型模型对浊点曲线进行了分析。
