Laboratory of Physical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
J Colloid Interface Sci. 2013 Jul 15;402:237-45. doi: 10.1016/j.jcis.2013.03.064. Epub 2013 Apr 11.
Dynamic and equilibrium surface tension experiments were carried out to study the adsorption kinetics of mixtures of the nonionic polymer hydroxypropylmethylcellulose (HPMC) with two double chain cationic surfactants, didodecyldimethylammonium bromide (di-DDAB) and ditetradecyldimethylammonium bromide (di-TDAB). Results are obtained concerning the capacity of the surfactants to lower surface tension, the rate of lowering, the extent of adsorption at the interface, the possibility of changing conformation during and after adsorption, and the interactions between the adsorbed molecules. A time-dependent synergy is observed in most of the mixtures, while in a few cases hindrance effects are observed. The interaction of HPMC with the double chain cationic surfactants resulted in complexes with higher surface activity than the two components alone. Two induction times were observed, the second ones being more significant in the presence of di-TDAB. At concentrations well below the critical micelle concentration (cmc), the critical aggregation concentrations (cac), evidence for clusters is observed.
进行了动态和平衡表面张力实验，以研究非离子聚合物羟丙基甲基纤维素（HPMC）与两种双链阳离子表面活性剂，双十二烷基二甲基溴化铵（di-DDAB）和双十四烷基二甲基溴化铵（di-TDAB）混合物的吸附动力学。结果涉及表面活性剂降低表面张力的能力、降低速率、界面吸附的程度、吸附过程中和吸附后的构象变化的可能性，以及吸附分子之间的相互作用。在大多数混合物中观察到时间依赖性协同作用，而在少数情况下观察到阻碍作用。HPMC 与双链阳离子表面活性剂的相互作用导致形成了比两种单独成分具有更高表面活性的复合物。观察到两个诱导时间，在存在 di-TDAB 的情况下第二个诱导时间更显著。在远低于临界胶束浓度（cmc）的浓度下，观察到临界聚集浓度（cac），表明存在聚集体。
