Dynamics of the liquid surface by surface-area control light scattering technique

我们建立的迄今为止的涟漪光散射技术是一种能够在宽频带内观测液体表面表面张力波(涟漪)的传播和色散的技术。我们通过本研究改进的装置安装了一种新概念的槽，在控制样品表面的面积和条件的同时进行光散射测量。用这种方法对液体表面和表面附近的分子动力学进行了研究，并用朗缪尔吸附方程与表面压力-浓度曲线估算的表面吸附密度进行了关联。提出了这一缓慢过程的两种可能机制：一种是吸附在表面上的分子之间的重取向或重分布；另一种是表面和亚表面分子具有高能垒的两态模型。

The ripplon light scattering technique that we caused established up to now is the technology that is able to observe the propagation and dispersion of the surface tension wave (ripplon) that happen to a/the liquid surface in a wide band. The device that we improved with this research installs the trough of a new concept and do light scattering measurement simultaneously while controlling the area and condition of a/the specimen surface. By using this method we did the study of the molecule dynamics of a/the liquid surface and the surface vicinity.These results were correlated with the surface adsorption density estimated by the observed curves of surface pressure vs. concentration with the aid of Langmuir's equation of adsorption. Two possible mechanisms of the very slow process were proposed : one is the re-orientation or re-distribution among the molecules adsorbed on the surface ; and the other assumes a two-state model with a high energy barrier for the molecules on the surface and those in the subsurface.