ENERGETICS OF ADSORPTION OF NEUTRAL AND CHARGED MOLECULES AT THE AIR-WATER-INTERFACE BY 2ND HARMONIC-GENERATION - HYDROPHOBIC AND SOLVATION EFFECTS
ENERGETICS OF ADSORPTION OF NEUTRAL AND CHARGED MOLECULES AT THE AIR-WATER-INTERFACE BY 2ND HARMONIC-GENERATION - HYDROPHOBIC AND SOLVATION EFFECTS
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DOI：
10.1063/1.461113
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发表时间：
1991-07-15
影响因子：
4.4
通讯作者：
EISENTHAL, KB
中科院分区：
文献类型：
--
作者：
CASTRO, A;BHATTACHARYYA, K;EISENTHAL, KB
表面二次谐波发生已用于研究烷基酚和苯胺及其各自的离子在空气/水界面上的吸附。 使用简单的朗缪尔模型获得中性分子的吸附自由能。 通过改变烷基酚盐和烷基苯铵离子的链长，研究了相反的疏水力和溶剂化力对分子吸附的定量影响。 发现至少五个碳的烷基链对于平衡本体离子溶剂化是必要的，从而使离子界面群达到水背景以上的水平。 离子的吸附可以通过使用修正的 Langmuir 模型来定量描述，该模型包括由 Gouy-Chapmann 理论给出的双电层的静电自由能。 通过二次谐波数据与该处理的完美拟合，获得了吸附的化学和静电自由能、界面电势和界面 pH 值。
Surface second harmonic generation has been used to study the adsorption of alkyl phenols and anilines and their respective ions to the air/water interface. The free energies of adsorption of the neutral molecules were obtained using a simple Langmuir model. The quantitative effects of the opposing hydrophobic and solvations forces on molecular adsorption were investigated by varying the chain length of alkylphenolate and alkylanilinium ions. An alkyl chain of at least five carbons was found to be necessary to balance the bulk ionic solvation and thereby bring the ion interface population to a level above the water background. The adsorption of the ions can be described quantitatively by using a modified Langmuir model that includes the electrostatic free energy of the electric double layer as given by the Gouy-Chapmann theory. From the excellent fit of the second harmonic data to this treatment, the chemical and electrostatic free energies of adsorption, interface electric potential, and interface pH were obtained.