Meister Annette, Kerth Andreas, Blume Alfred
Institute of Physical Chemistry, Martin Luther University Halle-Wittenberg, Mühlpforte 1, D-06108 Halle, Germany.
J Phys Chem B. 2005 Apr 7;109(13):6239-46. doi: 10.1021/jp045196u.
The adsorption of the surfactant n-nonyl-beta-D-glucopyranoside at the air-water interface after injection of the surfactant into the subphase was studied by infrared reflection absorption spectroscopy. In the first part, we investigated the equilibrium adsorption of n-nonyl-beta-D-glucopyranoside and the Gibbs adsorption isotherm was measured by applying the film balance technique. In the second part, the adsorption kinetics was followed by changes in the surface pressure and in the intensities of the OH band, which is related to the layer thickness, and the CH(2) antisymmetric stretching vibrational band. During an induction period, when the molecules are still highly diluted and the surface pressure is low, they are oriented parallel to the air-water interface. IR band simulations for the CH(2) antisymmetric stretching vibrational band support the idea of horizontally oriented molecules at the air-water interface. Later on, when more molecules are adsorbed to the air-water interface, they suddenly rearrange to an upright orientation as indicated by changes of the OH and the CH(2) bands. The observations are discussed in comparison to results obtained for the adsorption kinetics of n-decyl-beta-D-maltopyranoside, n-dodecyl-beta-D-maltopyranoside, and sodium dodecyl sulfate.
通过红外反射吸收光谱法研究了将表面活性剂注入亚相后，表面活性剂正壬基-β-D-吡喃葡萄糖苷在气-水界面的吸附情况。在第一部分中，我们研究了正壬基-β-D-吡喃葡萄糖苷的平衡吸附，并通过应用膜天平技术测量了吉布斯吸附等温线。在第二部分中，通过表面压力以及与层厚度相关的OH带和CH(2)反对称伸缩振动带强度的变化来跟踪吸附动力学。在诱导期，当分子仍高度稀释且表面压力较低时，它们平行于气-水界面取向。CH(2)反对称伸缩振动带的红外波段模拟支持了气-水界面处分子水平取向的观点。后来，当更多分子吸附到气-水界面时，如OH和CH(2)带的变化所示，它们突然重新排列成直立取向。将这些观察结果与正癸基-β-D-麦芽糖苷、正十二烷基-β-D-麦芽糖苷和十二烷基硫酸钠的吸附动力学结果进行了比较讨论。
